Sexual Dimorphism in the Asian Giant Forest Scorpion, Heterometrus laoticus Couzijn, 1981

Abstract

Morphological characters of adult male and adult female giant forest scorpions,Heterometrus laoticus, in a mixed deciduous forest at Phitsanulok Wildlife ConservationDevelopment and Extension Station showed sexual dimorphism. Among the observedcharacters, carapace width, chela length, chela width, telson length and shape of movablefinger of adult male and female scorpions were obviously different. The pectines of maleswere also significantly longer, and the number of sensilla-bearing teeth in male scorpionswas more than in females. Moreover, males had higher density of sensilla on the pectinalteeth than females. During the breeding season, mature males were mobile while maturefemales were mainly at their burrows.