Scholars@Duke
H. Frederik Nijhout

H. Frederik Nijhout

John Franklin Crowell Distinguished Professor of Biology
Biology
hfn@duke.edu
Duke Box 90338, Durham, NC 27708-0325
322 Bio Sci Bldg, Durham, NC 27708

Scholarly Works - Journal articles

Control of metabolism by hypoxia and starvation and the consequences for the pattern of ecdysone secretion in Manduca sexta.

Journal article The Journal of experimental biology · February 2026 When larvae of Manduca sexta pass a critical weight, they initiate an endocrine cascade that leads to molting and metamorphosis. The critical weight coincides with a leveling off of the metabolic rate, and we hypothesize that it is the size at which the me ... Full text Cite

Opposing insulin signals underlie the same developmental switch across hemipteran insects.

Journal article Science advances · February 2026 Across metazoans, the insulin/insulin-like signaling (IIS) pathway is assumed to promote organ growth. We found that genes within the IIS pathway evolved opposite roles in organ growth across wing-dimorphic insects, playing opposite roles in regulating the ... Full text Cite

Elevated Homocysteine is Associated With Liver Fibrosis in Metabolic Dysfunction-Associated Steatotic Liver Disease in a Sex- and Menopause-Specific Manner.

Journal article Gastro Hep Adv · 2026 BACKGROUND AND AIMS: Elevated hepatic homocysteine (Hcy) contributes to hepatic inflammation and fibrogenesis in metabolic dysfunction-associated steatotic liver disease (MASLD). We aimed to evaluate the association between serum Hcy levels and the risk of ... Full text Link to item Cite

In the Spotlight-Established Researcher.

Journal article Journal of experimental zoology. Part B, Molecular and developmental evolution · January 2026 Full text Cite

Genetic assimilation, robustness and plasticity are key processes in the development and evolution of novel traits.

Journal article Developmental biology · July 2025 This is a commentary on how C.H. Waddington's experiments in the 1950's, first published in 1953 in a provocatively titled paper "Genetic assimilation of an acquired character," laid the foundation for the field of phenotypic plasticity, and how the ideas ... Full text Open Access Cite

Molecular mechanisms underlying the evolution of a color polyphenism by genetic accommodation in the tobacco hornworm, <i>Manduca sexta</i>.

Journal article Proceedings of the National Academy of Sciences of the United States of America · March 2025 How organisms evolve under extreme environmental changes is a critical question in the face of global climate change. Genetic accommodation is an evolutionary process by which natural selection acts on novel phenotypes generated through repeated encounters ... Full text Cite

Differential effects of synthetic estrogen on serum homocysteine levels before and after menopause.

Journal article PLoS One · 2025 Homocysteine (Hcy), a sulfur-containing amino acid, is produced in prodigious quantities by the methionine cycle in the liver. Hcy is the major biomarker for cardio-vascular disorders and is associated with many other diseases. In previous work, we have ex ... Full text Link to item Cite

A mathematical model of melatonin synthesis and interactions with the circadian clock.

Journal article Mathematical biosciences · November 2024 A new mathematical model of melatonin synthesis in pineal cells is created and connected to a slightly modified previously created model of the circadian clock in the suprachiasmatic nucleus (SCN). The SCN influences the production of melatonin by upregula ... Full text Cite

Modulation of serotonin transporter expression by escitalopram under inflammation.

Journal article Communications biology · June 2024 Selective serotonin reuptake inhibitors (SSRIs) are widely used for depression based on the monoamine deficiency hypothesis. However, the clinical use of these agents is controversial, in part because of their variable clinical efficacy and in part because ... Full text Cite

Serotonin as a biomarker of toxin-induced Parkinsonism.

Journal article Molecular medicine (Cambridge, Mass.) · March 2024 BackgroundLoss of dopaminergic neurons underlies the motor symptoms of Parkinson's disease (PD). However stereotypical PD symptoms only manifest after approximately 80% of dopamine neurons have died making dopamine-related motor phenotypes unrelia ... Full text Cite

Sex differences in glutathione metabolism and acetaminophen toxicity

Journal article Metabolism and Target Organ Damage · January 1, 2024 Aims: Clinical and experimental evidence has shown that females in humans and other mammals have higher glutathione (GSH) levels than males, which are caused by higher levels of estradiol. Understanding how hepatic GSH level and synthesis velocity depend o ... Full text Cite

Lower hepatic CBS and PEMT expression in advanced NAFLD: inferencing strategies to lower homocysteine with a mathematical model

Journal article Metabolism and Target Organ Damage · January 1, 2024 Aim: Hepatic homocysteine (Hcy) accumulation promotes inflammation and fibrosis in experimental nonalcoholic fatty liver disease (NAFLD), while vitamin B12 and folate reduce hepatic Hcy and protect animals from nonalcoholic steatohepatitis. This suggests c ... Full text Cite

Homeostasis Patterns

Journal article SIAM Journal on Applied Dynamical Systems · January 1, 2024 Homeostasis is a regulatory mechanism that keeps a specific variable close to a set value as other variables fluctuate. The notion of homeostasis can be rigorously formulated when the model of interest is represented as an input-output network, with distin ... Full text Cite

Dynamical questions in volume transmission.

Journal article Journal of biological dynamics · December 2023 In volume transmission (or neuromodulation) neurons do not make one-to-one connections to other neurons, but instead simply release neurotransmitter into the extracellular space from numerous varicosities. Many well-known neurotransmitters including seroto ... Full text Cite

Serotonin is a common thread linking different classes of antidepressants.

Journal article Cell chemical biology · December 2023 Depression pathology remains elusive. The monoamine hypothesis has placed much focus on serotonin, but due to the variable clinical efficacy of monoamine reuptake inhibitors, the community is looking for alternative therapies such as ketamine (neurogenesis ... Full text Cite

Evaluating old truths: Final adult size in holometabolous insects is set by the end of larval development.

Journal article Journal of experimental zoology. Part B, Molecular and developmental evolution · May 2023 For centuries, it has been understood that the final size of adult holometabolous insects is determined by the end of the larval stage, and that once they transform to adults, holometabolous insects do not grow. Despite this, no previous study has directly ... Full text Cite

Ontogenetic trajectories and early shape differentiation of treehopper pronota (Hemiptera: Membracidae).

Journal article Evolution & development · May 2023 Membracids (family: Membracidae), commonly known as treehoppers, are recognizable by their enlarged and often elaborated pronota. Much of the research investigating the development and evolution of this structure has focused on the fifth instar to adult tr ... Full text Cite

Mathematical insights into the role of dopamine signaling in circadian entrainment.

Journal article Mathematical biosciences · February 2023 The circadian clock in the mammalian brain comprises interlocked molecular feedback loops that have downstream effects on important physiological functions such as the sleep-wake cycle and hormone regulation. Experiments have shown that the circadian clock ... Full text Cite

An In Vivo Definition of Brain Histamine Dynamics Reveals Critical Neuromodulatory Roles for This Elusive Messenger.

Journal article International journal of molecular sciences · November 2022 Histamine is well known for mediating peripheral inflammation; however, this amine is also found in high concentrations in the brain where its roles are much less known. In vivo chemical dynamics are difficult to measure, thus fundamental aspects of histam ... Full text Open Access Cite

The roles of growth regulation and appendage patterning genes in the morphogenesis of treehopper pronota.

Journal article Proceedings. Biological sciences · June 2022 Treehoppers of the insect family Membracidae have evolved enlarged and elaborate pronotal structures, which is hypothesized to involve co-opted expression of genes that are shared with the wings. Here, we investigate the similarity between the pronotum and ... Full text Cite

Voltammetric Approach for Characterizing the Biophysical and Chemical Functionality of Human Induced Pluripotent Stem Cell-Derived Serotonin Neurons.

Journal article Analytical chemistry · June 2022 Depression is quickly becoming one of the world's most pressing public health crises, and there is an urgent need for better diagnostics and therapeutics. Behavioral models in animals and humans have not adequately addressed the diagnosis and treatment of ... Full text Cite

The development of shape. Modular control of growth in the lepidopteran forewing.

Journal article Journal of experimental zoology. Part B, Molecular and developmental evolution · May 2022 The mechanisms by which tissues and organs achieve their final size and shape during development are largely unknown. Although we have learned much about the mechanisms that control growth, little is known about how those play out to achieve a structure's ... Full text Cite

Spiracular fluttering decouples oxygen uptake and water loss: a stochastic PDE model of respiratory water loss in insects.

Journal article Journal of mathematical biology · April 2022 In insect respiration, oxygen from the air diffuses through a branching system of air-filled tubes to the cells of the body and carbon dioxide produced in cellular respiration diffuses out. The tracheal system has a very large surface area, so water loss i ... Full text Cite

The genetic control paradigm in biology: What we say, and what we are entitled to mean.

Journal article Progress in biophysics and molecular biology · March 2022 We comment on the article by Keith Baverstock (2021) and provide critiques of the concepts of genetic control, genetic blueprint and genetic program. ... Full text Cite

Inflammation-Induced Histamine Impairs the Capacity of Escitalopram to Increase Hippocampal Extracellular Serotonin.

Journal article The Journal of neuroscience : the official journal of the Society for Neuroscience · July 2021 Commonly prescribed selective serotonin reuptake inhibitors (SSRIs) inhibit the serotonin transporter to correct a presumed deficit in extracellular serotonin signaling during depression. These agents bring clinical relief to many who take them; however, a ... Full text Open Access Cite

Genetic assimilation and accommodation: Models and mechanisms

Journal article Current Topics in Developmental Biology · July 1, 2021 Full text Link to item Cite

Mathematical Models of Serotonin, Histamine, and Depression

Journal article InTechOpen · May 19, 2021 Cite

Mechanism of threshold size assessment: Metamorphosis is triggered by the TGF-beta/Activin ligand Myoglianin.

