Mating strategy and sexual dimorphism of morphological traits of the leucosiid crab Pyrhila pisum were elucidated by analysing relative growth patterns of chelipeds and abdomen, and gonad development patterns. Male adults had long chelipeds compared with juvenile males and females. Among male adults, two phases with different slopes could be found in the regression lines; their chelipeds growth pattern changed from negative allometry to positive and longer chelipeds developed in large adults. The growth is more markedly expressed in the merus than in the propodus. Female adults had wider abdominal segments and a thicker body compared with juvenile females and males. Abdomen of females was greatly enlarged by a puberty moult. Male adults had well-developed gonads similar to female adults, and the weights of male gonads were often larger than those of females of the same body size. For adult males, a negative correlation was detected between carapace width and the weight ratio of their gonads, but no significant relationship was detected for adult females. Females had large and well-bloated seminal receptacles, whose weight was nearly equal to gonad weight. There was little difference in the amount of seminal receptacles regardless of the body size of females. There is a trade-off relationship in the development between chelipeds and gonads in adult males. Probably young adult males compensate for the disadvantageous condition of guarding by increasing the number of spermatozoids, and old adult males invest more of their energy to their chelae for guarding while decreasing investment in sperm production.

中文翻译：

---

白斑蟹Pyrhila pisum的性状及繁殖策略

鲎形态性状的交配策略与两性二态性豌豆通过分析螯足和腹部的相对生长模式以及性腺发育模式来阐明。与少年男性和女性相比，成年男性的螯肢较长。在成年男性中，回归线中存在两个斜率不同的阶段；它们的螯足生长模式从负异速异速生长转变为在大型成年人身上发育的正和更长的螯足。生长在梅鲁斯中比在前足中更明显地表达。与青少年女性和男性相比，成年女性的腹节更宽，身体更厚。雌性的腹部因青春期换羽而大大增大。成年雄性的性腺发育良好，与成年雌性相似，雄性性腺的重量往往大于相同体型的雌性。对于成年男性，甲壳宽度与其性腺重量比呈负相关，但成年雌性无显着相关性。雌性有大而膨胀的精囊，其重量几乎等于性腺重量。无论女性的体型大小，精囊的数量几乎没有差异。成年雄性螯足和性腺的发育存在权衡关系。可能年轻的成年男性通过增加精子的数量来弥补保护的不利条件，而老年男性将更多的精力投入到他们的螯肢上进行保护，同时减少对精子生产的投资。雌性有大而膨胀的精囊，其重量几乎等于性腺重量。无论女性的体型大小，精囊的数量几乎没有差异。成年雄性螯足和性腺的发育存在权衡关系。可能年轻的成年男性通过增加精子的数量来弥补保护的不利条件，而老年男性将更多的精力投入到他们的螯肢上进行保护，同时减少对精子生产的投资。雌性有大而膨胀的精囊，其重量几乎等于性腺重量。无论女性的体型大小，精囊的数量几乎没有差异。成年雄性螯足和性腺的发育存在权衡关系。可能年轻的成年男性通过增加精子的数量来弥补保护的不利条件，而老年男性将更多的精力投入到他们的螯肢上进行保护，同时减少对精子生产的投资。