Sexual dimorphism and reproductive behavior in Tityus pusillus from Brazil

Behavior studies of scorpions are not that common and we still have much to learn about different types of scorpion behavior. Andre Lira and co-workers have now published a new study investigating the sexual dimorphism and reproductive behavior in Tityus pusillus Pocock, 1893 (Buthidae) from Brazil. They have mapped the different behavior components involved in reproduction in this species and have analyzed the sexual dimorphism present in T. pusillus. See abstract and article for further details.

Abstract:
We studied sexual dimorphism (SD) and reproductive behavior in the litter-dwelling scorpion, Tityus pusillus. SD was determined by measuring seven body structure attributes (prosoma, mesosoma, and metasoma lengths, and pedipalp chelae and metasomal segment V lengths and widths) in 634 individuals (211 males and 423 females) from the Arachnological Collection of the Universidade Federal de Pernambuco. Reproductive behavior was observed in 55 couples during nocturnal activity observations conducted in the laboratory. In addition, we evaluated gestation time, hemispermatophore replacement, and sequential courtship. Individuals of T. pusillus exhibited typical reproductive behavior, with a short courtship time (averaging 10 5 min). Males only accepted new partners at least 48 h after first mating, suggesting that this period may be necessary for hemispermatophore production. Females did not accept new partners for 24–48 h after their first mating. The average gestation period was 85 12 d, ranging 60–100 d. Our results showed a more complex picture of SD than previously described for this species, including features characteristic of both sexual size dimorphism (SSD) and sexual body component dimorphism in scorpions. In general, considering the relatively large size of the prosoma and mesosoma in T. pusillus, it seems reasonable to conclude that female-biased SSD exists in the species, and that male-biased sexual body component dimorphism is evident in the metasoma and chelae.

Reference:
Lira AF, Pordeus LM, Rego FN, Iannuzzi K, Albuquerque CMJIB. Sexual dimorphism and reproductive behavior in the Brazilian scorpion Tityus pusillus (Scorpiones, Buthidae). Invertebr Biol. 2018;137(3):221-30. [Subscritpion required for full text]

Thanks to Andre Lira for sending me their article!