Journal article Insect biochemistry and molecular biology · November 2020 Although the mechanisms that control growth are now well understood, the mechanism by which animals assess their body size remains one of the great puzzles in biology. The final larval instar of holometabolous insects, after which growth stops and metamorp ... Full text Cite

Autoreceptor control of serotonin dynamics.

Journal article BMC neuroscience · September 2020 BackgroundSerotonin is a neurotransmitter that has been linked to a wide variety of behaviors including feeding and body-weight regulation, social hierarchies, aggression and suicidality, obsessive compulsive disorder, alcoholism, anxiety, and aff ... Full text Cite

The Arctiid Archetype: A New Lepidopteran Groundplan

Journal article Frontiers in Ecology and Evolution · June 10, 2020 The nymphalid groundplan (NGP) has proven to be extraordinarily useful in the study of butterfly color patterns because it allows for the identification of homologous elements across species. It has long been thought that the NGP is broadly applicable to a ... Full text Cite

Anterior–Posterior Patterning in Lepidopteran Wings

Journal article Frontiers in Ecology and Evolution · June 3, 2020 The color patterns on the wings of butterflies and moths are among the most complex manifestations of pattern formation in nature. The complexities of these patterns arise from the diversification of a conserved set of homologous elements known as the Nymp ... Full text Cite

TGF-beta/Activin ligand Myoglianin couples muscle growth to the initiation of metamorphosis

Journal article · April 23, 2020 ABSTRACT Although the mechanisms that control growth are now well understood, the mechanism by which animals assess their body size remains one of the great puzzles in biology. The final l ... Full text Cite

Fast serotonin voltammetry as a versatile tool for mapping dynamic tissue architecture: I. Responses at carbon fibers describe local tissue physiology.

Journal article Journal of neurochemistry · April 2020 It is important to monitor serotonin neurochemistry in the context of brain disorders. Specifically, a better understanding of biophysical alterations and associated biochemical functionality within subregions of the brain will enable better of understandi ... Full text Cite

Diverse nanostructures underlie thin ultra-black scales in butterflies.

Journal article Nature communications · March 2020 Recently, it has been shown that animals such as jumping spiders, birds, and butterflies have evolved ultra-black coloration comparable to the blackest synthetic materials. Of these, certain papilionid butterflies have reflectances approaching 0.2%, result ... Full text Cite

Origin of the mechanism of phenotypic plasticity in satyrid butterfly eyespots.

Journal article eLife · February 2020 Plasticity is often regarded as a derived adaptation to help organisms survive in variable but predictable environments, however, we currently lack a rigorous, mechanistic examination of how plasticity evolves in a large comparative framework. Here, we sho ... Full text Cite

Allometry, Scaling, and Ontogeny of Form-An Introduction to the Symposium.

Journal article Integrative and comparative biology · November 2019 Until recently, the study of allometry has been mostly descriptive, and consisted of a diversity of methods for fitting regressions to bivariate or multivariate morphometric data. During the past decade, researchers have been developing methods to extract ... Full text Cite

The multistep morphing of beetle horns.

Journal article Science (New York, N.Y.) · November 2019 Full text Cite

Systems biology of robustness and homeostatic mechanisms.

Journal article Wiley interdisciplinary reviews. Systems biology and medicine · May 2019 All organisms are subject to large amounts of genetic and environmental variation and have evolved mechanisms that allow them to function well in spite of these challenges. This property is generally referred to as robustness. We start with the premise tha ... Full text Cite

Contrasting Roles of Transcription Factors Spineless and EcR in the Highly Dynamic Chromatin Landscape of Butterfly Wing Metamorphosis.

Journal article Cell reports · April 2019 Development requires highly coordinated changes in chromatin accessibility in order for proper gene regulation to occur. Here, we identify factors associated with major, discrete changes in chromatin accessibility during butterfly wing metamorphosis. By co ... Full text Cite

Expanding the nymphalid groundplan's domain of applicability: Pattern homologies in an arctiid moth (Utetheisa ornatrix)

Journal article Biological Journal of the Linnean Society · March 27, 2019 The nymphalid groundplan allows for the identification of homologous characters across species, making this archetype an invaluable tool for research on the development and evolutionary diversification of butterfly wing patterns. However, whether the groun ... Full text Cite

Voltammetric evidence for discrete serotonin circuits, linked to specific reuptake domains, in the mouse medial prefrontal cortex.

Journal article Neurochemistry international · February 2019 The medial prefrontal cortex (mPFC) is an important brain region, that controls a variety of behavioral and functional outputs. As an important step in characterizing mPFC functionality, in this paper we focus on chemically defining serotonin transmission ... Full text Cite

Larval Development: Making Ants into Soldiers.

Journal article Current biology : CB · January 2019 Many ant species have complex caste systems, with reproductive queens and sterile workers, which often play distinct roles in the maintenance and defense of the colony. A new study sheds light on how these worker caste systems evolved and the mechanisms by ... Full text Cite

In vivo Hippocampal Serotonin Dynamics in Male and Female Mice: Determining Effects of Acute Escitalopram Using Fast Scan Cyclic Voltammetry.

Journal article Frontiers in neuroscience · January 2019 Depression is a highly prevalent psychiatric disorder, impacting females at a rate roughly twice that of males. This disparity has become the focus of many studies which are working to determine if there are environmental or biological underpinnings to dep ... Full text Cite

Corrigendum: In vivo Hippocampal Serotonin Dynamics in Male and Female Mice: Determining Effects of Acute Escitalopram Using Fast Scan Cyclic Voltammetry.

Journal article Frontiers in neuroscience · January 2019 [This corrects the article DOI: 10.3389/fnins.2019.00362.]. ... Full text Cite

Sex differences in hepatic one-carbon metabolism.

Journal article BMC systems biology · October 2018 BackgroundThere are large differences between men and women of child-bearing age in the expression level of 5 key enzymes in one-carbon metabolism almost certainly caused by the sex hormones. These male-female differences in one-carbon metabolism ... Full text Cite

Wing morphogenesis in Lepidoptera.

Journal article Progress in biophysics and molecular biology · September 2018 The wings of Lepidoptera develop from imaginal disks that are made up of a simple two-layered epithelium whose structure is always congruent with the final adult wing. It is therefore possible to map every point on the imaginal disk to a location on the ad ... Full text Cite

Hormonal control of growth in the wing imaginal disks of Junonia coenia: the relative contributions of insulin and ecdysone.

Journal article Development (Cambridge, England) · March 2018 The wing imaginal disks of Lepidoptera can be grown in tissue culture, but require both insulin and ecdysone to grow normally. Here, we investigate the contributions the two hormones make to growth. Ecdysone is required to maintain mitoses, whereas in the ... Full text Cite

The distinct roles of insulin signaling in polyphenic development.

Journal article Current opinion in insect science · February 2018 Many insects have the ability to develop alternative morphologies in response to specific environmental signals such as photoperiod, temperature, nutrition and crowding. These signals are integrated by the brain and result in alternative patterns of secret ... Full text Cite

Unmodern Synthesis: Developmental Hierarchies and the Origin of Phenotypes.

Journal article BioEssays : news and reviews in molecular, cellular and developmental biology · January 2018 The question of whether the modern evolutionary synthesis requires an extension has recently become a topic of discussion, and a source of controversy. We suggest that this debate is, for the most part, not about the modern synthesis at all. Rather, it is ... Full text Cite

Analysis of Homeostatic Mechanisms in Biochemical Networks.

Journal article Bulletin of mathematical biology · November 2017 Cell metabolism is an extremely complicated dynamical system that maintains important cellular functions despite large changes in inputs. This "homeostasis" does not mean that the dynamical system is rigid and fixed. Typically, large changes in external va ... Full text Cite

A Possible Link Between Pyriproxyfen and Microcephaly.

Journal article PLoS currents · November 2017 The Zika virus has been the primary suspect in the large increase in incidence of microcephaly in 2015-6 in Brazil. While evidence for Zika being the cause of some of the cases is strong, its role as the primary cause of the large number of cases in Brazil ... Full text Cite

Systems Biology of Phenotypic Robustness and Plasticity.

Journal article Integrative and comparative biology · August 2017 SynopsisGene regulatory networks, cellular biochemistry, tissue function, and whole body physiology are imbued with myriad overlapping and interacting homeostatic mechanisms that ensure that many phenotypes are robust to genetic and environmental ... Full text Open Access Cite

Synergism and Antagonism of Proximate Mechanisms Enable and Constrain the Response to Simultaneous Selection on Body Size and Development Time: An Empirical Test Using Experimental Evolution.

Journal article The American naturalist · November 2016 Natural selection acts on multiple traits simultaneously. How mechanisms underlying such traits enable or constrain their response to simultaneous selection is poorly understood. We show how antagonism and synergism among three traits at the developmental ... Full text Cite

A voltammetric and mathematical analysis of histaminergic modulation of serotonin in the mouse hypothalamus.

Journal article Journal of neurochemistry · August 2016 Histamine and serotonin are neuromodulators which facilitate numerous, diverse neurological functions. Being co-localized in many brain regions, these two neurotransmitters are thought to modulate one another's chemistry and are often implicated in the eti ... Full text Cite

Mathematical modeling of perifusion cell culture experiments on GnRH signaling.

