Leonardo Barros Ribeiro

Diet and Foraging Behavior of Two Species of Tropidurus (Squamata, Tropiduridae) in the Caatinga of Northeastern Brazil

ABSTRACT. Tropidurus semitaeniatus and Tropidurus hispidus are widely distributed lizard species in Brazil. The former is endemic to the Caatinga, where it lives in syntopy with the latter, which is distributed in other ecosystems and biomes. In this study, we explored the diet, its seasonal variation, as well as foraging behavior of both species inhabiting rock outcrops in a Caatinga area of Rio Grande do Norte, Brazil. Leaves were the most important food item in the diet of both species, followed by ants and termites. No significant difference was found in diet composition between the two species, although T. hispidus feeds on larger prey than T. semitaeniatus. Our results indicate that T. semitaeniatus and T. hispidus are opportunistic foragers with similar, generalized diets, showing temporal variation in their diets apparently related to prey availability.ABSTRACT. Tropidurus semitaeniatus and Tropidurus hispidus are widely distributed lizard species in Brazil. The former is endemic to the Caatinga, where it lives in syntopy with the latter, which is distributed in other ecosystems and biomes. In this study, we explored the diet, its seasonal variation, as well as foraging behavior of both species inhabiting rock outcrops in a Caatinga area of Rio Grande do Norte, Brazil. Leaves were the most important food item in the diet of both species, followed by ants and termites. No significant difference was found in diet composition between the two species, although T. hispidus feeds on larger prey than T. semitaeniatus. Our results indicate that T. semitaeniatus and T. hispidus are opportunistic foragers with similar, generalized diets, showing temporal variation in their diets apparently related to prey availability.

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.

Feeding Habits and Predator-Prey Size Relationships in the Whiptail Lizard Cnemidophorus ocellifer (Teiidae) in the Semiarid Region of Brazil

ABSTRACT. We studied the diet of the whiptail lizard Cnemidophorus ocellifer (Spix, 1825) and the relationships between predator size and prey size in a Caatinga area of northeastern Brazil. Lizards (N = 111) were collected during the day through active search. In the laboratory, we measured them and registered the number of ingested items of each prey category to Order, as well as the dimensions and frequencies of each. The main prey category in the C. ocellifer diet was insect larvae and pupae, followed by Orthoptera, Isoptera, Coleoptera and Araneae. Termites (Isoptera) were important only in numeric terms, having negligible volumetric contribution and low frequency of occurrence, an uncommon feature among whiptail lizards. The types and sizes of prey consumed by adult males and females were similar, despite sexual dimorphism in head size. Adults and juveniles ingested similar prey types, but differed in prey size. Maximum and minimum prey sizes were positively correlated with lizard body size, suggesting that in this population individuals experience an ontogenetic change in diet, eating larger prey items while growing, and at the same time excluding smaller ones.

Ventral Colored Patches in Tropidurus semitaeniatus (Squamata, Tropiduridae): Sexual Dimorphism and Association with Reproductive Cycle

Abstract We describe sexual dimorphism in coloration and the reproductive cycle in Tropidurus semitaeniatus, a widely distributed lizard species in the caatinga of northeastern Brazil. Yellow and yellow-and-black patches occurred on the ventral surface of the thighs and precloacal flap in 15 and 11 adult males, respectively. Thirteen reproductively active males (collected November to March) had ventral patches with intense pigmentation, contrasting with the faded pigmentation of these patches in two males during the maturation stage (collected in October) and in 11 individuals in regression phase (collected April to September). Thirty-six adult females, reproductively active and not, and 21 juveniles lacked ventral color patches. There was a significant relationship between snout–vent length and testis volume during maturation and regression stages in males with both types of color patches. We conclude that ventral color patches displayed by male T. semitaeniatus are closely associated with their reproductive cycles.

Reproductive and fat body cycles of Tropidurus hispidus and Tropidurus semitaeniatus (Squamata, Tropiduridae) in a caatinga area of northeastern Brazil

Este estudio evaluo los ciclos reproductivos y de grasa corporal de Tropidurus hispidus (Spix, 1825) y T. semitaeniatus (Spix, 1825) en una area de caatinga en el Serido 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 estacion 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 testiculos durante todo el ano, y su actividad reproductiva no fue relacionada con ninguna de las variables climaticas analizadas. El tamano 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 relaciono significativamente con el tamano corporal de la hembra solo en T. hispidus. La reserva de grasa vario 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 precipitacion sobre la duracion de la temporada reproductiva de estas dos especies de Tropidurus sugieren que sus ciclos reproductivos estan relacionados con las condiciones microclimaticas adecuadas para el desarrollo del embrion, asi como para la emergencia de los recien nacidos y su supervivencia, especialmente durante la temporada de lluvias, que es la que puede ofrecer una mayor disponibilidad de alimentos para las crias.

