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Two hundred and forty-four specimens of Parapharyngodon riojensis n. sp. were found in the large intestines of 2 adult lizards Phymaturus punae collected from Quebrada del Leoncito, Province of La Rioja, Argentina. Parapharyngodon riojensis n. sp. represents the ninth species of the genus from the Neotropical Realm and the first species to be described from Argentina. It can be distinguished from all species of Parapharyngodon on the basis of the morphology of the anterior cloacal lip, the location of the ovary, and geographical distribution. Parapharyngodon riojensis n. sp. is most similar to P. senisfaciecaudus in that the ovary does coil around the esophagus and the number and location of caudal papillae in the males are the same. These 2 species differ in that the eggs of P. senisfaciecaudus are slightly asymmetrical, with a smooth, thin shell, whereas the eggs of P. riojensis are oval, with a punctate thick shell. In addition, the cloacal lip of males of P. senisfaciecaudus is smooth, whereas the cloacal lip of males of P. riojensis is echinate. A key to the species of Parapharyngodon in the Neotropical Realm is provided.

A 1993-1994 study of the reproductive biology of Cnemidophorus communis in the Chamela region, Jalisco, Mexico, revealed that males reached sexual maturity at a snout-vent length (SVL) of 59 mm, and females reached sexual maturity at a SVL of 68 mm. Males exhibited maximum testicular activity from May through October, decreasing in November, and females were reproductive, having vitellogenic follicles or oviductal eggs, from July through October. The mean number of vitellogenic follicles was 6.69 ′ 0.59 (2-10, n = 13) and mean clutch size of oviductal eggs was 4.8 ′ 0.44 (3-9, n = 17). Clutch size and egg mass were positively correlated with SVL but relative clutch mass remained constant among females and years. Proximal climatic factors influenced timing and intensity of reproduction in C. communis, but the historical effect of foraging mode on teiid lizard morphology constrains relative clutch mass.

Lizard distribution is described for the Vizcaino Biosphere Reserve in the northern extreme of Baja California Sur, in central Baja California. The 20 species found include 74% of all the Baja California Sur lizards, excluding insular endemics. Five species are widely distributed throughout the Reserve. Four species are restricted to sandy soils (coarse and dunes) and open spaces. Seven species are restricted to rocky areas in the Sierras. Two species are included in the CITES list and 11 in the Official Mexican Norm (NOM 059-94) in some conservation category. This Reserve contains livestock (cows and goats), whose increasing numbers and grazing areas are often unrestricted. This disturbance is a potential threat for some species, especially those with restricted distributions in the eastern sierras where there are large numbers of goats.

We studied movement behavior, activity range size, habitat use, and diet of the Grand Canyon rattlesnake (Crotalus viridis abyssus) in the Little Colorado River Canyon (Arizona) by capturing 13 rattlesnakes and equipping 9 with radio-transmitters. On average, snakes moved 45 m per movement and 26 m per day; males moved longer distances than females, but movement frequency was not significantly different between sexes. Unlike some other populations of C. viridis, Grand Canyon rattlesnakes exhibited low directionality of movements. Activity range size ranged from 30 ha among individuals, and the corridor-like nature of the canyon bottom resulted in elongate activity ranges. Prey species of rodents were common in each of 4 subhabitats on the study site, and snakes appeared to be dietary opportunists, eating a variety of rodent and lizard prey. Snakes preferentially used riparian areas and avoided floodplains. Talus and upland mesquite habitats were used in rough proportion to their availability. Differential use of subhabitat may result from thermoregulatory constraints and from variation in predictability of rodent prey.

The Cnemidophorus laredoensis complex consists of 2 all-female, diploid, parthenogenetic species designated LAR-A and LAR-B. Field observations suggest LAR-B is behaviorally dominant to LAR-A and that both species defend their burrows from intruders. These hypotheses were tested by analyzing lizard behaviors with a series of laboratory trials. Prior to a trial, an LAR-A and an ŁAR-B were isolated on opposite sides of a large terrarium for 48 h by a partition; this allowed both lizards to establish burrows on their home side. A trial consisted of removing the partition and analyzing lizard behaviors for the next 60 min. Based on the criterion of winning over 50% of encounters, the LAR-B won 11 of the 13 trials in which there was a clear winner, suggesting that LAR-B is dominant to LAR-A; however, individuals of neither species exhibited burrow defense. LAR-A and LAR-B rarely shared burrows and both appeared reluctant to enter an occupied burrow although when one lizard did so, the burrow occupant generally left the burrow. Both LAR-A and LAR-B rested in their opponent's burrow more than in their own burrow during trials, and both showed a statistically significant preference to use their opponent's burrow as their overnight retreat after the conclusion of the trial, suggesting a lack of burrow site fidelity in these species.

Although the behavioral significance of bright female coloration has been evaluated for many organisms, its role in squamates is less clear. The conditional signal hypothesis posits that bright female coloration signals are conditional upon the degree of coloration: early in the breeding season low-intensity coloration signals courtship receptivity, whereas later in the season high-intensity pigmentation signals courtship rejection. This system is adaptive if the benefits of color maintenance and expression outweigh the costs associated with conspicuous markings. Results of this work on the lesser earless lizard, Holbrookia maculata, of southern New Mexico, suggest that females (1) maximize the potential for egg fertilization by stimulating courtship with low-intensity coloration when eggs are ready for fertilization, and (2) reject courtship with high-intensity pigmentation when carrying fertilized eggs. This line of evidence establishes a more complete explanation for the adaptive role of bright female coloration in lizards. The role of secondary sexual coloration in animals has been the focus of much research (Darwin, 1871; Andersson, 1994). Results of this research suggest that coloration evolves and is I Present address: Department of Biology, Augustana College, Rock Island, Illinois 61201-2296, USA; E-mail: bihager@augustana.edu l secondary sexual coloration in anee the focus of much research (Dar; dersson, 19 4). Results of this remaintained in individuals that are successful at signaling competitive and reproductive abilities. Where secondary sexual coloration exists in an animal system, males are usually the more colorful sex. Male color intensity is correlated with fighting ability and mate choice preferences by females (Bradbury and Andersson, 1987; Andersson, 1994). In some species, females are the more brightly colored sex, and color functions 624 This content downloaded from 157.55.39.27 on Mon, 05 Sep 2016 05:46:39 UTC All use subject to http://about.jstor.org/terms NUPTIAL COLORATION IN FEMALE LIZARDS in sex role reversal or courtship by females and mate choice by males in insects, fish, amphibians, and birds (Baird, 1988; Andersson, 1994). However, bright female lizard coloration seems to operate in additional ways. Intense female pigmentation in lizards occurs in some 36 species (Cooper and Greenberg, 1992). For about half of these, coloration is brightest between ovulation and oviposition and, thus, when females are gravid (carrying fertilized eggs in the oviducts). Generally, the onset of coloration occurs shortly before ovulation, quickly brightens after ovulation (within hours), and then fades following egg laying. In species with multiple clutches of eggs per season, coloration is more complex, and many do not fade completely following oviposition (Zucker and Boecklen, 1990; T. Baird, pers. comm.). There appears to be a hormonal basis to this phenomenon because pigmentation is exogenously induced by progesterone in at least some species and in progesterone and estradiol combinations (Cooper and Clarke, 1982; Cooper and Crews, 1988). From a behavioral point of view, female aggression is sometimes positively related to color intensity (Cooper and Greenberg, 1992). Of those species for which data have been collected, bright females display aggressive behavior toward males that are interpreted by researchers as rejection of male sexual advances. Recent studies have attempted to identify the adaptive significance of such coloration in lizards (Cooper and Greenberg, 1992; Watkins, 1997). Bright coloration in female lizards may serve to advertize gender and sexual maturity (Cooper and Greenberg, 1992). That males of some species whose females lack nuptial coloration identify plainly colored females as being reproductively mature suggests bright coloration functions in other capacities. One possibility is that brightly colored females signal "territoriality" of nest sites to each other (Yedlin and Ferguson, 1973), although recent evidence for Crotaphytus collaris that tested the behavioral significance of female aggression refuted this hypothesis (Sloan and Baird, 1999). Scattered accounts suggest that females are sexually receptive to males prior to ovulation and while in the process of developing nuptial coloration (the courtship stimulation hypothesis: Fitch, 1956; Cooper and Crews, 1988) and then are nonreceptive following ovulation when pigments are vivid and near peak intensity (the courtship rejection hypothesis: Cooper, 1988; Cooper and Crews, 1988). The conditional signal hypothesis was developed in response to these two latter observations (Cooper and Greenberg, 1992). This hypothesis states that males, while monitoring their territories, detect subtle color changes in females early in the breeding season that signal sexual receptivity. Some time later, intensification of color and aggression by females signal gravidness, and any further copulation is fruitless. That is, the initial onset of coloration signals female receptivity, whereas the full color display signals rejection by the female. Adult females of the lesser earless lizard (Holbrookia maculata) of White Sands, New Mexico, exhibit the phenomenon of bright pigmentation (Dixon, 1967). However, a detailed examination of the role of bright female coloration is lacking for this species. Preliminary observations of this population suggested that gravid females exhibit bright coloration during the breeding season during which time they are aggressive toward males and that coloration fades and aggression subsides later in the breeding season when females are no longer gravid (Hager, 1998). The objectives of this study were to (1) determine whether the onset of female coloration stimulates courtship and attempted copulation in males, (2) establish that bright female coloration at its peak intensity is effective in reducing male sexual advances, and (3) ascertain the detailed relationship of coloration with behavior and reproductive state in females. MATERIALS AND METHODS Holbrookia maculata is short, stout, and dorsally pallid with fairly well-defined ventro-lateral blotches (Smith, 1943). It is the only lizard endemic to the white gypsum dunes of the White Sands National Monument (WSNM), New Mexico (Atstatt, 1939; Dixon, 1967). Norris (1967) reported that, with the exception of Uta stansburiana of the Pisgah Lava Flow, San Bernardino County, California, White Sands H. maculata exhibit the best background color match of any phrynosomatid lizard in the United States. Body coloration of mature males and females is sexually dimorphic (Clarke, 1965; Hager, In press). Two black blotches are found bilaterally on both males and females and are confined to the ventro-lateral portion of the midtorso (Stebbins, 1985). These spots are always present but are smaller and less prominent in females. Males have throat patches that range from light orange to bright crimson. Bright female coloration is a phenomenon displayed only during the breeding season, from approximately mid-May to mid-July (Dixon, 1967; Hager, In press). At this time, the throat and much of the head is bright yellow. Also, reddish-orange pigmentation is deposited laterally on the body, from the shoulders and axillae posterior and including the rear limbs. The ventro-lateral black blotches do not appear to change with the development of breeding colors. Female H. maculata at WSNM 625 This content downloaded from 157.55.39.27 on Mon, 05 Sep 2016 05:46:39 UTC All use subject to http://about.jstor.org/terms

