First record of Thaumasia Perty, 1833 nursery web spider (Araneae: Pisauridae) preying upon Polistes canadensis (Linnaeus, 1758) (Hymenoptera: Vespidae) in the Neotropical region

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  First record of Thaumasia Perty, 1833 nursery web spider (Araneae: Pisauridae) preying upon Polistes canadensis (Linnaeus, 1758) (Hymenoptera: Vespidae) in the Neotropical region Abstract Thaumasia Perty, 1833 are opportunistic spiders that inhabit the Neotropical region. This study reports a spider of the genus Thaumasia preying upon Polistes canadensis (Linnaeus, 1758) in semiarid region of Brazil. A spider of the genus Thaumasia was observed moving rapidly from the fountain's water surface to capture an individual of P. canadensis . After successfully capturing the wasp, Thaumasia sp. was observed partially perched on the wall of the fountain, with the prey still on the water surface and trapped by its chelicerae. The pedipalps and chelicerae of Thaumasia sp. manipulated the head of P. canadensis , which stopped moving shortly after being captured, probably because of the action of the spider's venom. The study records a wasp in the diet of Thaumasia based on the ca...

Dimorphism in male pedipalps affects the reproductive behaviour in the litter-dwelling scorpion Tityus pusillus Pocock, 1893 (Scorpiones: Buthidae)

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ABSTRACT

This study investigates male pedipalp chela dimorphism and its association with reproductive behaviour in the litter-dwelling scorpion, Tityus pusillus. Using geometric morphometrics, two distinct male morphotypes were identified based on pedipalp chela shape: robust and gracile. These morphotypes were associated with measurable variation in courtship behaviour aspects. Males with robust chelae performed a higher number of reproductive attempts and female manipulations than gracile-chela males, although these differences were not statistically significant. Notably, robust-chela males completed courtship significantly faster than gracile-chelae males (8.03 ± 5.14 minutes vs. 18.40 ± 13.84 minutes), measured as the time until mating successful conclusion. Both morphotypes exhibited similar reproductive success rates (37% and 31%, respectively). These results indicate that robust and gracile differ in courtship dynamics, particularly in courtship duration and patterns of female handling. Variation in female resistance during courtship may help explain why male reproductive behaviours vary. This study documents male chela dimorphism in T. pusillus and reports its correlation with variation in courtship behaviour.

Macedo Pordeus, L., & Felipe de Araujo Lira, A. (2026). Dimorphism in male pedipalps affects the reproductive behaviour in the litter-dwelling scorpion Tityus pusillus Pocock, 1893 (Scorpiones: Buthidae). Invertebrate Reproduction & Development, 1–6. https://doi.org/10.1080/07924259.2026.2622073