Brown Skink Research Articles

Lack of Aggressive Behavior between Neonates of Little Brown Skinks (Scincella lateralis)

Nearly all studies of lizard behavior have been conducted on adults. Therefore, an important part of the lizard life cycle has been overlooked, the neonate stage. Lizards hatch at about the same time, briefly causing high density and increased chances that neonates engage in aggressive encounters. We studied the behavior of neonate Little Brown Skinks (Scincella lateralis) by staging a series of dyadic encounters between pairs of neonates in the laboratory. Two neonates were confined in an observation chamber on either side of a partition for 48 h. The partition was then removed, a single retreat was placed in the center of the observation chamber, and the behavior of the two neonates was recorded for 60 min. Neonate Little Brown Skinks almost never showed aggressive behaviors, such as biting and chasing, exhibited by adults. Neonates segregated themselves on opposite sides of the observation chamber when active on the surface, but frequently simultaneously occupied the retreat, something that almost never happens in adults. Limited data on species of skinks that form stable aggregations suggest that retreat sharing by neonates or juveniles may be common in members of the Scincidae.

AGGRESSIVE BEHAVIORS AND THEIR EFFECT ON RESOURCE USE BY FEMALE SINCELLA LATERALIS

Studies of aggression and space use are essential to understanding resource use by reptiles, particularly lizards. Research in this area, however, exhibits bias in that the seminal work has been done on (1) species that are highly visible in their habitats (e.g. Iguanians); and (2) males. Studies of secretive species such as skinks and of females are less common. Here, we present results of a lab study of dyadic encounters of adult females of a common North American skink: Scincella lateralis (Little Brown Skink), and compare them to results obtained from an earlier study of adult males of the same species. Female S. lateralis never interacted unless they were within one body length of each other. The most common behavior exhibited was avoidance of one lizard (the subordinate) away from the other lizard (the dominant). As a result, the two lizards spent more time apart than close together and rarely shared the retreat. The larger of the two females was dominant in 9 of 10 trials. Compared to adult males, adult females showed far fewer aggressive behaviors such as lunging or chasing, and never bit each other. Unlike males, however, subordinate female S. lateralis exhibited tail twitching significantly more often than did dominants, suggesting this behavior may be a social signal for females, though the data suggest there may be other possible functions. Despite differences in the frequency of behaviors exhibited, patterns of space use and retreat use were the same in females as they were in males.

Pattern biases, but not positional cues, influence learning in the little brown skink, Scincella lateralis

Abstract Studies of many lizard species have established they are capable of learning to escape to one specific retreat out of several available retreats and will escape to it when subjected to a simulated predator attack. Recently, researchers have focused on the processes involved in learning, including what cues lizards use to learn to escape to a retreat. Previous work on the little brown skink lizard, Scincella lateralis, has shown that it is capable of learning to escape to a specific retreat when it has gained prior experience with its environment and that its performance is better when a retreat is associated with a vertical stripe local cue than when the retreat was associated with a horizontal stripe one. Here I report the results of two additional experiments undertaken to gain a better understanding of how little brown skinks react to cues in their environment. In Experiment 1, the positional cue test, I tested if little brown skinks could be trained to escape to a specific retreat when the only cue available was a positional cue that lizards could use to orient themselves by conducting a series of trials in which little brown skinks were trained to escape to the retreat to the left or the right of a vertical cylinder. Only 2 of the 16 (12.5%) little brown skinks met the learning criterion. This was not significantly different from what is expected if lizards chose their retreats at random suggesting little brown skinks are poor at learning when only a positional cue is available. In Experiment 2, the pattern bias test, I tested if the little brown skink’s superior performance learning to escape to a retreat with a vertical stripe cue in previous experiments was due to a bias for vertical stripes (or against horizontal stripes) through a series of trials in which little brown skinks had to choose between two escape retreats: one with a vertical stripe local cue and the other with a horizontal stripe local cue. A significant bias for the vertical stripe local cue retreat was found among 24 adults, but not among 12 neonates. These results suggest pattern bias among adult little brown skinks impacted the results of previous studies. The possibility that lizards may have biases for colours or shapes and that these biases may have an impact on learning studies is discussed.

Response of Lizards to High-Severity Wildfires in a Southern United States Mixed Pine/Hardwood Forest

High-severity forest fires are increasing in large areas of the southern and western United States as the climate becomes warmer and drier. Natural resource managers need a better understanding of the short- and long-term effects of wildfires on lizard populations, but there is a paucity of studies focused on lizard-wildfire relationships. We used a before-after, control-impact (BACI) sample design to assess the response of three lizard species—Six-lined Racerunner (Aspidoscelis sexlineata), Prairie Lizard (Sceloporus consobrinus), and Little Brown Skink (Scincella lateralis)—to high-severity wildfires that occurred in the Lost Pines Ecoregion, Texas, USA. Specifically, we analyzed monitoring data collected across 17 trapping sessions from spring 2008 to spring 2013 using stratified N-mixture models to estimate trends in lizard abundances, while accounting for environmental parameters that might influence lizard detectability. We found no evidence of a fire-induced change in abundance for any of the lizar...

