Does heterochely and handedness exist in mud crab Scylla olivacea?
Rusydi Rozaimi1, Alexander Chong Shu-Chien2,3, Youji Wang4, Sutikno Sutikno5, Mhd Ikhwanuddin1,6, Xi Shi7, Ghazali Azmie1, Hanafiah Fazhan1,2,6, Khor Waiho1,2,6*

1 Higher Institution Centre of Excellence (HICoE), Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, Kuala Nerus, 21030, Terengganu, Malaysia
2 Centre for Chemical Biology, Universiti Sains Malaysia, Minden, 11900, Penang, Malaysia
3 School of Biological Sciences, Universiti Sains Malaysia, Minden, 11800, Penang, Malaysia
4 International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China
5 Research Center for Applied Zoology, National Research and Innovation Agency (BRIN), Cibinong-Bogor 16911, Indonesia
6 STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou, 515063, Guangdong, China
7 Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, College of Fisheries, Henan Normal University, Xinxiang, 453007, China

Abstract

Bilateral organisms often exhibit asymmetric body traits that serve different biological functions. Heterochely and handedness are especially common in crabs as crab chelipeds are used in food acquisition, courtship and mating, and territorial defense. However, little is known about the heterochely status of the economically important mud crab Scylla olivacea. Based on the analysis of 151 healthy individuals with intact appendages, we confirmed that S. olivacea is heterochelous, and most (70.2%) were right-handed, based on the significantly larger propodus length (PL), propodus depth (PD) and propodus width (PW) of the right cheliped and the presence of molariform teeth. The size of PL, PD, and PW on the major cheliped, regardless of if the major cheliped is left. Heterochely in S. olivacea is not influenced by sex. Understanding the heterochely and handedness of mud crabs is beneficial for the optimisation of limb autotomy method and mud crab aquaculture sector.

Keywords: Heterochely- mud crab- right-handedness- cheliped size- asymmetric body traits.

Topic: Aquatic Ecology and Conservation