Scincella Research Articles

Intra- and inter-sexual aggression in the ground skink (Scincella lateralis)

Differences in reproductive investment between males and females can be a basis for both intra- and inter-sexual conflict. In a series of laboratory experiments, I staged intra- and inter-sexual contests for food between pairs of adult ground skinks (Scincella lateralis). Males were significantly more aggressive than females. Size asymmetry between contestants significantly affected intrasexual behavior between females, as smaller individuals exhibited avoidance behaviors more frequently than larger individuals. Aggression was more prevalent in intersexual contests than in intrasexual contests, and males bit females significantly more often than females bit males. Females captured significantly fewer prey in the presence of a male than in control tests, but showed more avoidance behaviors in intersexual contests than did males. These results suggest that intersexual conflict may be important in social interactions in ground skinks, particularly with respect to spatial distribution.

Ecological factors influencing the antipredator behaviors of the ground skink, Scincella lateralis

I tested several hypotheses regarding the antipredator behaviors of ground akinks (SdnctUa lattraUs) based on a rimple-optimality model for avoiding predation. Field studies demonstrated that & lattraUs with lower body temperatures fled earlier in predatory events when the predator was farther away than did warmer animal^ This may reflect a compensatory shift in behavior related to decreased sprint speeds observed at lower temperatures. These differences in maTinmim sprint speeds at five substrate temperatures were not linked to morphological characteristics such as mass, snout-vent length, or tail length. Body temperatures of S. lattraUs were highly correlated with substrate temperatures in the field, and these environmental temperatures correlated with the daily and seasonal activity schedules of 5. lattraUs. The thennoregulatory strategy of ground skinks closely parallels theoretical predictions for forest-dwelling lizards based on optimum performance curves. In the laboratory, S. lattraUs did not alter flight responses based on the availability of cover objects or tail condition of the lizards. Escape behaviors of males and females did not differ. Likewise, £ lateratis showed no differences in response to differently sized predator models. Differences were found between the reactions of adult and juvenile tkinks to an approaching predator modeL Also, 5. lateralis collected in Louisiana fled from the same predator model with greater frequency than S. lateralis collected in Oklahoma. Kty words: antipredator responses, approach distance, behavior, SdnaUa lattraUs, skink*, tail autotomy, tbermoregulation. [Behav Ecol 8:622— 629 (1997)]

Two new species of Eimeria Schneider, 1875 (Apicomplexa: Eimeriidae) from skinks in Florida

Eimeria egregia n. sp. parasitises the gall-bladder of Eumeces egregius onocrepis, the brown red-tailed skink, in the Ocala National Forest, Marion County, Florida. Oocysts are oval, 27.6 × 17.4 µm (25–32 × 16–20), without micropyle, polar body or oocyst residuum. The oocyst length/width ratio is 1.59 (1.42–1.76). Sporocysts are ovoid, 10.3 × 8.3 µm (8.5–12 × 7–9 µm), with a length/width ratio of 1.24 (1.06–1.50,), without a Stieda body, but with a prominent sporocyst residuum. Sporozoites are 10–12 × 2.5–3 µm. The ground skink Scincella lateralis is infected by Eimeria scincellae n. sp. The oocysts are cylindrical, 29.8 × 15.9 µm (28–33 × 14–17), with no micropyle, polar body or oocyst residuum. The oocyst length/width ratio is 1.89 (1.68–2.14). Sporocysts are oval, 10.9 × 8.0 µm (9.5–12 × 7–9), with a length/width ratio of 1.36 (1.18–1.64,), no Stieda body and a prominent sporocyst residuum. Sporozoites are 9–11 × 2–2.5 µm.

Relative utilization of reptiles and rodents as hosts by immature Ixodes scapularis (Acari: Ixodidae) in the coastal plain of North Carolina, USA.

