Received: February 18, 2005, Accepted: June 10, 2005, Published online: February 24, 2006.

SELECTION OF ENVIRONMENTAL TEMPERATURE BY THE YELLOW SCORPION Tityus serrulatus LUTZ & MELLO, 1922 (SCORPIONES, BUTHIDAE)

HOSHINO K. (1), MOURA A. T. V. (1), DE PAULA H. M. G. (1)

(1) Department of Biological Sciences, Faculty of Sciences, São Paulo State University, UNESP, Bauru, São Paulo, Brazil.

ABSTRACT: The preferred temperature of the yellow scorpion Tityus serrulatus was investigated since its dispersion is a matter of concern. Adult T. serrulatus, weighing 1.24 + 0.20 g (mean + sd) and with a standard length of 59.3 + 2.5 mm, were used. A metallic corridor (120 cm long, 5 cm large and 10 cm high) with thermal gradient ranging from 0°C to 40°C was used. Tityus serrulatus chose and stayed in temperatures ranging from 14°C to 38°C when safe conditions were offered (dark and thigmotactic stimuli). The number of animals that remained in the 11°C-20°C, 21°C-30°C, and 31°C-40°C temperature zones were 8, 8, and 9, respectively. The chi-square test (degree of freedom = 2) showed that differences were not significant (p>0.05). Some animals moved to lower temperature areas (less than 8°C) when the corridor was completely illuminated and thigmotactic stimuli were absent, which led the animals to present a torpor state. It is concluded that T. serrulatus does not select a specific environmental temperature. Associated with the capacity of temporally surviving at low temperatures, this species seems to be highly adaptable to different thermal zones.

KEY WORDS: Tityus serrulatus, scorpion, temperature, thermal gradient, zoogeography.

CORRESPONDENCE TO:

KATSUMASA HOSHINO, Departamento Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista (UNESP), 17033-360, Bauru, SP, Brasil. Phone: +55 14 3103 6078. Fax: +55 14 3103 6092. Email: hoshino@fc.unesp.br