Journal article Mathematical biosciences · June 2016 The effects of pulsatile GnRH stimulation on anterior pituitary cells are studied using perifusion cell cultures, where constantly moving culture medium over the immobilized cells allows intermittent GnRH delivery. The LH content of the outgoing medium ser ... Full text Cite

Mathematical analysis of the regulation of competing methyltransferases.

Journal article BMC systems biology · October 2015 BackgroundMethyltransferase (MT) reactions, in which methyl groups are attached to substrates, are fundamental to many aspects of cell biology and human physiology. The universal methyl donor for these reactions is S-adenosylmethionine (SAM) and t ... Full text Cite

Using mathematical models to understand metabolism, genes, and disease.

Journal article BMC biology · September 2015 Mathematical models are a useful tool for investigating a large number of questions in metabolism, genetics, and gene-environment interactions. A model based on the underlying biology and biochemistry is a platform for in silico biological experimentation ... Full text Cite

Big or fast: two strategies in the developmental control of body size.

Journal article BMC biology · August 2015 Adult body size is controlled by the mechanisms that stop growth when a species-characteristic size has been reached. The mechanisms by which size is sensed and by which this information is transduced to the growth regulating system are beginning to be und ... Full text Open Access Cite

The role of skeletal muscle in liver glutathione metabolism during acetaminophen overdose.

Journal article Journal of theoretical biology · July 2015 Marked alterations in systemic glutamate-glutamine metabolism characterize the catabolic state, in which there is an increased breakdown and decreased synthesis of skeletal muscle protein. Among these alterations are a greatly increased net release of glut ... Full text Cite

Two insulin receptors determine alternative wing morphs in planthoppers.

Journal article Nature · March 2015 Wing polyphenism is an evolutionarily successful feature found in a wide range of insects. Long-winged morphs can fly, which allows them to escape adverse habitats and track changing resources, whereas short-winged morphs are flightless, but usually posses ... Full text Cite

To plasticity and back again.

Journal article eLife · March 2015 Both the gain and the loss of flexibility in the development of phenotypes have led to an increased diversity of physical forms in nematode worms. ... Full text Open Access Cite

Developmental mechanisms of body size and wing-body scaling in insects.

Journal article Annual review of entomology · January 2015 The developmental mechanisms that control body size and the relative sizes of body parts are today best understood in insects. Size is controlled by the mechanisms that cause growth to stop when a size characteristic of the species has been achieved. This ... Full text Cite

A Quantitative Analysis of Growth and Size Regulation in Manduca sexta: The Physiological Basis of Variation in Size and Age at Metamorphosis.

Journal article PloS one · January 2015 Body size and development time are important life history traits because they are often highly correlated with fitness. Although the developmental mechanisms that control growth have been well studied, the mechanisms that control how a species-characterist ... Full text Open Access Cite

Escape from homeostasis.

Journal article Mathematical biosciences · November 2014 Many physiological systems, from gene networks to biochemistry to whole organism physiology, exhibit homeostatic mechanisms that keep certain variables within a fairly narrow range. Because homeostatic mechanisms buffer traits against environmental and gen ... Full text Cite

Voltammetric and mathematical evidence for dual transport mediation of serotonin clearance in vivo.

Journal article Journal of neurochemistry · August 2014 The neurotransmitter serotonin underlies many of the brain's functions. Understanding serotonin neurochemistry is important for improving treatments for neuropsychiatric disorders such as depression. Antidepressants commonly target serotonin clearance via ... Full text Cite

Homeostasis and dynamic stability of the phenotype link robustness and plasticity.

Journal article Integrative and comparative biology · July 2014 Phenotypes are remarkably robust to genetic and environmental variation. Although the general control principles of robustness are well understood in simple systems, the actual mechanisms that convey robustness in realistically complex systems have been li ... Full text Cite

Targeted metabolomics and mathematical modeling demonstrate that vitamin B-6 restriction alters one-carbon metabolism in cultured HepG2 cells.

Journal article American journal of physiology. Endocrinology and metabolism · July 2014 Low vitamin B-6 nutritional status is associated with increased risk for cardiovascular disease and certain cancers. Pyridoxal 5'-phosphate (PLP) serves as a coenzyme in many cellular processes, including several reactions in one-carbon (1C) metabolism and ... Full text Cite

Plasticity of insect body size in response to oxygen: integrating molecular and physiological mechanisms.

Journal article Current opinion in insect science · July 2014 The hypoxia-induced reduction of body size in Drosophila and Manduca is ideal for understanding the mechanisms of body size plasticity. The mechanisms of size regulation are well-studied in these species, and the molecular mechanisms of oxygen sensing are ... Full text Cite

Mathematical modeling of the effects of glutathione on arsenic methylation.

Journal article Theoretical biology & medical modelling · May 2014 BackgroundArsenic is a major environmental toxin that is detoxified in the liver by biochemical mechanisms that are still under study. In the traditional metabolic pathway, arsenic undergoes two methylation reactions, each followed by a reduction, ... Full text Cite

The development of wing shape in Lepidoptera: mitotic density, not orientation, is the primary determinant of shape.

Journal article Evolution & development · March 2014 The wings of butterflies and moths develop from imaginal disks whose structure is always congruent with the final adult wing. It is therefore possible to map every point on the imaginal disk to a location on the adult wing throughout ontogeny. We studied t ... Full text Cite

Projecting biochemistry over long distances

Journal article Mathematical Modelling of Natural Phenomena · February 20, 2014 Mathematical and computational neuroscience have contributed to the brain sciences by the study of the dynamics of individual neurons and more recently the study of the dynamics of electrophysiological networks. Often these studies treat individual neurons ... Full text Cite

The developmental control of size in insects.

Journal article Wiley interdisciplinary reviews. Developmental biology · January 2014 The mechanisms that control the sizes of a body and its many parts remain among the great puzzles in developmental biology. Why do animals grow to a species-specific body size, and how is the relative growth of their body parts controlled to so they grow t ... Full text Cite

Body size determination in insects: a review and synthesis of size- and brain-dependent and independent mechanisms.

Journal article Biological reviews of the Cambridge Philosophical Society · November 2013 Body size determination requires a mechanism for sensing size and a mechanism for linking size information to the termination of growth. Although the hormonal mechanisms that terminate growth are well elucidated, the mechanisms by which a body senses its o ... Full text Cite

Arthropod developmental endocrinology

Journal article · October 1, 2013 Embryonic development in arthropods appears to be largely controlled by gene regulatory cascades and networks, and gene products that move by diffusion. By contrast, postembryonic growth and differentiation are controlled almost entirely by circulating hor ... Full text Cite

A mathematical model of tryptophan metabolism via the kynurenine pathway provides insights into the effects of vitamin B-6 deficiency, tryptophan loading, and induction of tryptophan 2,3-dioxygenase on tryptophan metabolites.

Journal article The Journal of nutrition · September 2013 Vitamin B-6 deficiency is associated with impaired tryptophan metabolism because of the coenzyme role of pyridoxal 5'-phosphate (PLP) for kynureninase and kynurenine aminotransferase. To investigate the underlying mechanism, we developed a mathematical mod ... Full text Cite

A population model of folate-mediated one-carbon metabolism.

Journal article Nutrients · July 2013 BackgroundPrevious mathematical models for hepatic and tissue one-carbon metabolism have been combined and extended to include a blood plasma compartment. We use this model to study how the concentrations of metabolites that can be measured in the ... Full text Open Access Cite

The relationship between intracellular and plasma levels of folate and metabolites in the methionine cycle: a model.

Journal article Molecular nutrition & food research · April 2013 ScopeFolate status and the status of the methionine cycle are typically assessed by measuring folate and metabolites in the plasma. It is assumed that plasma metabolite levels are proportional to their levels in tissues, but there is little inform ... Full text Cite

Development of polyploidy of scale-building cells in the wings of Manduca sexta.

Journal article Arthropod structure & development · January 2013 The developing wings of butterflies and moths are composed of two epithelial monolayers. Each epithelial sheet is made up of two kinds of cells, diploid cells that make up the epidermal surface and body of the wing, and large polyploid cells that become th ... Full text Cite

Multi-allelic major effect genes interact with minor effect QTLs to control adaptive color pattern variation in Heliconius erato.

Journal article PloS one · January 2013 Recent studies indicate that relatively few genomic regions are repeatedly involved in the evolution of Heliconius butterfly wing patterns. Although this work demonstrates a number of cases where homologous loci underlie both convergent and divergent wing ... Full text Cite

Computational studies of the role of serotonin in the basal ganglia.

Journal article Frontiers in integrative neuroscience · January 2013 It has been well established that serotonin (5-HT) plays an important role in the striatum. For example, during levodopa therapy for Parkinson's disease (PD), the serotonergic projections from the dorsal raphe nucleus (DRN) release dopamine as a false tran ... Full text Cite

A new mathematical approach for qualitative modeling of the insulin-TOR-MAPK network.

Journal article Frontiers in physiology · January 2013 In this paper we develop a novel mathematical model of the insulin-TOR-MAPK signaling network that controls growth. Most data on the properties of the insulin and MAPK signaling networks are static and the responses to experimental interventions, such as k ... Full text Cite

An eco-physiological model of the impact of temperature on Aedes aegypti life history traits.

Journal article Journal of insect physiology · December 2012 Physiological processes mediate the impact of ecological conditions on the life histories of insect vectors. For the dengue/chikungunya mosquito, Aedes aegypti, three life history traits that are critical to urban population dynamics and control are: size, ... Full text Cite

Blood biomarkers of methylation in Down syndrome and metabolic simulations using a mathematical model.

Journal article Molecular nutrition & food research · October 2012 ScopeThe study tests the metabolites of the methylation cycle in individuals with Down syndrome (DS) and applies a mathematical model in order to change this cycle by nutritional factors.Methods and resultsWe measured concentrations of th ... Full text Cite

Predicting the response to simultaneous selection: genetic architecture and physiological constraints.