Varanid lizards often tongue-flick in feeding and social contexts, but little is known regarding their abilities to identify a variety of prey using only chemical cues or to detect pheromones. We studied responses by juvenile Varanus exanthematicus to surface chemical stimuli from several animal taxa, two plant species palatable to herbivorous lizards, and conspecifics, using diluted cologne and deionized water as pungency and odorless controls. In 60-sec trials with stimuli presented on cotton swabs, lizards showed stronger responses to prey stimuli from mouse, cricket, earthworm, and a gekkonid lizard than to control stimuli. These findings suggest that the lizards are able to locate and identify prey from a wide variety of taxa, which would be adaptive for a generalist predator. Only mouse and cricket stimuli induced a greater proportion of individuals to bite swabs than control stimuli. Because these prey were the laboratory diet, biting frequency may depend on familiarity with the prey. Like other tested insectivores and carnivores, V exanthematicus showed no signs of discriminative responses to plant chemicals. The lizards tongue-flicked in response to conspecific cues at a higher rate than to the odorless control but at a lower rate than to cues from a gekkonid lizard, indicating that conspecific cues were detected and discriminated from prey cues.

The Texas horned lizard (Phrynosoma cornutum) has declined throughout its range. Understanding habitat selection by the Texas horned lizard is an important factor in its conservation. We examined daily and seasonal habitat requirements of Texas horned lizards and determined whether habitat selection differed among land management treatments in southern Texas. We used 5 study sites, each with a different burning and grazing treatment. Adult lizards caught in the study sites were fitted with backpacks carrying radiotransmitters and relocated daily. Habitat characteristics at radio locations and random points 10 m from the lizard were assessed using 50- × 20-cm quadrats. Relocations were made during 3 time intervals (morning, afternoon, evening) and 2 seasons (active, inactive). Horned lizards used bare ground and herbaceous vegetation similar to their availability in the morning and evening for thermoregulation and foraging purposes, but avoided bare ground in the afternoon. In the afternoons, lizards selected woody vegetation and litter as thermal refuges and cover from predators. Lizards also appeared less dependent on herbaceous vegetation and more dependent on woody vegetation and litter in the inactive season compared to the active season as a result of increased temperatures. We did not detect differences in habitat selection among land management treatments. Habitat management for Texas horned lizards should focus on creating a mosaic of bare ground, herbaceous vegetation, and woody vegetation in close proximity.

We studied habitat use, activity patterns, foraging mode, and prey spectrum of Tropidurus azureus werneri using a tower crane located in an Amazonian lowland rain forest in southern Venezuela. The lizards were strictly arboreal with a preference for the branches and twigs of the canopy. The horizontal distribution of lizards within the 1.4-ha study area was clustered and remained remarkably stable during two consecutive years. The lizards favored high and well-structured crowns with tree holes that served as shelters during the night. Activity was highest at air temperatures above 28°C measured at a height of 21 m. Activity patterns were influenced by cloud Cover and insolation. Tvopidums azureus werneri showed notable agility and tended toward more active foraging patterns than found in other tropidurid lizards. The prey spectrum was dominated by ants.

Seasonal differences in environmental conditions, such as precipitation, appear to regulate food diversity and abundance, and thereby indirectly influence changes in the diet of some lizards (Ballinger and Ballinger, 1979). Whitford and Creusere (1977) showed that the availability of insect prey varied according to the distribution and amount of rain throughout the year, and Maury (1995) found that variability in prey diversity and abundance was correlated with the effect of precipitation on primary productivity. The diet of the genus Uma remains somewhat unclear (D. S. Turner and C. R. Schwalbe, unpbul.). Commonly, it has been considered a carnivore, or perhaps opportunistic omnivore, but the data are contradictory. In Sonora (Mexico), Ortega-Rubio et al. (1995) found no plant matter in the diet of Uma notata. They reported a purely insect diet. In sharp contrast, a study of the more distantly related Mexican species, Uma paraphygas, found plant parts in nearly 56% of the 153 lizards examined, providing more than 40% of the total prey volume for adult males in two of four seasons (Gadsden and PalaciosOrona, 1997). The purpose of our paper is to describe seasonal variation in the diet of an endemic Mexican lizard species, Uma exsul, and to investigate sexual differences in diet. The study was conducted in the sand dune systems within the Mapimian subprovince of the Chihuahuan Desert (25023'N, 103?30'W), in the dry Laguna de Viesca in southwestern Coahuila, Mexico (1100 m elevation; INEGI, 1988). The vegetation is dominated by Larrea tridentata and Suaeda nigrescens (Instituto Nacional de Estadistica, Georgrafia e Informatica, 1988). Average monthly temperature ranges from 13?C in January to 28?C during the summer. Average annual rainfall is 200 mm but varies greatly among years (Schmidt, 1979). In 1992, adult U. exsul were noosed or shot with BB rifles each month (8.3 + 4.0 individuals each month), immediately placed on ice, and subsequently preserved in 10% formalin. Lizards were collected between 1000 and 1600 h. Monthly samples for each season were combined (winter = January-March, spring = April-June, summer = July-September, and autumn = October-December). Stomach contents were removed, and food items

The effectiveness of pitfall versus funnel traps was examined using drift fence data from five studies that employed different array designs, fencing materials, and numbers of traps in diverse Florida habitats. In general, salamanders, anurans, lizards, and snakes were captured more frequently than expected in funnel traps than in pitfall traps. In most studies, hylid frogs (Hyla, Acris, and Pseudacris) were captured significantly more often in funnel traps, but other anuran groups were captured either more often in funnel traps or equally as often in both types of traps. Most lizards and medium-sized and large snake species were captured more often in funnel traps, but semifossorial lizard (i.e, Eumeces egregius) and snake (e.g, Tantilla relicta) species were usually captured in pitfall traps. Too few turtle and small snake species were trapped to draw conclusions. Other studies that found funnel traps to be less effective than pitfall traps for some herpetofauna used funnel traps that were smaller or that might have been poorly constructed or installed. Reptiles had similar mortality rates in both types of traps, but in drier habitats, anurans were more prone to dying in funnel than in pitfall traps, despite the presence of shade covers and sponges. Overall herpetofaunal mortality rates were higher in funnel traps than pitfall traps, but this difference was significant only for the study with the longest interval between checking traps in terrestrial habitats. Traps should be checked at least every three days to minimize mortality. In the Coastal Plain of the southeastern United States, most species can be effectively sampled by using only funnel traps, but pitfall traps should be added in xeric upland habitats to increase the chance of capturing semifossorial or fossorial reptiles. In the Coastal Plain of the southeastern Unit

The distribution of maximum snout-vent length for 1206 of the approximately 1227 described species of scincid lizards ranges from 23-490 mm, has a mode of 55 mm, a median of 69 mm, a mean of 82 mm, and is strongly right skewed. At both the small and large ends of the distribution, there are noticeable lineage effects, that is, a few lineages contribute a large proportion of the species. Perhaps surprisingly given the surface-volume relationships of small animals, many of the smallest species occur in arid or seasonally arid habitats. Egg size may be the limiting factor in the evolution of small adult size. The larger species tend to be burrowers (litter and sand swimmers), have diets different from the usual (for scincids) arthropods, occur on small oceanic islands (absence of predators?), or are live-bearing. Species of skinks that have gone extinct in the last 200 years have been relatively larger than species that have survived. The overall shape of the size distributions for scincids and gekkonids, the only other major group for which there are comparable data, are surprisingly similar, suggesting a common cause such as tracking evolutionarily the same size spectrum of arthropod prey. al of Herpet logy, Vol. 35, No. 3, pp. 383-395, 2001 right 2 01 Society for the Study of Amphibi s and R ptiles ibution of Maximum Snout-Vent Length among Species of Size is a key feature in the biology of most animals because of its relationship to a wide variety of ecological and physiological attributes (Peters, 1983; Calder, 1984; Schmidt-Nielsen, 1984; Harvey and Pagel, 1991). But what determines size? One approach to this question is to examine the distribution pattern of some measure of size both within and among lineages. Here I present the distribution curve for one aspect of size, maximum snout-vent length, for the largest family of lizards, the skinks; make some observations about its shape and some attributes of the species at its extremes (where correlating factors are likely to be most pronounced), and compare it with the only other large group of lizards for which there are similar data, the geckos. There are approximately 1227 described species of living and recently extinct (since Euroe is a key feature in the biology of most i als because of its relationship to a wide vai ty of ecol gical nd physiological attributes pean expansion) scincid lizards (pers. obs.). These species comprise approximately 31.7% of all lizard species (based on a total of 3865 species, Bauer, 1992). Skinks are also one of the most diverse lizard groups, in part, because of their repeated reduction of limbs and their consequent extension into subsurface microhabitats. Data on size for 1206 species of skinks (98.3% of all skink species) form the basis of this analysis. MATERIALS AND METHODS Maximum snout-vent length (SVL and henceforth, size), measured to the nearest whole millimeter, was the variable chosen to estimate species size. There were two reasons for choosing this variable. First, it is easy to determine, especially from the literature, and, hence, it can be broadly surveyed. Second, it is indicative of the 383 This content downloaded from 157.55.39.35 on Wed, 31 Aug 2016 04:37:28 UTC All use subject to http://about.jstor.org/terms

