title: Circadian clocks and life-history related traits: is pupation height affected by circadian organization in Drosophila melanogaster?
abstract: In D. melanogaster, the observation of greater pupation height under constant darkness than under constant light has been explained by the hypothesis that light has an inhibitory effect on larval wandering behaviour, preventing larvae from crawling higher up the walls of culture vials prior to pupation. If this is the only role of light in affecting pupation height, then various light : dark regimes would be predicted to yield pupation heights intermediate between those seen in constant light and constant darkness. We tested this hypothesis by measuring pupation height under various light : dark regimes in four laboratory populations of Drosophila melanogaster. Pupation height was the greatest in constant darkness, intermediate in constant light, and the least in a light/dark regime of LD 14:14 h. The results clearly suggest that there is more to light regime effects on pupation height than mere behavioural inhibition of wandering larvae, and that circadian organization may play some role in determining pupation height, although the details of this role are not yet clear. We briefly discuss these results in the context of the possible involvement of circadian clocks in life-history evolution.
authors.affiliation: Chronobiology Laboratory, Jawaharlal Nehru Centre for Advanced Scientific Research, P.O. Box 6436, Jakkur, Bangalore 560 064, India.
authors.forename: Dhanashree A
authors.initials: DA
authors.lastname: Paranjpe
authors.forename: D
authors.initials: D
authors.lastname: Anitha
authors.forename: Vijay Kumar
authors.initials: VK
authors.lastname: Sharma
authors.forename: Amitabh
authors.initials: A
authors.lastname: Joshi
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal; D001683:Biological Clocks; D002940:Circadian Rhythm / Q000502:physiology*; D016001:Confidence Intervals; D004331:Drosophila melanogaster / Q000254:growth & development* / Q000502:physiology; D008018:Life Cycle Stages; D011679:Pupa / Q000254:growth & development / Q000502:physiology