Journal article Evolution; international journal of organic evolution · September 2012 A great deal is known about the evolutionary significance of body size and development time. They are determined by the nonlinear interaction of three physiological traits: two hormonal events and growth rate (GR). In this study we investigate how the gene ... Full text Cite

Developmental causes of allometry: new models and implications for phenotypic plasticity and evolution.

Journal article Integrative and comparative biology · July 2012 Shapes change during development because tissues, organs, and various anatomical features differ in onset, rate, and duration of growth. Allometry is the study of the consequences of differences in the growth of body parts on morphology, although the field ... Full text Cite

A mathematical modelling approach to assessing the reliability of biomarkers of glutathione metabolism.

Journal article European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences · July 2012 One of the main pathways for the detoxification of reactive metabolites in the liver involves glutathione conjugation. Metabolic profiling studies have shown paradoxical responses in glutathione-related biochemical pathways. One of these is the increase in ... Full text Cite

Supply-side constraints are insufficient to explain the ontogenetic scaling of metabolic rate in the tobacco Hornworm, Manduca sexta.

Journal article PloS one · January 2012 Explanations for the hypoallometric scaling of metabolic rate through ontogeny generally fall into two categories: supply-side constraints on delivery of oxygen, or decreased mass-specific intrinsic demand for oxygen. In many animals, supply and demand inc ... Full text Cite

Mathematical insights into the effects of levodopa

Journal article Frontiers in Integrative Neuroscience · 2012 Cite

The biochemistry of acetaminophen hepatotoxicity and rescue: a mathematical model

Journal article Theoretical Biology and Medical Modeling · 2012 Cite

Dependence of morphometric allometries on the growth kinetics of body parts.

Journal article Journal of theoretical biology · November 2011 As overall size varies, the sizes of body parts of many animals often appear to be related to each other by a power law, commonly called the allometric equation. Orderly scaling relationships among body parts are widespread in the animal world, but there i ... Full text Cite

The role of developmental plasticity in evolutionary innovation.

Journal article Proceedings. Biological sciences · September 2011 Explaining the origins of novel traits is central to evolutionary biology. Longstanding theory suggests that developmental plasticity, the ability of an individual to modify its development in response to environmental conditions, might facilitate the evol ... Full text Cite

Mathematical modeling predicts the effect of folate deficiency and excess on cancer-related biomarkers.

Journal article Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology · September 2011 BackgroundFolate is an essential B-vitamin that mediates one-carbon metabolism reactions, including nucleotide synthesis and others related to carcinogenesis. Both low- and high-folate status influences carcinogenesis.MethodsWe used a mat ... Full text Cite

Mathematical model insights into arsenic detoxification

Journal article Theoretical Biology and Medical Modelling · August 30, 2011 Background: Arsenic in drinking water, a major health hazard to millions of people in South and East Asia and in other parts of the world, is ingested primarily as trivalent inorganic arsenic (iAs), which then undergoes hepatic methylation to methylarsonic ... Full text Cite

Mathematical model insights into arsenic detoxification.

Journal article Theoretical biology & medical modelling · August 2011 BackgroundArsenic in drinking water, a major health hazard to millions of people in South and East Asia and in other parts of the world, is ingested primarily as trivalent inorganic arsenic (iAs), which then undergoes hepatic methylation to methyl ... Full text Cite

Control of body size by oxygen supply reveals size-dependent and size-independent mechanisms of molting and metamorphosis.

Journal article Proceedings of the National Academy of Sciences of the United States of America · August 2011 Body size profoundly affects many aspects of animal biology, including metamorphosis, allometry, size-dependent alternative pathways of gene expression, and the social and ecological roles of individuals. However, regulation of body size is one of the fund ... Full text Cite

Bursts and the efficacy of selective serotonin reuptake inhibitors.

Journal article Pharmacopsychiatry · May 2011 We present a new hypothesis for the efficacy of selective serotonin reuptake inhibitors (SSRIs). We propose that SSRIs bring the response to the phasic firing of raphe nucleus cells back to normal, even though the average extracellular 5HT concentration re ... Full text Cite

The cellular and physiological mechanism of wing-body scaling in Manduca sexta.

Journal article Science (New York, N.Y.) · December 2010 In animals, appendages develop in proportion to overall body size; when individual size varies, appendages covary proportionally. In insects with complete metamorphosis, adult appendages develop from precursor tissues called imaginal disks that grow after ... Full text Cite

Developmental constraints on the evolution of wing-body allometry in Manduca sexta

Journal article Evolution & Development · November 2010 Cite

Developmental constraints on the evolution of wing-body allometry in Manduca sexta.

Journal article Evolution & development · November 2010 Artificial selection on body size in Manduca sexta produced genetic strains with large and small body sizes. The wing-body allometries of these strains differed significantly from the wild type. Selection on small body size led to a change in the scaling o ... Full text Cite

Serotonin synthesis, release and reuptake in terminals: a mathematical model.

Journal article Theoretical biology & medical modelling · August 2010 BackgroundSerotonin is a neurotransmitter that has been linked to a wide variety of behaviors including feeding and body-weight regulation, social hierarchies, aggression and suicidality, obsessive compulsive disorder, alcoholism, anxiety, and aff ... Full text Open Access Cite

Photoperiodism in Insects: Effects on Morphology

Journal article · May 1, 2010 This chapter discusses the role of photoperiodism on phenotype expression in insects. Topics covered include general patterns of expression of seasonal morphs in insects, the interaction of photoperiod and temperature, how photoperiod affects development a ... Full text Cite

The biological significance of substrate inhibition: a mechanism with diverse functions.

Journal article BioEssays : news and reviews in molecular, cellular and developmental biology · May 2010 Many enzymes are inhibited by their own substrates, leading to velocity curves that rise to a maximum and then descend as the substrate concentration increases. Substrate inhibition is often regarded as a biochemical oddity and experimental annoyance. We s ... Full text Cite

A switch in the control of growth of the wing imaginal disks of Manduca sexta.

Journal article PloS one · May 2010 BackgroundInsulin and ecdysone are the key extrinsic regulators of growth for the wing imaginal disks of insects. In vitro tissue culture studies have shown that these two growth regulators act synergistically: either factor alone stimulates only ... Full text Open Access Cite

Models of dopaminergic and serotonergic signaling.

Journal article Pharmacopsychiatry · May 2010 Mathematical models of dopaminergic and serotonergic synapses have enabled the authors to study quantitative aspects of the synthesis, release and reuptake of dopamine and serotonin, to investigate the effects of autoreceptors, and to explore the influence ... Full text Cite

Evolutionary divergence of field and laboratory populations of Manduca sexta in response to host-plant quality

Journal article Ecological Entomology · April 1, 2010 The tobacco hornworm, Manduca sexta, has been an important model system in insect biology for more than 50 years. In nature, M. sexta successfully utilises a range of host plants that vary in quality. The consequences of laboratory domestication and rearin ... Full text Cite

Conflicting processes in the evolution of body size and development time.

Journal article Philosophical transactions of the Royal Society of London. Series B, Biological sciences · February 2010 Body size and development time of Manduca sexta are both determined by the same set of three developmental-physiological factors. These define a parameter space within which it is possible to analyse and explain how phenotypic change is associated with cha ... Full text Cite

A switch in the control of growth of the wing imaginal disks of Manduca sexta

Journal article PLoS ONE · 2010 Background: Insulin and ecdysone are the key extrinsic regulators of growth for the wing imaginal disks of insects. In vitro tissue culture studies have shown that these two growth regulators act synergistically: either factor alone stimulates only limited ... Full text Cite

Molecular and Physiological Basis of Colour Pattern Formation

Journal article · January 1, 2010 This chapter focuses on the recent developments for making understanding of the molecular, developmental and physiological mechanism of color pattern formation to place these in the context of antecedent work. The evolution of color patterns can be viewed ... Full text Cite

Partial co-option of the appendage patterning pathway in the development of abdominal appendages in the sepsid fly Themira biloba.

Journal article Development genes and evolution · December 2009 The abdominal appendages on male Themira biloba (Diptera: Sepsidae) are complex novel structures used during mating. These abdominal appendages superficially resemble the serially homologous insect appendages in that they have a joint and a short segment t ... Full text Cite

Singularity in polarization: rewiring yeast cells to make two buds.

Journal article Cell · November 13, 2009 For budding yeast to ensure formation of only one bud, cells must polarize toward one, and only one, site. Polarity establishment involves the Rho family GTPase Cdc42, which concentrates at polarization sites via a positive feedback loop. To assess whether ... Full text Link to item Cite

Use of pathway information in molecular epidemiology.

Journal article Human genomics · October 2009 Candidate gene studies are generally motivated by some form of pathway reasoning in the selection of genes to be studied, but seldom has the logic of the approach been carried through to the analysis. Marginal effects of polymorphisms in the selected genes ... Full text Cite

Use of pathway information in molecular epidemiology

Journal article Human Genomics · October 1, 2009 © 2009 Henry Stewart Publications. Candidate gene studies are generally motivated by some form of pathway reasoning in the selection of genes to be studied, but seldom has the logic of the approach been carried through to the analysis. Marginal effects of ... Full text Cite

Passive and active stabilization of dopamine in the striatum

Journal article Bioscience Hypotheses · June 3, 2009 Parkinson's disease is a neurodegenerative disorder associated with cell loss from the substantia nigra pars compacta (SNc). The dopaminergic cells of the SNc project to the striatum where the loss of dopaminergic tone is thought to be the main cause of Pa ... Full text Cite

A mathematical model gives insights into the effects of vitamin B-6 deficiency on 1-carbon and glutathione metabolism.

