The importance of environmental factors on scorpion populations in tropical forests

Scorpion ecology is still relatively unknown (with the exception of Gary Polis' and co-workers' extensive studies on North American desert scorpions), especially in tropical forests. Andre Lira and co-workers have now published a study on how environmental factors have an impact on the population structure on co-occuring scorpion species in a tropical forest.

The authors compared the relative abundance of Tityus pusillus Pocock, 1893 and Ananteris mauryi Lourenço, 1982 (Buthidae) and investigated how these species respond to habitat changes (remnant areas, understory density, diameter at breast height (DBH) of tree, canopy openness) and microhabitat requirement (litter depth and dry mass).

The results of this work suggests that environmental factors on a microhabitat scale rather than broad-scale variation in the forest fragments had more influence on the abundance of the leaf litter scorpions T. pusillus and A. mauryi in the Brazilian Atlantic Forest. Furthermore, differences related to hunting behavior (sit-andwait or wandering) and microhabitat selection may explain the influence of litter dry mass on the abundance of T. pusillus but not on the abundance of A. mauryi.

Abstract:
Understanding scorpion responses to environmental disturbances in forest remnants is important because, as generalist predators, they exert pressure on a wide variety of arthropod populations that contribute to forest health. In this study, we investigate the drivers of scorpion Tityus pusillus Pocock, 1893 and Ananteris mauryi Lourenço, 1982 abundance in 11 Brazilian Atlantic Forest remnants. Six environmental factors (litter dry mass, remnant area, leaf litter depth, diameter at breast height of tree, canopy openness, and tree density) were assessed. Field surveys were conducted at night using ultraviolet lamps. From a sample of 1125 captured specimens, approximately 90% were T. pusillus and 7% were A. mauryi. The abundance of T. pusillus, but not A. mauryi, was positively correlated with litter dry mass. Other variables had no effect on the abundance of either species. These results suggest differences in the response of the species to environmental factors on a smaller scale. Behavior difference in foraging between T. pusillus (sit-and-wait) and A. mauryi (wandering) and microhabitat selection may also contribute to explain the influence of litter dry mass on the abundance of T. pusillus but not on the abundance of A. mauryi.

Reference:
Lira AFA, Rego FNAA, Albuquerque CMR. How important are environmental factors for the population structure of co-occurring scorpion species in a tropical forest? Can J Zool. 2015;93:15-9. [Subscription required for full text]

Thanks to Andre Lira for sendign me his paper!