AGGRESSIVE BEHAVIORS AND THEIR EFFECT ON RESOURCE USE BY MALE LITTLE BROWN SKINKS, SCINCELLA LATERALIS

The aggressive behaviors of adult male Little Brown Skinks, Scincella lateralis, and their effects on access to an important resource (a single retreat) were the subject of a study consisting of 10 laboratory trials in which the behavioral interactions between a pair of individuals was recorded. Analysis of these interactions made it possible to identify a dominant and a subordinate male in each trial; the male with the greater bulk was dominant in 9 of the 10 trials. Aggressive behaviors recorded include lunging, chasing, and biting; the dominant male performed lunging significantly more often than the subordinate male and was the only individual to exhibit chasing. The most common behavior recorded was avoidance which was shown almost exclusively by the subordinate male. Both dominant and subordinate males exhibited tail twitching which we hypothesize to be a sign of agitation. The two males spent significantly more time on opposite sides of the observation chamber than on the same side and almost never occupied the single retreat simultaneously because the subordinate male repeatedly moved to avoid the dominant male. The implications of these results on spacing patterns and resource use of Scincella lateralis in the wild are discussed.

Commensal Nesting ofScincella lateralis(Little Brown Skinks) inAlligator mississippiensis(American Alligator) Nests andOndatra zibethicus(Muskrat) Houses in Southwestern Louisiana

Abstract Scincella lateralis (Little Brown Skink, hereafter Skink) are ubiquitous throughout the southeastern US and primarily nest in leaf litter on the forest floor. However, their presence in coastal marsh settings necessitates their use of alternate nesting habitats. We investigated Skink nesting ecology in Alligator mississippiensis (American Alligator) nests and Ondatra zibethicus (Muskrat) houses in an intermediate/brackish coastal marsh habitat at Rockefeller Wildlife Refuge in southwestern Louisiana. For our field studies, we found and collected Skink eggs from 16 June through 5 October, and hatched eggshells from 6 July through 5 October. We found Skink eggs/eggshells in 36 of 109 active American Alligator nests (33.0%), 19 of 36 inactive Alligator nests (52.8%), and 13 of 51 Muskrat houses (25.5%). Clutch size ranged from 1 to 5 eggs (average = 3.0). The mean depth of Skink eggs was 24.6 cm in American Alligator nests and 17.1 cm in Muskrat houses. Multiple clutches commonly occurred in a struc...

Herpetofaunal Diversity and Seasonality from a Remnant Coastal Chenier Forest in Southwestern Louisiana

Cheniers are ancient beach ridges in southwestern Louisiana that are often characterized by coastal forest surrounded by marshland. Coastal chenier forests (CCFs) are considered an imperiled habitat in Louisiana because many forest remnants are considerably impacted due to human activities and recent hurricanes. Because little is known about the herpetofaunal community of CCFs, I initiated a seasonal herpetofaunal diversity and abundance study on a privately-owned, remnant CCF in eastern Cameron Parish, Louisiana. Utilizing coverboards and drift fence arrays with pitfall and funnel traps, I documented 12 species (4 anuran, 4 snake, 3 lizard, and 1 turtle) comprising CCF obligate and facultative species, as well as one marsh transient species. Species-accumulation curves indicate the sample was representative of the small herpetofaunal community. Three amphibian (Incilius nebulifer [Gulf Coast Toad], Lithobates sphenocephalus utricularius [Coastal Plains Leopard Frog], and Gastrophryne carolinensis [Eastern Narrow-mouthed Toad]) and 2 reptile (Scincella lateralis [Little Brown Skink] and Thamnophis p. proximus [Orangestriped Ribbonsnake]) species comprised 94% of the captures. Diversity was highest during the spring, with 3 months (March–May) of sampling detecting 92% of the total diversity observed. Sampling during single months only yielded 42–75% of the diversity. Amphibian abundance varied by month (highest June to September) and with the presence of rain, whereas reptile abundance only varied by month (highest in March). Funnel traps were more effective and quantified diversity better than pitfall traps or coverboards. The herpetofaunal diversity at the site was low and comprised of mostly generalist species; regional specimen records also exhibit a modest herpetofaunal community. This data will provide baseline information to determine the impacts of future hurricanes on the herpetofaunal community, analyze recolonization dynamics following hurricanes, and make comparisons to other CCF remnants in the region. I also provide recommendations for improving herpetofauna sampling methodology in coastal settings.