Journal article The Journal of nutrition · April 2009 We experimented with a mathematical model for 1-carbon metabolism and glutathione (GSH) synthesis to investigate the effects of vitamin B-6 deficiency on the reaction velocities and metabolite concentrations in this metabolic network. The mathematical mode ... Full text Cite

Environment and genetic accommodation.

Journal article Biological Theory · 2009 Cite

Homeostatic mechanisms in dopamine synthesis and release: a mathematical model.

Journal article Theoretical Biology and Medical Modeling · 2009 Cite

Constraint and developmental dissociation of phenotypic integration in a genetically accommodated trait.

Journal article Evolution & development · November 2008 The genetic accommodation of novel adaptive traits may be accompanied by the evolution of correlated traits that constrain adaptive evolution. Very little is known about the removal of maladaptive correlated traits. In the present study, body size was foun ... Full text Cite

Size matters (but so does time), and it's OK to be different.

Journal article Developmental cell · October 2008 In this issue of Developmental Cell, Layalle et al. reveal new insights into how nutrition controls body size in Drosophila. Nutrition specifically affects the activity of target of rapamycin (TOR) in the prothoracic gland. Under low-nutrition conditions, ... Full text Cite

Environment and Genetic Accommodation

Journal article Biological Theory · September 1, 2008 Waddington’s experiments on genetic assimilation showed that selection on environmentally induced phenotypic variants can cause inherited evolutionary changes in the phenotype. We have recently extended this work by demonstrating that it is possible to sel ... Full text Cite

Mathematical models of one-carbon metabolism

Journal article Vitamins and Hormones · September 2008 Cite

Modeling folate, one-carbon metabolism, and DNA methylation.

Journal article Nutrition reviews · August 2008 Full text Cite

Mathematical modeling of folate metabolism: predicted effects of genetic polymorphisms on mechanisms and biomarkers relevant to carcinogenesis.

Journal article Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology · July 2008 Low-folate status and genetic polymorphisms in folate metabolism have been linked to several cancers. Possible biological mechanisms for this association include effects on purine and thymidine synthesis, DNA methylation, or homocysteine concentrations. Th ... Full text Cite

A mathematical model of glutathione metabolism.

Journal article Theoretical biology & medical modelling · April 2008 BackgroundGlutathione (GSH) plays an important role in anti-oxidant defense and detoxification reactions. It is primarily synthesized in the liver by the transsulfuration pathway and exported to provide precursors for in situ GSH synthesis by othe ... Full text Cite

Genetic basis of adaptive evolution of a polyphenism by genetic accommodation.

Journal article Journal of evolutionary biology · January 2008 Polyphenisms are evolved adaptations in which a genome produces discrete alternative phenotypes in different environments. In this study, the genetic basis of the evolution of a polyphenism by genetic accommodation was investigated. A polyphenic strain and ... Full text Cite

A mathematical model for the regulation of juvenile hormone titers.

Journal article Journal of insect physiology · January 2008 The titer of juvenile hormone (JH) is determined by three factors: its rate of synthesis, its rate of degradation, and the degree to which JH is protected from degradation by binding to a diversity of JH-binding proteins. All three of these factors vary th ... Full text Cite

Developmental phenotypic landscapes

Journal article Evolutionary Biology · January 1, 2008 Full text Cite

Mathematical models of folate-mediated one-carbon metabolism.

Journal article Vitamins and hormones · January 2008 Folate-mediated one-carbon metabolism is an unusually complex metabolic network, consisting of several interlocking cycles, and compartmentation between cytosol and mitochondria. The cycles have diverse functions, the primary being thymidylate synthesis (t ... Full text Cite

Flavin-dependent thymidylate synthase ThyX activity: implications for the folate cycle in bacteria.

Journal article Journal of bacteriology · December 2007 Although flavin-dependent ThyX proteins show thymidylate synthase activity in vitro and functionally complement thyA defects in heterologous systems, direct proof of their cellular functions is missing. Using insertional mutagenesis of Rhodobacter capsulat ... Full text Cite

Propagation of fluctuations in biochemical systems, I: linear SSC networks.

Journal article Bulletin of mathematical biology · August 2007 We investigate the propagation of random fluctuations through biochemical networks in which the number of molecules of each species is large enough so that the concentrations are well modeled by differential equations. We study the effect of network topolo ... Full text Open Access Cite

Evolution of novel abdominal appendages in a sepsid fly from histoblasts, not imaginal discs.

Journal article Evolution & development · July 2007 Abdominal appendages in male sepsid flies are a complex novel structure of unknown developmental and evolutionary origin. Although these abdominal appendages superficially resemble serially homologous insect appendages, they do not develop from imaginal di ... Full text Cite

Size and shape: the developmental regulation of static allometry in insects.

Journal article BioEssays : news and reviews in molecular, cellular and developmental biology · June 2007 Among all organisms, the size of each body part or organ scales with overall body size, a phenomenon called allometry. The study of shape and form has attracted enormous interest from biologists, but the genetic, developmental and physiological mechanisms ... Full text Cite

The control of growth and differentiation of the wing imaginal disks of Manduca sexta.

Journal article Developmental biology · February 2007 During the larval feeding period, the growth of the wing imaginal disks of Lepidoptera is dependent on continuous feeding. Feeding and nutrition exert their effect via the secretion of bombyxin, the lepidopteran insulin-like hormone. When larvae stop feedi ... Full text Cite

A day in the life of cell metabolism.

Journal article Biological Theory (in press) · 2007 Cite

In silico experimentation with a model of hepatic mitochondrial folate metabolism.

Journal article Theoretical biology & medical modelling · December 2006 BackgroundIn eukaryotes, folate metabolism is compartmentalized and occurs in both the cytosol and the mitochondria. The function of this compartmentalization and the great changes that occur in the mitochondrial compartment during embryonic devel ... Full text Cite

A mathematical model gives insights into nutritional and genetic aspects of folate-mediated one-carbon metabolism.

Journal article The Journal of nutrition · October 2006 Impaired folate-mediated 1-carbon metabolism has been linked to multiple disease outcomes. A better understanding of the nutritional and genetic influences on this complex biochemical pathway is needed to comprehend their impact on human health. To this en ... Full text Cite

Neural tube defects and folate pathway genes: family-based association tests of gene-gene and gene-environment interactions.

Journal article Environ Health Perspect · October 2006 BACKGROUND: Folate metabolism pathway genes have been examined for association with neural tube defects (NTDs) because folic acid supplementation reduces the risk of this debilitating birth defect. Most studies addressed these genes individually, often wit ... Full text Link to item Cite

The empirical nonequivalence of genie and genotypic models of selection: A (Decisive) refutation of genie selectionism and pluralistic genie selectionism

Journal article Philosophy of Science · July 1, 2006 Genic selectionists (Williams 1966; Dawkins 1976) defend the view that genes are the (unique) units of selection and that all evolutionary events can be adequately represented at the genie level. Pluralistic genie selectionists (Sterelny and Kitcher 1988; ... Full text Cite

Mathematical modeling: epidemiology meets systems biology.

Journal article Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology · May 2006 Full text Cite

The robustness of the transcriptional response to alterations in morphogenetic gradients.

Journal article BioEssays : news and reviews in molecular, cellular and developmental biology · March 2006 Sharp sigmoidal transitions of transcription in response to morphogenetic gradients are often involved in the generation of boundaries during development. Here we explore two simple models of transcription that generate sigmoidal outputs. Specifically, we ... Full text Cite

Evolution of a polyphenism by genetic accommodation.

Journal article Science (New York, N.Y.) · February 2006 Polyphenisms are adaptations in which a genome is associated with discrete alternative phenotypes in different environments. Little is known about the mechanism by which polyphenisms originate. We show that a mutation in the juvenile hormone-regulatory pat ... Full text Cite

A quantitative analysis of the mechanism that controls body size in Manduca sexta.

Journal article Journal of biology · January 2006 BackgroundBody size is controlled by mechanisms that terminate growth when the individual reaches a species-specific size. In insects, it is a pulse of ecdysone at the end of larval life that causes the larva to stop feeding and growing and initia ... Full text Cite

A physiological perspective on the response of body size and development time to simultaneous directional selection.

Journal article Integrative and comparative biology · June 2005 Natural selection typically acts on multiple traits simultaneously. Quantitative genetics provides the theory for predicting the response to selection of multiple traits and predicts symmetrical responses to selection (the response to upward selection on b ... Full text Cite

A mathematical model of the folate cycle: new insights into folate homeostasis.

Journal article The Journal of biological chemistry · December 2004 A mathematical model is developed for the folate cycle based on standard biochemical kinetics. We use the model to provide new insights into several different mechanisms of folate homeostasis. The model reproduces the known pool sizes of folate substrates ... Full text Cite

The physiological basis of reaction norms: the interaction among growth rate, the duration of growth and body size.

Journal article Integrative and comparative biology · December 2004 The general effects of temperature and nutritional quality on growth rate and body size are well known. We know little, however, about the physiological mechanisms by which an organism translates variation in diet and temperature into reaction norms of bod ... Full text Cite

Geographic variation of caste structure among ant populations.

Journal article Current biology : CB · March 2004 Morphologically distinct worker castes of eusocial insects specialize in different tasks. The relative proportions of these castes and their body sizes represent the demography of a colony that is predicted to vary adaptively with environments. Despite str ... Full text Cite

Trade-offs during the development of primary and secondary sexual traits in a horned beetle.

