Abstract Although inquilinism in the goby–alpheid shrimp association is well known, behavior inside the burrow remains unclear because it is difficult to observe. In this tank study, alpheid shrimp burrow morphology was investigated because it may reflect the behavior of the burrow inhabitants. The objective was to elucidate the effects of Acentrogobius sp. 2 (sensu Akihito et al., 2013) on the burrow morphology of Alpheus brevicristatus. Through mesocosm experiments, 12 burrows made by shrimp without goby (solitary treatment), and 14 burrows made by shrimp with goby (symbiotic treatment), were recovered. Differences between solitary and symbiotic treatments were identified using a univariate test of each burrow parameters (total depth, total length, horizontal extension, diameter, number of openings, and number of side branches) and multivariate methods (nMDS and ANOSIM). Results indicate that the effect of the symbiotic goby on the shrimp burrow is small or smaller than the effect of shrimp size. However, the treatments varied significantly in terms of the correlation between shrimp size and each burrow parameter. In the solitary treatment, almost all the burrow parameters showed a high correlation with shrimp carapace length, suggesting that the burrow size was optimal for the shrimps. In contrast, no significant correlation was observed between most of the burrow parameters and shrimp size in the symbiotic treatment. Smaller burrows may not be suitable for the shrimp, and larger burrows require more energy to construct and maintain, suggesting that this relationship is costly to the shrimps. This study was carried out using the facultatively symbiotic goby–shrimp interaction, because the obligate shrimp is known to stop burrowing activity without the symbiotic goby. Future investigation using obligately symbiotic goby might lead to different results from those of this study, because the more specialized mutualist gobies will provide greater services to the shrimps. Studying the ecology of both obligate and facultative associations would provide further insight into the evolution of goby–alpheid shrimp symbiosis.

中文翻译：

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Mesocosm 实验揭示了兼性共生虾虎鱼对寄主 alpheid 虾洞穴可能产生的负面影响

摘要 虽然虾虎鱼-黑斑虾协会的 inquilinism 是众所周知的，但由于难以观察，洞穴内的行为仍不清楚。在这项水族箱研究中，研究了 alpheid 虾洞穴形态，因为它可能反映洞穴居民的行为。目的是阐明 Acentrogobius sp. 的影响。2 (sensu Akihito et al., 2013) 关于 Alpheus brevicristatus 的洞穴形态。通过中观实验，回收了没有虾虎鱼（单独处理）的虾挖的洞穴12个，和有虾虎鱼（共生处理）的虾挖的洞穴14个。单独和共生处理之间的差异使用每个洞穴参数的单变量测试（总深度、总长度、水平延伸、直径、开口数量、和侧分支的数量）和多变量方法（nMDS 和 ANOSIM）。结果表明共生虾虎鱼对虾穴的影响小于或小于虾大小的影响。然而，就虾大小和每个洞穴参数之间的相关性而言，处理方式差异很大。在单独处理中，几乎所有的洞穴参数都显示出与虾甲壳长度的高度相关性，表明洞穴大小对虾来说是最佳的。相比之下，在共生处理中，大多数洞穴参数与虾大小之间没有观察到显着相关性。较小的洞穴可能不适合虾，而较大的洞穴需要更多的能量来建造和维护，这表明这种关系对虾来说代价高昂。这项研究是使用兼性共生的虾虎鱼-虾相互作用进行的，因为已知专性虾在没有共生虾虎鱼的情况下会停止挖洞活动。未来使用专性共生虾虎鱼的调查可能会导致与本研究不同的结果，因为更专业的共生虾虎鱼将为虾提供更好的服务。研究专性和兼性关联的生态学将提供对虾虎虾共生的进化的进一步见解。因为更专业的互惠虾虎鱼将为虾提供更多的服务。研究专性和兼性关联的生态学将提供对虾虎虾共生的进化的进一步见解。因为更专业的互惠虾虎鱼将为虾提供更多的服务。研究专性和兼性关联的生态学将提供对虾虎虾共生的进化的进一步见解。