HAHN, W. E., AND D. W. TINKLE. 1965. Fat body cycling and experimental evidence for its adaptive significance to ovarian follicle development in the lizard Uta stansburiana. J. Exp. Zool. 158:79-86. JAYNE, B. C., AND A. F BENNETT. 1990. Scaling of speed and endurance in garter snakes: a comparison of cross-sectional and longitudinal allometries. J. Zool. (Lond.). 220:257-277. KING, R. B. 1993. Determinants of offspring number and size in the brown snake, Storeria dekayi. J. Herpetol. 27:175-185. NAULLEAU, G., AND X. BONNET. 1996. Body condition threshold for breeding in a viviparous snake. Oecologia 107:301-306. NILSON, G. 1981. Ovarian cycle and reproductive dynamics in the female adder, Vipera berus (Reptilia, Viperidae). Amphib.-Reptilia 2:63-82. SEIGEL, R. A., AND H. S. FITCH. 1985. Annual variation in reproduction in snakes in a fluctuating environment. J. Anim. Ecol. 54:497-505. SEIGEL, R. A., AND N. B. FORD. 1987. Reproductive ecology. In R. A. Seigel, J. T. Collins, and S. S. Novak (eds.), Snakes, Ecology and Evolutionary Biology, pp. 210-252. McGraw-Hill, New York. . 1991. Phenotypic plasticity in the reproductive characteristics of an oviparous snake, Elaphe guttata: implications for life history studies. Herpetologica 47:301-307. SOKAL, R. R., AND F. J. ROHLF. 1981. Biometry. W. H. Freeman and Co., New York. WEATHERHEAD, P. J., G. P. BROWN, M. R. PROSSER, AND K. J. KISSNER. 1999. Factors affecting neonate size variation in northern water snakes, Nerodia sipedon. J. Herpetol. 33:577-589. WHITTIER, J. M., AND D. CREWS. 1990. Body mass and reproduction in female red-sided garter snakes (Thamnophis sirtalis parietalis). Herpetologica 46: 219-226.

The Cnemidophorus laredoensis complex consists of two, all-female parthenogenetic lizard species, designated LAR-A and LAR-B, that commonly coexist with their gonochoristic (= bisexual) relative Cnemidophorus gularis in southern Texas. The ecology and behavior of these Cnemidophorus lizards was studied in a Texas state park where LAR-A, LAR-B, and C. gularis coexist. I used time of capture records to estimate daily activity periods and used focal animal observations of free-ranging individuals to determine what proportion of time lizards spent using different microhabitats, occupying different exposures (full sun, partial sun, shade), and performing different behaviors during the May-June breeding seasons of 1994- 1996. There was little difference among the three species in daily activity period, microhabitat use, or exposure occupancy; added to previously published data on diet similarity, these results suggest that com- petition between the two parthenogens and C. gularis potentially is severe. The greatest behavioral differ- ences were between male C. gularis and female C. gularis, LAR-A, and LAR-B: male C. gularis spent a much greater percentage of their time interacting with other lizards and moved significantly farther per unit time than did females. These results reflect the large proportion of time male C. gularis devoted to trailing and courting female C. gularis as well as parthenogenetic females, especially LAR-A. The only major difference between C. gularis and the two parthenogens was that the latter spent a greater proportion of their time searching for prey. Despite this, LAR-A and LAR-B did not achieve a greater prey capture rate, nor a greater success at locating the preferred prey of termites than did C. gularis, suggesting the two parthenogens are less efficient foragers than their gonochoristic relative. This may account for the reason why the two par- thenogens are not competitively excluding C. gularis from the park despite advantage of a much greater population size. Overall, data from this and other studies lend support to the idea that parthenogenetic Cnemidophorus are ecologically and behaviorally "inferior" to their gonochoristic congeners and should, therefore, be able to coexist with them only in habitats where selective forces are relaxed.

Life-history theory seeks to explain patterns of variation between species or populations of the same species. Studies of squamates in general, and lizards in particular, have assumed a prominent place in the understanding of such variation. However, to date, there have been surprisingly few studies of the Scincidae, a major squamate taxon. We investigated geographic and interannual variation in life-history traits in two populations of the Tasmanian spotted snow skink, Niveoscincus ocellatus, living at the climatic extremes of the species' distribution. Within each population, there were no interannual or intersexual differences in adult body size. However, mature individuals from a cold subalpine/alpine site were significantly larger at maturity, and had a larger maximum body size than mature individuals from a warmer coastal site. These findings are consistent with current predictions of the proximate effect of the thermal environment on lizard growth and size and age at maturity. In both populations, female fecundity was size-related. Litter size did not vary between years at either site, but, contrary to expectations, females from the cold site had the same or higher size-adjusted reproductive output as those from the warm coastal site. We suggest that resource availability is high at both sites and that a high reproductive output by females from the cold site does not confer a significantly higher survival risk than a lower reproductive commitment. Offspring were largest at the cold site, which is consistent with variation in offspring size of other widespread species and may occur because of strong selective pressures on early survival and growth at the cold site.

We investigated the impacts of various logging practices on habitat choice by the endemic Florida scrub lizard (Sceloporus woodi) in the Florida scrub of Ocala National Forest (ONF). We used large outdoor mesocosms as a novel means to evaluate lizard preferences for habitats with different structural features produced by standard forestry practices. Captive lizards were offered a choice between two adjoin- ing habitats (= sides of a mesocosm) created using one of two substratum treatments (SAND = 75% open sand; WOOD = 75% coarse woody debris (CWD)) coupled with one of two insolation treatments (LIGHT = ambient sunlight; DARK = 45% ambient sunlight). The mesocosms proved to be an effective technique for evaluating lizard habitat preferences. Lizards were easily observed and remained active and healthy throughout the experiment Sighting frequencies differed significantly among the four mesocosm sides, yielding an overall preference ranking of DARK SAND > LIGHT SAND > DARK WOOD - LIGHT WOOD. Analysis of sighting frequencies by treatment factors (substratum and insolation) and of dissimilarity ma- trices both indicated that habitat choice was based primarily on substratum composition and only weakly determined by insolation level. In addition, size- and gender-specific preferences suggest that social inter- actions may help shape patterns of habitat used in conjunction with individual preferences. We conclude that the least favored mesocosm side (LIGHT WOOD) represents a habitat type that could potentially serve as a population sink for scrub lizards and recommend several methods to reduce the accumulation of CWD or to ameliorate its potential thermal stress on lizards. In addition, the most favored mesocosm side (DARK SAND) represents a shaded sandy habitat type not currently found in ONF timber stands. We present several alternative harvesting and site preparation methods that could produce such habitats and recommend further research on their potential value for enhancing populations of scrub lizards and other open-habitat scrub

