Abstract
Socio-sexual environment can have critical impacts on reproduction and survival of animals.Consequently,they need to prepare themselves by allocating more resources to competitive traits that give them advantages in the particular social setting they have been perceiving.Evidence shows that a male usually raises his investment in sperm after he detects the current or future in-crease of sperm competition because relative sperm numbers can determine his paternity share.This leads to the wide use of testis size as an index of the sperm competition level,yet testis size does not always reflect sperm production.To date,it is not clear whether male animals fine-tune their resource allocation to sperm production and other traits as a response to social cues during their growth and development.Using a polygamous insect Ephestia kuehniella,we tested whether and how larval social environment affected sperm production,testis size,and body weight.We exposed the male larvae to different juvenile socio-sexual cues and measured these traits.We demonstrate that regardless of sex ratio,group-reared males produced more eupyrenes(fertile and nucleate sperm)but smaller testes than singly reared ones,and that body weight and apyrene(infertile and anucleate sperm)numbers remained the same across treatments.We conclude that the presence of larval social,but not sexual cues is responsible for the increase of eupyrene pro-duction and decrease of testis size.We suggest that male larvae increase investment in fertile sperm cells and reduce investment in other testicular tissues in the presence of conspecific juvenile cues.
基金项目
a China Scholarship Council-Massey University PhD Scholars Programme(CSC 201806660018)
a Guangxi University Foundation Strengthening Program Postgraduate Overseas Research Project()
a Guangxi Scholarship Fund of Guangxi Education Department()
Massey University Research Funds()
维普
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