John S. Parmerlee

Population Densities, Water-loss Rates, and Diets of Sphaerodactylus Vincenti on St. Vincent, West Indies

Abstract We documented population densities, microhabitat preferences, desiccation rates, and diets of Sphaerodactylus vincenti on St. Vincent, West Indies. We predicted and observed high densities (to 5,625/ha) in moist, shaded leaf-litter. Such microhabitats provide refuges, access to prey, and protection against water loss, because S. vincenti is vulnerable to high desiccation rates. We found significant differences in mass-specific water-loss rates and body mass between conspecific populations at differing elevations, with larger geckos less resistant to water loss living in more mesic environments at higher elevations. Stomach content analysis suggests that S. vincenti is a dietary generalist that feeds on a variety of small arthropods primarily by day.

NICHE DIFFERENCES AMONG THREE SYMPATRIC SPECIES OF AMEIVA (REPTILIA : TEIIDAE) ON HISPANIOLA

GREENE, H. W. 1988. Antipredator mechanisms in reptiles. In C. Gans and R. Huey (eds.), Biology of the Reptilia, Vol. 16. Ecology, Defense, and Life History, pp. 2-151. Alan Liss, New York. KLUMP, G. M., AND E. CURIO. 1983. Reactions of blue tits Parus caeruleus to hawk models of different sizes. Bird Behav. 4:78-81. MACIAS GARCIA, C., AND H. DRUMMOND. 1995. Components of visual prey recognition by the Mexican aquatic garter snake Thamnophis melanogaster. Ethology 101:101-111. MOORE, E. L., AND H. C. MUELLER. 1982. Cardiac response of domestic chickens to hawk and goose models. Behav. Process. 7:255-258.

Herpetofaunal communities of the leeward slopes and coasts of St. Vincent: A comparison of sites variously altered by human activity

Like other Lesser Antillean islands, human-modified habitats are prevalent on much of St. Vincent, especially in coastal regions. Eighteen terrestrial species of reptiles and amphibians are known to occur on the island. Some species demonstrate considerable versatility, and are found in both altered and relatively natural habitats. Others, however, are restricted to one extreme or the other. To better understand the composition of herpetofaunal communities, we surveyed seven sites on the leeward side of the island, chosen to represent different degrees of human alteration. We found the highest diversity index in an urban area, where introduced species prevailed. Endemic species were more abundant in more natural sites. Three species, Eleutherodactylus johnstonei, Anolis griseus, and A. trinitatis, were at all sites.

Foraging Behavior in the Arboreal Boid Corallus grenadensis

Corallus grenadensis is an arboreal boa endemic to the Grenada Bank. Thirty-five encounters with boas resulted in 17.65 hours of observations, including 6.3 hours of video-tape (which included two acts of predation). Boas under 100 cm are largely active foragers that move slowly through bushes and trees and tongue-flick leaf and branch surfaces apparently seeking chemosensory evidence of nocturnally quiescent lizard (Anolis) prey. Significantly more search time was directed to branches below the snake rather than to either the branches supporting the snake or to those above the snake, and tongue-flick rates were significantly higher for moving snakes than for those that were stationary. Smaller snakes prey on nocturnally quiescent lizards and they spent more time moving than did large snakes that feed on nocturnally active rodents and often employ an ambush foraging strategy. Once visual and, presumably, thermal information was received from a sleeping anole, C. grenadensis adopted a lengthy stalking process devoid of tongue-flicks. Snakes approached inactive lizards from adjacent branches with great stealth, moving at a rate of about 1 cm/min. The strike was made from close range (within 3 cm), and the prey was never released once contact was made. We conclude that, if chemosensory cues successfully lead a treeboa to a visual encounter with a sleeping lizard, subsequent behavior ensures a high rate of predation success.

Four new coccidia (Apicomplexia: Eimeriidae) from anoles (Lacertilia: Polychrotidae) in the Dominican Republic.

Fecal samples from 25 Anolis armouri, 2 Anolis bahorucoensis, 48 Anolis cybotes, and 21 Anolis olssoni (Lacertilia: Polychrotidae) from southern Hispaniola were examined for coccidian oocysts. Two eimerians and 2 isosporans are herein described as new species. Sporulated oocysts of Eimeria schwartzi n. sp. from A. armouri are ellipsoidal, 22.7 (20.8-25.0) x 15.7 (14.6-17.7) microns, with spherical to subspherical sporocysts, 7.9 (6.2-9.4) x 7.4 (6.2-8.3) microns. Sporulated oocysts of Isospora reui n. sp. from A. bahorucoensis are spherical to subspherical, 18.2 (15.6-20.0) x 17.8 (15.6-19.8) microns, with ovoid sporocysts, 11.9 (10.4-12.7) x 8.5 (7.5-9.4) microns. Sporulated oocysts of Isospora hendersoni n. sp. from A. armouri and A. cybotes are spherical to subspherical, 23.2 (20.8-26.0) x 21.1 (18.4-23.9) microns, with ellipsoidal sporocysts, 14.7 (12.5-15.6) x 10.0 (9.2-11.4) microns. Sporulated oocysts of Eimeria avilae n. sp. from A. olssoni are cylindrical, 29.3 (26.0-33.3) x 15.9 (13.5-18.9) microns, with ellipsoidal sporocysts 10.2 (9.4-11.4) x 6.8 (5.2-8.0) microns.