We studied the egg-laying activities and the relationships between basic reproductive traits of Oplurus cuvieri cuvieri in a deciduous dry forest area of Madagascar. Oviposition was observed after the first heavy rain of the rainy season. Females migrated to the trails from their shelter trees in the forest and moved around along the trail, presumably making nest site selections. The egg-laying activities were divided into four phases: digging, laying eggs, filling, and covering. Females left the nests with a rapid bipedal locomotion after oviposition. Mean body temperature of the oviposited females was 42?C. Extensive predation on the eggs by snakes was confirmed. Clutch size was variable (2-5) and depended on maternal SVL. With female body size held constant, egg mass and egg length exhibited negative correlations with clutch size. Mean relative clutch mass was 20.4%. Behavioral elements such as migrations to egg-laying site should be evaluated as the female reproductive investment as well as relative clutch mass. al of Herpetology, Vol. 35, No. 2, pp. 209-217, 2001 ight 20 1 Society for the Study of Amphibians and Reptiles The Opluridae is a lizard family that was forrus consists of six species. All members of merly included as a subfamily of the Iguanidae Opluridae except one subspecies of 0. cuvieri, (Frost and Etheridge, 1989). Oplurid lizards are which occurs on Grand Comoro, are endemic to grouped into two genera, Chalarodon and OpluMadagascar (Blanc, 1977; Meirte, 1992). The rus. Chalarodon is a monotypic genus, and Opluecology and behavior of the Opluridae is poorly known, and even basic information on the life 1 Present Address: WCS Madagascar, BP8500, AnAAhistory of this unique taxon is largely lacking. tanarivo 101, Madagascar. Information on female reproductive invest2 Corresponding Author. E-mail: ment such as clutch size, egg size, and hatchling gappa@zool.kyoto-u.ac.jp size is vital for understanding life-history evo209 This content downloaded from 157.55.39.120 on Mon, 05 Sep 2016 05:27:59 UTC All use subject to http://about.jstor.org/terms H. J. A. R. RANDRIAMAHAZO AND A. MORI lution. Several factors are known to affect the reproductive traits of reptiles. Clutch size and offspring size are often related to each other and to maternal body size (e.g., Congdon and Gibbons, 1985; Seigel and Ford, 1987). Trade-offs between offspring size and the number of offspring are also well known (e.g., Salthe, 1969; Elgar and Heaphy, 1989). Some studies have demonstrated that physical constraints, such as the space available in the female's abdominal cavity, determine the upper limit for reproductive investment (Vitt and Congdon, 1978; Shine, 1988, 1992). Relative clutch mass, defined as the ratio of clutch mass to maternal mass, is commonly used to represent the female reproductive effort and considered a measure of female reproductive investment, suggesting optimal allocation of resources (Tinkle and Hadley, 1973, 1975; Congdon et al., 1982). However, egg-laying activity in lizards has not been as well studied as female reproductive effort. Probably because of the difficulty of observing egg-laying activities in the wild, this type of female behavior is rarely, reported. Several recent studies suggest that a female can influence the phenotypes of her offspring via selection of nest sites even after oviposition takes place (Resetarits, 1996; Roosenburg, 1996; Shine et al., 1997). The effects of the nest environment on egg survivorship and hatchling growth in oviparous lizards were reviewed by Overall (1994). Because egg survivorship depends partially on egg predation, any female effort toward the avoidance of egg predation could strongly affect her fitness. The spiny-tailed oplur, Oplurus cuvieri cuvieri, is the most common lizard species in the western forest of Madagascar and the largest species in the Opluridae (Randriamahazo, 1998). It has been the subject of various studies in systematics (Blanc, 1977; Blanc et al., 1983; Meirte, 1992; Titus and Frost, 1996; Sites et al., 1996) and functional anatomy (Delheusy and Bels, 1992; Delheusy et al., 1994). Ecological aspects such as food habit, reproductive activity, and habitat type and distribution have been briefly reported (Blanc, 1969; Bloxam et al., 1996; Randriamahazo, 1998). Here, we present data on egg-laying activities and reproductive traits in females of 0. c. cuvieri in a single population at Ampijoroa located in a dry deciduous forest habitat. MATERIALS AND METHODS The study site was a 1 km x 1 km dry forest habitat (16?15'S and 46?48'E) surrounded by main paths (width = 2-4 m). A plot of approximately 16.6 ha subdivided into 5 m x 5 m subplots by small trails (width = 0.5-1.5 m) was present in the middle area of the study site. All trails were human-made, and large trails (width > 1.5 m) were regularly maintained for tourism purposes. In this region, the climate is mainly dominated by a hot rainy season from Novemer to March alternating with a cold dry season rom April to October. From mid-September 1997 to mid-January 1998 and from mid-September 1998 to mid-November 1998, we walked daily along the main paths and grid of trails to search for gravid females. Because females ready to lay eggs had a distended abdomen, we easily recognized them. Each trail was censused at least every three hours from 0800-1800 h. Most of the females were individually marked by paint codes and toe clips, and their home ranges were already known. All but one female inhabiting the edge of the large trail used shelter trees within the forest for night-time retreat. Any female encountered on the path or trail was followed and observed, and in some cases we followed marked females from their shelter re s. We used a video camera to record egglaying activities. Later, we checked the time of the day and the duration of each behavioral ent (to the nearest second) from the video recording. As soon as each female retreated away from the egg-laying site, we collected her by noosing and measured her cloacal temperature (Tb) to the nearest 0.1?C. For each capture, the ambient temperature (Ta) in shade was also taken at the site of the nest. Snout-vent length (SVL) and body mass (BM) were measured to the nearest 1 mm (using steel calipers) and 1 g, respectively. The migration distance to oviposition site was measured to the nearest 5 m when the original tree shelter of the female was known. We also investigated the potential predators of eggs while surveying the trails. After releasing the females, we excavated the eggs and measured their length and width to the nearest 0.1 mm and mass to the nearest 0.1 g for each individual egg. In addition, we carefully investigated the trails to find nests that had been constructed between two consecutive censuses. We detected the nest by the presence of scraping marks on the soil surface made by the 2-mm long claws of the lizards. We recorded the measurements of eggs for additional clutches discovered during systematic trail surveys and those directly observed by other researchers. However, they were not included in any statistical analysis unless measurements were taken within 2 h of laying, to prevent errors related to water uptake or water loss by transpiration. Eggs laid during the first half of the study period were replaced into the nest, whereas those of the second half were collected for laboratory experiments. We calculated relative clutch mass (RCM) as the ratio of total wet egg mass to postpartum mass (Doughty, 1997). Egg volumes (in mm3) 210 This content downloaded from 157.55.39.120 on Mon, 05 Sep 2016 05:27:59 UTC All use subject to http://about.jstor.org/terms REPRODUCTION IN OPLURUS CUVIERI were calculated according to formulae in Maritz and Douglas (1994), using as constants X= 0.25 and elongation (E) = 1.56. The value of X was estimated from the table in Preston (1974) by matching the egg shape and the average lengthto-width ratio. Egg volume was calculated using the formula: Egg volume = rLW2(3c2 + 14c + 35)/210, where L and W were egg length and width, respectively, and c = X(E05 1) = 0.062. A mercury thermometer was placed into the forest at the height of 1 m to measure daily maximum and minimum temperature. Rainfall data were provided by T. Mizuta (pers. comm.). We used StatView J-4.5 (Abacus Concepts, 1995) to perform statistical analyses. Unless otherwise specified, means are presented with standard error (SE). We examined the differences between means by using ANOVA and the differences of positions by using a Kruskal-Wallis test. For egg measurements (mass, length, and width), an average value for each clutch was used to examine the correlation with clutch size. Because the range of clutch sizes was small and data were not normally distributed, Kendall's rank correlation was used. Linear regression analysis was used to address the relationship between maternal SVL and reproductive traits.

White Sands National Monument (WSNM), New Mexico, was established as a National Park to preserve the biotic and abiotic features of the "white" gypsum dunes environment. The lizards of WSNM are characterized as having special adaptive qualities that enable them to survive in gypsum sand. The lesser earless lizard (Holbrookia maculata) and the eastern fence lizard (Sceloporus undulatus) are white forms of their respective species that reside at the Monument (Ruthven, 1907; Smith, 1943; Lowe and Norris, 1956). At WSNM, Holbrookia maculata is short, stout, and dorsally pallid with fairly well-defined ventro-lateral blotches, and Sceloporus undulatus is medium-sized with a dorsal coloration of pale gray to nearly white with faint black shoulder patches (Smith, 1943). Dixon and Medica (1966) reported food of these lizards, and Dixon (1967) studied their activity and reproduction. MacFarland (1969) found that H. maculata and S. undulatus overlap greatly in daily activity, behavior, and food but differ in substrate preferences in seminatural enclosures at WSNM. Holbrookia maculata at WSNM had lower body temperatures and thermoregulated differently than a population of H. mniaculata from outside the dunes proper (Hager, 2000). Human-induced landscape alterations and increased land management practices threaten taxa adapted to aeolian habitats. Preservation of these organisms requires basic knowledge of their biology. Consequently, my goal was to understand more about the activity patterns and habitat use of H. maculata and S. undulatus in the gypsum dune field at WSNM. To my knowledge, this is the first systematic field study of these two lizards in their natural habitat across an entire activity season. For each species, I evaluated daily and seasonal surface activity and how this activity relates to the lizard's structural environment, use of microhabitats, proximity to vegetation, and population density. These data will allow monument personnel to make more informed management decisions on behalf of these lizards and the biotic resources, in general, and will ultimately contribute toward the preservation of the biodiversity of the gypsum environment. In broad terms, this information sheds more light on community structure in sand dune habitats. White Sands National Monument, New Mexico, (32?45'N; 106?15'W) encompasses approximately 450 km2 of active, moving dunes. Its edges house various

Three species of lacertid lizards (Lacerta bedriagae, Podarcis tiliguerta, and Podarcis sicula) are able to detect the former presence of the saurophagous snake Coluber viridiflavus by tongue flicking. Lizards tongue flicked more in cages previously inhabited by the predatory snake than in clean cages or in cages treated with eau-de-cologne. They also exhibited behavioral acts typically associated with stressful situations (foot shakes, tail vibrations, starts) more frequently when predator chemicals are present Individ- uals from the two Podarcis species that came from populations syntopic with C. viridiflavus were also able to distinguish between chemical cues from this saurophagous predator and a nonsaurophagous snake (Natrix maura). In these lizards, the former presence of N. maura did not elicit higher tongue-flick rates or stress- indicating behaviors. In contrast, individuals of Lacerta bedriagae collected from a snake-free area increased tongue-flick rate and frequency of stress-related behavior in response to chemicals of both snakes, suggesting that prior contact is not required for chemosensory recognition of snakes in this species but may facilitate the distinction between different species of snakes. The presence of predator (C. viridiflavus) chemical cues induces a shift in the microhabitat use of the lizard species studied. In a large terrarium containing various substrates, lizards chose different types of microhabitats when chemical cues of C. viridiflavus were present than when absent and avoided the side of the terrarium labeled with the chemicals.

An experimental study was carried out to determine whether self and conspecific chemical recognition occurs in Liolaemus bellii, a Tropidurid lizard from Central Chile. Experiments were performed during the autumn and the spring. Using the number of tongue flicks as an indicator of discrimination, it was found that L. bellii showed both self and conspecific chemical recognition. Lizards recognized their own territories, and conspecific chemical recognition showed seasonal changes. During autumn, lizards showed higher exploratory behavior (higher numbers of tongue flicks and motion time) than in spring, and female enclosures elicited in males higher numbers of tongue flicks. Similar results were previously found in other Liolaemus species from a different habitat The information available at present for Liolaemus suggests that recognition of own territory is more important than recognition of conspecifics, and the latter seems to be associated mainly to the reproductive season. Therefore, conspecific and self-chemical recog- nition seem to be independent of the habitat used by the species, although habitat could modulate the use of chemical signals.

