Geographical Variation in the Ecology of Populations of Some Brazilian Species of Cnemidophorus (Squamata, Teiidae)
We investigated geographical variation in ecological parameters among populations of Cnemidophorus cryptus, Cnemidophorus gramivagus, Cnemidophorus lemniscatus, Cnemidophorus ocellifer, and Cnemidophorus parecis, from three Brazilian biomes (Cerrado, Caatinga, and Amazonian Savannas). Lizards used mainly the open ground, with a high similarity in microhabitat use among populations. Differences in microhabitat use probably resulted from the availability of microhabitats and not from microhabitat preferences. Body temperatures were high and little influenced by environmental temperatures, there being no differences among populations. There were significant differences in diet among populations, with C. ocellifer from Caatinga and Cerrado consuming large quantities of termites, whereas Amazonian Savanna species used primarily ants and insect larvae. The data on reproductive seasonality indicated cyclical reproduction in seasonal biomes and continuous reproduction in unpredictable climate regions. We found significant differences in mean clutch size among populations, independent of body size, with C. lemniscatus having the smallest clutch size (1.50) and C. ocellifer from Cerrado the largest (2.10). There were fewer differences in clutch size among species from Amazonian Savannas, than between populations of C. ocellifer from Caatinga and Cerrado. Apparently, populations under seasonal climates concentrate their reproductive effort during the short reproductive season, producing larger clutches, whereas those under more stable or unpredictable climates reproduce continuously, yielding smaller clutches, corroborating the hypothesis that environmental conditions exert an important influence upon life-history parameters. There were significant differences in body shape among populations, but most of the variation was related to sex. We also observed significant differences in body size among populations, seemingly unrelated to differences in community structure, but the highly conservative morphology of Cnemidophorus species suggests the presence of historical constraints.Abstract
Collecting localities of Cnemidophorus from Brazil. 1, Brasília (30); 2, Pirenópolis (90); 3, Cristalina (25); 4, Caldas Novas (6); 5, Alto Paraíso (28); 6, Minaçu (144); 7, Mineiros (4); 8, Barra do Garças (60); 9, Chapada dos Guimarães (35); 10, Vilhena (103); 11, São Domingos-GO (10); 12, Mateiros (33); 13, Palmas (43); 14, Sebastião Laranjeiras (4); 15, Cocos (3); 16, Coribe (19); 17, Correntina (16); 18, Irecê (32); 19, Salvador (3); 20, Paulo Afonso (3); 21, Exu (33); 22, Humaitá (62); 23, Boa Vista (40); 24, Alter do Chão (53); 25, Macapá (62); and 26, Tartarugalzinho (17). Sample size in parentheses. Adapted from “Mapa de Vegetação do Brasil” by Instituto Brasileiro de Geografia e Estatística (IBGE)
Frequency distribution of individuals according to microhabitat categories, for four species of Cnemidophorus from Brazil. Sample sizes are indicated at the top of the bars
Frequency distribution of individuals collected according to hour of the day, for five species of Cnemidophorus from Brazil. Sample sizes are indicated at the top of the bars
Cluster analysis calculated with the diet similarity index of six Cnemidophorus populations from Brazil
Scores of first two canonical discriminant functions derived from size-adjusted morphometric variables of six populations of Cnemidophorus from Brazil. Horizontal and vertical lines represent one standard deviation, above and below the mean canonical score. Cnemidophorus cryptus: butterfly, Cnemidophorus gramivagus: triangles, Cnemidophorus lemniscatus: diamonds, Cnemidophorus ocellifer from Caatinga: squares, C. ocellifer from Cerrado: circles, Cnemidophorus parecis: inverted triangles. Empty symbols indicate males and filled symbols indicate females.