Higher Institution Centre of Excellence (HICoE), Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, Kuala Nerus, Malaysia.
Centre for Chemical Biology, Universiti Sains Malaysia, Penang, Malaysia.
PeerJ. 2023 Apr 3;11:e15143. doi: 10.7717/peerj.15143. eCollection 2023.
Asymmetric body traits in bilateral organisms are common and serve a range of different functions. In crustaceans, specifically among brachyuran crabs, heterochely and handedness in some species are known to aid in behavioural responses such as food acquisition, and sexual and territorial displays. However, the heterochely of the intertidal mud crab genus is still poorly understood. This study investigated the cheliped morphometric characteristics of orange mud crab and the relation of heterochely and handedness to sex. is heterochelous, with predominant right-handed (70.2%). Three morphometric variables, , propodus length (PL), propodus depth (PD), and propodus width (PW) were significantly larger in the right cheliped and the estimated handedness based on these three variables were consistent with the presence of molariform teeth. The effect of sex had no influence on the occurrence of heterochely or handedness. The frequency of left-handedness increased with size, especially in males. We postulate that handedness reversal, a phenomenon seen in other crab species when the dominant hand is lost, also occurs in , thereby resulting in a change in left-handedness frequency. The use of chelipeds by males in mate and territorial defenses might provide an explanation for the higher risk of losing a dominant cheliped and thus, higher left-handedness frequency compared to females. Future behavioural research could shed light on the selective forces that affect the handedness distribution in mud crabs. Knowledge on heterochely and handedness of mud crabs could be useful for future development of less aggressive crab populations by claw reversal and the optimisation of limb autotomy techniques.
双侧生物的不对称体特征很常见，具有多种不同的功能。在甲壳动物中，特别是短尾类螃蟹中，一些物种的异形螯和手性已知有助于行为反应，如食物获取、性和领地展示。然而，潮间带泥蟹属的异形螯的情况仍知之甚少。本研究调查了橙色泥蟹的螯肢形态特征，以及异形螯和手性与性别的关系。是异形螯的，主要是右手（70.2%）。三个形态变量，掌节长（PL）、掌节深（PD）和掌节宽（PW）在右螯肢中显著较大，基于这三个变量的估计手性与臼齿状牙齿的存在一致。性别的影响对手性或手性的发生没有影响。左手的频率随着体型的增加而增加，尤其是在雄性中。我们假设，在失去主导手时在其他蟹种中看到的手性反转现象也发生在中，从而导致左手频率的变化。雄性在配偶和领地防御中使用螯肢可能解释了与雌性相比，失去主导螯肢的风险更高，从而导致左手频率更高的原因。未来的行为研究可以揭示影响泥蟹手性分布的选择压力。泥蟹异形螯和手性的知识可能有助于通过爪反转和优化肢体自切技术来开发攻击性较低的蟹种群。
