The causes and consequences of sex differences and body size variation in fish

能量联系着所有动物的生理、行为、生长和繁殖产出。在像鱼类这样的变温动物中，温度的变化是能量使用（新陈代谢）的关键驱动因素，这可以影响动物如何通过生态系统吸收和转移营养。最近，遥测跟踪、动物数据记录仪和呼吸测量仪的普及为我们提供了一个机会，使我们对动物能量学的理解更加有力，从而帮助我们在气候变暖的情况下管理渔业。鱼类能量学的一个知识缺口是雌雄鱼之间以及不同大小/年龄的鱼之间能量使用及其与温度的关系是如何不同的。在包括一些鱼类在内的许多动物中，由于性别大小二态性（SSD），性别和体型是联系在一起的。在鱼类中，SSD可以发生在任何一个方向，但更常见的是雌性比雄性长得更大的进化压力，因为大的雌性有不成比例的更高的生殖输出（即生殖高异速生长）。例如，在北美最重要的鱼类之一的瓦利鱼中，雌性的体型比雄性大20%左右。尽管对SSD有一个被广泛接受的进化解释，但我们对女性如何实现更高的生长却知之甚少。SSD的“神秘”与生态过程有关，但也与鱼类生长和体型变化的未知因素有关，包括繁殖超异速对现有生长模型造成的问题，以及对导致鱼类随着气候变暖而“缩小”的机制缺乏明确认识。总的来说，在鱼类的生长过程、体型变化以及它们与性别差异和耐热性的关系方面，仍有相当大的发现空间。我的项目侧重于野生淡水鱼，并将在野外环境和实验室实验中量化野生鱼类的热耐受性和偏好、生长、摄食生态学/生理学和代谢率的模式。该计划将部分集中在作为模型的白眼鱼和黄鲈（这两个物种都表现出SSD），此外还有入侵的圆虾虎鱼（SSD方向相反，雄性长得更大）和溪鳟（没有SSD，和一个对比鲜明的冷水生活史）。该计划由三个整体项目组成。第一个项目将采用实地和实验室比较的方法，研究黄眼鲈和黄鲈性别大小二态性的能量机制。第二个项目的重点是利用生物能量模型，根据第一个项目获得的数据进行更新，预测气候变暖对斜眼鱼种群的影响，并探索SSD对食物网的影响。第三个项目关注的问题是，在有和没有SSD的物种中，热性能窗口（也称为热包层）在大小、生命阶段和性别之间是如何变化的。

Energy links physiology, behaviour, growth, and reproductive output in all animals. In ectotherms like fish, variation in temperature is a key driver of energy use (metabolism), which can affect how animals take in and transfer nutrients through their ecosystem. The recent proliferation of telemetry tracking, animal-borne data loggers, and respirometry provides an opportunity to make our understanding of animal energetics more powerful in ways that can help us manage fisheries in a warming climate. One knowledge gap in fish energetics is how energy use and its relationship with temperature differs between male and female fish, and among fish of different size/age classes. In many animals including some fishes, sex and body size are connected because of sexual size dimorphism (SSD). In fishes, SSD can occur in either direction, but more commonly there is evolutionary pressure for females to grow larger than males because large females have disproportionately higher reproductive output (i.e., reproductive hyperallometry). For example, in walleye-among the most important fishes in North America-females reach sizes about 20% larger than those of males. While there is a widely accepted evolutionary explanation for SSD, we know surprisingly little about how females achieve higher growth. The `mystery' of SSD is relevant to ecological processes but also to unknowns about fish growth and body size variation, including the problem reproductive hyperallometry poses for existing growth models and a lack of clarity about what mechanisms are causing fish to `shrink' with climate warming. Collectively, there remains considerable room for discovery about processes driving growth, variation in body size, and their connection to sex differences and thermal tolerance in fishes. My program has a focus on wild freshwater fishes and will quantify patterns of thermal tolerance and preference, growth, feeding ecology/physiology, and metabolic rate in wild fishes in field settings and in laboratory experiments. The program will focus partly on walleye and yellow perch as models (two species that exhibit SSD), in addition to the invasive round goby (SSD in the reverse direction; males grow to be larger) and stream-resident brook trout (no SSD, and a contrasting coldwater life history). The program consists of three overall projects. The first project will investigate the energetic mechanisms underlying sexual size dimorphism in walleye and yellow perch, using a comparative field- and lab-based approach. The second project focuses on using bioenergetic models, updated based on the data obtained in the first project, to predict changes to walleye populations with climate warming and explore the impacts of SSD on food webs. The third project focuses in on the question of how thermal performance windows (also called thermal envelopes) change across sizes, life stages, and between sexes in species with and without SSD.