Reciprocal specialization in ecological networks.

Theories suggest that food webs might consist of groups of species forming 'blocks', 'compartments' or 'guilds'. We consider ecological networks - subsets of complete food webs - involving species at adjacent trophic levels. Reciprocal specializations occur when (say) a pollinator (or group of pollinators) specializes on a particular flower species (or group of such species) and vice versa. Such specializations tend to group species into guilds. We characterize the level of reciprocal specialization for both antagonistic interactions - particularly parasitoids and their hosts - and mutualistic ones - such as insects and the flowers that they pollinate. We also examine whether trophic patterns might be 'palimpsests'- that is, there might be reciprocal specialization within taxonomically related species within a network, but these might be obscured when these relationships are combined. Reciprocal specializations are rare in all these systems when tested against the most conservative null model.

Duke Scholars

Author Stuart L. Pimm Environmental Sciences and Policy