Agonistic responses by a grass anole, Anolis olssoni from the Dominican Republic, to male conspecifics

Agonistic behaviour of male Anolis olssoni was elicited in natural habitats near Baraona, Barahona Province, Dominican Republic, through the introduction of tethered males. Videotaped responses consisted of various sequences and combinations of behaviours and modifiers and appeared to vary according to levels of arousal. Male A. olssoni assume a posture involving full head elevation and dewlap extension, which apparently signals the highest state of arousal to conspecifc males. This display was invariably accompanied by gaping with a protruded tongue, distinct extension of nuchal and dorsal crests, bulging eyes, and changes in body and tail colouration. Analysis of behaviours failed to identify a stereotypical display for this species. Males apparently monitor and defend their immediate surroundings, a strategy which may be adaptative in a densely occupied and complex microhabitat in which vision is restricted.

DO POLYMORPHIC FEMALE BROWN ANOLES (ANOLIS SAGREI) DIFFER IN SPRINT SPEED OR ESCAPE BEHAVIOR

Abstract:  The Brown Anole (Anolis sagrei) is a polymorphic species, with females often exhibiting one of three distinct pattern morphs. Efforts to correlate female-limited pattern polymorphism in anoles to ecological or physiological factors have largely been unsuccessful, with such correlations being either inconsistent among species or among populations of a single species. To test the hypothesis that morph types would differ in their response to putative predators, we observed escape behavior in 84 female A. sagrei from Cape Eleuthera (Eleuthera, Bahamas) and tested 103 females for sprint speed. We found differences between morph types in hindlimb span and perch height. Differences in sprint speed were not significant, nor did morphs differ in escape responses. We suggest further studies to determine whether differences between morphs in hindlimb span are genetic or plastic, and, if plastic, what factor might be responsible. We conclude that perching at different heights could be selectively advantageous for different morph types, and that differences among individuals in sprint speed are largely consequences of hindlimb length. Because morphs in this population did not differ in escape responses, we suggest that different dorsal patterns are not linked to specific behaviors that could reduce detection by a potential predator.

Invasive Anolis sagrei on St. Vincent and Its Potential Impact on Perch Heights of Anolis trinitatis

Abstract. The lizard genus Anolis (Polychrotidae) is essentially ubiquitous in the West Indies, with most species confined to one island bank. However, human-mediated transport of materials, plants, and animals has introduced species across natural boundaries, sometimes with deleterious effects on native anoles. Among the most recent introductions is Anolis sagrei on St. Vincent. We investigated the distribution of introduced populations and evaluated possible effects on perch heights of native anoles (A. griseus and A. trinitatis) at a site where all three species occur. We found little evidence that A. sagrei has affected either native species. Perch heights of A. trinitatis in the presence of A. sagrei were comparable to those found in habitats where A. sagrei did not occur. However, we suggest continued monitoring of this exotic on St. Vincent to evaluate potential long-term impact on native species and to determine whether any effects will extend beyond heavily altered low-elevation sites.

Rediscovery of the Grenada Bank Endemic Typhlops tasymicris (Squamata: Typhlopidae)

Abstract Typhlops tasymicris was known previously from only two specimens, both immature females collected on Grenada in 1968. In June 2010, we rediscovered the species on Union Island, St. Vincent and the Grenadines, where we encountered five individuals (and captured four) on the forested slopes above Chatham Bay. The new specimens agree closely with the two previously reported individuals for all scale characters and coloration, but they differ in sizes and proportions. At least two of the new specimens are adults, but all seem to be females. This first record of a typhlopid snake in the Grenadines suggests a greater range than indicated by the earlier specimens. Although suitable habitat occurs nowhere else on Union Island, the species could occur elsewhere in the Grenadines where relatively mature forests persist. DNA sequence data clearly show a closer affinity with South American species than with any West Indian congeners.

A Rapid Assessment of Reptilian Diversity on Union Island, St. Vincent and the Grenadines

ABSTRACT. Union Island, St. Vincent and the Grenadines (8.4 km2) has an unusually diverse reptilian fauna for such a small area, but lacks native or well-established introduced amphibians. In June 2010, we conducted a rapid assessment of 10 sites (coastal or with some variation of dry forest habitats) chosen on the basis of vegetative complexity, height and extent of canopy, and degree of human disturbance. We encountered 10 of the 15 species recorded from Union, missing only a few secretive litter-dwelling or fossorial forms and a recently introduced species for which the current status is unknown. Shannon-Weiner indices of diversity were negatively correlated with vegetative complexity, but the density of Anolis aeneus, the most frequently encountered species, was positively correlated with complexity. We supplemented the rapid assessment with visual surveys for Corallus grenadensis, an arboreal boid, smaller individuals of which feed largely on anoles. Encounter rates for C. grenadensis were not correlated with anoline densities, which we attribute to the relative paucity of both snakes and their prey on a small, dry island.