Lehtonen Topi K, Gagnon Karine, Sowersby Will, Wong Bob B M
Department of Biology, University of Turku, Turku, Finland.
School of Biological Sciences, Monash University, Melbourne, Australia.
BMC Evol Biol. 2016 Jan 4;16:3. doi: 10.1186/s12862-015-0569-9.
Aggressive behaviour can have significant evolutionary consequences-not only within species, but also in the context of heterospecific interactions. Here, we carried out an experimental field study to investigate the importance of phenotypic similarity on levels of aggression between species whilst controlling for familiarity effects using manipulated allopatric stimuli. Specifically, we investigated aggressive responses of territory holding males and females in two species of Neotropical cichlid fish, Amphilophus sagittae and Hypsophrys nicaraguensis, that differ in their phenotypic similarity to our allopatric stimulus species, Amphilophus astorquii.
We found that, independent of phenotypic similarity (and correlated phylogenetic proximity) between the territory holders and intruder, territorial aggression was not adjusted in relation to allopatric intruder colour markings that are associated with different levels of threat and known to provoke different responses in a sympatric setting. We also found that males and females did not differ in their overall patterns of aggression adjustment towards intruder cues. Nevertheless, the two focal species, which share the same breeding grounds and external threats, exhibited different sex roles in breeding territory defence.
Together with earlier studies assessing hetrospecific aggression in sympatry, our current results highlight the importance of coevolution and learning in species interactions.
攻击行为可能会产生重大的进化后果——不仅在物种内部，而且在异种相互作用的背景下。在这里，我们进行了一项实验性实地研究，以调查表型相似性对物种间攻击水平的重要性，同时使用人工异地刺激来控制熟悉度效应。具体而言，我们研究了两种新热带丽鱼科鱼类，即箭丽鱼（Amphilophus sagittae）和尼加拉瓜高身丽鱼（Hypsophrys nicaraguensis）中占据领地的雄性和雌性的攻击反应，这两种鱼与我们的异地刺激物种阿氏丽鱼（Amphilophus astorquii）在表型相似性上存在差异。
我们发现，与领地所有者和入侵者之间的表型相似性（以及相关的系统发育接近度）无关，领地攻击并未根据与不同威胁水平相关且已知在同域环境中会引发不同反应的异地入侵者颜色标记进行调整。我们还发现，雄性和雌性对入侵者线索的总体攻击调整模式没有差异。然而，这两种共享相同繁殖地和面临相同外部威胁的重点研究物种，在繁殖领地防御中表现出不同的性别角色。
与早期评估同域异种攻击的研究一起，我们目前的结果突出了协同进化和学习在物种相互作用中的重要性。
