In symbiotic crustaceans, host-use patterns vary broadly. Some species inhabit host individuals solitarily, other species live in heterosexual pairs, and even other species live in aggregations. This disparity in host-use patterns coupled with considerable differences in host ecology provide opportunities to explore how environmental conditions affect animal behavior. In this study, we explored whether or not symbiotic crustaceans inhabiting relatively large and structurally complex host species live in aggregations. We expected Periclimenes paivai, a small caridean shrimp that lives among the tentacles of the large and morphologically complex scyphozoan jellyfish Lychnorhiza lucerna, to live in groups given that the host traits above constraint host-monopolization behaviors by symbiotic crustaceans. We described the population distribution of P. paivai during a bloom of L. lucerna near the mouth of the Paraíba River estuary in Paraíba, Brazil. The population distribution of P. paivai did not differ statistically from a random Poisson distribution. Male shrimps were most often found dwelling on the surface of L. lucerna individuals as small groups (2–4 individuals), in agreement with expectations. Periclimenes paivai is a sexually dimorphic species with males attaining smaller average body sizes than females and exhibiting no elaborated weaponry (claws). Females, but not males, experience positive allometry in cheliped size and were found living solitarily in small but not large host individuals. The above suggest that females might be territorial or that they might be competing for resources (i.e., food) likely expected to impact their reproductive output. Our results agree, but only partially, with the idea that large and morphologically complex host species should harbor non-territorial gregarious symbiotic crustaceans. Symbiotic crustaceans represent excellent models to improve our understanding about the conditions driving the social behavior of marine organisms.

中文翻译：

---

脊椎水母Lychnorhiza lucerna上虾Periclimenes paivai的宿主使用模式：探究其领土性并推断其交配系统

在共生甲壳类动物中，宿主使用模式差异很大。一些物种孤独地居住在寄主个体中，其他物种成对生活在异性恋中，甚至其他物种也生活在聚集中。宿主使用方式的这种差异，加上宿主生态学上的巨大差异，为探索环境条件如何影响动物行为提供了机会。在这项研究中，我们探讨了居住在相对较大且结构复杂的宿主物种中的共生甲壳类动物是否生活在聚集体中。鉴于寄主性状高于共生甲壳动物的寄主垄断行为，我们预期寄居虫Periclimenes paivai（一种生活在大型且形态复杂的鳞茎水母Lychnorhiza lucerna的触角中的小caridean虾）将成群生活。我们描述了P的人口分布。在巴西帕拉伊巴州帕拉伊巴河河口附近的琉森卢塞纳河盛开期间的paivai。P. paivai的种群分布与随机Poisson分布在统计学上没有差异。与期望相符，雄虾最常被发现以小群（2-4只）栖息在琉森个体表面。Periclimenes paivai是一种双态性物种，雄性比雌性平均体型更小，并且没有精巧的武器（爪）。女性，而不是男性，经历了唇形大小的正向异形，并且发现孤独地生活在小的但不是大的寄主个体中。以上表明，女性可能是地域性的，或者他们可能是在争夺可能影响其生殖产出的资源（即食物）。我们的结果是一致的，但只是部分地考虑到，大型且形态复杂的寄主物种应携带非领土的合生甲壳类甲壳动物。共生甲壳动物代表了很好的模型，可以增进我们对驱动海洋生物社会行为的条件的了解。