The reproductive cycle and diet of a population of the viviparous lizard Sceloporus torquatus torquatus from the Pedregal de San Angel, Distrito Federal, Mexico, were studied. Ovarian activity began in June, and by October, one to five preovulatory follicles per ovary were present Ovulation took place in November and December, and parturition occurred in late April or early May. Relative litter and egg masses were higher at the end of development than at the beginning. Testes increased in size from June through September, when they reached their maximum volume and weight Testicular regression began at this point and was particularly accentuated in October and November. The diet of both sexes was composed primarily of insects; however, plant material (small flowers and fruits), spiders, isopods, and occasionally earthworms were also consumed. Both sexes consumed plant material throughout the year. In the dry season, males ingested twice as much food as females.

phibians and Reptiles of Louisiana. Louisiana State Univ. Press, Baton Rouge. FITCH, H. S. 1954. Life history and ecology of the fivelined skink, Eumeces fasciatus. Univ. Kans. Publ., Mus. Nat. Hist. 8:1-156. FITZGERALD, L. A., F. B. CRUZ, AND G. PEROTTI. 1999. Phenology of a lizard assemblage in the dry chaco of Argentina. J. Herpetol. 33:526-535. GIBBONS, J. W., AND R. D. SEMLITSCH. 1981. Terrestrial drift fences with pitfall traps: An effective technique for quantitative sampling of animal populations. Brimleyana 7:1-16. HASEGAWA, M. 1984. Biennial reproduction in the lizard Eumeces okadae on Miyake-Jima, Japan. Herpetologica 40:194-199. IRWIN, K. J. 1982. Life history notes: Eumeces anthracinus pluvialis (Southern coal skink) reproduction. Herpetol. Rev. 13:125-126. MARTOF, B. 1955. Some records of reptiles of Georgia. Copeia 1955:302-305. MITCHELL, J. C. 1994. Reptiles of Virginia. Smithsonian Institution Press, Washington, DC. MOUNT, R. H. 1975. The Reptiles and Amphibians of Alabama. Auburn Univ., Auburn, Alabama. RAMUS, E. 1998. The Herpetology Sourcebook, 19981999 Directory. Reptile and Amphibian Magazine, Pottsville, Pennsylvania. TRAUTH, S. E. 1994. Reproductive cycles in two Arkansas skinks in the genus Eumeces (Sauria: Scincidae). Proc. Arkansas Acad. Sci. 48:210-218. VITT, L. J., AND W. E. COOPER JR. 1985a. The evolution of sexual dimorphism in the skink Eumeces laticeps: An example of sexual selection. Can. J. Zool. 63: 995-1002. . 1985b. The relationship between reproduction and lipid cycling in the skink Eumeces laticeps with comments on brooding ecology. Herpetologica 41:419-432. . 1986. Skink reproduction and sexual dimorphism: Eumeces fasciatus in the southeastern United States, with notes on Eumeces inexpectatus. J. Herpetol. 20:65-76. WALLEY, H. D. 1998. Eumeces anthracinus (Baird). Cat. Am. Amp. Rept. 658:1-6. ZAR, J. H. 1984. Biostatistical Analysis, 2nd ed. Prentice-Hall Publ., Englewood Cliffs, New Jersey.

Lizards of the genus Tupinambis are large and, in places, common teiids of the tropical and subtropical regions of South America (Vanzolini, 1993). While the taxonomy of the genus is being clarified (Avila-Pires, 1995; Fitzgerald et al., 1999), aspects of their ecology, including reproductive patterns, remain largely unknown. Moreover, many thousands of individuals of two species in the genus, T teguixin and T rufescens are killed for their skins every year in southern South America (Norman, 1987; Fitzgerald, 1994a, b) making them important from a conservation viewpoint. Adult Tupinambis teguixin, often called T nigropunctatus (Avila-Pires, 1995) and known as black or common tegu lizards, weigh 1-2 kg and measure up to one m total length. They can be found in a variety of habitats in tropical South America, east of the Andes (Vanzolini, 1993). They are largely omnivorous, although animal prey, including vertebrate eggs and insect larvae, are preponderant in their diet (Herrera, 1980; Mercolli and Yanosky, 1994). Tupinambis appear to hibernate in southern South America (Gallardo, 1970) but they are active throughout the year in the

Examination and dissection of 216 museum specimens of two species of amphisbaenians (the shovel-snouted Monopeltis anchietae and round-headed Zygaspis quadrifrons) from southern Africa provided data on morphology, sexual dimorphism, reproduction, and dietary habits. The two species differed considerably in absolute size, in body proportions (eg, head width relative to snout-vent length), and in the degree of sexual dimorphism in these traits. In the relatively heavy-bodied Monopeltis both sexes attained similar body lengths, but females had wider heads than conspecific males. Conversely, in the thin-bodied Zygaspis, females attained larger body sizes than conspecific males, and there was no sexual dimorphism in head size. Clutch sizes were small in both species (means of 2.4 neonates in Monapeltis, 3.3 eggs in Zygaspis) and were not correlated with maternal body size. Termites were the most common prey far both taxa, but a wide variety of other soft-bodied invertebrates (beetle larvae, caterpillars) was also consumed. The two species differed in dietary composition, mean prey size, and in the numbers of prey items per stomach. Stomachs of Monopeltis contained more prey items than stomachs of Zygaspis (means of 72.2 versus 13.0 prey items) and prey ingested by Monopeltis were larger than those of Zygaspis. In Monopeltis, there was a significant positive correlation between predator size and prey number, but larger lizards continued to feed on relatively small prey. The reverse pattern was found in Zygaspis. The substantial differences in trophic biology between these two taxa and other sympatric fossorial reptiles, suggest that adaptations to fossoriality do not constrain ecological diversity within burrowing squamates.

On 25 August and 3-4 September 1999, I observed and captured four juvenile specimens of the Western Green Lacerta (Lacerta bilineata) in the yard of two residences in southwestern Topeka. Collins (1974, 1982, 1993) reported the Green Lacerta (as L. viridis) as occurring, or having occurred, in southwestern Topeka on the basis of a specimen collected in 1973. Conant and Collins (1991) noted that a specimen of this lizard had not been noted in Topeka for nearly two decades and for this reason did not include the Green Lacerta in the Peterson field guide to the amphibians and reptiles of eastern and central North America. Green Lacertas were rediscovered in

The course of infection of a malaria parasite (Plasmodium mexicanum) is highly variable in its host, the fence lizard (Sceloporus occidentalis). However, a seasonal trend is superimposed on this variation such that gametocyte production is intensified during mid- to late summer. Host testosterone levels follow a similar seasonal fluctuation and are variable among individual lizards. We sought to determine if testosterone levels affect seasonal and among-host variation in 11 P. mexicanum life history traits: rate of increase in level of infection (3 measures), peak parasitemia (3 measures), duration of increase (3 measures), time to detectable infection, and timing of production of gametocytes. We followed the course of infection in 125 male S. occidentalis, each randomly assigned to 1 of 4 treatment groups: castrated, castrated and implanted with exogenous testosterone, sham implanted, and unmanipulated controls. Median values for the 11 life history traits did not differ among treatment groups, and variances were homogeneous among the treatment groups for 10/11 traits. However, elevated testosterone significantly reduced the variation in timing of the onset of gametocyte production. Therefore, testosterone does not appear to be a primary regulator of P. mexicanum life history, yet testosterone may have some effect on when gametocytes first become detectable.

