Department of Biology, University of Central Florida, 4000 Central Florida Boulevard, Orlando, FL 32816, USA.
Proc Biol Sci. 2012 Sep 7;279(1742):3577-83. doi: 10.1098/rspb.2012.0654. Epub 2012 Jun 13.
All animals are under the constant threat of pathogenic infection. However, little is known regarding the influence of acute infection on sperm viability, particularly in female insects. This information is crucial for our understanding of mating and immune system coevolution, considering that females store sperm and serve as the site of sperm competition. Using the fruitfly, Drosophila melanogaster, we examined the influence of infection on sperm viability and storage. Twenty-four hours after haemocoel inoculation with a pathogen mimic (peptidoglycan, PGN) both sexes exhibited reduced sperm viability, indicating that systemic immune activation played a significant role in gamete survival. Surprisingly, sperm death did not appear to result from a reproductive-immune system trade-off, considering that sperm survived 24 h in vitro once removed from their somatic resources. Instead, our results are most consistent with death owing to immune effector collateral damage. We also examined the potential for sexually transmitted pathogens to influence sperm storage. Females mated with 'infected' males (created by dipping genitalia into a PGN solution) exhibited a higher proportion of empty sperm stores 48 h after mating compared to their controls. Remarkably, these data indicate that females may increase their fitness by removing 'infected' ejaculates from storage over time.
所有动物都面临着病原感染的持续威胁。然而，对于急性感染对精子活力的影响，特别是在雌性昆虫中，我们知之甚少。考虑到雌性储存精子并作为精子竞争的场所，这些信息对于我们理解交配和免疫系统共同进化至关重要。我们使用果蝇，黑腹果蝇，研究了感染对精子活力和储存的影响。在血腔接种病原体模拟物（肽聚糖，PGN） 24 小时后，雌雄两性的精子活力均降低，表明全身免疫激活对配子存活起重要作用。令人惊讶的是，精子死亡似乎并不是生殖与免疫系统权衡的结果，因为精子一旦脱离体细胞资源，在体外就可以存活 24 小时。相反，我们的结果与免疫效应物的附带损伤导致的死亡最吻合。我们还研究了性传播病原体对精子储存的潜在影响。与对照组相比，与“感染”（通过将生殖器浸入 PGN 溶液中）雄性交配的雌性在交配后 48 小时表现出更高比例的空精子储存。值得注意的是，这些数据表明，随着时间的推移，雌性可能会通过从储存中去除“感染”的精液来增加自身的适应性。
