Argyrodes Fissifrons Inhabiting Webs of Cyrtophora Hosts: Prey Size Distribution and Population Characteristics

裂額寄居姬蜘之族群特性及覓食行為研究

卓逸民(I-Min Tso) ； 劉小如(Lucia Severinghaus Liu)

《Zoological Studies》 39卷3期 (2000/07) Pp. 236-242

摘要

本研究藉探討裂額寄居姬蜘之族群特性及覓食行為來了解其對於雲斑蜘宿主之影響。我們檢視：（一）裂額寄居姬蜘之自然族群大小差異是否與宿主之網大小呈密切相關，（二）裂額寄居姬蜘是否長期依附於某些宿主之網上，以及（三）裂額寄居姬蜘之覓食行為是否會影響宿主之攝食。於蘭嶼所進行之野外調查結果顯示，宿主網之障礙網（tangle barrier）高度及水平皿網（bowl web）之面積與寄居其中之裂額寄居姬蜘平均數呈顯著之正相關。每一宿主網上之裂額寄居姬蜘平均數每日不同，顯示有若千數目之該種蜘蛛每日於宿主網內。停留於宿主網內之裂額寄居姬蜘與離開者在性別比例、攝食量及體型上並無顯著差異。宿主與裂額寄居姬蜘在所攝入之獵物體長分布上有極顯著之差異，且前者所攝取之獵物平均體長遠大於後者。這些結果顯示裂額寄居姬蜘之主要食物來源為宿主不會攝食之大型獵物，因此該蜘蛛應不會對宿主之攝食造成顯著影響。

關鍵字

裂額寄居姬蜘 ； 雲斑蜘 ； 蘭嶼 ； 蜘蛛

並列摘要

In this field study we investigated the impact of Argyrodes fissifrons (Araneae: Theridiidae) on two species of Cyrtophora spider hosts (Araneae: Araneidae) by studying several aspects of its population and foraging. We examined (1) if natural population variations of A. fissifrons occur with different web sizes of the hosts, (2) if A. fissifrons form long-term associations with particular hosts, and (3) if the size range of prey consumed by A. fissifrons overlaps with that of Cyrtophora hosts. Results from field surveys indicated that a positive relationship exists between the average number of A. fissifrons and the size of the host webs. The number of A. fissifrons per host web per day changed daily, indicating the daily occurrence of immigration-emigration events. However, as inferred from monitoring marked A. fissifrons for 3 nights, some individuals form a long-term association with a particular host. The sexratio, body size , and prey intake of A. fissifrons spiders staying in particular hosts' webs during monitoring did not differ from those that left a web. A significant difference was found in prey size distribution between Cyrtophora hosts and A. fissifrons, and the average prey size of the former was far greater than of the latter. This result suggests that A. fissifrons scavenge on webs of Cyrtophora hosts by collecting small prey ignored by the hosts.

並列關鍵字

Argyrodes ； Cyrtophora ； Orchid island ； Spider