The interaction of immature black-legged ticks, Ixodes scapularis, with reptiles and rodents was investigated in various woodland habitats in the coastal plain of North Carolina. Reptiles were sampled from April 1 to September 30, 1991. No ticks were found on 95 specimens representing 16 species of snakes. Ticks were found on 54 (36.7%) of 147 lizards. I. scapularis was the only tick recovered from lizards. Some lizards were collected in drift fence traps each month of the study except August. Capture rates averaged one lizard per 16 trap-days. Larvae and nymphs of I. scapularis were removed from the southeastern five-lined skink (Eumeces inexpectatus), the ground skink (Scincella lateralis), the broad-headed skink (E. laticeps) and the eastern glass lizard (Ophisaurus ventralis), but ticks were not found on three other lizard species. Tick infestation rates and loads for parasitized species are presented. Ticks were almost exclusively attached at the base or in the axils of forelimbs of skinks and in the lateral grooves of eastern glass lizards. Rodents were live-trapped at sites where lizards were sampled and at other sites from 1 July, 1990 to 30 January, 1992. Capture rates averaged one rodent per 47 trap-nights. Ticks were found on 23 (17.8%) of 129 animals inspected. Five species of rodents were examined but only four species were found to be tick-infested. In contrast to lizards, few I. scapularis were collected. Rodents, principally the white-footed mouse (Peromyscus leucopus) and cotton mouse (P. gossypinus) were most frequently infested with immature American dog ticks, Dermacentor variabilis, during winter and early spring months. Burdens of D. variabilis on these rodents averaged 0.3 ticks per rodent. Effects of the diversion of ticks from feeding on Peromyscus mice on the transmission of the Lyme disease spirochete are discussed.

Energetic costs of prey ingestion in a scincid lizard, Scincella lateralis

The relative importance of aerobic and anaerobic metabolism during feeding was investigated in the ground skink, Scincella lateralis. Animals were fed crickets of three different sizes relative to body mass (5, 10, and 15% of body mass). Oxygen consumption and lactic acid production of animals during feeding were compared with those of animals at rest and when exercising intensely. Oxygen consumption was higher in feeding and exercising animals than in those at rest. Rates of oxygen consumption of animals consuming prey of 5 and 10% of body mass were not significantly different from each other, but were lower than rates of animals consuming prey of 15% of body mass. Lactic acid concentrations in feeding animals increased with increasing prey size. Concentrations in resting and feeding animals were not different, but those of exercising animals were significantly higher. These data suggest that, despite a positive correlation between prey size and lactic acid concentration, anaerobiosis is relatively unimportant in the support of prey handling for Scincella lateralis. The energetic requirements of feeding in this species are met largely by increased aerobic metabolism.

Behavioural compensation for tail loss in the ground skink, Scincella lateralis

Behavioural compensation for tail loss in the ground skink, Scincella lateralis

Isospora manchacensis n. sp., an Intranuclear Coccidian from the Louisiana Ground Skink, Scincella lateralis (Say, 1823) (Lacertilia: Scincidae)

Isospora manchacensis n. sp. is described from ground skinks, Scincella lateralis (Say, 1823) from Louisiana. Overall prevalence at 6 sites near Lake Ponchartrain was 43.1% (59/137) and ranged from 8% (1/13) to as high as 60% (6/10). Endogenous stages develop inside the nuclei of epithelial cells in the small intestine. Infected hypertrophic nuclei migrate from the basal lamina of the host cell to the luminal striated border. Oocysts in freshly passed fecal pellets usually contain a single contracted sporont that divides to form 2 sporoblasts. These undergo a brief pyramid stage followed by sporulation within 45-50 hr. Sporulated oocysts have a single-layered wall and measure 25.0 X 22.6 (20.0-28.9 X 18.6-26.0) micron. The lemon-shaped sporocysts measure 12.8 X 10.2 (11.1-15.2 X 9.0-11.0) micron and contain a Steida body, a spherical to oval substeida body, and a dispersed, granular sporocyst residuum. Prepatent periods in skinks fed 700 and 1,400 oocysts ranged from 24 to 32 days. Experimentally infected skinks produced large numbers of oocysts continuously during the 3-4 wk they were monitored after the onset of patency, but exhibited no signs of disease. Experimental doses of 200 oocysts failed to produce infections in skinks monitored for as long as 7 wk.