Journal article The American naturalist · February 2004 Resource allocation trade-offs during development affect the final sizes of adult structures and have the potential to constrain the types and magnitude of evolutionary change that developmental processes can accommodate. Such trade-offs can arise when two ... Full text Cite

A mathematical model of the methionine cycle.

Journal article Journal of theoretical biology · January 2004 Building on the work of Martinov et al. (2000), a mathematical model is developed for the methionine cycle. A large amount of information is available about the enzymes that catalyse individual reaction steps in the cycle, from methionine to S-adenosylmeth ... Full text Cite

The effects of environmental variation on a mechanism that controls insect body size

Journal article Evolutionary Ecology Research · January 1, 2004 Adult body size in animals is determined by the duration of the growth period and the amount of mass gained during that period. Few models of body size regulation distinguish between these two components or explicitly address the mechanisms that control th ... Cite

The control of growth.

Journal article Development (Cambridge, England) · December 2003 The growth of a cell or tissue involves complex interactions between genes, metabolism, nutrition and hormones. Until recently, separate lines of investigation have concentrated in isolated sections of each of the many independent levels of growth control; ... Full text Cite

Polymorphic mimicry in Papilio dardanus: mosaic dominance, big effects, and origins.

Journal article Evolution & development · November 2003 The mocker swallowtail, Papilio dardanus, has a female-limited polymorphic mimicry. This polymorphism is controlled by allelic variation at a single locus with at least 11 alleles. Many of the alternative morphs are accurate mimics of different species of ... Full text Cite

A perspective for understanding the modes of juvenile hormone action as a lipid signaling system.

Journal article BioEssays : news and reviews in molecular, cellular and developmental biology · October 2003 The juvenile hormones of insects regulate an unusually large diversity of processes during postembryonic development and adult reproduction. It is a long-standing puzzle in insect developmental biology and physiology how one hormone can have such diverse e ... Full text Cite

On the association between genes and complex traits.

Journal article The journal of investigative dermatology. Symposium proceedings · October 2003 Full text Cite

The control of body size in insects.

Journal article Developmental biology · September 2003 Control mechanisms that regulate body size and tissue size have been sought at both the cellular and organismal level. Cell-level studies have revealed much about the control of cell growth and cell division, and how these processes are regulated by nutrit ... Full text Cite

The importance of context in genetics

Journal article American Scientist · September 1, 2003 Full text Cite

Pigmentation pattern formation in butterflies: experiments and models.

Journal article Comptes rendus biologies · August 2003 Butterfly pigmentation patterns are one of the most spectacular and vivid examples of pattern formation in biology. They have attracted much attention from experimentalists and theoreticians, who have tried to understand the underlying genetic, chemical an ... Full text Cite

A mechanistic study of evolvability using the mitogen-activated protein kinase cascade.

Journal article Evolution & development · May 2003 Evolvability is a function of the way genetic variation interacts with the mechanisms that produce the phenotype. We explore an explicitly mechanistic way of studying the evolvability of phenotypes that are produced by a relatively simple genetic mechanism ... Full text Cite

Rapid evolution of a polyphenic threshold.

Journal article Evolution & development · May 2003 Polyphenisms are thought to play an important role in the evolution of phenotypic diversity and the origin of morphological and behavioral novelties. However, the extent to which polyphenic developmental mechanisms evolve in natural populations is unknown. ... Full text Cite

Critical weight in the development of insect body size.

Journal article Evolution & development · March 2003 Body size is one of the most important life history characters of organisms, yet little is known of the physiological mechanisms that regulate either body size or variation in body size. Here, we examined one of these mechanisms, the critical weight, which ... Full text Cite

Development and evolution of adaptive polyphenisms.

Journal article Evolution & development · January 2003 Phenotypic plasticity is the primitive character state for most if not all traits. Insofar as developmental and physiological processes obey the laws of chemistry and physics, they will be sensitive to such environmental variables as temperature, nutrient ... Full text Cite

Bombyxin is a growth factor for wing imaginal disks in Lepidoptera.

Journal article Proceedings of the National Academy of Sciences of the United States of America · November 2002 The mechanisms that control the growth rate of internal tissues during postembryonic development are poorly understood. In insects, the growth rate of imaginal disks varies with nutrition and keeps pace with variation in somatic growth. We describe here a ... Full text Cite

Developmental mechanisms of threshold evolution in a polyphenic beetle.

Journal article Evolution & development · July 2002 Polyphenic development is thought to play a pivotal role in the origin of morphological novelties. However, little is known about how polyphenisms evolve in natural populations, the developmental mechanisms that may mediate such evolution, and the conseque ... Full text Cite

The nature of robustness in development.

Journal article BioEssays : news and reviews in molecular, cellular and developmental biology · June 2002 A trait is robust to a genetic or environmental variable if its variation is weakly correlated with variation in that variable. The source of robustness lies in the fact that the developmental processes that give rise to complex traits are nonlinear. A con ... Full text Cite

The role of wing veins in colour pattern development in the butterfly Papilio xuthus (Lepidoptera: Papilionidae)

Journal article European Journal of Entomology · January 1, 2002 Naturally occuring veinless specimen of the swallowtail Papilio xuthus show an extremely aberrant colour pattern. In spite of the fact that we have no breeding data, these veinless specimen are provisionally called veins-reduced mutant. In these mutants se ... Full text Cite

A method for sexing final instar larvae of the genus Onthophagus Latreille (Coleoptera: Scarabaeidae)

Journal article Coleopterists Bulletin · January 1, 2002 Dung beetles of the genus Onthophagus Latreille are used as model systems in behavioral ecology, evolutionary biology, and insect development. In the past, studies on the developmental control of larval and adult form, and studies that seek to integrate de ... Full text Cite

Insect polyphenisms and adaptation.

Journal article AMERICAN ZOOLOGIST · December 1, 2001 Link to item Cite

The role of low levels of juvenile hormone esterase in the metamorphosis of Manduca sexta

Journal article Journal of Insect Science · October 16, 2001 The activity of juvenile hormone esterase (JHE) in feeding fifth instar larvae of Manduca sexta increases gradually with larval weight and rises to a peak after larvae pass the critical weight when juvenile hormone secretion ceases. Starvation of larvae of ... Full text Cite

Elements of butterfly wing patterns.

Journal article The Journal of experimental zoology · October 2001 The color patterns on the wings of butterflies are unique among animal color patterns in that the elements that make up the overall pattern are individuated. Unlike the spots and stripes of vertebrate color patterns, the elements of butterfly wing patterns ... Full text Cite

Nonlinear developmental processes as sources of dominance.

Journal article Genetics · September 2001 Phenotypes are the products of developmental processes whose dynamics are controlled by genes. In many developmental processes there is a nonlinear relationship between genetic variation and phenotypic variation. These nonlinear relationships can result in ... Full text Cite

Hormonal control of male horn length dimorphism in Onthophagus taurus (Coleoptera: Scarabaeidae): a second critical period of sensitivity to juvenile hormone.

Journal article Journal of insect physiology · September 2001 Male dung beetles (Onthophagus taurus) facultatively produce a pair of horns that extend from the base of the head: males larger than a threshold body size develop long horns, whereas males that do not achieve this size develop only rudimentary horns or no ... Full text Cite

The developmental and physiological basis of body size evolution in an insect.

Journal article Proceedings. Biological sciences · August 2001 The evolution of body size is a dominant feature of animal evolution. However, little is known about how the underlying developmental mechanisms that determine size change as body size evolves. Here we report on a case of body size evolution in the tobacco ... Full text Cite

Food availability controls the onset of metamorphosis in the dung beetle Onthophagus taurus (Coleoptera: Scarabaeidae)

Journal article Physiological Entomology · July 11, 2001 In nature, larvae of the dung beetle Onthophagus taurus (Schreber 1759) are confronted with significant variation in the availability of food without the option of locating new resources. Here we explore how variation in feeding conditions during the final ... Full text Cite

The role of low levels of juvenile hormone esterase in the metamorphosis of Manduca sexta.

Journal article Journal of insect science (Online) · January 2001 The activity of juvenile hormone esterase (JHE) in feeding fifth instar larvae of Manduca sexta increases gradually with larval weight and rises to a peak after larvae pass the critical weight when juvenile hormone secretion ceases. Starvation of larvae of ... Full text Cite

The development and evolution of exaggerated morphologies in insects.

Journal article Annual review of entomology · January 2000 We discuss a framework for studying the evolution of morphology in insects, based on the concepts of "phenotypic plasticity" and "reaction norms." We illustrate this approach with the evolution of some of the most extreme morphologies in insects: exaggerat ... Full text Cite

When developmental pathways diverge.

Journal article Proceedings of the National Academy of Sciences of the United States of America · May 1999 Full text Cite

Ultrabithorax function in butterfly wings and the evolution of insect wing patterns.

Journal article Current biology : CB · February 1999 Background. The morphological and functional evolution of appendages has played a critical role in animal evolution, but the developmental genetic mechanisms underlying appendage diversity are not understood. Given that homologous appendage develo ... Full text Cite

Genetics of fluctuating asymmetry: A developmental model of developmental instability

Journal article Evolution · 1999 Although numerous studies have found that fluctuating asymmetry (FA) can have a heritable component, the genetic and developmental basis of FA is poorly understood. We used a developmental model of a trait, according to a diffusion-threshold process, whose ... Cite

Hormonal control of male horn length dimorphism in the dung beetle Onthophagus taurus (Coleoptera: Scarabaeidae).

Journal article Journal of insect physiology · January 1999 Male dung beetles (Onthophagus taurus) facultatively produce a pair of horns that extend from the base of the head: males growing larger than a threshold body size develop long horns, whereas males that do not achieve this size grow only rudimentary horns ... Full text Cite

Population genetics and microevolution developmental mechanisms.

