How do males inhbit female remating? Case studies from two tephritid fruit flies

ABRAHAM SOLANA; PÉREZ-STAPLES DIANA

Buenos Aires

Simposio; 9th Meeting of Tephritid Workers of the Western Hemisphere; 2016

SENASA

Ideally, sterile males released through the SterileInsect Technique should transfer sterile sperm to wild females and prevent themfrom remating with other wild males. The inhibition of female receptivity aftercopulation is usually related to the quality of the first mating. Males areable to modulate female receptivity through various mechanisms. Among these,there are the act of copulation per seand the transfer of the ejaculate, composed mainly by sperm and accessory glandproteins (AGPs). Here we review which mechanisms are used by males to prevent femaleremating in the South American fruit fly Anastrephafraterculus and the Mexican fruit fly Anastrephaludens.In both species, neither the act of copulation withoutejaculate transfer (studied by using aedeagus-cut males which could mate butnot transfer ejaculates) nor the number of sperm stored (comparing the numberof sperm stored by females who showed or not, willingness to remate) inhibitedfemale receptivity. Copulation duration differs between females that wanted toremate and those that refused to remate in A.fraterculus but not in A. ludens,suggesting that the role of copulation duration may differ between species. Onthe other hand, whereas AGP injections inhibit female receptivity in A. fraterculus, in A. ludens injection of AGPs failed to inhibit receptivity. Evenclosely related species can inhibit remating through different mechanisms.Finally, we want to highlight the importance of femaleintrinsic factors modulating their remating behavior. When different strains ofA. fraterculus were crossed, femaleremating was determined by female strain, irrespective of male origin.Similarly, in A. ludens femaleremating is strongly affected by female age, irrespective of male age. We suggest that female receptivity in both flies isinhibited by the mechanical and/or physiological effect of the full ejaculate. Thesefindings bring us closer to understanding the mechanisms through which femalereceptivity can be modulated.