Habitat structure and their influence in lizard’s presence

Many species are declining due to environmental and physical changes in their habitats. Such disturbs alter the availability of micro-habitats and influences the presence of lizards, being even worse for threatened and endemic species. Glaucomastix littoralis is a teiid species restricted to four restingas areas of Brazil. The understanding about the use and preferences of micro-habitats by the species and the consequents effects of substrate loss is important to prevent local extinctions. This study took place in restingas of Maricá, Jurubatiba and Grussaí, in Rio de Janeiro State. We sampled the vegetation of all areas, to access differences between the physical structures, and recorded the individuals sighted and the micro-habitat they were in, to investigate the relation of individuals and habitat structure. We calculated the frequency utilization of each micro-habitat and made a presence estimation of individuals (occupancy and detection probability) to assess which structural parameters of vegetation guide the settlement of the studied populations. Our data showed structural vegetation particularities among the areas and a trend concerning the use of micro-habitat by Glaucomastix littoralis, with a general preference for leaf litter inside bushes, guriri and bare sand and a low utilization of cactus and herbaceous. We also found positives (bare sand and cactus) and negatives (bushes) influences of micro-habitats in relation to the occupation of the areas by the individuals. Since vegetation is fundamental to lizards, due to their use as a refuge, site for thermoregulation and feeding, the understanding about the effects habitat degradation/fragmentation can cause is essential to create appropriate management plans and develop public policies to conserve the species

A morphometric study of Eutrombicula alfreddugesi (Acari: Trombiculidae) infesting four sympatric species of Tropidurus (Squamata: Tropiduridae) in northeastern Brazil

We undertook a sampling program to understand the extent of morphological variation in Eutrombicula alfreddugesi among the fourhost species of Tropidurus at Morro do Chapéu, Brazil

Variation in feeding ecology of five cnemidophorine lizard species along Brazilian eastern coast

Feeding ecology of a particular species is associated to population dynamics and contributes for the understanding of natural history and trophic interactions in ecosystems. We investigated changes in the feeding habits of 16 populations belonging to five cnemidophorine lizard species (being four bisexual and one unisexual) along approximately 4000 km extension of the Brazilian eastern coast. Fieldwork was carried out in 15 areas of restinga habitats and for each cnemidophorine population, the composition of the diet was analyzed based on the number, volume (mm3) and frequency of each prey category or plant material.The arthropods were categorized in the taxonomic level of Order or Family (e.g.Formicidae). Cnemidophorine populations/species studied were mainly carnivorous and had, in general, a diet consisting predominantly of larvae and/or termites, with few instances of plant material consumption. The availability of termites locally at each restinga habitat was not a determinant factor in the increase of termite consumption by the local cnemodophorine population. However, differences in diet composition among populations partially resulted from differential consumption of termites, leading to the formation of two distinct groups depending on higher or lesser consumption of termites. Some populations had onthonegetic variation in diet, but males and females of different populations/species tended to have similar diet composition. The head width of lizards affected significantly the volume and the length of the largest prey ingested in 60% (3/5) of the species studied, indicating that adults tended to consume larger food items compared to coespecifics juveniles. The high level of importance of termites and larvae in almost all populations/species probably contributed to the low intra-and interspecific differences in food habit. The diet of cnemidophorine species studied in restinga habitats in general, tended to be similar to that found to other cnemidophorines, regardless its geographic distribution. Invertebrates were the dominant prey on cnemidophorines diet, but predation on vertebrates was also registered.A ecologia alimentar de uma determinada espécie está associada a dinâmica da população e contribui para a compreensão da história natural e das interações tróficas nos ecossistemas. No presente estudo, investigamos mudanças nos hábitos alimentares de 16 populações pertencentes a cinco espécies de lagartos cnemidophorines (quatro bissexuais e uma unissexual) ao longo de aproximadamente 4000 km da costa leste brasileira. O trabalho de campo foi realizado em 15 áreas de restinga. A composição da dieta de cada população foi baseada no número, volume (mm3) e frequência de cada categoria de presa e de material vegetal. Os artrópodes foram categorizados no nível taxonômico de Ordem ou Família (por exemplo, Formicidae). As populações/ espécies de cnemidophorines estudadas foram principalmente carnívoras com uma dieta constituída predominantemente por larvas e/ou cupins, com pouco consumo de material vegetal. A disponibilidade de cupins localmente em cada restinga não foi um fator determinante no aumento do consumo de cupins pela população do lagarto cnemidophorino local. No entanto, as diferenças na composição da dieta entre as populações resultaram do consumo diferencial de cupins, levando a formação de dois grupos distintos, dependendo do consumo maior ou menor de cupins. Algumas populações apresentaram variação ontogenética na dieta, mas machos e fêmeas tenderam a ter uma composição alimentar semelhante em cada população/espécie. A largura da cabeça afetou significativamente o volume e o comprimento da maior presa ingerida em 60% (3/5) das espécies estudadas, indicando que os adultos tendem a consumir itens alimentares maiores que os jovens coespecíficos. O elevado índice importância de cupins e larvas em quase todas as populações/espécies provavelmente contribuiu para as baixas diferenças intra e interespecíficas no hábito alimentar. A dieta das espécies estudadas, em geral, tendeu a ser semelhante a encontrada para outros cnemidophorinos, independentemente de sua distribuição geográfica. Os invertebrados foram as presas predominantes na dieta, mas a predação em vertebrados foi também registrada.Asociación Herpetológica Argentin

