The Influence of Habitat Structure On a Nolis Foraging Behavior

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Abstract
1. A series of seven species of Anolis lizards was studied at two sites in southwest Haiti (Ducis, 350 m, and Les Platons, 750 m). Data consisted primarily of continuous observations of individuals. 2. Species differed in their structural microhabitats by the heights and diameters of their perches. Species occupying larger perches and perches higher above the ground tended to confine their movements to a perch surface rather than jumping between surfaces. 3. A series of six "foraging zones" was recognized. These were specific configurations of surfaces which were believed to influence the scanning and movement patterns of hunting lizards. 4. Comparisons of the distributions of distances between scanning locations and waiting times between moves for all species showed patterns consistent with the size and complexity of the area scanned. 5. Differences in orientation in space and with respect to the perch surface were consistent with predicted movement and scanning patterns of particular foraging zones. 6. Plots of waiting time versus distance moved were used to distinguish species with different search strategies but similar rates of progression through the habitat. 7. A stylized diagram of foraging zones as they are connected in a typical habitat was used to compare the niche breadths of the seven species. Species which used a wider array of foraging zones were most widely distributed in southwest Haiti. 8. Although all the species could be classed as sit-and-wait predators, the various analyses revealed consistent site-specific foraging patterns which can be functionally related to the structural configuration of foraging zones. 9. It is suggested that optimal choice of patch types (structural microhabitats) is influenced by the locomotion costs associated with hunting in each patch type. Selection should act to enhance adaptation for site-specific foraging which will reinforce the predictions of the niche compression hypothesis. 1. A series of seven species of Anolis lizards was studied at two sites in southwest Haiti (Ducis, 350 m, and Les Platons, 750 m). Data consisted primarily of continuous observations of individuals. 2. Species differed in their structural microhabitats by the heights and diameters of their perches. Species occupying larger perches and perches higher above the ground tended to confine their movements to a perch surface rather than jumping between surfaces. 3. A series of six "foraging zones" was recognized. These were specific configurations of surfaces which were believed to influence the scanning and movement patterns of hunting lizards. 4. Comparisons of the distributions of distances between scanning locations and waiting times between moves for all species showed patterns consistent with the size and complexity of the area scanned. 5. Differences in orientation in space and with respect to the perch surface were consistent with predicted movement and scanning patterns of particular foraging zones. 6. Plots of waiting time versus distance moved were used to distinguish species with different search strategies but similar rates of progression through the habitat. 7. A stylized diagram of foraging zones as they are connected in a typical habitat was used to compare the niche breadths of the seven species. Species which used a wider array of foraging zones were most widely distributed in southwest Haiti. 8. Although all the species could be classed as sit-and-wait predators, the various analyses revealed consistent site-specific foraging patterns which can be functionally related to the structural configuration of foraging zones. 9. It is suggested that optimal choice of patch types (structural microhabitats) is influenced by the locomotion costs associated with hunting in each patch type. Selection should act to enhance adaptation for site-specific foraging which will reinforce the predictions of the niche compression hypothesis.