Habitat use, daily activity periods, and thermal ecology of Ameiva ameiva (Squamata: Teiidae) in a caatinga area of northeastern Brazil.

Estudamos o uso dos recursos espaciais, temporais e térmicos pelo lagarto neotropical Ameiva ameiva durante as estaçõesseca e chuvosa em um ambiente de caatinga do nordeste do Brasil. Os lagartos utilizaram os hábitats e micro-hábitats de vegetação baixa, mas nunca foram observados no hábitat rochoso. Os adultos utilizaram usualmente o hábitat arbóreo-arbustivo, enquanto os juvenis foram observados maisfrequentemente no hábitat arbustivo-herbáceo. Diferenças ontogenéticas no uso do espaço parecem estar relacionadas a diferentes necessidades térmicas entre as classes de idade devido a diferenças de tamanho corporal. As temperaturas corporais dos juvenis foram significativamente maiores que asdos adultos. A maioria das espécies de Teiidae possui temperaturas corporais elevadas, usualmente acima de 37oC, e atividade concentrada nas horas mais quentes do dia, como observado em A. ameiva neste estudo. A sazonalidade influenciou o uso do hábitat e os períodos diários de atividade dos adultos, mas não influenciou as temperaturas corporais. Verificamos flutuações anuais na abundância de indivíduos adultos, com um declínio de lagartos ativos na estação seca; esse fenômeno pode estar relacionado à estivação e/ou ao aumento da taxa de mortalidade durante os meses mais secos.We studied the use of spatial, temporal, and thermal resources by the Neotropical lizard Ameiva ameiva during rainy and dry seasons in a caatinga (xerophilous open forests) environment in northeastern Brazil. Lizards used the vegetation habitats and microhabitats in the ground, but never were seen in the rocky habitat. Adults usually used the arboreal-shrubby habitat, whereas juveniles were sighted more often in the shrubby-herbaceous habitat. Ontogenetic differences in spatial use seem to be linked to different thermal needs between age groups owing to differences in body size. Body temperatures were significantly higher in juveniles than in adults. Most teiid species have elevated body temperatures, usually above 37oC,and are active during the hottest times of day, as was observed for A. ameiva in this study. Seasonality influenced habitat use and daily activity periods of adults, but not body temperatures. We verified annual fluctuations in adult abundance, with a decline of active lizards in the dry season; this phenomenon may be related to aestivation and/or increased mortality rate during the driest months

Trophic ecology and foraging behavior of Tropidurus hispidus and Tropidurus semitaeniatus (Squamata, Tropiduridae) in a caatinga area of northeastern Brazil

This study aimed to analyze the seasonal variation in diet composition and foraging behavior of Tropidurus hispidus (Spix, 1825) and T. semitaeniatus (Spix, 1825), as well as measurement of the foraging intensity (number of moves, time spent stationary, distance traveled and number of attacks on prey items) in a caatinga patch on the state of Rio Grande do Norte, Brazil. Hymenoptera/Formicidae and Isoptera predominated in the diet of both species during the dry season. Opportunistic predation on lepidopteran larvae, coleopteran larvae and adults, and orthopteran nymphs and adults occurred in the wet season; however, hymenopterans/Formicidae were the most important prey items. The number of food items was similar between lizard species in both seasons; however the overlap for number of prey was smaller in the wet season. Preys ingested by T. hispidus during the wet season were also larger than those consumed by T. semitaeniatus. Seasonal comparisons of foraging intensity between the two species differed, mainly in the wet season, when T. hispidus exhibited less movement and fewer attacks on prey, and more time spent stationary if compared to T. semitaeniatus. Although both lizards are sit-and-wait foragers, T. semitaeniatus is more active than T. hispidus. The diet and foraging behavior of T. hispidus and T. semitaeniatus overlap under limiting conditions during the dry season, and are segregative factors that may contribute to the coexistence of these species in the wet season

Tropidurus semitaeniatus (Squamata: Tropiduridae) as seed disperser of the plant Commiphora leptophloeos (Burseraceae) in the Caatinga of Northeastern Brazil

Tropidurus semitaeniatus is broadly distributed in the rocky habitats of the caatingas of northeastern Brazil (Vanzolini et al., 1980). In the context of a behavioral ecology work, a T. semitaeniatus population was studied at the Estação Ecológica do Seridó (ESEC Seridó; 06.5767º S, 37.2558º W, datum: WGS84; elev. 192 m), Serra Negra do Norte municipality, Rio Grande do Norte State, Brazil. One of the studied aspects included the foraging behavior of lizards recorded by focal animal samples that consisted of 10 continuous minutes of behavioral monitoring on different individuals, with one session from 0700-1000 h and other from 1400- 1700 h, during two consecutive days

