Potter Tamara I, Greenville Aaron C, Dickman Christopher R
Desert Ecology Research Group, School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia.
National Environmental Science Programme Threatened Species Recovery Hub, University of Sydney, Sydney, New South Wales, Australia.
R Soc Open Sci. 2018 May 2;5(5):171872. doi: 10.1098/rsos.171872. eCollection 2018 May.
Interspecific competition may occur when resources are limited, and is often most intense between animals in the same ecological guild. Intraguild predation (IGP) is a distinctive form of interference competition, where a dominant predator selectively kills subordinate rivals to gain increased access to resources. However, before IGP can be identified, organisms must be confirmed as members of the same guild and occur together in space time. The lesser hairy-footed dunnart (, Dasyuridae) is a generalist marsupial insectivore in arid Australia, but consumes wolf spiders ( spp., Lycosidae) disproportionately often relative to their availability. Here, we test the hypothesis that this disproportionate predation is a product of frequent encounter rates between the interactants due to high overlap in their diets and use of space and time. Diet and prey availability were determined using direct observations and invertebrate pitfall trapping, microhabitat use by tracking individuals of both species-groups, and temporal activity using spotlighting and camera traps. Major overlap (greater than 75% similarity) was found in diet and temporal activity, and weaker overlap in microhabitat use. Taken together, these findings suggest reasonable potential, for the first time, for competition and intraguild predation to occur between taxa as disparate as marsupials and spiders.
当资源有限时，种间竞争可能会发生，并且在同一生态群落中的动物之间往往最为激烈。种内捕食（IGP）是一种独特的干扰竞争形式，其中占主导地位的捕食者会选择性地杀死从属对手，以增加获取资源的机会。然而，在确定种内捕食之前，必须确认生物是同一群落的成员，并且在时空上同时出现。毛足袋鼬（Sminthopsis youngsoni，袋鼬科）是澳大利亚干旱地区的一种杂食性有袋食虫动物，但相对于狼蛛（Lycosa spp.，狼蛛科）的可获得性而言，它对狼蛛的捕食频率过高。在这里，我们检验了这样一个假设：这种不成比例的捕食是由于相互作用者之间在饮食、空间和时间利用上的高度重叠，导致它们频繁相遇的结果。通过直接观察和无脊椎动物陷阱诱捕来确定饮食和猎物可获得性，通过追踪两个物种组的个体来确定微生境利用情况，并利用聚光灯和相机陷阱来确定时间活动。研究发现，在饮食和时间活动方面存在主要重叠（相似度大于75%），而在微生境利用方面的重叠较弱。综合来看，这些发现首次表明，在有袋动物和蜘蛛等截然不同的分类群之间，存在竞争和种内捕食的合理可能性。
