Department of Environmental Biology, Sapienza University of Rome, Rome, 00185, Italy.
CoNISMa, National Inter-University Consortium for Marine Sciences, Rome, 00196, Italy.
Sci Rep. 2024 Nov 18;14(1):28424. doi: 10.1038/s41598-024-79957-0.
Global warming and the introduction of non-native fish represent major threats to freshwater biodiversity worldwide, but their effects have usually been investigated separately. Since most fish are ectotherms, their metabolism and feeding behaviour are highly influenced by temperature. Increasing water temperatures may thus exacerbate the impact of non-native fish, particularly those adapted to warmer conditions, on prey populations. Increasing temperature can also result in divergences between the impacts of females and males, especially in sexually dimorphic species.The globally invasive tropical guppy Poecilia reticulata Peters, a popular aquarium fish also used for control of mosquito-borne diseases and as a model species in ecological and evolutionary studies, exhibits strong sexual dimorphism and larvivory. This laboratory study examined prey consumption and prey size selection by guppies fed with chironomid larvae under varying temperature conditions. The effect of sex, pregnancy and prey body size on the guppy's predatory response was also assessed by comparing Functional Responses.The results highlighted four key points: (1) increased temperature led to increased prey consumption in both females and males by decreasing handling time; (2) prey consumption was disproportionately higher in females than males, regardless of temperature; (3) temperature influenced females' prey size selection; and (4) pregnancy reduced prey handling time among females.These findings show that temperature and intraspecific differences influence the feeding response of invasive fish, and they should both be taken into account when investigating and predicting the ecological impact of invasive species on invaded food webs.
全球变暖与非本地鱼类的引入对全球淡水生物多样性构成了重大威胁，但这些因素的影响通常是分开研究的。由于大多数鱼类是变温动物，其新陈代谢和摄食行为受温度的影响很大。因此，水温升高可能会加剧非本地鱼类对猎物种群的影响，尤其是那些适应温暖条件的鱼类。温度升高还会导致雌雄两性的影响出现差异，特别是在性二态性物种中。全球入侵性热带孔雀鱼 Poecilia reticulata Peters 是一种受欢迎的水族馆鱼类，也被用于控制蚊媒疾病，以及作为生态和进化研究中的模式物种，具有强烈的性二态性和幼虫捕食性。这项实验室研究考察了在不同温度条件下，以摇蚊幼虫为食的孔雀鱼的猎物消耗和猎物大小选择。通过比较功能反应，还评估了性、怀孕和猎物身体大小对孔雀鱼捕食反应的影响。研究结果强调了四个关键点：（1）通过减少处理时间，高温导致雌雄孔雀鱼的猎物消耗增加；（2）无论温度如何，雌性的猎物消耗都不成比例地高于雄性；（3）温度影响雌性对猎物大小的选择；（4）怀孕会减少雌性对猎物的处理时间。这些发现表明，温度和种内差异会影响入侵鱼类的摄食反应，在调查和预测入侵物种对入侵食物网的生态影响时，应同时考虑这两个因素。