Comparative Aspects of Diet and Habitat in some New Caledonian Lizards

AbstractNo comparative ecological studies have previously been conducted on the lizards of New Caledonia. This study examines two parameters of resource partitioning-diet and microhabitat, for eleven species of native lizards (Gekkonidae and Scincidae). Differences in diel activity patterns and coarse habitat differences tend to segregate geckos from skinks. Microhabitat and dietary differences were found among four sympatric species in a forest assemblage at Mt. Koyaboa, but retreat sites and some food resources were employed by all. Rock piles and crevices are important retreats for all the forest species studied and are a crude predictor of lizard abundance. Crickets and terrestrial isopods are the most important items in the diet of the predominant gecko Bavayia sauvagii. Though generally considered arboreal, this lizard is frequently active on the ground as well. Ants are an important food source of the forest skink Leiolopisma tricolor, whereas the ubiquitous ground skink Leiolopisma austrocaledonicum eats a wide variety of prey, with smaller individuals selectively taking smaller prey. Larger individuals consume feew large prey items but these may be of great energetic importance.

The Relative Roles of Vision and Olfaction in Prey Detection by the Ground Skink, Scincella lateralis

Scincella lateralis responds primarily to the visual stimulus of prey. Nineteen lizards were randomly presented visual, chemical, and visual and chemical cues of prey. When chemical cues of normal concentrations were presented only those treatments containing a visual cue elicited a greater rate of tongue flicking, stimulated orientation to the prey, and attack behavior. However, lizards presented concentrated chemical cues of prey had a significantly greater rate of tongue flicking than when presented a control. This increase in the rate of tongue flicking was not due to the mere strength of the stimulus, as lizards presented a novel chemical stimulus did not demonstrate an increase in tongue flicking.

Responses of Five-Lined Skinks (Eumeces fasciatus) and Ground Skinks (Scincella lateralis) to Conspecific and Interspecific Chemical Cues

olfactometer. In the first experiment, five-lined skinks significantly approached odors of conspecifics. Males also exhibited significantly higher snout-dip and tongue-flick rates than females. Ground skinks also responded to conspecific odors, but in a more complex fashion. Male odors were avoided by both male and female ground skinks. Males, but not females, significantly approached female odors. Females responded randomly to female odors (i.e., they were neither approached nor avoided). Although male and female ground skinks were equivalent with respect to tongue-flick rates, females exhibited greater snout-dip rates. In the second experiment skinks of both species responded randomly when presented with odors of the other species. The results demonstrate that five-lined and ground skinks utilize and respond to conspecific chemical signals, or pheromones. Potential roles of these pheromone-mediated responses in nature are discussed.

The strategy of tail-autotomy in the ground skink, Lygosoma laterale.

AbstractThe adaptation of tail‐autotomy is paradoxical in lizards which utilize the tail as a major fat‐storage organ, because high rates of tail‐loss are normal and because surrender of large fat reserves seems to amount to selective pressure favoring predation on such lizards. Experimental results demonstrate the existence of ta behavioral mechanism in Lygosoma laterale consisting of return by the lizard to where its tail was lost, a strong ingestion response to an inanimate automized tail, and movements by the autotomized tail which make its capture less likely. Laboratory evidence includes rates of ingestion of autotomized tails averaging nearly 40% for five species of skinks. This contrasts with rates averaging 3.4% for two iguanid lizards in which fat reserves are not stored in the tail. Tests with free‐ranging L. laterale show that ingestion occurs in nature. Additional laboratory experiments quantitatively demonstrate escape behavior by tails of L. laterale. The results confirm a behavioral mechanism in L. laterale which compensates for the ready autotomy of major fat reserves. At the same time, two divergent evolutionary strategies of adaptation of the autotomic tail are defined.

Population Ecology of the Ground Skink, Lygosoma laterale (Say)

Ecological MonographsVolume 37, Issue 2 p. 71-87 Article Population Ecology of the Ground Skink, Lygosoma laterale (Say) Garnett R. Brooks Jr., Garnett R. Brooks Jr.Search for more papers by this author Garnett R. Brooks Jr., Garnett R. Brooks Jr.Search for more papers by this author First published: Spring 1967 https://doi.org/10.2307/2937336Citations: 20AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume37, Issue2Spring 1967Pages 71-87 RelatedInformation

Physiological Responses to Temperature in the Ground Skink, Lygosoma laterale

of the 62 days of July and August, 1963 (U.S. Weather Bureau, Houston, Texas). Moreover, on only 7 days did the ambient temperature drop under 26 C. Furthermore, physiological studies of lizards less than 2 g in size have not, insofar as we are aware, been done. Physiological data we secure are of value, therefore, in extending the physiological characterization of lizards to the lower limits of adult