Diet and microhabitat use by two Hylodinae species (Anura, Cycloramphidae) living in sympatry and syntopy in a Brazilian Atlantic Rainforest area

We analyzed the diet and microhabitat use for two Hylodinae anurans (Cycloramphidae), Hylodes phyllodes Heyer & Cocroft, 1986 and Crossodactylus gaudichaudii Duméril & Bibron, 1841, living in sympatry at an Atlantic Rainforest area of Ilha Grande, in southeastern Brazil. The two species live syntopically at some rocky streams. The two species differed strongly in microhabitat use. Hylodes phyllodes occurred mainly on rocks, whereas C. gaudichaudii was observed mostly on the water. Regarding diet, coleopterans, hymenopterans (ants), and larvae were the most important prey item consumed by both species. Data suggest that microhabitat use appears to be an important parameter differentiating these frogs with respect to general resource utilization.

Diet of Teius oculatus (Sauria, Teiidae) in southern Brazil (Dom Feliciano, Rio Grande do Sul)

We analyzed stomach contents of 58 specimens of Teius oculatus (D'Orbigny & Bibron, 1837) (20 adult males, 17 adult females and 21 juveniles) captured in Dom Feliciano, RS, Brazil, to evaluate diet composition and sexual and ontogenetic variations in prey consumption. Diet was composed of 15 prey categories, all arthropods. Orthoptera was the most frequent prey type. Quantitatively, termites were the most important prey item (59.5%). There were no significant differences between the diets of adult males and females. Ontogenetic differences were found, mainly concerning volume of prey consumed. Adult lizards ingested significantly larger prey than juveniles (U = 170.00; p < 0.001). Juveniles, although having a comparatively less diverse diet (10 prey types) consumed a larger number of items (45.7% of total). Diet similarity was higher between juveniles and adult males (Ojk = 0.97) and prey diversity was higher in the diet of adult females (H' = 2.65). Based on importance value index the most important item in the diet of T. oculatus was Orthoptera. We conclude that T. oculatus in Dom Feliciano has a relatively generalized diet and it is an opportunist lizard, feeding on arthropods, mainly insects.

Temporal variability of benthic macrofauna on Cassino beach, southernmost Brazil

The temporal variability of benthic macrofauna on Cassino beach, southernmost Brazil, was studied for a period of one year (June 2004 to May 2005) based on monthly sampling. Three sites were selected distant 50m from each other. At each site, 3 transects were established, 2m equidistant from one another. Each transect extended from the base of the primary dunes to the inner surf zone at approximately 1m in depth, with 7 or 8 sampling levels. Within transects, the distance between the levels was 20m until the upper swash zone, from which distance was 10m until the 1-meter isobath. The temporal variation in the abundance of benthic macrofauna observed in the present study can be attributed to (1) the positive effects of the recruitment peaks and migration of particular species to the swash zone and (2) negative effects of the migration of some species to deeper waters, as well (3) as mortality through natural causes (stranding and action of predators) and (4) human causes (harvesting and vehicle transit). We attribute the expressive abundance increase of benthic macrofauna to recruitment. The stranding, that is, the trapping of the organisms on the upper parts of the beach, is likely the main cause of abrupt drops in benthic macrofauna abundance.

Feeding of Pellona flavipinnis (Clupeiformes, Pristigasteridae)in a Central Amazonian floodplain

The feeding habits of Pellona flavipinnis (Valenciennes, 1836) at Catalão, a floodplain area on the Brazilian Central Amazon was studied. Data was obtained during three hydrological cycles, between September 1999 and September 2003. Diet composition, daily and seasonal variation in the feeding activity and the relationship between predator's size and its prey were analyzed. Almost 80% of the food consumed has autochthonous origin and diet was composed basically by insects and fish. Juvenile fish predominated in the stomach contents of all size classes but there was no significant relationship between predator's size and its prey. Pellona flavipinnis may be considered a carnivorous species which feeds mainly on juvenile (young-of-the-year) specimens of other fish. More intense feeding activity occurred at night and in the high water period.

