Seasonal variations in scorpion activities (Arachnida: Scorpiones) in an area of caatinga vegetation in northeastern Brazil

Abstract

Seasonal variations in scorpion activity were investigated during a 24 month period in an area of Caatinga (dryland) vegetation in the state of Paraíba, Brazil. The total number of scorpions captured was correlated with climatic variables and prey abundance. Scorpions were captured monthly using pitfall traps; their potential prey was captured using malaise, beating trays and pitfalls. A total of 104 scorpions were captured, representing four species: the bothriurids Bothriurus asper (Pocock, 1893) (n = 74; 71.2%) and B. rochai (Mello-Leitão, 1932) (n = 20; 19.2%), and the buthids Rhopalurus rochai (Borelli, 1910) (n = 4; 3.8%) and Tityus stigmurus (Thorell, 1876) (n = 1; 1.0%). The sex ratios (male:female) of the two most abundant species were 14:1 for B. asper and 7:1 for B. rochai. The abundance of scorpions captured was significantly correlated with precipitation, real evapotranspiration, and abundance of invertebrates (mainly insects). Scorpion activities, especially those of B. asper and B. rochai, may be closely related to their reproductive cycles. Reproduction apparently reaches its maximum when there is an abundance of food, which in the Caatinga is strongly associated with rainfall patterns. © 2010 Sociedade Brasileira de Zoologia.