Distinct edge effects and reproductive periods of sympatric litter-dwelling scorpions (Arachnida: Scorpiones) in a Brazilian Atlantic forest

Genotoxic Effects of Anthropogenic Environments in the Leaf Litter-dwelling Scorpion Tityus pusillus Pocock, 1893 (Scorpiones; Buthidae)

Invertebrates are harmed by pollution of their habitats. Litter-dwelling sedentary scorpions, such as Tityus pusillus, studied here, may be good models for examining the genotoxic effects of xenobiotics in soil. Thirty specimens were collected from five sites in Northeast Brazil with different levels of human disturbance, as well as a laboratory group. The comet assay was performed on hemolymph cell samples. Damage Index (DI) and Damage Frequency (DF%) were measured. Much higher genotoxicity was observed in animals collected in an area with human interference and solid waste, compared to those obtained in more pristine areas or the laboratory. T. pusillus may be a useful model for environmental genotoxicity assays.

Vegetation structure as the main source of variability in scorpion assemblages at small spatial scales and further considerations for the conservation of Caatinga landscapes

Even at the local scale, environmental changes due of anthropogenic actions represent a source of disturbance in terrestrial ecosystems, forcing species to respond according to their ecological plasticity. Thus, stenotopic species and those with low-dispersal ability will likely be negatively affected by landscape modifications that reduce environmental complexity. In this study, we identify and quantify the effects of biotic and abiotic factors related to habitat complexity on the variation in scorpion assemblages in terms of both species’ richness, abundance and composition across 18 transects covering Caatinga landscapes with different levels of degradation. Using ultraviolet flashlights, we sampled 269 scorpions, belonging to six species and two families. The results showed contrasting patterns of species richness and abundance that depend on the level of habitat complexity. More specifically, we reported that scorpion species richness could be predicted by the number of trees, while the coefficient of variation of the diameter at breast height of trees (cvDBH) is a predictor of scorpion abundance. These findings suggest that vegetation structure is deterministic for the maintenance of scorpion assemblages in Caatinga landscapes. In addition, the cvDBH and tree number may explain 39% and 40% of the variability observed amongst scorpion assemblages in terms of richness difference and species composition, respectively. This study provides insights concerning the development of conservation strategies, clarifying the role of habitat complexity for the preservation of low-dispersal animals in neglected environments, such as those within the Caatinga domain.

Male courtship behavior is triggered by female chemical cues in the scorpion Tityus pusillus (Scorpiones: Buthidae)

Recognizing conspecific individuals from other members of the community is important for many interactive behaviors, especially those involved in mate selection. We investigated whether male courtship behavior is triggered by chemical cues left by females on the substrate using the sedentary litter-dwelling scorpion Tityus pusillus Pocock, 1893, which is a small and common species distributed throughout the northeast Atlantic Forest in Brazil. In experiments using 50 pairs, we tested whether males recognize females by detecting sex-specific chemicals on the substrate. All males changed their behavior, performing pre-courtship acts when exposed to female-specific chemicals on the substrate, but they did not change their behavior when exposed to a clean substrate lacking female-specific chemicals. These results show that the male T. pusillus alters its behavior in the presence of female chemical cues, suggesting that males recognize females by detecting compounds left on the substrate and that the presence of these chemicals trigger the courtship behavior of the male T. pusillus.