In gekkonoid lizards, a few species of actively foraging eublepharids have been shown to identify prey chemicals by tongue-flicking and a few ambush foragers have been shown not to do so. Gekkonids in the omnivorous genus Rhacodactylus identify both plant and animal food by lingually sampling chemical cues. We conducted experiments with several species of geckos to provide further evidence on the evolutionary association between active foraging and lingually mediated prey chemical discrimination, to begin examination of the relationship between plant diet and chemosensory response to plant foods, and examine the utility of palatable plant chemicals as a pungency control for studies of insectivores. Chemosensory discriminations were investigated by observing tongue-flicking and biting responses to cotton swabs bearing animal prey chemicals, palatable plant chemicals, and control substances. The eublepharids Goniourosaurus luii and Eublepharis macularius both responded strongly to cricket chemicals, but not to control stimuli, whereas the gekkonids Gekko gecko and Uroplatus were unresponsive to all cues. These data support and extend the evidence for correlated evolution between prey chemical discrimination and foraging mode. They provide support of limited scope for the hypotheses that insectivorous geckos do not respond to plant chemicals and that such responses evolve with inclusion of plants in the diet. The lack of any strong response to plant chemicals by insectivores indicates the potential usefulness of plant chemical as pungency controls. Vomerolfactory discriminations are usually indicated by tongue-flicking, but several G. luii bit swabs bearing cricket chemicals without first tongue-flicking. This suggests that those individuals may have identified prey by olfaction, corroborating evidence for two other species of geckos. Squamate reptiles use the lingual-vomeronasal system to sample and sense chemical stimuli carrying information in several selectively important biological contexts, including feeding, avoidance of predators, and pheromonal communication (Burghardt, 1970; Halpem, 1992; Mason, 1992; Cooper,. 1994a). Chemical cues provide a means to locate and identify prey in many snakes and lizards (Burghardt, 1970; Cooper, 1994a). All snakes tested rely on lingually sampled chemical cues at some stage of foraging, whether in selection of ambush sites, active search for prey, or strike-induced chemosensory searching for prey released after biting and/or envenomation (e.g., Burghardt, 1970; Chiszar et al., 1983; Duvall et al., 1990). Among lizards, Corresponding Author. E-mail: cooperw@ipfw.edu foraging mode determines whether prey are so ght and identified by lingually sampled chemical cues (Cooper, 1994b, 1995a, 1997, 1999a). A large majority of lizard species are insectivores that forage actively or by ambush. Active foragers tongue-flick repeatedly while moving through the habitat (Evans, 1961) and can discriminate between lingually sampled prey chemicals and control substances (Cooper, 1994a, b, 1995a, 1997, 1999a). Ambush foraging lizards do not exhibit prey chemical discrimination and would have little or nothing to gain from such ability (Cooper, 1994a, 1995a, 1997). Tongue-flicking substrates upon arrival at a new site might provide information about the presence of prey in the area, but once an ambush forager becomes immobile to wait for prey, additional tongue-flicking cannot help it locate raging mode det rmines wheth r prey are ought and identified by lingually sampled hemical cues (Cooper, 1994b, 19 5a, 1997, 360 This content downloaded from 207.46.13.76 on Wed, 24 Aug 2016 04:13:11 UTC All use subject to http://about.jstor.org/terms FOOD CHEMICAL DISCRIMINATIONS BY GECKOS prey (Cooper et al., 1994; Cooper, 1995a). Because ambushers often adopt elevated ambush posts and attack moving prey detected visually, sometimes several meters away from the ambush post, chemical prey cues at the ambush site may differ from those where prey is likely to be found. There may even be selection against tongue-flicking while waiting for prey because the motion might cause the lizard to be detected by predator or prey (Cooper, 1994a, 1995a). More data are needed on the relationship between foraging mode and prey chemical discrimination in insectivorous lizards because the above generalizations are based on tests of small numbers of species in most lizard families. Although generalization appears to be justified by the taxonomic stability of foraging mode in most families and on corresponding stability of prey chemical discrimination for all available data (Cooper, 1994a, b, 1995a), confirmatory information on additional species carefully selected in relation to phylogeny and existing data would increase confidence that correlated evolution has occurred between forging mode and prey chemical discrimination. Despite the predominance of insectivory in lizards, herbivory and omnivory occur in several lineages (Pough, 1973; Iverson, 1982). Because plants cannot usually be ambushed, although blowing seeds might be, herbivorous species have fewer constraints on tongue-flicking related to detection by prey or predator. Variation in nutritional content and chemical defenses of plants should favor the ability to use chemical cues to assess food quality. This prediction has been confirmed for the iguanid Dipsosaurus dorsalis (Cooper and Alberts, 1990). To determine whether adoption of herbivory/omnivory is accompanied by evolution of chemosensory responsiveness to plant food chemicals, it will be necessary to determine whether lizards in many independently evolved lineages of herbivores exhibit discriminative responses to plant chemicals and to show that these responses are absent in closely related insectivores. In most previous studies of insectivorous lizards, prey chemical discrimination has been established by greater tongue-flick rates and/or proportion of individuals biting in response to swabs bearing prey chemicals than both deionized water, an odorless control, and cologne, a pungency control. The pungency control is important because it permits us to determine experimentally whether lizards respond differently to an easily detected, but nonfood stimulus, than to food stimuli. Because undiluted cologne can be noxious (Dial and Schwenk, 1996; Cooper, 1998a, b), it is diluted to levels not noxious to experimenters and not apparently noxious to lizards (Cooper, 1998a, b). Nevertheless, an alternative pungency control might be preferable. Palatable plants that are detectable to herbivorous nd omnivorous species may provide a useful alternative pungency control. Tests for response to plant chemicals by insectivores can simultaneously permit assessment of the utility of plant chemicals as pungency controls by comparison of responses to plant chemicals with those to deionized water and cologne. Here we present information bearing on the relationship between foraging mode and prey chemical discrimination, on possible lingual responses to plant chemicals, and on the utility of plant chemical stimuli as a pungency control in some geckos. Gekkonoidea is a speciose taxon containing numerous active and ambush foragers among insectivores and a few omnivores. Previous studies of insectivorous gekkonoid lizards have indicated that the actively foraging eublepharids Eublepharis macularius and Coleonyx variegatus exhibit lingually mediated prey chemical discrimination, often leading to biting attacks on sources of prey chemicals, but the ambushing gekkonids Gekko gecko, Pachydactylus turneri, and Thecadactylus rapicauda show virtually no responses to the same chemicals (Fig. 1; Cooper, 1995b, 1998b, 1999b). Two species of the omnivorous gekkonid genus Rhacodactylus show strong responses to plant food chemicals, and one species also exhibits elevated responses to animal prey chemicals (Fig. 1. Cooper, unpubl. data). The active and ambush foraging modes do not apply to feeding on plants, and the method of foraging for prey by Rhacodactylus has not been described. Here we present experimental data on some previously unstudied insectivorous geckos representing both foraging modes, the actively foraging eublepharid Goniourosaurus luii and several species of the ambushing gekkonid genus Uroplatus to test further the generality of the relationship between foraging mode and prey chemical discrimination. We also tested the reponses of three insectivorous gecko species, the eublepharids G. luii and E. macularius and the gekkonid Gekko gecko to chemical stimuli from plants palatable to other lizards. These tests also permit comparison with responses to plants by herbivores and evaluation of plant chemical cues as pungency controls. Although responses by E. macularius and G. gecko to prey chemicals had been tested previously, it is important to know whether insectivores respond to plant chemicals as do herbivores. MATERIALS AND METHODS Thirteen G. luii and 17 Uroplatus sp. (seven U henkeli, three each of U fimbriatus and U lineatus, two U ebenaui, and one each of U malema and U phantasticus were observed at the Dallas Zoo. 361 This content downloaded from 207.46.13.76 on Wed, 24 Aug 2016 04:13:11 UTC All use subject to http://about.jstor.org/terms W. E. COOPER AND J. J. HABEGGER Foraging Response to Response to Phylogeny Species mode Diet prey chemicals plant chemicals Source L Rhacodactylus Ep. ? O + + Cooper, unpub. data R. leachianus ? O + Cooper, unpub. data -Gekko gecko AM I Cooper, 1995b, this

We examined morphology, habitat use, movement patterns, and sprinting capacities of ju- veniles and adult males of two distantly related, yet ecologically similar species, Anolis lineatopus and A. gundlachi. Juveniles of both species tended to perch on lower and narrower perches than adult males, a finding that is consistent with other studies of Anolis. Juveniles used jumping more often as a mode of locomotion than adult males, with jumps constituting 54.1% (A. lineatopus) and 41.6% (A. gundlachi) of the movements of juveniles for these two species. Adult males of both species also were, on average, 25.9% (A. lineatopus) and 29.7% (A. gundlachi) faster than juveniles. Differences in sprinting capacity may have influ- enced the evolution of escape behavior of adult males and juveniles: juveniles typically run shorter distances and frequently escape by jumping to the ground rather than relying only on speed to elude a threat. By contrast, adult males more frequently escape by running longer distances on branches or tree trunks. Com- parisons with other lizard taxa show that slower juveniles frequently use escape behaviors that rely less on sprinting capacities than adults. Examination of how different age or sex clas- ses within a species utilize the habitat within a community is critical to understanding how ecological communities are structured (Werner and Gillam, 1984). A number of studies of a va- riety of animal taxa have shown that juveniles often differ markedly from adults in morphol- ogy, habitat use, behavior, and performance ca- pacity (Wemer and Gillam, 1984). In many cas- es, differences between juveniles and adults in one aspect (e.g., morphology) results in corre- lated differences in other variables (e.g., behav- ior). For instance, the size of prey that a fish can eat is limited by the size of its mouth, which increases as fish become older and larger. Thus, studies on sunfish have shown that this differ- ence in prey-capturing ability results in juve- niles occupying different portions of the pond habitat than adults (Wainwright et al., 1991). Therefore, documenting both how ontogenetic classes differ from adults, and understanding relationships between morphology, habitat use, behavior, and performance may shed light on how ecological communities are structured. Caribbean Anolis lizards provide an excellent opportunity for understanding how ontogenetic classes differ in morphology, habitat use, behav- ior, and performance capacity. Caribbean Anolis lizards have been studied extensively over the past 30 years, with particular attention being fo- cused on differences in habitat use and behavior

Department of Biology, William Jewell College, 500 College Hill, Liberty, MO 64068 (GRS) School of Biological Sciences, University of Nebraska, 348 Manter Hall, Lincoln, NE 68588 (REB) Laboratorio de Ecologia, Unidad de Biologia, Tecnologia y Prototipos, Escuela Nacional de Estudios Profesionales Iztacala, Av. de los Barrios s/n, Los Reyes Iztacala, Estado de Mixico, 54090 Mixico (JAL-E) Present address of GRS: Department of Biology, Denison University, Granville, OH 43023

A recent review of the methods for study of reptile populations convincingly argued that data on age-specific survival, reproduction, immigration, and emigration are essential for testing all facets of life history theory (Dunham et al., 1994). These authors also noted that such data can only be obtained from long-term studies of populations in their natural habitats. However, the obstacles to conducting long-term field studies are considerable. One difficulty is developing a method to mark animals so they may be identified reliably for long periods after they were initially captured. Ideally, the marks in long-term studies should (1) be permanent, (2) identify the animals as particular individuals, (3) be easy to use and to read in the field, (4) not cause excessive pain or discomfort to the animals, and (5) not affect the behavior or survival of the animals (Ferer, 1979). In studies of lizards, the technique that is used most frequently is clipping 14 toes in unique combinations (Ferner, 1979; Dunham et al., 1994). This technique results in a permanent mark (since lizard toes do not regenerate) that is easily applied and read in the field. Toe-clipping appears to cause lizards little trauma and has been used success

Morphologically, the five recognized species of Chamaeleolis (C. agueroi, C. barbatus, C. chamaeleontides, C. guamuhaya, and C. porcus), all endemic to Cuba, are among the most bizarre West Indian lizards. Chamaeleolis is characterized by a prominent bony head casque, relatively large body size (snout-vent length [SVL] of up to 177 mm), proportionately short limbs, cryptic coloration, the ability to move its eyes independently, and lack of tail autotomy (Wilson, 1957; Garrido and Schwartz, 1968; Williams and Rand, 1969). Based on these features, Chamaeleolis traditionally has been considered to be an early offshoot of the anoline lizard radiation that diverged prior to the evolution of Anolis (Etheridge, 1960; Williams, 1969). However, recent molecular systematic studies indicate that Chamaeleolis evolved within Anolis (Hass et al., 1993; Jackman et al., 1999), suggesting that the unusual morphology of Chamaeleolis indicates relatively rapid evolution, rather than antiquity of the lineage (and also suggests that the generic name Chamaeleolis might be subsumed within Anolis [Hass et al., 1993; Jackman et al., 1999]). Few published reports exist on the ecology and behavior of Chamaeleolis. Wilson (1957, 1994) commented on the sluggish behavior of a captive C. porcus named Methuselah, noting that it would remain in the same spot for hours or even days without changing position. Gorman et al. (1969) mentioned that captive C. porcus actively moved between perches, jumped toward prey (crickets, grasshoppers, and mealworms), and displayed to each other by extending their dewlaps, opening their mouths and protruding their tongues. Garrido (1982) suggested that the simple courtship display repertoire in C. barbatus, which consists only of head-bobs displays, supported the idea that Chamaeleolis diverged early in the anole radiation. All previous observations on Chamaeleolis have been conducted on captive animals. During the course of field work on the community ecology of Cuban anoles in 1997 and 1999, we had the opportunity to study the behavior and ecology of this lizard under natural conditions. Here we report data on the habitat use, locomotion, display, and foraging behavior of C. barbatus and C. porcus. Observations on C. barbatus were conducted at So

