赤腹寄居姬蜘（Argyrodes miniaceus）之寄主選擇

Abstract

The goal of this research was to study how the red abdomen Argyrodes（Argyrodes miniaceus）select their two hosts Nephila pilipes and Leucauge magnifica by conducting: (1) field survey: to investigate host preference and to monitor the numbers of A. miniaceus; (2) selection experiments: to test whether A. miniaceus would search and select webs by olfaction or by following their silks; (3) Introduction test 1: to test whether host species or host existence would affect remaining time of A. miniaceus on webs; and (4) Introduction test 2: to test whether different level of food availability and density of A. miniaceus would affect remaining time of A. miniaceus. Over 90% A. miniaceus were found on the webs of N. pilipes, and web monitoring revealed that immigration rate was greater than emigration rate. Selection experiments indicated that A. miniaceus preferred walking along silks, but did not show preference for any kinds of silks. When A. miniaceus was introduced to the web of two hosts, L. magnifica showed intensive expelling behavior until A. miniaceus left, whereas N. pilipes hardly showed such behavior. Therefore host response may be an important factor of host preference. Furthermore, the remaining time that A. miniaceus stayed on webs of L. magnifica without host was significantly shorter than that on webs of N. pilipes without host, suggesting that A. miniaceus may able to actively differentiate host. The higher level of food supply on webs, the longer A. miniaceus would stay, and there was a significant positive correlation between forging time of A. miniaceus and their remaining time, suggesting that food intake may affect the remaining time of A. miniaceus. Based on the results, this research concluded that the following factors: (1) response of hosts, (2) active selection of A. miniaceus on the web, and (3) food availability are the most possible reasons why A. miniaceus prefer the webs of Nephila pilipes.