Extrinsic light:dark cycles, rather than endogenous circadian cycles, affect the photoperiodic counter in the pitcher-plant mosquito, Wyeomyia smithii

  • Kevin J. Emerson
  • Alathea D. Letaw
  • William E. Bradshaw
  • Christina M. Holzapfel
Original Paper

DOI: 10.1007/s00359-008-0334-2

Cite this article as:
Emerson, K.J., Letaw, A.D., Bradshaw, W.E. et al. J Comp Physiol A (2008) 194: 611. doi:10.1007/s00359-008-0334-2

Abstract

A wide diversity of organisms use photoperiod (daylength) as an environmental cue to anticipate the changing seasons and to time various life-history events such as dormancy and migration. Photoperiodic time measurement consists of two main components, (1) the photoperiodic timer that discriminates between long and short days, and (2) the photoperiodic counter that accumulates and stores information from the timer and then induces the phenotypic output. Herein, we use extended night treatments to show that light is necessary to accumulate photoperiodic information across the geographic range of the mosquito, Wyeomyia smithii and that the photoperiodic counter counts extrinsic (external) light:dark cycles and not endogenous (internal) circadian cycles.

Keywords

EvolutionDiapauseCircadian rhythmPhotoperiodismGeographic variation

Abbreviations

LDC50

Number of light:dark cycles necessary to elicit 50% development

L:D

Light:dark

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Kevin J. Emerson
    • 1
  • Alathea D. Letaw
    • 1
  • William E. Bradshaw
    • 1
  • Christina M. Holzapfel
    • 1
  1. 1.Center for Ecology and Evolutionary Biology5289 University of OregonEugeneUSA