Utilization of a Photosystem by Drosophila melanogaster Larvae (Diptera: Drosophilidae)

Foraging-stage third-instar larvae from most wild-type (normal) Drosophila melanogaster stocks are generally repelled by light. To identify factors that affect the larval photoresponse, we elucidated the effects of age, temperature, and time on the photoresponse of larvae from a wild-type Canton-S stock. In addition, we analyzed the larvae from the LI2 isofemale line, which are unresponsive to light in a photoassay. To determine whether LI2 larvae behave abnormally on other behavioral paradigms, in comparison to Canton-S controls, we tested larvae in taste and olfactory assays and observed them to determine whether they dispersed in a food source. Like Canton-S larvae, LI2 larvae and other isofemale lines whose progenitors were collected from the same natural population are responsive to taste and olfactory stimuli. Moreover, LI2 larvae disperse in the food source, as do Canton-S larvae tested in the dark. Larvae expressing para^sbl mutations, which respond normally to light but not to chemical stimuli, do not disperse normally in the food source, suggesting that dispersal may be mediated by perception of chemical cues.