Feeding habits of six anuran (Amphibia: Anura) species in a rainforest fragment in Northeastern Brazil

Although Brazil encompasses one of the most abundant anuran faunas in the world, quantitative information on anuran ecology and diet are limited, especially in the Northeastern region. We analyzed the diet of six species: Hyla albomarginata, Hyla cf. branneri, Hyla minuta, Phyllomedusa aff. hypochondrialis (Hylidae), Leptodactylus natalensis, and Physalaemus cuvieri (Leptodactylidae) in a temporary pond in a rainforest remnant in Pernambuco, between 1999-2000. We analyzed diet composition, degree of food preference, and seasonal variations in diet. Leptodactylus natalensis and P. cuvieri showed higher diet diversity, whereas H. minuta consumed fewer food items. Insecta, Arachnida, and plants were preferential items for most species. Acari were consumed by all species; Hymenoptera, Odonata, and Coleoptera were also often consumed. A slight increase in diet diversity occurred in the rainy season. The species showed a generalist feeding behaviour, although P. cuvieri consumed Formicidae as major prey item.

Feeding ecology in the small neotropical amphisbaenid Amphisbaena munoai (Amphisbaenidae) in southern Brazil

We analyzed the alimentary tract of 66 specimens of Amphisbaena munoai Klappenbach, 1969 from the Serra do Sudeste, state of Rio Grande do Sul, southern Brazil. Forty specimens (60.6%) had prey items in their gut. The diet consisted mainly of small invertebrate prey, such as termites, insect larvae and ants. The most abundant prey item was termites, found in 62.5% of the non empty stomachs. The high number of individual prey items in the majority of stomachs, the small size of the regular prey items, and the absence of gut content in specimens of A. munoai kept alive for about two days, indicate that this species forages very frequently. The predominance of fossorial prey items and the occasional records of nomadic ants lead us to suggest that A. munoai usually feeds underground, and occasionally forages on the surface.

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.

Feeding ecology of Ozotoceros bezoarticus: conservation implicationsin Uruguay

The pampas deer (Ozotoceros bezoarticus Linnaeus, 1758) was in the recent past one of the most characteristic species in the Uruguayan grasslands. However, today the species is very rare, with small relict populations inhabiting in few ranches. To improve our understanding of pampas deer habitat use in modified ecosystems and propose management guidelines we analyzed the pampas deer feeding ecology at Los Ajos ranch. We performed an annual vegetation survey with the purpose to identify the main components of pampas's deer diet and the spatial overlap with livestock. Vegetation offer was characterized by predominance of monocotyledon plants; in three of the four sample periods. The preference values for the crops were positive for ryegrass in winter (0.24) and spring (0.54), the moments of greatest productivity of this pasture; while the rice crops values were negative all year round. The spatial overlap indexes with sheep show a complete exclusion, whereas with cattle the indexes gave values of 0.95 in spring to 0.14 in summer. The niche amplitude was significantly correlated with the spatial overlap levels with cattle. Pampas deer foraging behaviour is opportunistic, typical of mixed feeders. Conservation efforts should focus on implementation of management guidelines of agriculture and cattle breeding activities.

Feeding ecology of Pterodoras granulosus (Siluriformes, Doradidae) in the Lajeado Reservoir, Tocantins, Brazil

The diet and feeding habits of armado catfish, Pterodoras granulosus (Valenciennes, 1821), were studied in the Lajeado Reservoir, Tocantins, Brazil, and the mouth of its tributaries. Stomach contents of 327 specimens were analyzed by the percentage composition and volumetric methods. The feeding of armado on a wide variety of foods, including both animal and plant items, leads to its classification as a euriphagic species with herbivorous tendency. However, it should be noted that armado showed a strong ontogenetic diet shift, with the gradual replacement of detritus and sediment by plant items, especially terrestrial ones. The environmental use pattern of P. granulosus corroborates the ontogenetic shift observed in its diet. Small fish predominated mainly in the benthic region and detritus and sediment represented an important resource, whereas large fish fed mainly on terrestrial plants, as they explore open water sites and the surface of the water column.

Freshwater sponges (Porifera, Demospongiae) in a benthic filter feeding community at the Guanacaste Dry Forest, Costa Rica

The freshwater sponges Trochospongilla variabilis Bonetto & Ezcurra de Drago (1973), Radiospongilla crateriformis (Potts, 1882), Spongilla cenota Penney & Racek (1968) and Corvoheteromeyenia heterosclera (Ezcurra de Drago, 1974) compose with the sphaerid bivalve Eupera cubensis (Prime, 1865) and several Phylactolaemata bryozoans a benthic filter feeding community living in seasonal lentic and lotic habitats with high Particulate Organic Carbon (POC), low conductivity and acid pH within the Costa Rica Dry Forest biome. The sponge specimens gathered led to the re-description of the four species.

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.

