Male crustaceans engage in precopulatory mate-guarding to monopolize a female. However, a conspecific rival often takes the female from the guarding males during male–male contests, so guarding males should invest in behavior to decrease the rate of encounters with rivals, especially when they are potentially weak and guard a valuable female. We examined this idea using a net-climbing (avoidance) response by precopulatory guarding males of the hermit crab Pagurus minutus. Guarding males more often climb revetment walls in the field than solitary males and females, and the guarders were larger in body size than the solitary males on the walls. Guarding males increased climbing effort in the presence of rivals compared to controls (no stimulus), but not when faced with a non-threat organism. Compared to intact guarding males, those without a major cheliped (“weaponless”) were less likely to succeed in defending their partner in direct fights, but increased climbing investment overall, rather than especially when a rival was present. Although female size positively correlates with clutch size in this species, male climbing height decreased with increasing size of the guarded female. We discuss the effectiveness and importance of climbing in this species as it relates to conditions at our study site and the general vulnerability of guarding males depending on weapon status.

中文翻译：

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寄居蟹Pagurus minutus中守卫雄性的攀爬行为：对手、雌性体型和无武器的影响

雄性甲壳类动物进行交配前的配偶保护以垄断雌性。然而，在男性与男性的比赛中，一个同种的竞争对手经常从守卫的男性手中夺走雌性，所以守卫的雄性应该在行为上进行投资，以降低与竞争对手的相遇率，尤其是当它们可能很弱并保护有价值的女性时。我们使用寄居蟹 Pagurus minutus 的前交配守卫雄性的爬网（回避）反应研究了这个想法。守卫的雄性比独居的雄性和雌性更经常在野外攀爬护岸墙，而且守卫者的体型比壁上的独居雄性要大。与对照（无刺激）相比，守卫的雄性在有竞争对手的情况下增加了攀爬努力，但在面对非威胁生物时则不然。比起完整的守卫雄性，那些没有主要螯肢（“无武器”）的人不太可能在直接战斗中成功保护他们的伙伴，但总体上增加了攀登投资，而不是特别是在有对手的情况下。尽管雌性大小与该物种的离合器大小呈正相关，但雄性攀爬高度随着受保护的雌性体型的增加而降低。我们讨论了在该物种中攀爬的有效性和重要性，因为它与我们研究地点的条件以及根据武器状态保护雄性的一般脆弱性有关。雄性攀爬高度随着被保护的雌性体型的增加而降低。我们讨论了在该物种中攀爬的有效性和重要性，因为它与我们研究地点的条件以及根据武器状态保护雄性的一般脆弱性有关。雄性攀爬高度随着被保护的雌性体型的增加而降低。我们讨论了在该物种中攀爬的有效性和重要性，因为它与我们研究地点的条件以及根据武器状态保护雄性的一般脆弱性有关。