Feeding ecology of Tropidurus torquatus (Wied) (Squamata, Tropiduridae) in two areas with different degrees of conservation in Marambaia Island, Rio de Janeiro, Southeastern Brazil

Abstract

We compared the effects of habitat disturbance on the feeding ecology of two local populations of Tropidurus torquatus (Wied, 1820) in restinga habitats on Ilha da Marambaia, Southeastern Brazil. Both populations presented a relatively diverse diet and differ in the number (D Max = 0.22, DF = 2, p = 0.00) and volume of prey consumed (D Max = 0.82, DF = 2, p = 0.00). Ants were the most frequent and numerous preys in both areas, and plant matter and coleopterans were the most important alimentary items in volume. The population from the disturbed area presented a larger niche breadth for number of prey items consumed (Bi num = 3.06) and volume (Bi vol = 2.98), when compared to the other population (Bj num = 2.44, Bj vol = 1.52). Niche overlap was higher for number of items consumed between the populations (Oij num = 0.82) but lower for volume (Oij vol = 0.05). Our data suggest dietary differences between the two lizard populations, and these differences may be associated with environmental modifications. Our main hypothesis to explain the dietary differences is based in the Optimal Foraging Theory. However, the alimentary behavior, and consequently the diet of these lizards, seems to be constrained phylogenetically, with a pattern that may have evolved in the ancestor of all iguanids.

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

“…Conversely, for T. torquatus (caRValHo et al, 2007) and for another population of T. oreadicus (RocHa & siqueiRa, 2008) the authors failed to find an effect of lizard size on prey dimensions. Thus, factors other than lizard body size or head measurements may also be important in determining the size of prey consumed by these lizards.…”

“…oreadicus Rodrigues, 1987: RocHa & siqueiRa, 2008T. torquatus (Wied, 1820): caRValHo et al, 2007. In addition, the high termite consumption by these lizards, as well as characterizing predation on insects with clumped distribution, also identifies them as important sources of water (nagy et al, 1984).…”

“…Tropidurus torquatus is also known for its consumption of plant matter, mainly fruits (fialHo et al, 2000). The fact that plant parts (leaves, flowers, fruits and seeds) account for a sizable portion of the total volume ingested in the diet of Tropidurus species (caRValHo et al, 2007;RocHa & siqueiRa, 2008), suggests that ingestion is not accidental, and that plants are indeed a common food item for these lizards. At ESEC Seridó, in addition to invertebrates and plant material, the stomach contents of an adult female included an adult hylid frog Scinax x-signatus (6,280 mm 3 in volume) (RibeiRo & fReiRe, 2009c).…”

Feeding and reproduction ecology of the lizard Tropidurus torquatus (Squamata: Tropiduridae) in a rock outcrop area in southeastern Brazil

“…The food pattern where adults ingest mostly vegetable parts and the juveniles consume preferentially ants and secondarily other insects was also reported for T. psammonastes in dunes of the São Francisco River flowing through a Brazilian caatinga (Lima & Rocha 2006) and for T. torquatus in restinga habitats in southeastern Brazil (Carvalho et al 2007). According to Frost et al (2001) and Vitt et al (2003), ingestion of both ants and plants is plesiomorphic for the Tropidurinae, occurring from basal branches (Eurolophosaurus spp.)…”

“…Lizards are able to capture the most abundant preys in the environment (personal obser vation), showing wide trophic niche with generalized diet, reducing the hunting period, while also they are able to perform other functions, such as thermoregulation and territorial defense. The sit-and-wait foraging behavior described for this species (Araújo 1987, Van Sluys 1993, 1995, Teixeira & Giovanelli 1999, Carvalho et al 2007) is a strategy that occurs in opportunist and generalist predators (Jaksic 2001).…”