同功群間捕食在生物防治中所扮演之角色

Abstract

生物防治媒介 (biological control agent) 的挑選對害蟲管理的成功與否相當重要。但由於生物防治媒介之間有相互攻擊的可能性，使防治媒介的挑選變得格外困難 (即同生態功能群個體間相互捕食；intraguild predation)。根據實際研究，使用多種生物防治媒介時，與僅使用單一防治媒介相比，害蟲族群量有上升、下降或不變等情形。然而，現有的模型無法解釋為何有效果上的差異。為了讓理論研究能夠與實際研究相符，此篇論文同時使用實作與理論等研究方法。在實作方面，進行了四種常見生物防治媒介 (基徵草蛉、小十三星瓢蟲、赤星瓢蟲、錨紋瓢蟲) 的功能反應 (functional response) 實驗。在理論部份，藉由實驗數據的支持，建立了一同功群間捕食的數學模型。對新模型進行分析後發現，此模型能夠解釋實際研究時效果上的差異。且此數學模型的分析結果，也討論了生物防治媒介上的挑選。

The selection of biological control agents is a crucial decision for the success of pest management practices, which is made difficult by predation among agents (i.e., intraguild predation, IGP). Empirical studies show that the use of multiple agents can have positive, negative, or neutral effects on the control of pest populations (compared to the use of the single most efficient agent). However, current theoretical models are unable to explain the observed variation in biological control outcomes. This study combined theoretical and empirical approaches to bridge the gap between theory and observed patterns. In the empirical part, the functional responses of four common biological agents (Mallada basalis, Harmonia dimidiate, Lemnia saucia and Lemnia biplagiata) were determined. In the theoretical part, a mathematical model of IGP was developed by using the functional response model that was best supported in the experiment. The analysis of the model indicated that the model can explain the variation in biological control outcomes found in empirical studies. Biological control implications of model predictions are discussed with respect to the selection of biological control agents.