Schrempf Scott D, Burke Kevin W, Wettlaufer Jillian D, Martin Paul R
Department of Biology, Queen's University, Kingston, ON, Canada.
PeerJ. 2021 Feb 23;9:e10797. doi: 10.7717/peerj.10797. eCollection 2021.
Asymmetric interference competition, where one species is behaviorally dominant over another, appears widespread in nature with the potential to structure ecological communities through trade-offs between competitive dominance and environmental tolerance. The details of how species interact and the factors that contribute to behavioral dominance, however, are poorly known for most species, yet such details are important for understanding when and why trade-offs occur. Here, we examine behavioral interactions between two species of burying beetles (Coleoptera: Silphidae) that compete for limited breeding resources (i.e., small vertebrate carcasses) in nature, to identify behaviors involved in interference competition and to test if large body size, species identity, or time of arrival best predict behavioral dominance among species. To test these ideas, we placed same-sex individuals of (early to mid-summer breeder) and (late summer to fall breeder) into an enclosure together with a 25-30 g mouse carcass (). We then video-recorded all behaviors, including neutral and aggressive interactions, for 13 h per trial ( = 14 trials). For each interaction, we assigned a winner based on which beetle retained its position instead of fleeing or retained possession of the carcass; the overall behavioral dominant was determined as the individual that won the most interactions over the length of the trial. We found that large body size was the best predictor of behavioral dominance. In most interactions, was larger and dominant over ; however, when was larger they outcompeted smaller , illustrating the importance of body size in aggressive contests. The order of arrival to the carcass (priority effects) did not predict behavioral dominance. The larger size and abundance of in nature suggest a competitive asymmetry between the species, supporting the idea that constrains the ability of to breed earlier in the summer.
不对称干扰竞争，即一个物种在行为上比另一个物种更具优势，在自然界中似乎很普遍，它有可能通过竞争优势和环境耐受性之间的权衡来构建生态群落。然而，对于大多数物种来说，物种间相互作用的细节以及导致行为优势的因素却知之甚少，而这些细节对于理解权衡何时以及为何发生很重要。在这里，我们研究了两种埋葬甲虫（鞘翅目：埋葬虫科）之间的行为相互作用，它们在自然界中争夺有限的繁殖资源（即小型脊椎动物尸体），以确定参与干扰竞争的行为，并测试体型大小、物种身份或到达时间是否最能预测物种间的行为优势。为了验证这些想法，我们将同性别的（夏初至仲夏繁殖者）和（夏末至秋季繁殖者）个体与一具25 - 30克的小鼠尸体（）一起放入一个围栏中。然后，我们对每次试验的13小时内的所有行为进行录像，包括中性和攻击性相互作用（ = 14次试验）。对于每次相互作用，我们根据哪只甲虫保留其位置而不是逃离或保留对尸体的占有来确定获胜者；总体行为优势被确定为在试验过程中赢得最多相互作用的个体。我们发现体型大小是行为优势的最佳预测指标。在大多数相互作用中，体型较大且比更具优势；然而，当体型更大时，它们比体型较小的更具竞争力，这说明了体型大小在攻击性竞争中的重要性。到达尸体的顺序（优先效应）并不能预测行为优势。在自然界中的较大体型和数量表明这两个物种之间存在竞争不对称，支持了限制在夏季更早繁殖能力的观点。
