Spatial Dynamics of an Acarine Predator-pey System: Responses of Amblyseius ovalis (Evans) to Its Egg-laying Behavior and Density and Aggregation of Tetranychus urticae Koch (Acarina: Phytoseiidae: Tetranychidae)

螨類捕食者餌系統之空間動態卵形捕植螨（Amblyseius ovalis (Evans)）對其產卵行為及二點葉螨(Tetranychus urticae Koch) (Acarina: Phytoseiidae: Tetranychidae)密度與聚集之反應

施劍鎣(Chain-Ing T. Shih) ； 王前智(Chain-Ji Wang)

《中華昆蟲》 17卷2期 (1997/06) Pp. v+100-118

https://doi.org/10.6660/TESFE.1997011

摘要

Stage specific spatial distribution pattern of Amblyseius ovalis on carambola fruit orchards was evaluated by the index of dispersion (ID), Green's coefficient of dispersion (Cx), Lloyd's mean crowding index (mc) and patchiness index (mc/m), Taylor's power law (log a and b), and Iwao's patchiness regression (a, b) from 250 sets of sampling-date data during 1990-1995. All stage-specific populations of A. ovalis distributed intensively in random to uniform pattern; however, eggs, females, and overall stages were contagious. The degree of contagiousness of the eggs and the females was the highest among all stage-specific populations according to the results of Taylor's power law analyses of log a and b. Density-independence of contagiousness of A. ovalis was found from their low correlation coefficients between the calculated indices and prey Tetranychus urticae or predator densities, but the eggs exhibited a high relationship to its prey density. From the estimated a and b values, we found the basic component units (patches) of the eggs were formed by single egg, but two or more females aggregated in the patch. The female exhibited single-egg-laying behavior within the contagiously-distributed prey cohort which resulted in the egg-aggregation among the prey patch. However, the egg and larval aggregates were due to the prey-aggregation among the patches. The species character, a high degree of uniform distribution and repulsive mechanism of egg and larva, was interpreted as the results of female egg-laying behavior in the prey cohort.

關鍵字

spatial distribution ； predator-prey system ； density ； egg-laying behavior

並列摘要

楊桃上卵形捕植螨（Amblyseius ovalis (Evans)）之五年（1990~95）250組族群資料依分布指數（ID），Green's分布係數（Cx），Lloyd平均聚集指數（mc）及聚落度指數（mc/m），Taylor乘冪定律迴歸（log a及b），及Iwao聚落度迴歸（α，β）等分析結果評估齡別差之空間分布型。卵形捕植螨各齡期之空間分布傾向隨機至均勻，但是卵、雌成螨及全部齡期總合之族群則傾向聚集分布。依Taylor乘冪定律迴歸分析所獲得之截距log a及斜率b評估各期之聚集度，捕植螨卵及雌成螨的聚集度（degree of contagiousness）為各期中最高。卵形捕植螨之分布指數或係數值與其食餌二點葉螨（Tetranychus urticae Koch）密度間呈極低相關關係，顯示卵形捕植螨之聚集度為低食餌密度依變。依Iwao迴歸分析所測得的截距α及斜率β值，評估得卵在小聚落（patch）中之組成單位為“單一個體”，但多個體的雌成螨則為小聚落之構成單元。雌成螨產單卵於聚集分布之葉螨小聚落內的行為，顯然是構成捕植螨卵聚集之主因。該等小聚落內捕植螨卵或幼螨之單一均勻分布及斥拒機制（另一卵或幼螨同時出現或存在同一小聚落內之機制）應為雌成螨在食餌聚落內之產卵行為特性所致，亦為構成該卵形捕植螨種空間分布特性之主因。

並列關鍵字

空間分布 ； 捕食者食餌系統 ； 密度 ； 產卵行為