Lingually mediated chemosensory identification of food is widespread in scleroglossan lizards, and has been studied in representatives of all but a few families (Cooper, 1994a, 1995, 1997). It is strongly linked to active foraging mode, having been lost in taxa that secondarily adopted ambush foraging (Cooper, 1995; 1999a). One of the few major unstudied groups is the North and Central American family Xantusiidae, for which foraging mode also is unknown. Insectivorous xantusiids are anachoretic (Zweifel and Lowe, 1966; Del Toro, 1982; Bezy, 1988), i.e., they occupy narrow spaces that restrict access by predators (Edmunds, 1974), which makes their foraging difficult to observe. Although it might be thought that chemical senses would be useful to locate food at night or in enclosed spaces having limited light, most nocturnal gekkonid lizards are ambush foragers (Cooper, 1994a). Thus, the presence or absence of prey chemical discrimination of xantusiids cannot be predicted a priori. If they do detect and identify foods using chemical cues, it may be predicted that they tongue-flick and bite more in response to food than to various nonfood sources of organic and inorganic chemical cues. I experimentally studied chemosensory responses to food and a variety of other stimuli by observing tongue-flicking, which indicates chemical sampling for vomerolfaction (Cooper and Burghardt, 1990a; Halpern, 1992), and biting, which is a predatory attack, in the xantusiid Lepidophyma favimaculatum. This Central American species is known in the pet trade as the bark lizard because it is often found hiding during daylight hours in narrow spaces under bark of decaying fallen trees, but it also occupies rock crevices (Del Toro, 1982). The lizards emerge at night to climb on trees or rocks in search of food (Del Toro, 1982). Because L. flavimaculatum is an insectivore, I predicted that any discrimination among stimuli by this species would be manifested by stronger response to chemical stimuli from animal food than from plants or other control substances. Previous work with two species of primarily herbivorous lizards shows that they respond strongly to both animal and plant food chemicals (Cooper and Alberts, 1990; Cooper, 2000b). However, under the hypothesis that chemosensory responsiveness is adjusted to match diet, insectivores which do not eat plants should not respond to plant chemicals by elevated tongue-flick and biting rates. Plant chemicals from species palatable to herbivores were among the stimuli used as a first test of this hypothesis for an insectivore.

contouring of scalation, size and shape of the lizard Gallotia galloti. Evolution 41:256-268. , AND . 1993. Geographic variation in scalation of the lizard Gallotia stehlini within the island of Gran Canaria. Biol. J. Linn. Soc. 48:75-87. ,D. P. MCGREGOR, A. M. CUMMING, AND W. C. JORDAN. 1994. DNA evolution and colonization sequence of island lizards in relation to geological history: mtDNA RFLP, cytochrome b, cytochrome oxidase, 12s rRNA sequence, and nuclear RAPD analysis. Evolution 48:230-240. VITT, L. V., J. P. CALDWELL, P. A. ZANI, AND T. A. TITUS. 1997. The role of habitat shift in the evolution of

The Australian gidgee skink, Egernia stokesii, is gregarious and lives in stable social aggre- gations. In this study we investigated whether individuals can recognize group members and distinguish them from non-group members, and we investigated whether recognition is based on relatedness. In one experiment, ten groups of three or four unrelated subadult lizards had been maintained for two years. Lizards from these groups were each presented with stimuli from themselves, from a member of their own group, and from a conspecific member of another group. Two types of stimuli were used; a paper substrate which had absorbed lizard body secretions, and lizard scats. For each type of stimulus, lizards showed a significantly stronger response, as measured by number of tongue flicks and by time in contact, to the stimulus from the non-group member, than to the stimuli from themselves or from a group member. In a second experiment, there were eight "related" groups each of three sibling lizards, and seven "unrelated" groups each of three individual lizards from different litters. Again lizards responded more strongly to stimuli from non-group members than to stimuli from group members. In a third experiment, juvenile lizards responded as strongly to stimuli from non-group members if they were related or unrelated. Together, these results imply that individuals in this lizard species can discriminate between two other lizards de- pending on whether they do or do not belong to the same social group. This suggests that individual lizards have unique chemical signals, and that an important component of social cohesion, the ability to recognize group members, is present in this gregarious lizard species. The results also suggest that familiarity, rather than relatedness, explains recognition of group members.

The holotype of Stenocercus marmoratus is redescribed, and morphological variation is doc- umented for this poorly known tropidurid lizard. Stenocercus marmoratus has a more extensive distribution than previously thought and inhabits subhumid habitats of the Andes from Cochabamba, Bolivia to north- ernmost Argentina. Dumeril and Bibron are the authors of the name marmoratus and not D'Orbigny as believed by some revisors of this species. A key to the genus Stenocercus in Bolivia and Argentina is provided. Five species of Stenocercus are currently rec- ognized in Argentina and Bolivia: S. caducus, S. doellojuradoi, S. pectinatus, S. marmoratus, and S. roseiventris. Stenocercus variabilis Boulenger has been reported from Bolivia (e.g., Burt and Burt, 1933; Fugler, 1989) although this species is most likely endemic to Peru: Fritts (1974) argued that Boulenger's (1901) locality information for this species was in error and that the holotype of S. variabilis came from Palca, Junin, Peru rather than "Palca," Bolivia. Three of the Argentinean and Bolivian species were included in the gen- era Ophryoessoides (S. caducus) and Proctotretus (S. doellojuradoi and S. pectinatus) before Frost (1992) reviewed the taxonomy of the Tropidurus group of lizards and concluded that these genera should be considered synonyms of Stenocercus. Stenocercus marmoratus and S. roseiventris have long been included in the genus Stenocercus.

This study investigates predator size and prey type as potential proximal causes of differences among diets of three lizard species (family Scincidae) and three frog species (subfamily Limnodynastinae) that coexist in wet subtropical forest in eastern Australia. Frogs eat smaller prey than lizards having the same gape size and there were significant differences in the types of arthropods eaten by frogs and lizards. Differences among species within frogs and lizards were small and not statistically significant Frogs ate more amphipods, mites, and ants than the lizards, and lizards ate more termites, millipedes, isopods, and orthopterans than the frogs. Other categories were eaten in similar quantities by both frogs and lizards. The degree of specialization in types and sizes of prey often changes with the body size of a predator. Change of diet with ontogeny has been related to changes in prey size in lizards (Schoener and Gorman, 1968; Rose, 1976; Dominguez and Salvador, 1990; Magnusson and Silva, 1993). Frogs change both prey type and prey size as they grow (Pengilley, 1971; Labanick, 1976; Christian, 1982; Donnelly, 1991; Simon and Toft, 1991; Wiggins, 1992). The latter authors suggested that the change in prey types is a result of the shift in prey size, because different types of arthropods have different mean sizes. However, diet composition differs among species in some assemblages of frogs (Lima and Magnusson, 1998) and lizards (Magnusson and Silva, 1993), and the shift in prey types with growth is more than a passive effect of selection for larger prey in seven species of leaf-litter frogs of Central Amaz6nia (Lima and Moreira, 1993; Lima, 1998). Caldwell and Vitt (1999) showed consistent differences between species of lizards and species of frogs in one Amazonian locality, but there are no other published studies of differences in diet between syntopic lizards and frogs. In this study, we make use of extensive collections of subtropical lizards and frogs in the Australian Museum to investigate the effects of predator size and species identity on diet composition within and between three species of lizards (family Scincidae) and three species of frogs (subfamily Limnodynastinae) that coexist in subtropical rainforest in eastern Australia. MATERIALS AND METHODS The frogs and lizards were collected during a New South Wales National Parks and Wildlife 40 This content downloaded from 157.55.39.239 on Thu, 15 Sep 2016 05:29:31 UTC All use subject to http://about.jstor.org/terms DIFFERENCES IN DIET AMONG FROGS AND LIZARDS Service (NSW NPWS) project coordinated by Harry Hines between 1988 and 1992 and deposited in the Australian Museum in Sydney. The collections were made in Nightcap National Park, Dome Mountain Area, Eastern Border Ranges National Park, Mount Warning National Park, Spirabo State Forest, Forestland State Forest, and adjacent areas in areas of humid subtropical forest in northern New South Wales. In most areas, pitfall traps with formalin were used by members of the NSW NPWS survey team to sample invertebrates, and the capture of vertebrates was accidental. Frogs and lizards (35% of individuals) deposited in the museum that had been collected in the same region but lacking exact geographic coordinates were used to increase sample sizes. We used only specimens that were available in the collection of the Australian museum and did not collect or kill any of the animals ourselves. Only three species of scincid lizards, Calyptotis scutirostrum (N = 39), Eulamprus murrayi (N = 23), and Saproscincus challengeri (N = 30) and three species of frogs of the family Myobatrachidae (Limnodynastinae), Assa darlingtoni (N = 36), Lechriodus fletcheri (N = 26), and Philoria loveridgei (N = 18) were sufficiently common and had enough items in the stomach to justify analysis. The animals were fixed in formalin and maintained in

I investigated the relationship between lizard body size and prey size, particularly as it relates to challenges faced by neonatal lizards in the Neotropics. Within the large-bodied teiid lizard Ameiva ameiva, juveniles feed on smaller prey than adults, but adults continue to feed on prey eaten by juveniles. Adults eat invertebrates and vertebrates, including other lizards, and these likely have a much higher payoff in terms of energy gained per unit risk. Prey types and sizes vary among lizard species in an Amazonian rain forest near the Rio Curua-Una. Larger lizard species feed on larger prey, and smaller lizards, by virtue of their small body sizes, cannot feed on many prey taken by large lizards. Large lizards continue to take small prey. The larger non-vertebrate prey taken by lizards in this assemblage are mostly spiders and centipedes, many of which are larger than smaller lizard species and individuals. A combined data set from numerous Neotropical sites shows that the trend observed at the Curua-Una is a general one even though the smallest clade of lizards eat prey smaller than predicted based on body size alone. I suggest that small lizards, neonates in particular, are at great risk in diverse lizard assemblages because of their body size relative to other organisms. They likely compete with adults of their own and other species for food, they are eaten by larger lizards and other vertebrates, and they are likely prey for numerous highly abundant predaceous arthropods, especially spiders and centipedes.

