Editorial Type:
Article Category: Research Article
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Online Publication Date: 01 May 2002

Life in Shade: The Ecology of Anolis trachyderma (Squamata: Polychrotidae) in Amazonian Ecuador and Brazil, with Comparisons to Ecologically Similar Anoles

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Page Range: 275 – 286
DOI: 10.1643/0045-8511(2002)002[0275:LISTEO]2.0.CO;2
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Abstract

The Amazonian lizard Anolis trachyderma was studied at three sites stretching from eastern Ecuador to the central Amazon of Brazil. These lizards occupy low vegetation and leaf litter microhabitats in well-shaded, damp rain forest. Their body temperatures are low (27.8 C on average) and only slightly higher than corresponding substrate and air. They are as likely to be active on cloudy as on sunny days but are usually found in shade. The diet is varied, but dominated volumetrically by grasshoppers-crickets, insect larvae-eggs-pupae, spiders, roaches, and lizard shed skin. Although dietary overlaps among populations are low, no significant differences in prey choice existed based on a randomization analysis. Locality-based and sexual variation in morphology was evident. Overall, A. trachyderma appears similar ecologically across a large portion of the Amazon. Comparisons with three ecologically similar anoles, Anolis nitens scypheus (sympatric with A. trachyderma) and Anolis humilis (no range overlap), reveal similar microhabitat use, body temperatures, and diets, but substantially different morphology. The ecomorph concept may not apply as well to mainland anoles as to island ones, possibly because taxonomically distant lizard species may have had a stronger historical effect on mainland anoles than on island species.

Copyright: The American Society of Ichthyologists and Herpetologists
 Fig. 1. 
 Fig. 1. 

Top panel: Variation among sites in habitat use by Anolis trachyderma. Bottom panel: Variation among sites in microhabitat use

 Fig. 2. 
 Fig. 2. 

Relationship between lizard body temperatures and substrate temperatures for Anolis trachyderma. Regression line and 95% confidence interval of the mean are shown

 Fig. 3. 
 Fig. 3. 

Daily activity pattern of Anolis trachyderma at three Amazonian localities

 Fig. 4. 
 Fig. 4. 

Variation in prey use among populations of Anolis trachyderma. Prey categories are: Ss = lizard shed skin, A = ants, B = beetles, E = earwigs, F = flies, G = grasshoppers-crickets, He = hemipterans, Ho = homopterans, Hy = hymenopterans, Is = isopods, La = larvae, eggs, pupae, Le = lepidopterans, M = millipedes, Mi = mites, Mo = mollusks, Ps = pseudoscorpions, R = roaches, Sp = spiders, St = springtails, T = termites. n = number of lizards

 Fig. 5. 
 Fig. 5. 

Relationship between lizard stomach volume and body size for Anolis trachyderma. Regression line and 95% confidence interval of the mean are shown. The upper line (dashed) is an estimate of full stomach volume based on a combination of the regression slope and the fullest stomachs

 Fig. 6. 
 Fig. 6. 

Distributions of mean prey sizes (volumes) for individual Anolis trachyderma from three localities

 Fig. 7. 
 Fig. 7. 

Top panel: Plot of first two axes from size-adjusted PCA scores based on regression residuals from regressions of morphological variables on body size. Envelopes indicate different localities. Bottom panel: Same plot but comparing sexes

 Fig. 8. 
 Fig. 8. 

Size-adjusted PCA scores based on residuals from regressions of morphological variables on body size comparing Anolis trachyderma, Anolis nitens scypheus, and Anolis humilis. Envelopes enclose species

Received: 28 Mar 2001
Accepted: 06 Dec 2001
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