QEIB: Predicting the Effects of Diffusion-limitation in a Predator-prey System

用于预测物种相互作用的生态学理论通常没有考虑到小尺度空间结构的影响。据推测，像瓢虫这样的捕食者，无论它们是在玉米植株上还是在豌豆植株上，它们的成功与否是差不多的。这个假设不符合我们对世界的常识性经验。由于空间的复杂性，在某些环境中移动比在其他环境中移动更困难，这种流动性的限制应该会影响物种的相互作用，例如捕食者-猎物关系。随着环境变得更加复杂，捕食者和猎物的相遇率应该会降低。因此，以同样的方式，化学反应在复杂的介质中减慢（即，由于分子在复杂空间中的缓慢运动，它们是“扩散限制”的），所以我们预计在复杂形状的植物上捕食成功率会降低。在拟议的研究中，基于这一期望的模型将被开发并使用在农业中很重要的捕食者-猎物系统进行测试。自然发生的豌豆突变体已被广泛用于商业用途，然而，这些豌豆更复杂的形状可能会改变有益昆虫的功效。利用不同叶片复杂程度的豌豆突变体，作者将在实验室和温室条件下研究一种常用的益虫瓢虫对豌豆蚜虫的捕食成功。通过使用这个实验系统，她将同时测试一个新的生态学理论，并评估植物形态对生物防治方案的影响。

Ecological theories used to predict species interactions typically do not take into account the effects of small-scale spatial structure. It is assumed that the success of predators, like ladybugs, is more or less the same whether they are found on corn plants or pea plants. This assumption does not fit our commonsense experience of the world. It is harder to move through some environments than others because of spatial complexity, and this limitation of mobility should affect species interactions such as the predator-prey relationship. As environments become more complex the encounter rate of predators and prey should decrease. Therefore, in the same way that chemical reactions slow down in complex media (i.e., they are "diffusion-limited" because of the slow movement of molecules in complex spaces), so to we expect a reduction in predation success on plants with complex shapes. In the proposed research, models based on this expectation will be developed and tested using a predator-prey system that is important in agriculture. Naturally occurring pea mutants have been widely adopted for commercial use, however the more complex shape of these peas may alter the efficacy of beneficial insects. Using pea mutants with differing degrees of leaf complexity, the author will examine the predation success of the ladybug Harmonia axyridis, a commonly used beneficial insect, on pea aphids in laboratory and greenhouse conditions. By using this experimental system she will simultaneously test a new ecological theory and evaluate of the effects of plant morphology on biological control programs.