The effects of seasonality on the foraging behavior of Tropidurus hispidus and Tropidurus semitaeniatus (Squamata: Tropiduridae) living in sympatry in the Caatinga of northeastern Brazil

In this study, we performed field observations of 38 and 84 specimens of the lizards Tropidurus hispidus (Spix, 1825) and Tropidurus semitaeniatus (Spix, 1825), respectively, inhabiting a Caatinga in the state of Rio Grande do Norte, northeastern Brazil, in order to describe the foraging behavior, measure the foraging intensity (number of movements, time spent stationary, distance traveled and number of attacks on preys) and investigate the effects of seasonality on the foraging strategies of these two species of lizards. During the dry season, both species showed no significant differences in foraging intensity. In the wet season, on the other hand, only the distance traveled was similar for both species. Tropidurus semitaeniatus displayed a larger mean number of movements (9.8 ± 1.2) and attacks on preys (1.7 ± 0.3) when compared to T. hispidus (3.0 ± 0.8 moves; 0.3 ± 0.1 attacks). Additionally, mean time spent stationary was significantly longer for T. hispidus (596.6 ± 1.0 seconds) than for T. semitaeniatus (587 ± 2.1 seconds). Results suggest that the low number of movements and short distance traveled (maximum of 1000 cm during 10-minute intervals) are consistent with the categorization of T. hispidus and T. semitaeniatus as sit-and-wait foragers. Given our results, we conclude that both species co-exist under limiting conditions during the dry season, with similar foraging behavior and similar rates of foraging intensity, segregating with respect to these variables in the wet season.

Mating behavior and female accompaniment in the whiptail lizard Cnemidophorus ocellifer (Squamata, Teiidae) in the Caatinga region of northeastern Brazil

We report here a set of observations on mating behavior and female accompaniment by the whiptail lizard Cnemidophorus ocellifer in an area of Caatinga (xerophilous open forests) in the state of Rio Grande do Norte, northeastern Brazil. We observed a stationary male lizard performing repeated vibratory movements of the pelvis and tail base upon the sandy soil. Since that male was in front of a burrow in which a female of the same species was sheltered, we hypothesize that this behavior may be part of a courtship display. We continued the observation and later, when the female emerged from the burrow, the male climbed on her and the copulation occurred. The incident of accompaniment observed was characterized by one male continuously accompanying a female during foraging. Plausible functional explanations for a male accompany a female include mating guarding, post-copulatory courtship, and sperm loading. By accompanying females, males would be guaranteeing insemination by multiple copulation and stimulation of the female, and protecting their paternity by chasing away other males, diminishing the chances of extra-pair copulations.

Forced copulation attempt in the Blue-tailed Lizard, Micrablepharus maximiliani (Reinhardt & Luetken, 1862) (Squamata, Gymnophthalmidae) in the Caatinga of Northeastern Brazil

Forced copulation is characterized by jerky and rapid movements performed by a female in an apparent attempt to escape from a mounting male. This short communication reports a forced copulation attempt by the gymnophthalmid lizard Micrablepharus maximiliani in a forest enclave inside the Caatinga biome, Tenente Laurentino Cruz municipality, Rio Grande do Norte, Brazil. The rejection behavior of the female consisted of running, pushing and hiding from the mounting male. Although the causes of female mate rejection remain unclear, it may be possible that on this occasion the female M. maximiliani may not have been reproductively active and/or avoided the male deliberately.

Range extension, new state record and geographic distribution map of Acratosaura mentalis (Amaral, 1933) (Squamata: Gymnophthalmidae)

We provide new records of Acratosaura mentalis from three localities in the state of Pernambuco, Brazil, these records extending the known geographical distribution of the species to the municipalities of Sertânia, Custodia and Floresta. We also report A. mentalis from the municipality of Mauriti, which is the first record for the state of Ceara, Brazil.

Reptilia, Squamata, Leiosauridae, Enyalius bibronii Boulenger, 1885: distribution extension and geographic distribution map

This article provides a new record for Enyalius bibronii from municipality of Tenente Laurentino Cruz, state of Rio Grande do Norte, northeastern Brazil. The collection site is located in a mountain forest enclave belonging to the Caatinga domain. This record extends the species distribution towards central region of the state.