Premium
Sperm competition and maternal effects differentially influence testis and sperm size in Callosobruchus maculatus
Author(s) -
GAY L.,
HOSKEN D. J.,
VASUDEV R.,
TREGENZA T.,
EADY P. E.
Publication year - 2009
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.1420-9101.2009.01724.x
Subject(s) - callosobruchus maculatus , sperm , biology , sperm competition , zoology , competition (biology) , population , evolutionary biology , reproductive success , female sperm storage , ecology , andrology , botany , pest analysis , demography , medicine , sociology
The evolutionary factors affecting testis size are well documented, with sperm competition being of major importance. However, the factors affecting sperm length are not well understood; there are no clear theoretical predictions and the empirical evidence is inconsistent. Recently, maternal effects have been implicated in sperm length variation, a finding that may offer insights into its evolution. We investigated potential proximate and microevolutionary factors influencing testis and sperm size in the bruchid beetle Callosobruchus maculatus using a combined approach of an artificial evolution experiment over 90 generations and an environmental effects study. We found that while polyandry seems to select for larger testes, it had no detectable effect on sperm length. Furthermore, population density, a proximate indicator of sperm competition risk, was not significantly associated with sperm length or testis size variation. However, there were strong maternal effects influencing sperm length.