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Intra‐specific variation in the morphology and the benefit of large genital sclerites of males in the adzuki bean beetle ( Callosobruchus chinensis )
Author(s) -
SAKURAI G.,
HIMURO C.,
KASUYA E.
Publication year - 2012
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/j.1420-9101.2012.02517.x
Subject(s) - biology , callosobruchus chinensis , variation (astronomy) , morphology (biology) , sex organ , callosobruchus maculatus , zoology , botany , pest analysis , physics , astrophysics
Rapid evolution has led to a large diversity in the sizes and morphology of male genitals across taxa, but the mechanisms driving this evolution remain controversial. In this study, we investigated the function of male genital sclerites in the adzuki bean beetle ( Callosobruchus chinensis ) and compared the length and morphology of genital sclerites between two populations that vary in their degree of polyandry. We found that the length of male genital sclerites was negatively correlated with copulation duration but positively correlated with the speed of matings with multiple females. Additionally, we found that the average length and number of genital sclerite spines of males from the more polyandrous population were larger than those from the less polyandrous population. We suggest that the genital sclerite of male adzuki bean beetles evolved by sexual selection, and a larger genital sclerite has a selective advantage because it allows for rapid copulations with multiple females.