Dissertation Research: Habitat Partitioning by Notonectids: Temporal Patterns and the Role of Spatial Complexity

9902177吉尔伯特共存的intraguild捕食者，潜在的竞争对手，也是相互捕食，很少预测的模型，尽管它的普遍发生。一个机制，冲突可能是最小化的空间分区的栖息地。在一个小的浅水池塘中观察到了这样的地带性，池塘里有四种昆虫--贪婪的昆虫捕食者，它们分享资源，很容易互相取食。这种划分可能会减少冲突，但这些模式表现出季节性和昼夜变化的方式，可能会大大危及或加强共存。在本论文的研究中，实地研究将定量地证实这里提出的初步意见。将在实验微观世界中研究导致空间分区和时间变化的机制。季节中期的分布变化的青少年可能是一个响应成年食肉动物的下降，让青少年完成发展中的高资源栖息地。相反，物种分布的昼夜变化通过增加夜间重叠增加了冲突的可能性。白天和夜间饮食的现场收集的notonectids将进行比较，使用电泳肠内容物分析，以确定是否intraguild捕食增加在夜间的预期。此外，昼夜水平迁移提出了一个新的假设：盈利的空间复杂和开放的栖息地是扭转在夜间的捕食者使用视觉和mechanoreception。

9902177GilbertCoexistence of intraguild predators, potential competitors that are also mutually predaceous, is rarely predicted by models despite its commonplace occurrence. One mechanism by which conflict may be minimized is spatial partitioning of habitat. Such zonation has been observed in a small shallow pond with four notonectid species - voracious insect predators which share resources and readily feed on each other. Conflict may be reduced by this partitioning, but these patterns exhibit seasonal and diel shifts in ways that could substantially endanger or enhance coexistence. In this dissertation research, field study will quantitatively confirm the preliminary observations presented here. Mechanisms leading to spatial partitioning and temporal changes will be investigated in experimental microcosms. Mid-season distributional shifts of juveniles may be a response to a decline in adult predators, allowing juveniles to complete development in a high-resource habitat. Conversely, diel shifts in species distribution increase potential for conflict by increasing nocturnal overlap. Diurnal and nocturnal diet of field-collected notonectids will be compared, using electrophoretic gut content analysis, to determine whether intraguild predation increases at night as expected. In addition, a new hypothesis for diel horizontal migration is proposed: profitability of spatially complex and open habitat is reversed at night for predators using both vision and mechanoreception.