Sheppard Catherine E, Boström-Einarsson Lisa, Exton Dan A, Williams Gareth J, Keith Sally A
Lancaster Environment Centre, Lancaster University, Bailrigg, Lancaster, LA1 4YQ UK.
Marine and Environmental Sciences Centre (MARE) & Aquatic Research Network (ARNET), Laboratório Marítimo da Guia, Faculdade de Ciências, Universidade de Lisboa, Cascais, 2750-374 Portugal.
Behav Ecol Sociobiol. 2025;79(9):89. doi: 10.1007/s00265-025-03636-x. Epub 2025 Aug 30.
Aggressive territoriality can have significant benefits for resource acquisition yet is a costly behaviour. Selection should therefore favour mechanisms that allow individuals to modify their behaviour to maintain and defend their territory whilst minimising costs. One such mechanism between intraspecific territorial competitors is neighbour-stranger discrimination. The familiarity hypothesis suggests that territory holders will respond less aggressively to neighbours they recognise than to strangers they do not recognise. Conversely, in systems where neighbours pose a greater threat to territory loss than strangers, the threat-level hypothesis predicts that neighbours will elicit a greater aggressive response. We tested these opposing hypotheses in territorial farming damselfishes using a common bottle presentation experiment design to initiate aggressive responses by territory holders to neighbouring and non-neighbour individuals. Neighbours that were smaller in body size than the territory holder elicited the greatest aggressive response, whereas larger neighbours elicited the weakest. The aggressive response elicited by non-neighbours did not vary greatly with body size difference between the stimulus fish and territory holder. We demonstrate that aggressive response in territorial farming damselfishes is influenced by both familiarity and potential threat determined by body size. These findings add to the growing pool of evidence that an understanding of multiple factors is needed to identify the drivers of neighbour-stranger discrimination.
Both familiarity and body size may mediate aggressive behaviour yet are not often included in the same study. Using manipulative field experiments, we investigated the interplay between familiarity and body size in shaping patterns of aggressive behaviour in farming damselfishes. We found that territory holders were less aggressive towards neighbours than non-neighbours, but only when they were larger than themselves. Our results showing an interaction between the effects of familiarity and body size on aggressive behaviour may hint at nuances in patterns of neighbour-stranger discrimination, such as dominance relationships.
The online version contains supplementary material available at 10.1007/s00265-025-03636-x.
积极的领地行为对于资源获取可能具有显著益处，但却是一种代价高昂的行为。因此，自然选择应倾向于那些能让个体调整行为以维持和保卫其领地，同时将成本降至最低的机制。种内领地竞争者之间的一种此类机制是对邻居和陌生者的区分。熟悉度假说表明，领地所有者对其认识的邻居的攻击性反应会比对不认识的陌生者的反应弱。相反，在邻居对领地丧失构成的威胁大于陌生者的系统中，威胁水平假说预测邻居会引发更强烈的攻击性反应。我们在领地性养殖雀鲷中测试了这些相反的假说，采用常见的瓶子呈现实验设计来引发领地所有者对相邻和非相邻个体的攻击性反应。体型比领地所有者小的邻居引发了最强烈的攻击性反应，而体型较大的邻居引发的反应最弱。非邻居引发的攻击性反应随刺激鱼与领地所有者之间的体型差异变化不大。我们证明，领地性养殖雀鲷的攻击性反应受熟悉度和由体型决定的潜在威胁两者影响。这些发现进一步证明，需要了解多种因素才能确定邻居 - 陌生者区分的驱动因素。
熟悉度和体型都可能调节攻击行为，但它们并不常被纳入同一研究中。通过操纵性野外实验，我们研究了熟悉度和体型在塑造养殖雀鲷攻击行为模式中的相互作用。我们发现，领地所有者对邻居的攻击性比对非邻居弱，但仅当邻居比其自身大时才如此。我们的结果表明熟悉度和体型对攻击行为的影响之间存在相互作用，这可能暗示了邻居 - 陌生者区分模式中的细微差别，例如支配关系。
在线版本包含可在10.1007/s00265 - 025 - 03636 - x获取的补充材料。