Lizard Microhabitat and Microclimate Relationships in Southeastern Pine-Hardwood Forests Managed With Prescribed Burning and Thinning

Understanding the impacts of disturbances in forest ecosystems is essential for long-term biodiversity conservation. Many studies have evaluated wildlife responses to various disturbances but most generally do not use changes in microclimate features or microhabitat structure to explain these responses. We examined lizard responses to two common forest management practices (prescribed burning and thinning) in pine-hardwood forests of the Bankhead National Forest, Alabama, USA. Over 4 years, we captured 719 individual lizards representing seven species. Lizards exhibited species-specific responses to forest management: eastern fence lizard (Sceloporus undulatus) captures were positively associated with an increasing forest disturbance gradient and were greatest in thin with burn treatments, whereas little brown skink (Scincella lateralis) captures were positively associated with increasing litter depth and were greatest in control sites during the first year posttreatment. Green anole (Anolis carolinensis) captures increased in forest stands with concomitant increases in air temperature, whereas common five-lined skink (Plestiodon fasciatus) captures were related to coarse woody debris cover during posttreatment sampling. We were unable to detect a treatment response or microhabitat/microclimate associations for broad-headed skinks (Plestiodon laticeps). Through an information-theoretic approach, we were able to identify treatment effects along with changes in microclimate and microhabitat features potentially responsible for driving responses of southeastern lizard species to forest management.

The role of visual cues in learning escape behaviour in the little brown skink (Scincella lateralis)

Many small animals escape predators by running under an escape retreat such as a rock, log, or pile of leaves. Rapid escape to a retreat would be facilitated if the animal already learned the location of the retreat before it ever had to flee from a predator. One way a small animal might do this is to attend to a prominent ‘local cue’, that is, a visual cue that is part of, or contiguous with, the retreat. I tested the hypothesis that a small lizard commonly known as the little brown skink, Scincella lateralis, can use a local visual cue to learn an escape behaviour. Little brown skinks were presented with two retreats side-by side in an observation chamber. One retreat was backed with a vertical striped cue and the other backed with a horizontal striped cue. Each lizard was induced to run from one end of the observation tank to the opposite end with the two retreats; the retreat that each lizard chose for escape was recorded through a series of 15 trials conducted over three days. Half of the lizards were trained to escape to the vertical cue retreat; half were trained to escape to the horizontal cue retreat. About one-third of little brown skinks met the learning criterion of escaping to the correct retreat in five consecutive trials. However, significantly more of the vertical cue lizards met the learning criterion than did horizontal cue lizards. Also, the vertical cue lizards escaped to the correct retreat significantly more often than expected by chance. Furthermore, even the horizontal cue lizards showed a preference for escaping to the vertical cue retreat. This suggests little brown skinks can use a local visual cue to learn an escape behaviour, but only if it a vertical cue. This may be related to the use of a vertical cue to obtain positional information to locate a retreat or perhaps to the tendency of this forest species to attend to abundant vertical cues in its habitat.

Geographic variation in learning of escape behavior in the little brown skink (Scincella lateralis)

A previous study showed that little brown skinks, Scincella lateralis, from a population in Louisiana, USA were poor at learning to escape to a specific retreat in a series of laboratory trials. The study was repeated on little brown skinks from a population in Oklahoma (650 km from the Louisiana population). The Oklahoma lizards were significantly better at learning to escape to a specific retreat than their Louisiana counterparts. This result demonstrates that geographic variation in the ability to learn an escape behavior exists in this species.

Case 3510Cyclodina aeneaGirard, 1857 (currentlyOligosoma aeneum; Reptilia, Squamata, scincidae): proposed conservation of the specific name and suppression of the senior subjective synonymTiliqua ornataGray, 1843 (currentlyOligosoma ornatumGray, 1843)

The purpose of this application, under Article 75.6 of the Code, is to conserve the specific name of the name Oligosoma aeneum (Girard, 1857), widely used for a species of New Zealand skink, commonly known as the copper skink. We have found Tiliqua ornata Gray, 1843 (currently Oligosoma ornatum) to be a senior subjective synonym and the oldest available name for this species. The name Oligosoma ornatum has been incorrectly applied since 1977 to a similar but larger sympatric species, commonly known as the ornate skink, and prior to 1977 was in use for a third species, now identified as the brown skink, Oligosoma zelandicum (Gray, 1843). With various generic name changes the name Oligosoma ornatum has been in widespread usage for the larger ornate skink and Oligosoma aeneum for the smaller copper skink, for more than 30 years. Application of the specific name Oligosoma ornatum to a third species within 35 years will cause extreme confusion and inaccuracy of recording of biological data and conservation status. The Commission is requested to maintain the use of the junior synonym Oligosoma aeneum as a nomen protectum and suppress the name Oligosoma ornatum as a nomen oblitum.

