萼花臂尾轮虫对晶囊轮虫反捕食行为及形态响应的母体效应

THE MATERNAL EFFECT OF ANTI-PREDATOR BEHAVIOURAL AND MORPHOLOGICAL RESPONSES TO ASPLANCHNA IN BRACHIONUS CALYCIFLORUS

为研究轮虫通过母体效应诱导能否产生行为响应,以萼花臂尾轮虫(Brachionus calyciflorus)为例,研究其反捕食漂浮行为响应的母体效应。通过控制轮虫母体在捕食者诱导液中的暴露时间及带卵状态,收集母体产生的后代,再将这些后代再次用捕食者诱导液处理,观察后代的漂浮行为及形态特征。研究发现:暴露于捕食者诱导液诱导较长时间的母体产生的后代个体,当再次暴露于捕食者诱导液时,其产生的行为响应强于没有母体暴露经历的后代;母体暴露时间越长,后代形态和行为响应均更加强烈。研究显示萼花臂尾轮虫可通过母体效应产生漂浮行为响应。

Predation is vital in regulating population and community structure in aquatic ecosystems. When predators exist, many organisms can reduce the risk of predation by generating specific anti-predator responses. Therefore, one pivotal goal in ecology is to investigate how prey respond to particular predators, and how prey pass the predator stress on to offspring. In Monogononta, Phylum Rotifera, when coexisting with predators, some rotifers are able to exhibit morphological, behavioural or life-history responses. And rotifer individuals without direct predator experience can exhibit morphological anti-predator defences via maternal effects. But no study has so far investigated if the behavioural anti-predator response could be triggered via maternal effect. Hence, in this study, we used B. calyciflorus as the model organism to investigate whether its floating behavioural response could be triggered through maternal effect. We hypothesized that B. calyciflorus individuals with maternal predator experience could express stronger floating behaviour when exposed to the predator. In the experiments, we independently investigated the effect of exposure time(2h and 18h) and oocyte status(with and without eggs) of B. calyciflorus on the floating behaviour or morphology of their offspring when re-expose the offspring to predator kairomone. Our results suggested that(1) when expose to Asplanchna predator kairomone, the rotifer offspring with maternal long time exposure experience(18h exposure) have higher proportion floating to the water surface than individuals without maternal experience;(2) the intensity of anti-predator morphological and behavioural responses depends on the maternal exposure time when the mother generation exposed to predator kairomone for longer time, the offspring would exhibit both stronger morphological and behavioural responses. Our results provide novel evidence that behavioural anti-predator response could be affected by maternal effect.