New insights into maternal care and juvenile dispersal in Pterinopelma roseum (Araneae: Theraphosidae)
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Tarantulas, egg sac, dispersal, urticating setaeAbstract
Tarantulas (Theraphosidae) exhibit a wide diversity of reproductive behaviors, yet many aspects of their natural history, particularly those related to maternal care and juvenile dispersal, remain poorly known. Pterinopelma roseum is a species distributed in southern Brazil and northeastern Argentina for which information on reproductive biology is limited. The aim of this study was to document maternal care, egg sac composition, and juvenile dispersal through the monitoring of a female collected together with its egg sac in Misiones Province, Argentina. The female was maintained under controlled laboratory conditions and observed daily until juvenile dispersal. During the incubation period, the female actively protected the egg sac, remaining in contact with it most of the time and displaying defensive behaviors when disturbed, while continuing to feed regularly. The egg sac was densely covered with urticating setae, and its analysis revealed the presence of type I and type III setae. After hatching, the juveniles remained aggregated within the refuge for 13 days, and no cannibalistic events were recorded. Subsequently, they initiated terrestrial dispersal characterized by movement in single-file formations and the deposition of silk threads on the substrate. A total of 382 juveniles emerged from the egg sac. These findings expand current knowledge of the reproductive biology of P. roseum and provide novel information for understanding the natural history of Neotropical tarantulas.
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