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Maternal Effects on Brood Reduction in Common Grackles

Joseph Dylan Maddox

出版	University of Illinois at Urbana-Champaign, 2009
URL	http://books.google.com.hk/books?id=F9KwjwEACAAJ&hl=&source=gbs_api

註釋

This suggests that mothers cannot increase the number of fledglings they produce by preferentially allocating sex. I did not find the predicted patterns of yolk testosterone and estradiol relative to clutch size and laying order that would suggest yolk hormones act as a compensatory mechanism to offset the deleterious effects of asynchronous hatching. Finally, I found a disconnect between the maternal effects that were beneficial to mothers versus their offspring. Within nests offspring that hatched earlier than their siblings were heavier and more likely to fledge, whereas among nests mothers that initiated their clutches early in the breeding season fledged more young than females breeding later in the population. Thus, the one maternal effect that repeatedly had the largest impact on offspring performance had absolutely no effect on the productivity of mothers in the short term. There are two ways to interpret this result.^