Photoresponses of Chaoborus larvae


Journal Article

The diel vertical migration of Chaoborus larvae is a well known phenomenon. In order to quantify the ability of larvae to utilize underwater light cues in their migration, we measured photoresponses of fourth-instar Chaoborus punctipennis larvae in the laboratory. The action spectrum for these larvae was characterized by a maximum in sensitivity at 400 nm, a plateau at a lower sensitivity from 480 to 560 nm, and a region of much lower sensitivity at wavelengths longer than 620 nm. Dark-adapted larvae exhibited a positive phototaxis at low light intensity which shifted to a negative phototaxix as light intensity increased. At 540 nm the threshold intensity was 1.5 × 10-9 W/m2 for positive phototaxis and about 10-6 W/m2 for negative phototaxis. Light adaptation decreased sensitivity and altered the phototactic pattern. Larvae have a clear circadian rhythm in negative phototaxis, in which greatest responsiveness occurs early in the day. We suggest that the rhythm in photoresponsiveness primarily controls the timing of the downward migration at dawn. © 1980.

Full Text

Duke Authors

Cited Authors

  • Swift, MC; Forward, RB

Published Date

  • January 1, 1980

Published In

Volume / Issue

  • 26 / 6

Start / End Page

  • 365 - 371

International Standard Serial Number (ISSN)

  • 0022-1910

Digital Object Identifier (DOI)

  • 10.1016/0022-1910(80)90006-2

Citation Source

  • Scopus