Natural history of the lizard Enyalius iheringii (Squamata, Leiosauridae) in southern Brazilian Atlantic forest

Studies on the natural history of the lizard Enyalius iheringii Boulenger, 1885, as well as other tropical lizards, are rare. In this study, some aspects of the natural history of this endemic species from the Atlantic forest are reported in areas of Vale do Itajaí, state of Santa Catarina, Brazil. Twenty individuals were found, of which 18 were collected. Most of them were found over the vegetation (n=17) and on the ground (n=3). The main defensive strategy displayed was camouflage (n=16). Jumping (n=1), jumping and running (n=1) and running (n=2) were also observed in some individuals. When handled, lizards exhibited mouth wide open, hissing, and occasionally biting, as well as color change in males. Regarding its diet, the numerically most important prey was beetles (Coleoptera), followed by Lepidoptera larvae. Beetles, lepidopteran larvae and spiders were the most frequent food items. Males and females did not differ in size. Three sexually mature females (100-113 mm SVL) were found in December and January.

Buccal apparatus and gastrointestinal tract dimensions associated to the diet of early life stages of Centropomus undecimalis (Centropomidae, Actinopterygii)

The present study aims to compare the buccal apparatus and gastrointestinal tract of early life stages of Centropomus undecimalis (Bloch, 1792), and relate them to its diet. A total of 190 individuals collected with a channel net in the Catuama estuary (07º40'9.9''S, 34º50'36.7''W), northern coast of the state of Pernambuco, were examined. Morphometrical and meristic data were analyzed for the two initial developmental periods (larval and juvenile). Their digestive tube was morphologically characterized and its content identified. The longest transverse axis of food items was measured, and compared to the standard length (SL) and mouth gape size (D) of the individuals. Body measurement regressions differed significantly (p<0.001) between larvae and juveniles. The stomachs with food content (n=118 individuals) presented a proportion of 62% full and 30% empty (being 8% damaged). They differed in relation to the fullness level and presented a coiled shape when empty. The number of food items in relation to SL and D did not present an evident correlation. Larvae (SL<10 mm) feed on small copepods, while juveniles (SL=11.1 to 64.7 mm) ingest larvae of various decapod species, showing a distinct diet between these initial developmental stages.

Reproduction and feeding ecology of Amphisbaena munoai and Anops kingi (Amphisbaenia, Amphisbaenidae) in the Escudo Sul-Rio-Grandense, southern Brazil

This study presents original data on the reproduction and feeding ecology of two syntopic amphisbaenians, Amphisbaena munoai Klappenbach, 1969 and Anops kingi Bell, 1833, from southern Brazil. Sampling was carried out from April 2004 to April 2006 at a highland area located in São Jerônimo and Barão do Triunfo municipalities, Rio Grande do Sul, Brazil. A total of 647 amphisbaenians were collected, 510 specimens of A. munoai and 137 specimens of A. kingi, of which 130 and 93, respectively, had their gonads and gut content analyzed. Both species presented a unimodal pattern of seasonal distribution, sexually mature females with significantly larger snout vent length (SVL) than sexually mature males, and seasonal reproductive cycle. Adults of A. kingi had significantly larger (SVL) than those of Amphisbaena munoai. Both species had generalist diets, but termites (Isoptera) was a staple item in their diet. Greater predominance of insect larvae was observed in the diet of A. kingi, which may be due to its larger body in comparison to A. munoai. Insect larvae ingested by A. kingi were significantly larger than those ingested by A. munoai. Diets of adult males and females of both species were not significantly different. The ontogenetic diet comparison in both species revealed significant numerical differences, with adults consuming higher numbers of prey.

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.

