Short Notes Activity temperatures in Oplurus cyclurus, Oplurus cuvieri and Zonosaurus laticaudatus and resting metabolic rates in the latter two species Herilala Jean Aimé Rodolph Randriamahazo Laboratoryof Ethology,Department of Zoology,Faculty of Science,Kyoto University, Kitashirakawa-Oiwakecho,Sakyo-ku, Kyoto 606-01, Japan email:
[email protected] During activity, lizards usually maintain body temperatures within a relatively narrow range which encompasses their optimal body temperature, in spite of ambient tempera- tures that may fluctuate considerably (Avery, 1982). Huey (1982) defines microhabitat use by the complex interactions between abiotic and biotic factors. Simplifying this com- plexity, an important abiotic factor influencing ectotherm life histories and growth rate is temperature (Sinervo and Adolph, 1989, 1994; Sinervo, 1990). Moreover, microhabi- tat differences between some sympatric lizards reflect differing temperature preferences (Roughgarden et al., 1981; Hertz, 1992; Grover, 1996). In this paper, I report observa- tions on activity temperatures and distribution patterns in three Malagasy diurnal lizards species. Their distribution ranges overlap in Ampijoroa forest (Preston-Mafham, 1991; Glaw and Vences, 1994). Resting metabolic rates were also compared between the two medium-sized species, Zonosaurus laticaudatus (Gerrhosauridae) a ground burrowing lizard, and Oplurus cuvieri (Opluridae), an arboreal species. Oplurus cyclurus, the third species, is a rather small arboreal lizard that appears allotopic but also uses commonly the ground to catch large prey (Brillet, 1982; Meier, 1988). The climate in Ampijoroa is relatively dry, sub-arid with a low and seasonal pre- cipitation (Nicoll and Langrand, 1989). The physiognomy of the vegetation is rather interesting. Even on a very small scale, large trees with wide canopy are abundant in lower altitudes whereas shrub-like irregularly distributed trees constitute the vegetation of higher places with west-facing slope (Razafy, 1987).