Aspects of the biology of the cool-temperate scorpion : Cercophonius squama in Tasmania

This project investigated sexual dimorphism of the scorpion, Cercophonius squama, in southern Tasmania using morphometrics. Results were applied in a population investigation, which explored the density and seasonal variability of activity in a population of scorpions in Hobart, Tasmania. The reproductive behaviours were observed and recorded for the first time in this species and a predictive model of distribution for C. squama in Tasmania was developed. A set of eight measurements was taken from individuals and a MANOVA was performed to test for any differences between the sexes. A capture mark and release program was employed to study the size and surface activity of the population during the summer months. Reproductive behaviours were recorded in the laboratory under low intensity red and white light. A new biogeographical regionalisation model for Tasmania was used to develop a theoretical distribution of C. squama in the state. Males and females are significantly different from each other using morphometrics. Additionally, a secondary sexual characteristic was found in mature males that can identify sex in adults. Seasonal activity is different between males and females. Females have a peak in late spring, which coincides with the late stages of embryonic development. The surface activity of males increases throughout the summer to peak in autumn during the mating season. Juveniles are less abundant than adults and do not demonstrate a peak in activity during anytime of the year. Females give birth to 20-30 young during late summer to autumn in southern Tasmania. Mating occurs in autumn, soon after birth. A naïve model was developed that needs verification with sampling of predicted areas. This study gained valuable information about the biology of C. squama that can be used in future investigations. This scorpion appears to demonstrate life history strategies similar to those of other scorpions (vivipary). An environmental cline in reproduction may occur across the state with the colder, higher elevation regions lagging behind in the time of year in which females give birth. Investigations into population dynamics, geographical variation and reproductive ecology can now be undertaken with this species