Table_1_Male Age Influences Re-mating Incidence and Sperm Use in Females of the Dengue Vector Aedes aegypti.DOCX

Diseases transmitted by female Aedes aegypti mosquitoes are public health issues in countries in the tropics and sub-tropics. As in other insects, A. aegypti females undergo behavioral and physiological changes upon mating that principally act to facilitate the production of progeny. The primary effectors of A. aegypti female post-mating responses are male-derived seminal proteins that are transferred to females during mating. Increased male age reduces ejaculate function in numerous taxa and alters seminal protein composition in Drosophila melanogaster, but the impacts of male age on female A. aegypti post-mating responses are unknown. Here, we used “old” (21–22 days old) and “young” (4–5 days old) A. aegypti males to assess the influence of male age on oviposition, fertility, and re-mating incidence in their mates. We also examined how age influenced paternity share in females initially mated to young or old males that subsequently re-mated with a transgenic male that transferred RFP-labeled sperm and whose progeny inherited a larval-expressed GFP marker. We found that increased male age had no effect on female fecundity or fertility but significantly impacted their ability to prevent re-mating in their mates—more than half (54.5%) of the females mated to an old male re-mated, compared to 24% of females initially mated to a young male. Polyandrous A. aegypti females displayed first male precedence regardless of the age of their initial mate. However, young males were better able to compete with rival male sperm, siring significantly more progeny (77%) compared to old males (64%). Young males had significantly more sperm in their seminal vesicles than old males at the time of mating, although males of both age groups transferred similar numbers of sperm to their mates. Our results suggest that male senescence differentially impacts the induction of some post-mating changes in A. aegypti females. As the effect of age may be further exacerbated in the field, age-related declines in male ability to induce sexual refractoriness have implications for A. aegypti population control programs that release adults into the environment.

由雌性埃及伊蚊传播的疾病是热带和亚热带国家公共卫生的棘手问题。与其他昆虫类似，埃及伊蚊雌蚊在交配后会发生行为和生理上的变化，这些变化主要作用于促进后代的产生。埃及伊蚊雌蚊交配后反应的主要效应因子是来自雄蚊的精液蛋白，这些蛋白在交配过程中转移到雌蚊体内。在许多生物群体中，雄蚊年龄的增长会降低射精功能并改变果蝇中的精液蛋白组成，但雄蚊年龄对埃及伊蚊雌蚊交配后反应的影响尚不清楚。在本研究中，我们使用“老龄”（21-22天）和“幼龄”（4-5天）的埃及伊蚊雄蚊来评估雄蚊年龄对配偶产卵、生育能力和再婚发生率的影響。我们还探讨了年龄如何影响最初与年轻或老龄雄蚊交配的雌蚊，这些雌蚊随后与一个转移了标记精子（携带荧光蛋白标记）的转基因雄蚊再婚，其后代继承了幼虫表达绿色荧光蛋白标记。我们发现，雄蚊年龄的增加对雌蚊的繁殖能力和生育能力没有影响，但显著影响了她们防止配偶再婚的能力——与最初与年轻雄蚊交配的雌蚊相比，超过一半（54.5%）的与老龄雄蚊交配的雌蚊再婚，而后者仅为24%。多夫制的埃及伊蚊雌蚊在无论其初始配偶的年龄如何时，都会表现出对第一任配偶的优先选择。然而，年轻雄蚊在与竞争者精子竞争方面更具优势，能够产生显著更多的后代（77%），相比之下，老龄雄蚊的后代比例为64%。在交配时，年轻雄蚊的精囊中含有比老龄雄蚊更多的精子，尽管两组年龄的雄蚊向配偶转移的精子数量相似。我们的结果表明，雄蚊衰老对埃及伊蚊雌蚊某些交配后变化的诱导具有不同的影响。由于年龄的影响在野外可能进一步加剧，因此雄蚊诱导性交耐受能力的相关下降对释放成虫至环境中的埃及伊蚊种群控制计划具有潜在影响。