McCurdy D G, Boates J S, Forbes M R
Department of Biology, Carleton University, Ottawa, Ontario, Canada.
J Parasitol. 2001 Feb;87(1):24-30. doi: 10.1645/0022-3395(2001)087[0024:AEMOTO]2.0.CO;2.
Life-history theory predicts that hosts should reproduce when first infected by parasites if hosts are capable and if parasites have a lower cost on current than on future reproduction of hosts. We constructed an empirical model to explore fitness of females of the intertidal amphipod Corophium volutator that reproduced soon versus long after infection by the trematode Gynaecotyla adunca. For uninfected females, the optimal time to reproduce was at their maximum body length. However, for females infected by low or high intensities of trematode metacercariae, reproductive potential (realized fecundity) was highest for females that mated immediately after becoming infected. Even after removing a high cost of delaying reproduction for infected amphipods (high likelihood of depredation by sandpipers, which are final hosts of G. adunca), realized fecundity remained highest if reproduction occurred immediately following infection by trematodes. Results from our model support the view that early reproduction of female amphipods following infection by G. adunca is an adaptive life-history response to parasitism.
生活史理论预测，如果宿主有能力，并且寄生虫对宿主当前繁殖的成本低于对未来繁殖的成本，那么宿主在首次感染寄生虫时就应该进行繁殖。我们构建了一个实证模型，以探究潮间带双壳贝类卷钩虾（Corophium volutator）的雌性个体在感染吸虫（Gynaecotyla adunca）后不久繁殖与长时间后繁殖的适合度。对于未感染的雌性个体，最佳繁殖时间是在其体长达到最大值时。然而，对于感染了低强度或高强度吸虫尾蚴的雌性个体，在感染后立即交配的雌性个体的繁殖潜力（实际繁殖力）最高。即使消除了感染的双壳贝类延迟繁殖的高成本（被矶鹬捕食的高可能性，矶鹬是G. adunca的终末宿主），如果在感染吸虫后立即繁殖，实际繁殖力仍然最高。我们模型的结果支持这样一种观点，即雌性双壳贝类在感染G. adunca后早期繁殖是对寄生现象的一种适应性生活史反应。