Thermal ecology and thermoregulatory behavior of Coleodactylus natalensis (Squamata: Sphaerodactylidae), in a fragment of the Atlantic forest of northeastern, Brazil

We studied the thermal ecology and thermoregulatory behavior of Coleodactylus natalensis Freire, 1999 in a remnant of a northern coastal patch of the Brazilian Atlantic Forest. Data were collected during four 20-day field excursions over the course of one year. We assessed the importance of substrate and air temperatures, in addition to time of exposure to sunlight, as relevant factors for the regulation of body temperature in this species. After each specimen was captured, body (Tb), substrate (Ts) and air (Ta) temperature were measured 10 cm above the ground, using a temperature sensor coupled to a fast response thermo-hygrometer. Ad libitum and focal animal methods were used to describe thermoregulatory behavior. The mean body temperature of C. natalensis was 31.3 ± 3°C (amplitude of 26.9 and 38.4°C, n = 20). A positive relationship was found between Tb and environmental temperatures; further, substrate temperature explained the additional variability of temperature variations in this species. With respect to environmental observations, individuals of C. natalensis did not expose themselves directly to the sun, moving equally between full and filtered sun. Our results indicate that C. natalensis is umbrophylic and a passive thermoregulator

Reproductive and fat body cycles of Tropidurus hispidus and Tropidurus semitaeniatus (Squamata, Tropiduridae) in a caatinga area of northeastern Brazil Ciclos reproductivos y de grasa corporal de Tropidurus hispidus y Tropidurus semitaeniatus (Squamata, Tropiduridae) en una área de caatinga del nordeste de Brasil

This study assessed the reproductive and fat body cycles of Tropidurus hispidus (Spix, 1825) and T. semitaeniatus (Spix, 1825) in an area of caatinga in the Serido of Rio Grande do Norte, Brazil, from October 2006 to May 2008. In both species, the females were reproductively active from the middle of the dry season to the beginning of the rainy season. Female reproductive activity was influenced by precipitation, whereas males exhibited spermatozoa in their testes throughout the year, and their reproductive activity was not related to any of the climatic variables analyzed. Mean clutch size (± SD) was 8.1 ± 2.0 and 2.1 ± 0.6 eggs in T. hispidus and T. semitaeniatus, respectively, and was significantly related to female body size only in T. hispidus. The fat stock varied inversely with reproductive activity in the two species, and there was no difference in fat body mass between females and males. The effects of precipitation on the length of the breeding season of these two Tropidurus species suggest that their reproductive cycles are related to the microclimatic conditions suitable for embryo development, as well as for the neonates' emergence and survival especially during the rainy season, which may offer greater food availability to the hatchlings.<br>Este estudio evaluó los ciclos reproductivos y de grasa corporal de Tropidurus hispidus (Spix, 1825) y T. semitaeniatus (Spix, 1825) en una área de caatinga en el Seridó de Rio Grande do Norte, Brasil, de octubre de 2006 a mayo de 2008. En ambas especies, las hembras se encontraron reproductivamente activas a partir de mediados de la estación seca para el inicio de la temporada de lluvias. La actividad reproductiva de las hembras fue influenciada por las precipitaciones, mientras que los machos presentaron espermatozoides en los testículos durante todo el año, y su actividad reproductiva no fue relacionada con ninguna de las variables climáticas analizadas. El tamaño medio (± DE) de la nidada fue de 8.1 ± 2.0 y 2.1 ± 0.6 huevos en T. hispidus y T. semitaeniatus, respectivamente, y se relacionó significativamente con el tamaño corporal de la hembra solo en T. hispidus. La reserva de grasa varió inversamente con la actividad reproductiva en las dos especies, y no hubo diferencia en la cantidad de grasa corporal entre hembras y machos. Los efectos de la precipitación sobre la duración de la temporada reproductiva de estas dos especies de Tropidurus sugieren que sus ciclos reproductivos están relacionados con las condiciones microclimáticas adecuadas para el desarrollo del embrión, así como para la emergencia de los recién nacidos y su supervivencia, especialmente durante la temporada de lluvias, que es la que puede ofrecer una mayor disponibilidad de alimentos para las crías