Arthropoda de solo em um ecossistema semi-árido da região neotropical: composição, variabilidade temporal e estratificação

Caatinga is an important laboratory for studies about arthropods adaptations and aclimatations because its precipitation is highly variable in time. We studied the effects of time variability over the composition of Arthropods in a caatinga area. The study was carried out at a preservation area on Almas Farm, São José dos Cordeiros, Paraíba. Samples were collected in two 100 m long parallel transects, separated for a 30 m distance, in a dense tree dominated caatinga area, between August 2007 and July 2008. Samples were collected in each transect every 10 m. Ten soil samples were taken from each transect, both at 0-5 cm (A) and 5-10 cm (B) depth, resulting in 40 samples each month. The Berlese funnel method was used for fauna extraction. We registered 26 orders and the arthropods density in the soil ranged from 3237 to 22774 individuals.m-2 from January 2007 to March 2008, respectively. There was no difference between layers A and B regarding orders abundance and richness. The groups recorded include groups with few records or that had no records in the Caatinga region yet as Pauropoda, Psocoptera, Thysanoptera, Protura and Araneae. Acari was the most abundant group, with 66,7% of the total number of individuals. Soil Arthropods presented a positive correlation with soil moisture, vegetal cover, precipitation and real evapotranspiration. Increases in fauna richness and abundance were registered in February, a month after the beginning of the rainy season. A periodic rain events in arid and semiarid ecosystems triggers physiological responses in edafic organisms, like arthropods. Edafic arthropods respond to time variability in the Caatinga biome. This fauna variation has to be considered in studies of this ecosystem, because the variation of Arthropods composition in soil can affect the dynamics of the food web through time

Caracterização do nicho alimentar do polvo octopus insularis (cephalopoda: octopodidae): da população ao indivíduo

Octopus insularis, target species in this study, is the dominant benthic octopus of the North and Northeast Brazil. Studies on behavior and ecology of the species have been conducted primarily on oceanic islands, with little information on the continental populations. In this study, two regions of the coast of RN, Rio do Fogo and Pirangi, were chosen for the characterization of the niche by O. insularis populations. The dietary niche, habitat and distribution of O. insularis of oceanic islands and the mainland, were compared. In addition, individual characteristics of feeding behavior in a population at Atol das Rocas was studied, taking into account the size of individuals, the proximity of the dens and characteristics of their "personality". The diet of the Rio do Fogo population was composed mainly of bivalve molluscs (82%), unlike Pirangi population that has a diet consisting mainly of crustaceans Decapoda (68%), similar to that described for the populations of the islands. Consequently, the feeding niches of the island populations were more similar, with greater overlap, but the niche breadth of the continent was larger. The habitats of occurrence on the coast includes reefs, rocks, gravel and an environment called Restinga, a plateau composed of biogenic gravel, sand, sponges and algae, showed a high density of animals. Similarly to that found in the islands, O. insularis in the continent, had a clumped distribution, and a bathymetric segregation between small and large individuals. The differences in diet composition among populations were explained by differences in habitat and coverage of the substrate, which may be directly influencing the diversity and prey availability in these environments. The individual analyzes of the population at Atol das Rocas, showed no relationship between the degree of individual specialization and the different personalities, or the distance between dens. The results suggest that the foraging strategy with greater availability of prey in the environment has an influence on diet octopuses over preferences or personalities

Ingestão alimentar e nutricional de callithrix jacchus: relaçao com hierarquia social e disponibilidade de alimento

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Dinâmica populacional e alimentar de Stegastes fuscus, (Osteichthyes:pomacentridae) em arrecifes da praia de Búzius, no Rio Grande do Norte

The damselfish, Stegastes fuscus Cuvier, 1830 (Osteichthyes: Perciformes: Pomacentridae), is abundant in the coastal reefs of Búzios Beach, Rio Grande do Norte, Brazil and they play an important role in the reef community ecology. The present study investigated the feeding strategy of this species considering the food habits and morfo-histology of the digestive tract. Influence of the environmental correlates such as temperature, rainfall and luminosity in the tidal rock pools were studied. The fish were captured on a monthly basis from September 2004 to August 2005, during which period 842 individuals of S. fuscus were captured, 125 males, 437 females and 280 individuals without sex identification. The sex ratio observed was 1 M : 3,5 F. The total body length of males varied from 3.6 to 11.3 cm, with a mean of 7.77 cm; that of females varied from 2.9 to 11.4 cm, with a mean of 7.85 cm, and that of sex grouped individuals varied from 2.9 to 11.4 cm, with a mean of 7.83. However, there was no difference between males and females in total body length. This species presented a positive alometric growth and the equations obtained for the relation between body mass and total body length were: Wt =0,0174Lt 3,1123 for males; Wt =0,0137Lt 3,2294 for females and Wt = 0,0148Lt 3.1928 for sex grouped individuals. The relation between total body length and standard length was L t = 1 ,3223Ls + 0,1527 for sex grouped individual s. February to August was associated to a long period of gonadal resting. The fish spawned during January and in September -October. The frequency of fish with empty stomachs occurred during August to December, whereas frequency of fish with food contents i n stomachs occurred during January to July. This species is considered as a preferential herbivore based on the volume of macroalgae in its diet composition. The morfo -histological aspects of S. fuscus confirm herbivory. Among the environmental factors con sidered only rainfall showed a correlation with the feeding habits of this species

Ecologia alimentar do boto cinza, sotalia guianensis (van banédén, 1864), no litoral do rio grande do norte (rn)