Abundance, breeding and food of the Little Blue Heron Egretta caerulea (Aves, Ardeidae) in the Patos Lagoon estuary, a recently colonized area in southern Brazil

We document the expansion of the breeding distribution of the Little Blue Heron Egretta caerulea (Linnaeus, 1758) to 850 km beyond its previous southern limit in South America. In addition we present data on abundance, breeding biology and food of the species in the Patos Lagoon estuary, the area which the species recently colonized. The maximum abundance recorded in the breeding colony and in a nocturnal roosting site was 53 and 49 individuals respectively. Nesting occurred from September to March. Birds nested in a mixed breeding colony together with about 3,000 breeding pairs of seven other species of Pelecaniformes, in a swampy forest near the margin of the estuary. Five nests were between 1.5 and 4.3 m from the ground, on the shrub Daphnopsis racemosa (Thymelaeaceae), on the trees Sebastiana brasiliensis (Euphorbiaceae) and Mimosa bimucronata (Leguminosae), or on the bamboo Bambusa sp. (Poaceae). Four nests produced two fledglings each, while one nest was abandoned. Of 13 grouped samples of food regurgitated by five nestlings, Pink Shrimp Farfantepenaeus paulensis (Perez-Farfante, 1967) constituted 70% in mass, while total length of ingested fishes and shrimps varied mostly between 20 and 50 mm. Estuarine prey items represented 99% of the total food mass. The recent southward expansion of the breeding range of the Little Blue Heron in South America may be a response to climate warming of the Patos Lagoon estuary. Degradation of estuaries in the southwestern Atlantic may also be forcing the birds to breed in areas outside previous geographical range.

Trophic ecology of Lontra longicaudis (Carnivora, Mustelidae) in lotic and semilotic environments in southeastern Brazil

Lontra longicaudis (Olfers, 1818) (Carnivora, Mustelidae) is a semi-aquatic animal spread through the Central and South America, except in Chile. The implantation of a hydroelectric power plant along a river alters the dynamics of the watercourse, transforming a lotic environment into a lentic or semilotic one, what can damage the otter's feeding. From April 2008 to March 2009 we analysed the otter's food habits in lotic (streamlet) and semilotic (hydroelectric reservoir) environments of Paranapanema Valley, in southeastern Brazil. Aiming to compare the otter's diet of these two environments, we analyzed statistically the frequency of occurrence of main items in the scats. Fishes represent the base of the diet both in the reservoir and in the streamlet and, despite of the total otter's diet showing up similarities in the two environments, the results evidenced modifications on the fish species consumed between them. In the reservoir the otters ate more exotic fish Oreochromis niloticus (Linnaeus, 1758) probably because it is an easy capture prey in this place. The fact that the otters get established and feed in the reservoir doesn't mean that this structure is benefic to the species because the food supplied for it consists mainly of exotic fish species.

The diet of the South American sea lion (Otaria flavescens) at Río Negro, Patagonia, Argentina, during the winter-spring period

The South American sea lion, Otaria flavescens (Shaw, 1800) population is steadily expanding along the Patagonian coast of Argentina in the last decades. However, little is known about the feeding ecology of the species in the area. The aim of this study was to analyze the food habits of O. flavescens from 91 scats collected at Río Negro province, during the winter and spring of 2005. Fish occurred in 96% of scats containing prey remains, followed by cephalopods (26%). Raneya brasiliensis (Kaup, 1856) was the most frequent and abundant species occurring in 58.6% of samples and constituting almost 50% of fish predated. Second in importance were Porichthys porosissimus (Cuvier, 1829) and Cynoscion guatucupa (Cuvier, 1830) in terms of occurrence (%FO 20.7) and numbers (29.6%) respectively. The squid Loligo gahi (d'Orbigny, 1835) was the most frequent cephalopod prey (42.1%), whereas Octopus tehuelchus (d'Orbigny, 1834) was the most abundant (77%). The higher amount and diversity of prey found in the spring in comparison with the winter season might be related to a higher feeding activity of seals or to a seasonal increase in food availability in the area.

The diet of the black widow spider Latrodectus mirabilis (Theridiidae) in two cereal crops of central Argentina

The spider Latrodectus mirabilis (Holmberg, 1876) is commonly found in cereals crops of central Argentina. We studied its diet composition at the field and capture rate on leaf-cutting ants based on laboratory experiments. This study comprises the first approach that documents the diet of L. mirabilis in wheat and oat fields of central Argentina. We identified 1,004 prey items collected from its webs during the last phenological stages of both cereal crops. The prey composition was variable but the spiders prey mainly on ants (Formicidae, Hymenoptera), who represented more than 86% of the total. Meanwhile, in the capture rate experiences we registered a high proportion of ants captured by spiders at the beginning of experiences, capturing the half of the ants from total in the first four hours. Summarizing, we reported a polyphagous diet of this spider species in wheat and oat fields. Ants were the most important prey item of this spider, as found in other Latrodectus spiders around the world.

