James Noelle, Furukawa Megan
Neuroscience Program, University of Illinois at Urbana Champaign, Urbana, IL, U.S.A.
Department of Evolution, Ecology and Behavior, University of Illinois at Urbana Champaign, Urbana, IL, U.S.A.
Anim Behav. 2020 Aug;166:9-17. doi: 10.1016/j.anbehav.2020.05.010. Epub 2020 Jul 4.
Constructing a nest within a mating territory provides a clear benefit to the resident, particularly by improving the opportunity to mate. It is unclear whether animals who use nests exclusively for reproductive purposes account for either the effort invested or the resulting increase in mating potential when valuing their territories. We sought to explicitly reveal a nest's added subjective resource value through within-group comparison of aggressive behaviour before and after nest construction. An increase in aggression following construction would indicate that the resident perceives greater subjective value in his territory, and thus values the nest. Threespine stickleback, , fish demonstrate stereotypical aggressive behaviours during an easily induced territorial defence. The male's nest is used exclusively for reproductive purposes, avoiding any confound of shelter. Contrary to our hypothesis, neither nest presence, timing of construction, nor nesting outcome was associated with differences in behavioural measures of territorial aggression. Assessed behaviours were robust, repeatable and inter-correlated. We conclude that territorial aggression is neither predictive of nor altered by nesting in threespine stickleback fish. Our results suggest that nests used transiently for a portion of the mating season add negligible subjective resource value to a territory. We additionally demonstrate that examinations of territorial aggression in sticklebacks do not need to control for nest building, improving statistical power by decreasing dropout rates. These results dovetail with recent work in other fish species to suggest that assessment of territorial aggression absent a nest may be practicable for fish in general.
在交配区域内建造巢穴对居住者有明显益处，特别是能增加交配机会。尚不清楚仅将巢穴用于繁殖目的的动物在评估其领地时，是否会考虑建造巢穴所投入的精力或由此带来的交配潜力的增加。我们试图通过比较筑巢前后群体内攻击行为，来明确揭示巢穴额外的主观资源价值。筑巢后攻击行为增加，表明居住者认为其领地具有更高的主观价值，从而重视这个巢穴。三刺鱼在容易引发的领地防御中表现出刻板的攻击行为。雄鱼的巢穴仅用于繁殖目的，避免了与庇护所相关的任何混淆因素。与我们的假设相反，巢穴的存在、筑巢时间或筑巢结果均与领地攻击行为的测量差异无关。所评估的行为是稳健、可重复且相互关联的。我们得出结论，在三刺鱼中，领地攻击行为既不能预测筑巢行为，也不会因筑巢行为而改变。我们的结果表明，在交配季节的一部分时间里临时使用的巢穴，为领地增加的主观资源价值可忽略不计。我们还证明，在刺鱼中进行领地攻击行为的研究无需控制筑巢行为，通过降低失访率提高了统计效力。这些结果与最近在其他鱼类物种中的研究相吻合，表明对于一般鱼类而言，在没有巢穴的情况下评估领地攻击行为可能是可行的。