This study investigated factors that influence the group size during the behavior foraging of estuarine dolphin Sotalia guianensis in the coast south of the state Rio Grande do Norte (RN), it also characterized the diet of estuarine dolphins and elaborated an otoliths catalog for aid in the identification of the preys found in the stomach contents. In relation to the group size during behaviour foraging, inside of the Curral Bay, larger frequency of solitary hunt was observed. Factors as tide variation, group composition and seasons didn't present correlation with the number of animals observed during a feeding episode. Capture success for participant was shown significantly larger when the animals hunted alone, what possibly explains the largest frequency of solitary hunt inside of the Curral Bay. About diet, were identified 18 bone fishes species, with predominance of species the families Haemulidae and Sciaenidae and five cephalopods species, including two new species in the diet of Sotalia guianensis in Brazil. Our results indicated that estuarine dolphin in the coast oriental from Rio Grande do Norte (RN) feeds predominantly of fish that form shoal, of habitat estuarino and producing of sounds. The analysis of the images, otoliths of 43 species of coastal fish of the coast of the state of Rio Grande do Norte (RN), aided by the offered descriptions, demonstrated to be an effective methodology for the knowledge of those structures, as well as it represented a form of reducing the subjectivity in the identification of the bone fishes found in stomach content

Ecologia alimentar e comportamento de forrageamento de Ameivula aff. ocellifera (Squamata: Teiidae) em área de caatinga do nordeste do Brasil

This study investigated the influence of intrinsic and extrinsic factors on the feeding ecology and foraging behavior of the whiptail lizard Ameivula aff. ocellifera, a new species widely distributed in the Brazilian Caatinga, and that is in process of description. In attendance to the objectives, the Dissertation was structured in two chapters, which correspond to scientific articles, one already published and the other to be submitted for publication. In Chapter 1 were analyzed the general diet composition, the relationship between lizard size and prey size, and the occurrence of sexual and ontogenetic differences in the diet. Chapter 2 contemplates a seasonal analysis of diet composition during two rainy seasons interspersed with a dry season, and the quantitative analysis of foraging behavior during two distinct periods. The diet composition was determined through stomach analysis of lizards (N = 111) collected monthly by active search, between September 2008 and August 2010, in the Estação Ecológica do Seridó (ESEC Seridó), state of Rio Grande do Norte. Foraging behavior was investigated during a rainy and a dry month of 2012 also in ESEC Seridó, by determining percent of time moving (PTM), number of movements per minute (MPM) and prey capture rate by the lizards (N = 28) during foraging. The main prey category in the diet of Ameivula aff. ocellifera was Insect larvae, followed by Orthoptera, Coleoptera and Araneae. Termites (Isoptera) were important only in numeric terms, having negligible volumetric contribution (<2%) and low frequency of occurrence, an uncommon feature among whiptail lizards. Males and females did not differ neither in diet composition nor in foraging behavior. 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. The diet showed significant seasonal differences; during the two rainy seasons (2009 and 2010), the predominant prey in diet were Insect larvae, Coleoptera and Orthoptera, while in the dry season the predominant prey were Insect larvae, Hemiptera, Araneae and Orthoptera. The degree of mobility of consumed prey during the rainy seasons was lower, mainly due to a greater consumption of larvae (highly sedentary prey) during these periods. Population niche breadth was higher in the dry season, confirming the theoretical prediction that when food is scarce, the diets tend to be more generalized. Considering the entire sample, Ameivula aff. ocellifera showed 61,0 ± 15,0% PTM, 2,03 ± 0,30 MPM, and captured 0,13 ± 0,14 per minute. Foraging mode was similar to that found for other whiptail lizards regarding PTM, but MPM was relatively superior. Seasonal differences were verified for PTM, which was significantly higher in the rainy season (66,4 ± 12,1) than in the dry season (51,5 ± 15,6). It is possible that this difference represents a behavioral adjustment in response to seasonal variation in the abundance and types of prey available in the environment in each season

Arthropoda de solo em um ecossistema semi-árido da região neotropical: composição, variabilidade temporal e estratificação

Caatinga is an important laboratory for studies about arthropods adaptations and aclimatations because its precipitation is highly variable in time. We studied the effects of time variability over the composition of Arthropods in a caatinga area. The study was carried out at a preservation area on Almas Farm, São José dos Cordeiros, Paraíba. Samples were collected in two 100 m long parallel transects, separated for a 30 m distance, in a dense tree dominated caatinga area, between August 2007 and July 2008. Samples were collected in each transect every 10 m. Ten soil samples were taken from each transect, both at 0-5 cm (A) and 5-10 cm (B) depth, resulting in 40 samples each month. The Berlese funnel method was used for fauna extraction. We registered 26 orders and the arthropods density in the soil ranged from 3237 to 22774 individuals.m-2 from January 2007 to March 2008, respectively. There was no difference between layers A and B regarding orders abundance and richness. The groups recorded include groups with few records or that had no records in the Caatinga region yet as Pauropoda, Psocoptera, Thysanoptera, Protura and Araneae. Acari was the most abundant group, with 66,7% of the total number of individuals. Soil Arthropods presented a positive correlation with soil moisture, vegetal cover, precipitation and real evapotranspiration. Increases in fauna richness and abundance were registered in February, a month after the beginning of the rainy season. A periodic rain events in arid and semiarid ecosystems triggers physiological responses in edafic organisms, like arthropods. Edafic arthropods respond to time variability in the Caatinga biome. This fauna variation has to be considered in studies of this ecosystem, because the variation of Arthropods composition in soil can affect the dynamics of the food web through time