Some Niche Differences in Three Lesser Antillean Lizards of the Genus Anolis

Abstract

This paper documents interspecific and intraspecific differences in certain niche parameters among 3 species of lizards of the genus Anolis occurring in the southern Lesser Antilles. The 2 species whose ranges broadly overlap in Grenada show significant differences in body temperatures and food size distributions. Although there is considerable difference in the maximum size attained by the 2 species, animals with identical head and body lengths have radically contrasting distributions of prey size: smaller individuals of the larger species take larger food than larger individuals of the smaller species. The rate of increase of average prey length with increasing head length for the smaller species is lower than that for the larger one. In all species, the larger adult makes take significantly larger prey than adult females or subadult males. For the 2 species on Grenada, adult females take significantly smaller food than subadult males of the same species and head length; there is a slight reversal of this trend for the solitary species on Martinique. For all 3 species, adult males eat a greater amount of plant matter and draw more of their prey from fewer taxonomic categories than do lizards of the smaller—sized classes, In general, as the size of lizard increases, range of prey size increases and the number of prey items ingested decreases; variances for these distributions are quite large. Modes of niche segregation on Grenada are contrasted with those among anoles of other small islands, and hypotheses are offered as to how climatic features and the spatial arrangement of individuals of varying size within a species might determine the critical niche dimensions.

Influence of structural habitat use on the thermal ecology of Gonatodes humeralis (Squamata: Gekkonidae) from a transitional forest in Maranhão, Brazil

“…If there is sexual dimorphism in size, the match between lizard and perch may reduce intraspecific competition by habitat partitioning (COLLETTE 1961, SCHOENER 1968, WILLIAMS 1983, LOSOS 1990). However, the sexual dimorphism in size observed for G. humeralis in this study was less pronounced than that observed for Anolis species, from which habitat partitioning related to the match between lizard size and perch diameter has been repeatedly reported (SCHOENER 1968, SCHOENER & GORMAN 1968, HUEY et al 1983. Moreover, many studies have demonstrated that in areas with marked rainfall seasonality, arthropods are more abundant during the rainy season (e.g., BALLINGER & BALLINGER 1979, GRIFFITHS & CHRISTIAN 1996 which may reflect a higher abundance of resources.…”

Nonsynchronous Spatial Overlap of Lizards in Patchy Habitats

“…Insolation preferences of the two species contrast throughout Grenada. In the same species, the larger the head and body size, the larger the average prey size and proportion of large prey (for an elaboration see Schoener and Gorman 1968). Despite highly significant statistical differences between the prey size distribu-1 Received February 7, 1969;accepted October 9, 1%9. tions of the two species, common utilization of certain prey sizes was considerable.…”

Characterization of the larval stages of Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) using head capsule width

“…1, that the inclination of the regression line was significant (p < 0.05), the progression of the line occurred within Dyar's constant. The diferential growth from one instar to the other suggests to us that this occurs due to the superposition of niches, for, the fewer the larval instars, the greater will be the competition for food items of a given dimension studies in bird populations (MacArthur, 1958;Orians & Horn, 1969;MacArthur, 1971;Cody, 1974;Diamond, 1975;Hespenheide, 1975), in rodent populations (Brown, 1975;Rosenzweig et al, 1975;Mares & Williams, 1977), in lizard populations (Schoener & Gorman, 1968;Pianka, 1973;Schoener, 1975) and in fish populations (Zaret & Rand, 1971;Roughgarden, 1974;Werner, 1977), have suggested that competition exerts a major part regarding structure and function within the communities. These studies have shown that that the differential utilization of micro-habitat and food (size and/or taxons) were the factors that most influenced the minimization of competition and yet contributing to establish coexistence.…”