Diet and functional feeding groups of Chironomidae (Diptera) in the Middle Paraná River floodplain (Argentina)

The gut contents of nine genera of benthic Chironominae and Tanypodinae from the Middle Paraná River floodplain habitats (a lake and a secondary channel) were analyzed to determine their feeding patterns and functional feeding groups. Amorphous detritus, animal and vegetal tissues, and mineral materials (predominantly sand) were observed in the larval guts. Amorphous detritus were the main food item found for Polypedilum (Tripodura) sp., Chironomus gr. decorus sp., Endotribelos sp., Phaenopsectra sp., Cladopelma sp., and Pelomus sp. (Chironominae), while animal tissues (mainly oligochaetes) were the most important food item found for Ablabesmyia (Karelia) sp., Coelotanypus sp., and Procladius sp. (Tanypodinae). Dietary overlap was calculated for all pairs of genera. Within predators, the highest overlap was obtained between Coelotanypus sp. and Ablabesmyia (Karelia) sp., while within detritivores the highest niche overlap was obtained between Endotribelos sp. and Phaenopsectra sp.

Behavior of triatomines (Hemiptera, Reduviidae) vectors of Chagas' disease. II. Influence of feeding, lighting and time of day on the number of mating, mating speed and duration of copulation of Panstrongylus megistus (Burm, 1835) under laboratory conditions

To determine in influence of feeding, lighting and time of day on the copulating behavior of Panstrongylus megistus, 480 insect pairs were divided into four groups of 120 each and tested in the following respective situations: without food deprivation (F.D.), with five days of F.D., with ten days of F.D., and with 20 days of F. D. The tests were performed between 9:00 a.m. to 12:00a.m. and 7:00 p.m. to 10:00 p.m., with light (700-1400 lux) and in the dark (1.4-2.8 lux) and behavior was recorded by the time sampling technique. Mating spped (MS) and duration of copulation (DC) were also calculated for each situation. The maximum frequency of copulation was observed after five days of F.D., at night, in the dark (n = 16), and the minimum was observed for recently-fed pairs, at night, with light (n = 4). Males approached females more often than females approached males. MS was lowest in pairs with twenty days of F.D., at night, with light (X = 23.0 ± 16.0 minutes), and highest in recently-fed pairs, during the day, with light (X = 2.9 ± 2.5 minutes). DC was shortest in recently-fed insects, during the day, in the dark (X = 23.5 ± 6.7 minutes), and longest in recently-fed animals, at night, in the dark (X = 38.3 ± 6.9 minutes).

Infective stages of Leishmania in the sandfly vector and some observations on the mechanism of transmission

Infective stages of Leishmania (Leishmania) amazonensis, capable of producing amastigote infections in hamster skin, were shown to be present in the experimentally infected sandfly vector Lutzomyia flaviscutellata 15, 25, 40, 49, 70, 96 and 120 hours after the flies had received their infective blood-meal. Similarly, infective stages of Leishmania (L.) chagasi were demonstrated in the experimentally infected vector Lu. longipalpis examined 38, 50, 63, 87, 110, 135, 171 and 221 hours following the infective blood-meal, by the intraperitoneal inoculation of the flagellates into hamsters. The question of whether or not transmission by the bite of the sandfly is dependent on the presence of [quot ]metacyclic[quot ] promastigotes in the mouthparts of the vector is discussed.

The study of insect blood-feeding behaviour: 1. Feeding equipment, physical and endogenous factors, dose effect analysis, and diet destination

Experimental techniques that we have found useful during our studies of insect blood-feeding behaviour are reviewed. Some of the principal findings resulting from these techniques are discussed. Where directly applicable, the work of others is included, but no complete review of the subject has been attempted.

The study of insect blood-feeding behaviour: 2. Recording techniques and the use of flow charts

This paper continues a discussion of approaches and methodologies we have used in our studies of feeding in haematophagous insects. Described are techniques for directly monitoring behaviour: electrical recording of feeding behaviour via resistance changes in the food canal, optical methods for monitoring mouthpart activity, and a computer technique for behavioural event recording. Also described is the use of "flow charts" or "decision diagrams" to model interrelated sequences of behaviours.

Anti-schistosomal drugs: observations on the mechanism of drug resistance to hycanthone, and on the involvement of host antibodies in the mode of action of praziquantel

This paper reports recent observations from our laboratory dealing with the anti-schistosome drugs hycanthone (HC) and praziquantel (PZQ). In particular, we discuss a laboratory model of drug resistance to HC in Schistosoma mansoni and show that drug sensitive and resistant lines of the parasite can be differentiated on the basis of restriction fragment length polymorphisms using homologous ribosomal gene probes. In addition, we summarize data demonstrating that effective chemotherapy of S. mansoni infection with PZQ in mice requires the presence of host anti-parasite antibodies. These antibodies bind to PZQ treated worms and may be involved in an antibody-dependent cellular cytotoxicity reactions which result in the clearance of worms from the vasculature.