BioOne.org will be down briefly for maintenance on 17 December 2024 between 18:00-22:00 Pacific Time US. We apologize for any inconvenience.
How to translate text using browser tools
1 October 2003 THE CONTRIBUTION OF AN HOURGLASS TIMER TO THE EVOLUTION OF PHOTOPERIODIC RESPONSE IN THE PITCHER-PLANT MOSQUITO, WYEOMYIA SMITHII
W. E. Bradshaw, M. C. Quebodeaux, C. M. Holzapfel
Author Affiliations +
Abstract

Photoperiodism, the ability to assess the length of day or night, enables a diverse array of plants, birds, mammals, and arthropods to organize their development and reproduction in concert with the changing seasons in temperate climatic zones. For more than 60 years, the mechanism controlling photoperiodic response has been debated. Photoperiodism may be a simple interval timer, that is, an hourglasslike mechanism that literally measures the length of day or night or, alternatively, may be an overt expression of an underlying circadian oscillator. Herein, we test experimentally whether the rhythmic response in Wyeomyia smithii indicates a causal, necessary relationship between circadian rhythmicity and the evolutionary modification of photoperiodic response over the climatic gradient of North America, or may be explained by a simple interval timer. We show that a day-interval timer is sufficient to predict the photoperiodic response of W. smithii over this broad geographic range and conclude that rhythmic responses observed in classical circadian-based experiments alone cannot be used to infer a causal role for circadian rhythmicity in the evolution of photoperiodic time measurement. More importantly, we argue that the pursuit of circadian rhythmicity as the central mechanism that measures the duration of night or day has distracted researchers from consideration of the interval-timing processes that may actually be the target of natural selection linking internal photoperiodic time measurement to the external seasonal environment.

W. E. Bradshaw, M. C. Quebodeaux, and C. M. Holzapfel "THE CONTRIBUTION OF AN HOURGLASS TIMER TO THE EVOLUTION OF PHOTOPERIODIC RESPONSE IN THE PITCHER-PLANT MOSQUITO, WYEOMYIA SMITHII," Evolution 57(10), 2342-2349, (1 October 2003). https://doi.org/10.1554/03-124
Received: 22 February 2003; Accepted: 1 May 2003; Published: 1 October 2003
JOURNAL ARTICLE
8 PAGES

This article is only available to subscribers.
It is not available for individual sale.
+ SAVE TO MY LIBRARY

KEYWORDS
Biological clocks
circadian rhythms
evolutionary physiology
geographical variation
photoperiodism
Seasonality
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top