School of Biological Sciences, Flinders University, Adelaide, SA 5001, Australia.
Proc Natl Acad Sci U S A. 2014 Feb 11;111(6):2206-11. doi: 10.1073/pnas.1322363111. Epub 2014 Jan 27.
For millimeter-scale aquatic crustaceans such as copepods, ensuring reproductive success is a challenge as potential mates are often separated by hundreds of body lengths in a 3D environment. At the evolutionary scale, this led to the development of remote sensing abilities and behavioral strategies to locate, to track, and to capture a mate. Chemoreception plays a crucial role in increasing mate encounter rates through pheromone clouds and pheromone trails that can be followed over many body lengths. Empirical evidence of trail following behavior is, however, limited to laboratory experiments conducted in still water. An important open question concerns what happens in the turbulent waters of the surface ocean. We propose that copepods experience, and hence react to, a bulk-phase water pheromone concentration. Here we investigate the mating behavior of two key copepod species, Temora longicornis and Eurytemora affinis, to assess the role of background pheromone concentration and the relative roles played by males and females in mating encounters. We find that both males and females react to background pheromone concentration and exhibit both innate and acquired components in their mating strategies. The emerging swimming behaviors have stochastic properties that depend on pheromone concentration, sex, and species, are related to the level of reproductive experience of the individual tested, and significantly diverge from both the Lévy and Brownian models identified in predators searching for low- and high-density prey. Our results are consistent with an adaptation to increase mate encounter rates and hence to optimize reproductive fitness and success.
对于毫米级的水生甲壳类动物，如桡足类，确保繁殖成功是一个挑战，因为潜在的配偶在 3D 环境中通常相隔数百个体长。在进化尺度上，这导致了远程感应能力和行为策略的发展，以定位、跟踪和捕获配偶。化学感受在通过信息素云团和信息素轨迹增加配偶相遇率方面起着至关重要的作用，可以在多个体长上进行跟踪。然而，关于跟踪行为的经验证据仅限于在静止水中进行的实验室实验。一个重要的未解决的问题是在海洋表面的动荡水域中会发生什么。我们提出桡足类动物会经历（因此会对）主体相水信息素浓度做出反应。在这里，我们研究了两种关键桡足类动物，长刺拟哲水蚤和狭长真哲水蚤的交配行为，以评估背景信息素浓度的作用以及雄性和雌性在交配遭遇中的相对作用。我们发现雄性和雌性都对背景信息素浓度做出反应，并在交配策略中表现出先天和后天的成分。新兴的游泳行为具有随机特性，这些特性取决于信息素浓度、性别和物种，与个体的生殖经验水平有关，与捕食者在寻找低密度和高密度猎物时确定的 Lévy 和布朗模型明显不同。我们的研究结果与适应增加配偶相遇率的假设一致，从而优化生殖适应性和成功。
