Ecology and reproductive biology of Acanthodactylus schmidti in Central Arabia

Abstract

The ecology and reproductive biology of Acanthodactylus schmidti (lacertidae) in Central Arabia north of Riyadh was studied from 1983 to 1985. The ecology of Acanthodactylus boskianus was also studied as a comparison during the same period. Growth of both species, survival and the morphological adaptations to the desert environment were examined. Home range size of both species was estimated in the study area. Home range size of male A. schmidti was four times that of the female's home range during spring. The male A. boskianus home range was about two times greater than that of the females. Utilization of home range and the social interactions of invdividuals of both species was investigated. Home range overlap, burrowing behaviour and burrow structure was also examined in the field. Male A. schmidti were observed to defend their home range against other males during spring. Activity and thermal ecology of both species was studied during winter and spring. Emergence behaviour, basking behaviour, daily and seasonal activity was studied and analysed. Both species were active throughout the year. However, it was found that during winter, activity was unimodal, which contrasted with the bimodal pattern during spring. The winter mean eccritic body temperature was 33.0 and 34.1oC for A. schmidti and A. boskianus respectively, and 36oC, 35.3oC during spring. A. schmidti was found to thermoregulate more effectively than A. boskianus during both winter and spring. Selected body temperature and critical minimum of both species were studied and measured in the laboratory. The reproductive biology of A. schmidti was studied in some detail. The reproductive season commenced in November and continued throughout May and was found to coincide with the rainy season of the area. Young lizards were observed between February and mid-June. This suggests the presence of multiple clutches (possibly 2-3) during the reproduction season. It was concluded that multiple clutches were an important adaptation for lizards in such an unpredictable desert environment. Reproductive behaviour, male and female reproductive cycle, and fat body cycle also were studied. Finally, the general ecology and conservation of Arabian desert reptiles is discussed and suggestions for management of desert reptile communities are suggested. (D73648/87)</p