Edwards Dale D, Smith Heather G
Department of Biology, University of Evansville, Evansville, Indiana 47722, USA.
J Parasitol. 2003 Aug;89(4):681-5. doi: 10.1645/GE-2997.
This study examined whether ecoparasitic larval Unionicola foili exhibited a sex bias when infecting laboratory populations of the host insect Chironomus tentans and whether an association with male or female midges increased the likelihood of larval mites returning to the aquatic habitat. When laboratory populations of C. tentans were exposed to larval U. foili, there was a higher prevalence of mites among female hosts at emergence (17 of 30 males vs. 25 of 30 females infected by mites). However, there was no significant difference in the distribution or abundance of larvae among infected male (mean = 2.3 larvae per host) and female (mean = 2.6 larvae per host) midges. Larval mites parasitizing both male and female chironomids were more likely to return to water than could be expected by chance. Mite larvae infesting female C. tentans were more likely to return to water when female hosts deposited egg masses in water, suggesting that oviposition plays an important role in cueing larvae parasitizing female midges to detach. The mechanism responsible for increasing the likelihood that mites parasitizing male hosts return to water remains unclear. Future studies will address the possibility of parasite-mediated changes in host behavior.
本研究调查了体外寄生幼虫福氏合鼓螨（Unionicola foili）在感染宿主昆虫摇蚊（Chironomus tentans）的实验室种群时是否表现出性别偏向，以及与雄性或雌性摇蚊的关联是否会增加螨幼虫返回水生生境的可能性。当将摇蚊的实验室种群暴露于福氏合鼓螨幼虫时，羽化时雌性宿主中螨的患病率更高（30只雄性中有17只被螨感染，30只雌性中有25只被螨感染）。然而，在被感染的雄性摇蚊（平均每只宿主2.3只幼虫）和雌性摇蚊（平均每只宿主2.6只幼虫）中，幼虫的分布或丰度没有显著差异。寄生在雄性和雌性摇蚊上的螨幼虫比偶然情况下更有可能返回水中。当雌性宿主在水中产卵时，寄生在雌性摇蚊上的螨幼虫更有可能返回水中，这表明产卵在提示寄生在雌性摇蚊上的幼虫脱离方面起着重要作用。寄生在雄性宿主上的螨返回水中可能性增加的机制尚不清楚。未来的研究将探讨寄生虫介导宿主行为变化的可能性。
