Female-biased sex allocation of offspring by an <Emphasis Type="Italic">Apodemus</Emphasis> mouse in an unstable environment |
| |
Authors: | Fumihito Shibata Takeo Kawamichi |
| |
Institution: | (1) Department of Biology, Osaka City University, Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan;(2) Present address: Wakayama Shin’ai Women’s Junior College, Sozaka 702-2, Wakayama 640-0341, Japan |
| |
Abstract: | We investigated the effects of population fluctuation on the offspring’s sex allocation by a weakly polygynous mouse, Apodemus argenteus, for 3 years. In acorn-poor seasons, heavier mothers invested more in sons, and lighter mothers invested more in daughters.
In acorn-rich seasons, heavier mothers invested more in daughters, and lighter mothers invested more in sons. Maternal body
condition and litter size affected the sex allocation. Furthermore, there was a maternal investment trade-off between a son’s
birth mass and the number of daughters. Based upon the effect of population fluctuation on the lifetime reproductive success
of each sex, we proposed the new “safe bet hypothesis”. This hypothesis predicts that frequent and unpredictable change in
female distribution, which is often caused by abrupt fall in food condition, favors female-biased maternal investment to offspring
by polygynous mammals and is applicable to many small mammals inhabiting in unstable environments. |
| |
Keywords: | Apodemus argenteus Trivers and Willard’ s hypothesis Sex allocation Maternal investment trade-off Safe bet hypothesis |
本文献已被 SpringerLink 等数据库收录! |
|