Short-day experience is not a prerequisite for the termination of photorefractoriness in the reproductive cycle of baya weaver, Ploceus philippinus.
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Date
1992-03
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Abstract
In most photoperiodic avian forms (irrespective of temperate or tropical
distribution) including the baya weaver, Ploceus philippinus, seasonal reproduction comes
to an end due to the development of a photoperiodically controlled photorefractory phase
when birds cease to respond to the stimulatory effect of long days. In the present paper
photoperiodic control of the termination of photorefractory phase has been examined by
studying the effect of short-day exposure lasting 4–6 months on long-day response of birds.
Results indicate that unlike in other photoperiodic birds short-day exposure of winter is
not a prerequisite for the termination of photorefractory phase in the reproductive cycle of
baya weaver. Artificial long days on the other hand hasten the termination of this phase.
Refractory phase in baya weaver, therefore, unlike that in temperate forms, is a temporary
state resulting most likely from a sequel of physiological events triggered by long days of
spring/summer which temporarily mask the photostimulatory response. Spontaneous
termination of photorefractoriness in birds of tropical habitats may have a selective value
imparting to the reproductive cycle the necessary elasticity for adaptation to diverse
ecological conditions.
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Keywords
Photorefractoriness, photoperiod, reproductive cycle, tropical baya
Citation
Bisht Mahabir, Chandola-Saklani Asha. Short-day experience is not a prerequisite for the termination of photorefractoriness in the reproductive cycle of baya weaver, Ploceus philippinus. Journal of Biosciences. 1992 Mar; 17(1): 29-34.