Journal article AMERICAN ZOOLOGIST · January 1, 1999 Link to item Cite

Competition among growing organs and developmental control of morphological asymmetry

Journal article Proceedings of the Royal Society B Biological Sciences · June 22, 1998 Fluctuating asymmetry is often used as a measure of developmental instability, although its developmental basis is poorly understood. Theoretical models and experimental studies have suggested that feedback interactions between structures on the left and r ... Full text Cite

Homeosis in a butterfly wing

Journal article DEVELOPMENTAL BIOLOGY · June 1, 1998 Link to item Cite

Control of pupal commitment in the imaginal disks of Precis coenia (Lepidoptera: Nymphalidae).

Journal article Journal of insect physiology · March 1998 When final (5th) instar larvae of Precis coenia were treated with the juvenile hormone analog (JHA) methoprene, they underwent a supernumerary larval molt, except for certain regions of their imaginal disks, which deposited a normal pupal cuticle. Evidentl ... Full text Cite

Competition among body parts in the development and evolution of insect morphology.

Journal article Proceedings of the National Academy of Sciences of the United States of America · March 1998 Changes in form during ontogeny and evolution depend in large measure on changes in the relative growth of the various parts of the body. The current consensus in developmental biology is that the final size of appendages and internal organs is regulated a ... Full text Cite

Erratum: "Growth Models of Complex Allometries in Holometabolous Insects"

Journal article The American Naturalist · March 1, 1997 Full text Cite

Ommochrome Pigmentation of the linea and rosa Seasonal Forms of Precis coenia (Lepidoptera: Nymphalidae)

Journal article Archives of Insect Biochemistry and Physiology · January 1, 1997 Precis coenia exhibits a seasonal color polyphenism. Animals reared under long-day conditions develop a pale tan pigmentation on their ventral hind wing (the linea form), whereas animals reared under short-day conditions develop a dark reddish-brown pigmen ... Full text Cite

Developmental models and polygenic characters

Journal article American Naturalist · January 1, 1997 Full text Cite

Growth models of complex allometries in holometabolous insects

Journal article American Naturalist · November 14, 1996 Allometries among body parts of adult holometabolous insects differ from allometries among body parts of many other animals because adult structures (many of which are derived from imaginal disks) do not grow synchronously with the body. Imaginal structure ... Full text Cite

Focus on butterfly eyespot development.

Journal article Nature · November 1996 The beautiful eyespot patterns on the wings of butterflies help them to evade predators, but they also present biologists with a unique opportunity to investigate the reciprocal interactions of development and evolution. ... Full text Cite

Genetic control of a seasonal morph in Precis coenia (Lepidoptera: Nymphalidae)

Journal article Journal of Insect Physiology · January 1, 1995 The seasonal color polyphenism of the buckeye butterfly, Precis coenia, is controlled by environmental and genetic factors. Environmental stimuli, such as photoperiod and tempertaure, alter the pattern of ecdysteroid secretion. If ecdysteroids are present ... Full text Cite

Pattern induction across a homeotic boundary in the wings of Precis coenia (Hbn.) (Lepidoptera: Nymphalidae)

Journal article International Journal of Insect Morphology and Embryology · January 1, 1995 We report on a series of homeotic transformations in the buckeye butterfly, Precis coenia (Lepidoptera: Nymphalidae), in which portions of the ventral hind wing were transformed and acquired the pigmentation, color pattern, and scale structure of homologou ... Full text Cite

Hormonal control of a seasonal polyphenism in Precis coenia (Lepidoptera: Nymphalidae)

Journal article Journal of Insect Physiology · January 1, 1995 Adults of the buckeye butterfly, Precis coenia, exhibit a seasonal color polyphenism. During the late spring and summer, under high temperatures and long photoperiods, the ventral surface of the hind wing and that of the exposed portion of the fore wing ar ... Full text Cite

Genes on the wing.

Journal article Science (New York, N.Y.) · July 1994 Full text Cite

Symmetry systems and compartments in Lepidopteran wings: The evolution of a patterning mechanism

Journal article Development · January 1, 1994 The wing patterns of butterflies are made up of an array of discrete pattern elements. Wing patterns evolve through changes in the size, shape and color of these pattern elements. The pattern elements are arranged in several parallel symmetry systems that ... Cite

PHENOTYPIC CORRELATION STRUCTURE AMONG ELEMENTS OF THE COLOR PATTERN IN PRECIS COENIA (LEPIDOPTERA: NYMPHALIDAE).

Journal article Evolution; international journal of organic evolution · April 1993 The component parts of butterfly wing patterns are arranged in sets of serially homologous pattern elements, repeated from wing cell to wing cell. Measurements were made on the sizes and positions of these elements on two successive, independent, sets of s ... Full text Cite

ITERATION AND SYMMETRY

Journal article SOUTH ATLANTIC QUARTERLY · 1991 Link to item Cite

Metaphors and the role of genes in development.

Journal article BioEssays : news and reviews in molecular, cellular and developmental biology · September 1990 In describing the flawless regularity of developmental processes and the correlation between changes at certain genetic loci and changes in morphology, biologists frequently employ two metaphors: that genes 'control' development, and that genomes embody 'p ... Full text Cite

Color pattern specific proteins in black scales in developing wings ofPrecis coenia Hübner (Nymphalidae, Lepidoptera).

Journal article Roux's archives of developmental biology : the official organ of the EDBO · May 1990 A set of stage specific proteins of approximally 86 to 90 kDal are synthesized by isolated wings ofPrecis coenia on day 5 of the pupal stage. They are named "B proteins". They are synthesized in presumptive black wing areas in higher amounts than in presum ... Full text Cite

An analysis of the phenotypic effects of certain colour pattern genes in Heliconius (Lepidoptera: Nymphalidae)

Journal article Biological Journal of the Linnean Society · January 1, 1990 The colour patterns of Heliconius butterflies are built up from an array of serially homologous pattern elements known as the nymphalid groundplan. An analysis of the phenotypic effects of ten genetic loci from H. melpomene and H. cydno reveals that each a ... Full text Cite

A comprehensive model for colour pattern formation in butterflies

Journal article Proceedings of the Royal Society B Biological Sciences · January 1, 1990 This paper presents an attempt to construct a single model that can account for pattern formation in a very broad diversity of Lepidoptera. A pattern database is developed for 330 genera and 2208 species in the family Nymphalidae. It is argued that because ... Full text Cite

Juvenile hormone controls the onset of pupal commitment in the imaginal disks and epidermis of Precis coenia (Lepidoptera: Nymphalidae)

Journal article Journal of Insect Physiology · January 1, 1989 The commitment of tissues to pupal development occurs early during the last larval instar of many holometabolous insects, usually at least several days before pupal differentiation begins in response to the moulting hormone, 20-hydroxyecdysone. Pupal commi ... Full text Cite

In formation

Journal article Nature · August 1988 Full text Cite

Homologies in the colour patterns of the genus Heliconius (Lepidoptera: Nymphalidae)

Journal article Biological Journal of the Linnean Society · January 1, 1988 The colour patterns of Heliconius butterflies are composed from a relatively simple set of pattern elements whose homologues are recognizable throughout the genus. Although Heliconius colour patterns look quite different from those of most nymphalids, thes ... Full text Cite

Colour pattern regulation after surgery on the wing disks of Precis coenia (Lepidoptera: Nymphalidae)

Journal article Development · January 1, 1988 Partial ablations were done in situ on the imaginal disks of the hindwing in larvae of Precis coenia at ages between 2 and 9 days prior to pupation. While there was no regeneration of the wing lamina, the cut edge developed normal marginal scales and a mar ... Cite

Pattern and Pattern Diversity on Lepidopteran Wings

Journal article BioScience · September 1986 Full text Cite

Homologies in the colour patterns of the genus Charaxes (Lepidoptera: Nymphalidae)

Journal article Biological Journal of the Linnean Society · January 1, 1986 The phylogenetically and morphologically diverse patterns of Charaxes can be reduced to a simple set of pattern elements which can be homologized throughout the genus. At least five types of correspondence (homologies) exist among pattern elements: those b ... Full text Cite

Ontogeny, phylogeny and evolution of form: An algorithmic approach

Journal article Systematic Zoology · January 1, 1986 A computer model that simulates general aspects of ontogeny is presented as a heuristic device for studying the relationship between ontogenetic changes and the evolution of morphologies. The model consists of a set of developmental rules limited to known ... Full text Cite

Cautery-induced colour patterns in Precis coenia (Lepidoptera: Nymphalidae).

Journal article Journal of embryology and experimental morphology · April 1985 Cautery of the dorsal hindwing in the butterfly, Precis coenia, induces the formation of a concentric colour pattern around the site of injury. The induced pattern is identical in pigmentation to the eyespots that normally develop on this wing surface. Thi ... Full text Cite

Independent development of homologous pattern elements in the wing patterns of butterflies.

Journal article Developmental biology · March 1985 Rank correlation analyses demonstrate that the degree of color pattern development in each wing cell of Cercyonis pegala (Satyridae) and Smyrna blomfildia (Nymphalidae) is either weakly or not at all correlated with that in other wing cells. There is much ... Full text Cite

The Developmental Physiology of Color Patterns in Lepidoptera

Journal article Advances in Insect Physiology · January 1, 1985 The Lepidoptera are a fairly recent and monophyletic taxon and, next to the Coleoptera, perhaps the largest such taxon among living things. The attractive feature of lepidopteran color patterns is that they develop in a tissue that is essentially a two-dim ... Full text Cite

Colour pattern modification by coldshock in Lepidoptera.