Foraging behavioral of Phylloscartes ventralis (Aves, Tyrannidae) in native and planted forests of southern Brazil

Few studies have related the effects of silviculture practices to the behavior of bird species in the Neotropics. The present study examined the foraging behavior of Phylloscartes ventralis (Temminck, 1824) in a native forest and in silviculture areas of Pinus elliotti and Araucaria angustifolia with different structures and ages. We tested two general hypotheses: (1) areas of commercial forest plantation change the foraging behavior of P. ventralis in relation to native forest, and (2) the foraging behavior of P. ventralis in silviculture areas with understories (complex structures) is different from its behavior in areas without understory. The results showed that P. ventralis changed its foraging behavior depending on the type of forest, and on the presence of an understory in silviculture areas. Main changes involved the height and angle of substrate where the prey was captured. Phylloscartes ventralis showed the same set of attack maneuvers, with more maneuvers type in young Pinus planted without understory. The frequency of use of attack maneuvers was more similar in areas of silviculture with understory and in the native forest. The results highlight the importance of an understory structure and the utilization of native plant species in silviculture practices, to the foraging behavior of native bird species.

Factors influencing predation of the Waterbugs Sphaerodema annulatum (Fab.) and S. rusticum (Fab.) on the Disease Transmitting Snail Lymnaea (Radix) luteola (Lamarck)

Variations in the rate of predation of the waterbugs Sphaerodema annulatum and S. rusticum on the snails Lymnaea (Radix) luteola have been noted in respect to the morphs of the waterbugs, size of the prey individuals, densities of prey and predators, temperature and surface area of the waterbody concerned and the seasons. Consumption rate was highest (7.2 and 2.2 individuals per day per individual of S. annulatum and S. rusticum, respectively) in prereproductive ages of the waterbugs. This was followed by a gradual decline with the increase in age of the predators. The consumption rate was gradually higher with the increase of temperature from 20 °C to 35 °C. The bugs failed to survive beyond 35 days at 35 °C. Though the bugs prey upon the snails of all sizes preference for 6.5 ÷ 4.5 mm to 8 ÷ 5 mm individuals by S. annulatum and for 5 ÷ 3 mm to 6.5 ÷ 4.5 mm individuals belonged to 3 ÷ 2 - 4 ÷ 3 mm size group maximum when supplied separately. The rate of predation gradually declined with the rise of predator's desity irrespective of waterbug species. Predation rate increased with increasing prey density. This was level off when the prey snails were 1100 and 700 in number for S. annulatum and S. rusticum respectively. An adult S. annulatum and S. rusticum consumed 5.04, 3.7, 1.43 and 3.36, 2.49, 1.04 snails per day respectively in summer, monsoon and winter.

Succession and Abundance of Staphylinidae in Cattle Dung in Uberlândia, Brazil

Fimicolous Staphylinidae prey on rearing dipterous in cattle dung, acting as their natural controllers, including pests such as horn fly. To survey the abundance and succession of these coleopterans in cattle dung deposited in pasture, six experiments were conducted from March to October 1995 in Uberlândia, State of Minas Gerais, Brazil. Cattle dung pats were exposed at a pasture for 1 hr, 8 hr, 24 hr, 2, 3, 7 and 10 days and were than taken to laboratory separate from each other, for Staphylinidae extraction. A total of 156 dung pats were exposed at pasture, from which 6225 Staphylinidae were recovered. Representing at least 30 species. Staphylinidae sp.1 (29.6%), Philonthus flavolimbatus (22.2%), Heterothops sp.1 (16.6%), Oxytelus sp.2 (7.6%), Aleochara sp.2 (7.6%) and Criptobium sp.1 (4.4%) were the most abundant, representing 87.8% from the total. The increased frequency of the majority of these species along the dung exposition time at pasture, indicated tha, they would be preying on at all the immature stages of the dipterous, or eggs and first instar larvae of species that lay eggs on the dung after its second exposition day at the pasture