COMPORTAMENTO DE TERMORREGULAÇÃO EM LAGARTOS BRASILEIROS

Reptiles present one of the most complex mechanisms found within vertebrates to regulate body temperature. In lizards, this regulationmechanism achieves a remarkable degree of refinement in which behavior plays a crucial role. The present review deals with a set of factors of thermoregulation in Brazilian lizards, illustrating it as the result of a physiological and behavioral process in lizards and discussing other factors such as the relationship between phylogeny and body temperature in activity, the environmental sources of heat, the costs of behaviors associated with thermoregulation, the complex relationships between body temperature, foraging intensity and diet, and the relationship between thermoregulation and some aspects of their life history such as degree of herbivory and reproductive condition. Based on various sources of information available on body temperature regulation by Brazilian lizards, we aimed at providing a comprehensive review on the subject of thermoregulatory behaviors in Brazilian lizards.Uno de los más complejos mecanismos de regulación de la temperatura corporal es encontrado en réptiles. En los lagartos, este mecanismo alcanza un grado destacado de refinamiento en que el comportamiento es un factor determinante. En este artículo presentamos una revisión de los elementos involucrados en el comportamiento de termorregulación de los lagartos brasileros. En esta amplia revisión discutimos topicos como: la termorregulación como proceso fisiológico y de comportamiento en los lagartos, el efecto y la relación entre la filogenia y la temperatura corporal en actividad, las fuentes ambientales de calor, la termorregulación y los costos asociados a la regulación de la temperatura corporal a través del comportamiento, la complejainterrelación entre temperatura corporal, intensidad de forrajeo y dieta, y la relación entre la termorregulación y otros aspectos de la historia de vida como el grado de herbivoria y el estado reproductivo. Con base enlas más variadas fuentes de información disponibles sobre regulación de la temperatura corporal en lagartos brasileros, proporcionamos también una relevante revisión sobre el tema y un estado del arte del conocimiento sobre el comportamiento de termorregulación en los lagartos brasileros.Um dos mais complexos mecanismos de regulação da temperatura corpórea é encontrado entre os répteis, e nos lagartos, este mecanismo atinge um destacável grau de refinamento em que o comportamento é um fator preponderante. No presente artigo apresentamos uma revisão do conjunto de elementos envolvidos no comportamento de termorregulação em lagartos brasileiros. Nesta ampla revisão abordamos aspectos como a termorregulação como processo fisiológico e comportamental nos lagartos, o efeito e a relação entre a filogenia e a temperatura corpórea em atividade, as fontes ambientais de calor, a termorregulação e os custos associados na regulação comportamental da temperatura corpórea, a complexa interrelação entre temperatura corpórea, intensidade de forrageamento e dieta, e a relação entre a termorregulação e outros aspectos da história de vida como o grau de herbivoria e o estado reprodutivo. Com base nas mais variadas fontes de informação disponíveis sobre regulação da temperatura corpórea em lagartos brasileiros, fornecemos também uma relevante revisão sobre o tema e um estado da arte do conhecimento sobre o comportamento de termorregulação nos lagartos brasileiros

A method for testing the host specificity of ectoparasites: give them the opportunity to choose

Host-choice experiments were carried out with rodent and bat ectoparasites on Ilha Grande, state of Rio de Janeiro, Brazil. We constructed experimental chambers that enclosed three different rodent or bat host species, and then introduced a selected set of ectoparasitic arthropods. When given the opportunity to choose among host species, the ectoparasites showed a strong tendency to select their primary hosts, and reject novel host species. These kinds of simple experiments can be valuable tools for assessing the ability of ectoparasites to locate and discern differences between host species, and make choices about which hosts to infest, and which hosts to avoid

Clutch size in populations and species of cnemidophorines (Squamata: Teiidae) on the eastern coast of Brazil

We analyzed some reproductive aspects of 16 coastal populations, belonging to five lizard species (A. ocellifera, A. abaetensis, A. nativo, A. littoralis and C. lacertoides) from different restinga habitats along the eastern coast of Brazil. This study aimed to evaluate to what extent the reproductive aspects vary geographically and among species. For each female, we recorded the number of vitellogenic follicles, size and color of the largest follicle, presence and size of corpora lutea, and number and size of oviductal eggs. Clutch size of almost all coastal populations/species of Ameivula had little variation and most clutches were composed of two eggs. There was a significant relationship between female size and the mean clutch size when females from different species were pooled. Mean egg volume, among species, varied from 420 to 655 mm3. Relative clutch mass varied from 0.129 to 0.159 and did not differ significantly among species. We concluded that the five coastal species studied (four bisexuals and one parthenogenetic) had similar reproductive characteristics. Most of them presented multiple clutches, low clutch size and low relative clutch mass, similar to other species in the genus and to unisexual and bisexual species of the Teiidae family