Journal article Journal of embryology and experimental morphology · June 1984 When young pupae of Vanessa cardui, V. virginiensis and Precis coenia (Lepidoptera: Nymphalidae) are exposed to severe coldshock many develop aberrant adult wing patterns. For each species, a synchronous cohort of experimental animals always develops a bro ... Full text Cite

Abdominal stretch reception in Dipetalogaster maximus (Hemiptera: Reduviidae)

Journal article Journal of Insect Physiology · January 1, 1984 Each half abdominal segment in 5th-instar larvae of the giant bloodsucking reduviid, Dipetalogaster maximus, contains 3 stretch receptor neurones, one associated with the tergosternal muscles, one with the ventral intersegmental muscles and one with the do ... Full text Cite

Soldier determination in Pheidole bicarinata: Inhibition by adult soldiers

Journal article Journal of Insect Physiology · January 1, 1984 In the ant Pheidole bicarinata, adult soldiers suppress the induction of soldier developments in larvae that have been treated with methoprene, as well as in acetone-treated controls. Induction of soldier development is inhibited in methoprene-treated larv ... Full text Cite

Definition of a juvenile hormone-sensitive period in Rhodnius prolixus

Journal article Journal of Insect Physiology · January 1, 1983 This paper is an attempt to establish the times of onset and termination of the juvenile hormone-sensitive period for metamorphosis in fifth-instar larvae of Rhodnius. Small regions of the abdominal integument were exposed to discrete pulses of the juvenil ... Full text Cite

In vitro stimulation of cell death in the moulting glands of Oncopeltus fasciatus by 20-hydroxyecdysone

Journal article Journal of Insect Physiology · January 1, 1983 The moulting glands of the milkweed bug, Oncopeltus fasciatus, normally degenerate just before the time of ecdysis to an adult (day 7 of the fifth instar). Morphologically normal cell death can be prematurely stimulated in vitro by 20-hydroxyecdysone. Brea ... Full text Cite

Soldier determination in Pheidole bicarinata: Effect of methoprene on caste and size within castes

Journal article Journal of Insect Physiology · January 1, 1983 Topical application of methoprene to final-instar larvae of the ant Pheidole bicarinata can induce soldier development. Soldier induction takes place if methoprene levels are above a soldier-determining threshold during a critical period of juvenile hormon ... Full text Cite

Juvenile hormone and the physiological basis of insect polymorphisms.

Journal article Quarterly Review of Biology · January 1, 1982 Juvenile hormone is involved in the control of gene switching and exerts this control only during certain critical periods. As a rule one or more critical periods exist during each pre-reproductive instar. The presence or absence of JH during any given cri ... Full text Cite

Ultrastructural changes accompanying secretion and cell death in the molting glands of an insect (Oncopeltus).

Journal article Tissue & cell · January 1982 During the fifth (last) larval instar of Oncopeltus fasciatus, morphological changes in the molting glands associated with ecdysone secretion include a increase in cytoplasmic volume relative to that of the nucleus, increased amounts of rough endoplasmic r ... Full text Cite

Synchrony of juvenile hormone-sensitive periods for internal and external development in last-instar larvae of Oncopeltus fasciatus

Journal article Journal of Insect Physiology · January 1, 1982 Breakdown of the moulting glands in Oncopeltus can be completely inhibited by topical application of a juvenile hormone analogue prior to day 2 of the fifth instar, and partially inhibited by application prior to day 4. The analogue-sensitive period for th ... Full text Cite

Physiological control of molting in insects

Journal article Integrative and Comparative Biology · December 1, 1981 SYNOPSIS. The initiation of a molting cycle in insects is neither a random nor a strictly periodic event. Insofar as molting can accomplish different things under different circumstances, such as a change in size or a change in form, it is reasonable to as ... Full text Cite

Soldier determination in ants: new role for juvenile hormone.

Journal article Science (New York, N.Y.) · July 1981 Topical application of juvenile hormone analog induces soldier development in the ant Pheidole bicarinata. Soldier induction takes place if the juvenile hormone analog is present during a period of sensitivity that occurs during the last larval instar. Con ... Full text Cite

Effects of a juvenile hormone analogue on the duration of the fifth instar in the milkweed bug Oncopeltus fasciatus

Journal article Journal of Insect Physiology · January 1, 1981 Topical application of JHA to fifth instar nymphs of Oncopeltus fasciatus, immediately following ecdysis from the fourth instar, decreases the duration of the fifth instar by approximately 36 hr in addition to inducing a supernumerary larval moult. JHA app ... Full text Cite

The color patterns of butterflies and moths

Journal article Scientific American · January 1, 1981 Full text Cite

Imaginal wing discs in larvae of the soldier caste of Pheidole bicarinata vinelandica Forel (Hymenoptera : Formicidae)

Journal article International Journal of Insect Morphology and Embryology · January 1, 1981 In Pheidole bicarinata vinelandica, soldier larvae have prominent mesothoracic wing discs. Imaginal wing discs are suppressed in minor worker larvae. In soldiers, wing discs appear abruptly late in larvae life and are unusually large when compared with win ... Full text Cite

Pattern formation on lepidopteran wings: determination of an eyespot.

Journal article Developmental biology · December 1980 Full text Cite

PHYSIOLOGICAL CONTROL OF PROTHORACICOTROPIC HORMONE-SECRETION

Journal article AMERICAN ZOOLOGIST · January 1, 1980 Link to item Cite

Antennal hair erection in male mosquitoes: a new mechanical effector in insects.

Journal article Science (New York, N.Y.) · November 1979 Male Anopheles mosquitoes erect their antennal hairs prior to mating. The erectile mechanism resides in a unique annulus at the base of each hair whorl. It appears that the insect regulates the degree of hydration of this annulus. When the annulus is made ... Full text Cite

Stretch-induced moulting in Oncopeltus fasciatus

Journal article Journal of Insect Physiology · January 1, 1979 Fifth instar nymphs of Oncopeltus fasciatus initiate a moulting cycle when they reach a critical weight of 27.9±1.1 (±S.D.) mg for females or 23.7±1.2 mg for males. This critical weight is not absolute. Its precise value depends on the somatic size of the ... Full text Cite

Alpha-adrenergic activity of isoproterenol in mosquito antennae

Journal article Experientia · June 1, 1978 Hair erection in isolated antennae of Anopheles stephensi males is induced by alpha-adrenergic agonists and blocked by alpha-adrenergic blocking drugs. Hair erection is also induced by a single beta-adrenergic agonist, isoproterenol. The activity of isopro ... Full text Cite

Diuresis after a bloodmeal in female Anopheles freeborni

Journal article Journal of Insect Physiology · January 1, 1978 Female Anopheles freeborni discharge urine rapidly and copiously for a brief time after taking a meal of blood. This diuresis begins immediately upon cessation of feeding and continues for about 30 min at a constant rate. A decline in this rate follows and ... Full text Cite

Wing pattern formation in Lepidoptera: A model

Journal article Journal of Experimental Zoology · January 1, 1978 A formal model is presented that demonstrates how the color patterns of the wings of butterflies and moths can be analysed in terms of current concepts of pattern formation. A review of pertinent literature on this little‐known developmental system is prov ... Full text Cite

CONTROL OF ANTENNAL HAIR ERECTION IN MALE MOSQUITOES

Journal article The Biological Bulletin · December 1977 Full text Cite

The rôle of ecdysone in pupation of Manduca sexta

Journal article Journal of Insect Physiology · 1976 Slow infusions of β-ecdysone are more effective in eliciting a normal physiological response than are discrete injections of the hormone. Infusion of β-ecdysone into final instar larvae in the presence of juvenile hormone (JH) induces apolysis and the depo ... Cite

The rôle of ecdysone in pupation of Manduca sexta

Journal article Journal of Insect Physiology · January 1, 1976 Slow infusions of β-ecdysone are more effective in eliciting a normal physiological response than are discrete injections of the hormone. Infusion of β-ecdysone into final instar larvae in the presence of juvenile hormone (JH) induces apolysis and the depo ... Full text Cite

Excretory role of the midgut in larvae of the tobacco hornworm, Manduca sexta (L.).

Journal article The Journal of experimental biology · February 1975 Caterpillars of Manduca sexta use two distinct transport mechanisms for the excretion of dyes. One pump (Type A) has a high affinity for acid (anionic) dyes and occurs in the midgut and medial Malpighian tubules. Acid dyes accumulate rapidly in the lumen o ... Full text Cite

Axonal pathways in the brain-retrocerebral neuroendocrine complex of Manduca sexta (L.) (Lepidoptera: Sphingidae)

Journal article International Journal of Insect Morphology and Embryology · January 1, 1975 Axonal pathways of the various neurosecretory cell groups in the brain of larvae and pupae of Manduca sexta were studied, using a cobalt diffusion and precipitation technique. Five groups of cells were found to send axons to each retrocerebral complex. Axo ... Full text Cite

Permanent loss of male fecundity following sperm depletion in Aedes aegypti (L.).

Journal article Journal of medical entomology · January 1975 Full text Cite

REPRODUCTIVE ISOLATION IN STEGOMYIA MOSQUITOES. III EVIDENCE FOR A SEXUAL PHEROMONE

Journal article Entomologia Experimentalis Et Applicata · January 1, 1971 Males of several species of the subgenus Stegomyia of Aedes copulate preferentially with conspecific females. Recognition of females is independent of flight sound or ultrasonic frequencies but seems to be effected by contact chemoreception. The tarsi of t ... Full text Cite

Homeostasis Despite Instability

Journal article Mathematical Biosciences Open Access Cite