Habitat relationships of reptiles in pine beetle disturbed forests of Alabama, U.S.A. with guidelines for a modified drift-fence sampling method

Abstract Understanding vertebrate habitat relationships is important to promote management strategies for the longterm conservation of many species. Using a modified drift fence method, we sampled reptiles and compared habitat variables within the William B. Bankhead National Forest (BNF) in Alabama, U.S.A from April 2005 to June 2006. We captured 226 individual reptiles representing 19 species during 564 total trap nights. We used canonical correspondence analysis to examine habitat associations for the reptiles sampled and we detected a distinct habitat gradient ranging from sites with greater litter depth and percent canopy cover to more open sites with greater woody, herbaceous, and coarse woody debris (CWD) coverage, and CWD volume. Little brown skinks Scincella lateralis and eastern worm snakes Carphophis a. amoenus were associated with sites with greater litter depth and canopy cover, whereas eastern fence lizards Sceloporus undulatus, copperheads Agkistrodon contortrix, and gray ratsnakes Pantherophis spiloides were associated with sites possessing greater CWD coverage and volume. We found that disturbances due to the southern pine beetle Dendroctonus frontalis were likely important for influencing reptile distributions through the creation of canopy gaps and fallen coarse woody debris. Compared to other studies, our modified drift-fence trap technique was successful for sampling larger snake species (66 snakes in 564 trap nights). We have also provided detailed schematics for constructing drift fence array and box traps used in this study.

Phylogeography of two New Zealand lizards: McCann’s skink ( Oligosoma maccanni) and the brown skink ( O. zelandicum)

The New Zealand skink fauna has proven to be an ideal taxonomic group in which to examine the impact of climatic and geological processes on the evolution of the New Zealand biota since the Pliocene. Here we examine the phylogeography of McCann’s skink ( Oligosoma maccanni) in order to gain insight into the relative contribution of Pliocene and Pleistocene processes on patterns of genetic structure in the South Island biota, and investigate the phylogeography of the brown skink ( O. zelandicum) to examine whether Cook Strait landbridges facilitated geneflow between the North and South Islands in the late-Pleistocene. We obtained mitochondrial DNA sequence data (ND2 and ND4; 1282 bp) from across the range of both species. We examined the phylogeographic patterns evident in each species using Neighbour-Joining, Maximum Likelihood and Bayesian methods. We found substantial phylogeographic structure within O. maccanni, with seven distinct clades identified. Divergences among clades are estimated to have occurred during the Pliocene. Populations in the Otago/Southland region (south of the Waitaki River valley) formed a well-supported lineage within O. maccanni. A substantial genetic break was evident between populations in east and west Otago, either side of the Nevis-Cardrona fault system, while north-south genetic breaks were evident within the Canterbury region. Within-clade divergences in O. maccanni appear to have occurred during the mid- to late-Pleistocene. Shimodaira–Hasegawa topology tests indicated that the ‘Garston’ skink is not genetically distinct from O. maccanni. There was only relatively minor phylogeographic structure within O. zelandicum, with divergences among populations occurring during the mid- to late-Pleistocene. Our genetic data supports a single colonisation of the North Island by O. zelandicum from the South Island, with the estimated timing of this event (0.46 mya) consistent with the initial formation of Cook Strait.

Spatial learning in the little brown skink, Scincella lateralis: the importance of experience

Previous studies have shown that squamates (lizards and snakes) are capable of spatial learning, but only after extensive training. In nature, squamates' capacity to learn may be better than that suggested by laboratory studies, because they have the opportunity to become familiar with the location of important landmarks and vital resources as they wander through their home range. I conducted three laboratory experiments to test the hypothesis that prior experience with a habitat improves spatial learning in little brown skinks. Individual lizards were subjected to a simulated predatory attack and tested for their ability to take refuge under one of two cardboard retreats (experiment 1) and to choose the ‘correct’ retreat without prior experience (experiment 2) and with 48 h of prior experience (experiment 3) in the ‘habitat’. Although little brown skinks learned to take refuge under cardboard retreats (experiment 1), inexperienced lizards did not learn to take refuge under the ‘correct’ retreat (experiment 2). However, experienced lizards did learn to take refuge under the correct retreat (experiment 3) and did so after only a few trials. I discuss the influence of experience, the ecological relevance of stimuli used in learning experiments, and other methodological issues.

The Glaphyromorphus isolepis Species Group (Lacertilia: Scincidae): Diagnosis of the Taxon and Description of a New Species from Timor

The Glaphyromorphus isolepis Species Group (Lacertilia: Scincidae): Diagnosis of the Taxon and Description of a New Species from Timor