Viviparous squamates offer opportunities for exploring the importance of past maternal resources (yolk) and current resources (placentotrophy) to support embryonic growth during gestation, and to optimize offspring fitness. Both thermal and nutritional environment of the mother during gestation may be expected to be important in determining offspring fitness. Using a two-way factorial design, we have investigated possible interactions between food intake and thermal environment during gestation in the viviparous skink Niveoscincus metallicus . Among the females given restricted basking opportunities, fewer females gave birth, there was a significant increase in gestation length, and relative clutch mass was reduced due to smaller neonatal size; none of these parameters were influenced by nutritional status. Neonates from mothers given restricted basking opportunities were lighter, had shorter snout-vent lengths (SVL), and smaller fat bodies than neonates from mothers given optimal basking opportunities; their postnatal growth rate (over eight weeks) was also significantly lower and they showed a reduced incidence of basking behavior. There were interaction effects between thermal regime and food supply for neonate SVL and neonatal fat body weight. Sprint speed within 24 hours of birth was significantly increased in neonates from mothers given restricted thermal opportunities; however, for weeks 1-8 postnatally, there were no differences in sprint speed in offspring from any of the treatments. These results suggest that, contrary to our initial hypothesis, females maintained in nutritionally favorable conditions are unable to compensate for the gestational effects of a thermally poor environment. We now suggest that in Niveoscincus metallicus facultative placentotrophy may allow mothers to improve offspring fitness by increasing neonatal fat body size.

HALL, W. P. 1970. Three probable cases of parthenogenesis in lizards (Agamidae, Chamaeleontidae, Gekkonidae). Experientia 26:1271-1273. HOUSTON, T. E 1974. Revision of the Amphibolurus decresii complex (Lacertilia: Agamidae) of South Australia. Trans. Roy. Soc. S. Aus. 98:49-60. INGER, R. E, AND GREENBERG, B. 1966. Annual reproductive patterns of lizards from a Bornean rain forest. Ecology 47:1007-1021. JAMES, C. D., AND SHINE, R. 1985. The seasonal timing of reproduction: a tropical-temperate comparison in Australian lizards. Oecologia 67:464-474. JOHNSTON, G. R. 1982. The herpetofauna of the Middleback Range area, South Australia 1. An annotated checklist. Herpetofauna (Australia) 14:52-60. 1997. Behavioural Ecology of the Peninsula Dragon Lizard, Ctenophorus fionni. Unpubl. Ph.D. Thesis, Flinders Univ. South Australia. KRANZ, C. 1992. Results of breeding the peninsula dragon, Ctenophorus fionni. Monitor 4:54-57. SMYTH, M. AND SMITH, M. J. 1968. Obligatory sperm storage in the skink Hemiergis peronii. Science 161: 575-576.

The grand skink, Oligosoma grande, is a diurnal rock-dwelling lizard from the tussock grass- lands of Central Otago, New Zealand. Foraging behavior, diet, and spacing patterns were examined for two populations of individually marked adults. Adults of both sexes search for arthropod prey using pause- move (=saltatory) searching. Males and females spent the same amount of time moving across outcrops but differed in the characteristics of their searching behavior. Females made more frequent but shorter moves than males. The two sexes also differed in diet Males directed most of their pursuit effort towards large flying insects, but occasionally consumed smaller, easy to capture prey and visited fruiting plants. By con- trast, females fed primarily on the small prey types and plant material. Males and females had home ranges (HR) and core areas (CA) of comparable size and with comparable levels of total neighbor overlap However, the patterns of HR overlap differed between the sexes. Both males and females tended to have greater average HR overlap with male neighbors. Core area overlap was less extensive than HR overlap and some animals concentrated their activity in CAs that were exclusive from those of other lizards. Females appeared to be dominant to males; the most common conspecific interaction was adult females chasing adult males.

I tested the putative correlation between insularity and herbivory in lacertid lizards. Analysis of literature data on 97 populations of 52 species shows that lizard populations on islands more often include plant material in their diet than do mainland populations. To investigate whether this finding reflects adaptation due to recent selection or is merely a product of the phylogenetic history of the populations, I reconstructed the ancestral states for diets and insularity and incorporated them in the analysis. Changes in habitat (island-mainland or mainland-island) often went with changes in diet (herbivore-insectivore or insectivore-omnivore). Insectivorous lizards that find themselves on islands more often turn towards herbivory than do lizards living in mainland situations. Lizards that already have plants in their diet when living on the mainland seem more successful in colonizing islands. Herbivorous populations of lacertids tend to be larger than insectivorous populations, but there is considerable overlap No difference in mean snout-vent length was found between island and mainland populations. etolog , Vol. 33, No. 4, pp. 6 3-674, 19 ciet for the Study of Amphibians and Reptiles i or in Lacertid Lizards: Ef ects of Insularity and As expected from their great taxonomic diversity, lizards have evolved a great range of diets; insects and other arthropods, mammals and birds, vertebrate eggs, snails, fish, nectar, and various mixtures of leaves, flowers, and fruits. Although the dietary range of lizards is great, the distribution of foods eaten reveals that complete herbivory is rare compared to a diet of arthropods. Only about 3% of all extant lizard species are known to eat significant quantities of plant food (King, 1996). On the other hand, many species occasionally shift away from a diet only of arthropods, toward an omnivorous or herbivorous diet (e.g., Pough, 1973; Schluter, 1984; Perez-Mellado and Corti, 1993; King, 1996). Several authors have speculated on the ecological circumstances that could induce insectivorous lizards to expand their diet to include plant material (Pough, 1973; Schluter, 1984; Perez-Mellado and Corti, 1993; King, 1996). Because plant material is less digestible and may produce substantially slower growth (Pough, 1973; Schluter, 1984), herbivory is often considered a 'forced move', that lizards will not make unless arthropods are insufficient to meet their energy requirements (but see Johnson and Lillywhite, 1979; Sadek, 1981; Troyer, 1984). Lizards living in habitats where insect abundance is (periodically) low may benefit from (partial) herbivory. Large body size is also considered an incentive for herbivory, because larger lizards putatively have greater energetic needs and are les adept at catching small prey because they must move a greater mass in pursuit (Sokol, 1967; Pough, 1973; Sadek, 1981; but see Greene, 1982). The bulk of exclusively herbivorous lizard species is indeed larger than 300 g (Sokol, 1967; Pough, 1973; but see Greene, 1982). If the above presumptions are true, insular lizard populations can be expected to feed more often on plant material than mainland populations. Indeed, islands (especially small ones) often have poor arthropod faunas (Janzen, 1973a, b), and at least for some families and genera of lizards, there is a tendency for larger body size in island races (Case, 1978). Although many au663 This content downloaded from 157.55.39.231 on Thu, 06 Oct 2016 04:43:17 UTC All use subject to http://about.jstor.org/terms

Individual species' phenologies can play an important role in the structure of lizard assem- blages over short time scales. Data from a pitfall study carried out in the dry Chaco of Argentina were used to address the question of how species are distributed in their assemblage through time. Lizard activity and species richness were highest in the spring breeding season and declined in the cool months of the year. Variations in seasonal activity patterns and reproductive chronology resulted in significantly different dis- tributions of species in every sample month. Not only did the species composition of the assemblage change through time, but the mean size of lizards and the proportions of males, females, and juveniles varied significantly for several species. Large lizards, regardless of species, disappeared from the assemblage during the cool, dry winter, while juveniles of the large species remained active year round. Adults of the smallest species were also active throughout the year. We propose an hypothesis based on thermoregulatory con- straints of lizard body size to account for these patterns. An approach focusing on the energetics and phys- iological ecology of individual species would be fruitful in understanding the dynamics of fluctuating lizard communities.

Nineteen species of lizards simultaneously studied at the Curua-Una in the central Amazon of Brazil separate on the basis of microhabitat use and prey types. There is no relationship between microhabitat niche breadths and dietary niche breadths, species using the greatest diversity of microhabitats do not necessarily use the greatest diversity of prey types. A pseudocommunity analysis revealed that the lizard assemblage is structured with respect to microhabitat and diets. A comparison of dietary overlaps with phylogenetic similarities indicates that much of the variation in dietary similarity in this assemblage is associated with phylogenetic similarity. A similar analysis with microhabitat overlaps yielded no relationship to phylogenetic similarity. These results suggest that much of the structure in this particular assemblage is historical, i.e., not the direct result of ongoing species interactions at the local level. Because this assemblage is comprised of lizards from a diversity of higher taxa (families), we suggest that historical factors may be more important in determining structure in phylogenetically deeply rooted assemblages than in phylogenetically shallow-rooted assemblages.