Weiberg M, Edwards D D
Department of Biology, University of Evansville, Indiana 47722, USA.
J Parasitol. 1997 Feb;83(1):173-5.
Parasitic associations between larval Unionicola foili and the dipteran Chironomus tentans were established in the laboratory, and the effects of these water mite larvae on survival and reproduction of C. tentans were determined. Longevity of parasitized insects was not significantly different from those that were unparasitized. Furthermore, there was no significant difference in the onset of oviposition between parasitized and unparasitized female chironomids. However, infected females oviposited significantly more eggs compared to uninfected controls. This study contradicts others indicating that water mite larvae severely reduce the survivorship and reproductive output of insects. The results are consistent with analyses indicating that degree of parasitism is not correlated with either duration of the parasitic phase or longevity of larvae following their parasitic association with chironomids. Larval U. foili apparently secure sufficient nutritional resources to complete their development, yet their hosts still exhibit fitness components expected for unparasitized individuals. Extreme site specificity exhibited by larval U. foili may limit the degree of parasitism on host insects and in doing so preclude larval mites from achieving infection levels that could negatively impact host survival and reproduction.
在实验室中建立了叶氏合新恙螨幼虫与摇蚊（Chironomus tentans）之间的寄生关系，并确定了这些水螨幼虫对摇蚊生存和繁殖的影响。被寄生昆虫的寿命与未被寄生的昆虫没有显著差异。此外，被寄生和未被寄生的雌性摇蚊产卵开始时间没有显著差异。然而，与未感染的对照组相比，受感染的雌性摇蚊产卵量显著更多。这项研究与其他表明水螨幼虫会严重降低昆虫存活率和繁殖产量的研究结果相矛盾。这些结果与分析结果一致，即寄生程度与寄生阶段的持续时间或幼虫与摇蚊建立寄生关系后的寿命均无关联。叶氏合新恙螨幼虫显然获得了足够的营养资源来完成其发育，但其宿主仍表现出未被寄生个体所预期的适合度特征。叶氏合新恙螨幼虫表现出的极端位点特异性可能会限制对宿主昆虫的寄生程度，从而使螨幼虫无法达到可能对宿主生存和繁殖产生负面影响的感染水平。
