四紋豆象(Callosobruchus maculatus)之繁殖行為與生活史策略(1/3)
Date Issued
2003
Date
2003
Author(s)
洪淑彬
DOI
912313B002334
Abstract
The aedeagus of the male seed beetle, Callosobruchus maculatus bears
sclerotized spines that damage the female genital tract during copulation. The
female repeatedly kicks the male towards the end of copulation. These
functionally diametric sexual traits were proposed to form the basis of sexual
conflict. There are at least two non-exclusive ways in which genital wounding
could increase the fitness of male C. maculatus. First, increased-oviposition
hypothesis. Second, delayed re-mating hypothesis. This study was designed to test
these two hypotheses. C. maculatus copulation behavior was observed in detail
and divided into three distinct stages, patting, stability, and kicking. Females that
performed a longer kicking duration, may have sustained more genital damage,
did not laid significantly more eggs. This result thus does not support the
increased-oviposition hypothesis. Moreover, when copulation was interrupted (so
that kicking did not occur), interrupted females laid more eggs than did females
that were not interrupted. These results suggest that male-induced genital-tract
damage is costly for females. In addition, we found that females that copulated
completely postponed re-mating for a longer time than did females whose kicking
behavior was interrupted. Therefore, a male increased his fitness by extending the
female re-mating interval, and the eggs that a female laid during that re-mating
interval would be fertilized with his sperm. Higher fertilization success favor
males that cause genital damages in females. Male-male competition therefore
leads to sexual conflict in C. maculatus.
sclerotized spines that damage the female genital tract during copulation. The
female repeatedly kicks the male towards the end of copulation. These
functionally diametric sexual traits were proposed to form the basis of sexual
conflict. There are at least two non-exclusive ways in which genital wounding
could increase the fitness of male C. maculatus. First, increased-oviposition
hypothesis. Second, delayed re-mating hypothesis. This study was designed to test
these two hypotheses. C. maculatus copulation behavior was observed in detail
and divided into three distinct stages, patting, stability, and kicking. Females that
performed a longer kicking duration, may have sustained more genital damage,
did not laid significantly more eggs. This result thus does not support the
increased-oviposition hypothesis. Moreover, when copulation was interrupted (so
that kicking did not occur), interrupted females laid more eggs than did females
that were not interrupted. These results suggest that male-induced genital-tract
damage is costly for females. In addition, we found that females that copulated
completely postponed re-mating for a longer time than did females whose kicking
behavior was interrupted. Therefore, a male increased his fitness by extending the
female re-mating interval, and the eggs that a female laid during that re-mating
interval would be fertilized with his sperm. Higher fertilization success favor
males that cause genital damages in females. Male-male competition therefore
leads to sexual conflict in C. maculatus.
Subjects
genital damage
sexual conflict
copulating behavior
Callosobruchus maculatus
SDGs
Publisher
臺北市:國立臺灣大學昆蟲學系暨研究所
Type
report
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