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Akiko Matsumoto-Oda Miya Hamai Hitosige Hayaki Kazuhiko Hosaka Kevin D. Hunt Eiiti Kasuya Kenji Kawanaka John C. Mitani Hiroyuki Takasaki Yukio Takahata 《Behavioral ecology and sociobiology》2007,61(5):661-668
Although estrous synchrony has been reported in a number of mammalian species, most often among primates, methodological and
analytical problems make it difficult to interpret these results. We developed a novel estrous synchrony index and employed
a randomization procedure to analyze long-term observations of female chimpanzee (Pan troglodytes schweinfurthii) estrous cycles at the Mahale Mountains National Park, Tanzania. Our results revealed that female chimpanzees at Mahale avoid
synchronizing their estrous periods with each other. We also found that birthrates decreased as the breeding sex ratio increased.
We suggest that estrous asynchrony decreases female–female competition for mates. Asynchrony may also reduce the potential
for male sexual coercion by nonpreferred mating partners. 相似文献
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Michael J. L. Magrath Peter Santema Karen M. Bouwman Dušan M. Brinkhuizen Simon C. Griffith Naomi E. Langmore 《Behavioral ecology and sociobiology》2009,63(5):661-672
Reproductive success within populations often varies with the timing of breeding, typically declining over the season. This
variation is usually attributed to seasonal changes in resource availability and/or differences in the quality or experience
of breeders. In colonial species, the timing of breeding may be of particular importance because the costs and benefits of
colonial breeding are likely to vary over the season and also with colony size. In this study, we examine the relationship
between timing of breeding and reproductive performance (clutch size and nest success) both within and between variable sized
colonies (n = 18) of fairy martins, Petrochelidon ariel. In four of these colonies, we also experimentally delayed laying in selected nests to disentangle the effects of laying
date and individual quality/experience on reproductive success. Within colonies, later laying birds produced smaller clutches,
but only in larger colonies. The general seasonal decline in nest success was also more pronounced in larger colonies. Late
laying birds were generally smaller than earlier laying birds, but morphological differences were also related to colony size,
suggesting optimal colony size also varies with phenotype. Experimentally delayed clutches were larger than concurrently produced
non-delayed clutches, but only in larger colonies. Similarly, delayed clutches were more likely to produce fledglings, particularly
later in the season and in larger colonies. We suggest that the reduced performance of late breeding pairs in larger colonies
resulted primarily from inexperienced/low quality birds preferring to settle in larger colonies, possibly exacerbated by an
increase in the costs of coloniality (e.g., resource depletion and ectoparasite infestations) with date and colony size. These
findings highlight the importance of phenotype-related differences in settlement decisions and reproductive performance to
an improved understanding of colonial breeding and variation in colony size. 相似文献
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Yin-Quan Liu Carlos Bernstein Andra Thiel 《Behavioral ecology and sociobiology》2009,63(10):1459-1469
Foraging animals usually keep track of how costly it is to reach new resource patches and adjust patch residence time and
exploitation rate accordingly. There are at least two potential factors, which are not necessarily closely linked, that animals
could measure to estimate costs of traveling: the time the forager needs to reach the next patch and the amount of energy
it has to invest until arrival. In the parasitoid wasp Venturia canescens, females forage for hosts from which their offspring can develop. Two different types of this parasitoid exist. The thelytokous
type lives in anthropogenic habitats where flight is not necessarily linked with foraging. The arrhenotokous type lives under
field conditions and shows frequent flight activity. We tested whether the wasps would use time or energy needed to assess
patch availability, by either confining them into vials or letting them travel actively in a flight mill between patch visits.
Our results show that in thelytokous lines, time is a sufficient cue influencing patch exploitation and an additional effect
of the energy needed was not visible. In the arrhenotokous wasps, however, only the number of rounds flown in the mill influenced
subsequent behavior, while mere time spent traveling did not.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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Remodeling the clock: coactivators and signal transduction in the circadian clockworks 总被引:1,自引:0,他引:1
Frank Weber 《Die Naturwissenschaften》2009,96(3):321-337
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