Alexandre Vasconcellos

Seasonality of insects in the semi-arid Caatinga of northeastern Brazil

Seasonality of insects in the semi-arid Caatinga of northeastern Brazil. Insects are essential to tropical ecosystems functioning. In semi-arid regions, the increase in abundance and/or activity (e.g. reproduction and foraging behavior) of insects is usually associated with climatic variables. The present study investigates which climatic variables are best predictors of insect abundance in an area of Caatinga in northeastern Brazil. Individuals were sampled for 24 months using Malaise and pitfall traps, and beating trays. A total of 58925 individuals belonging to 20 insect orders were collected. The most abundant orders were Hymenoptera, Diptera, Collembola and Coleoptera. Most orders studied showed a clear maximum abundance in the rainy season. Rainfall and humidity were the best predictors of insect abundance in the Caatinga. However, no climatic variable could explain Psocoptera and Blattodea variance in abundance/activity. Our results suggest that climatic changes associated with rainfall patterns in the Caatinga may affect ecosystem processes and services that depend direct or indirectly on insect abundance/activity.

Termite usage associated with antibiotic therapy: enhancement of aminoglycoside antibiotic activity by natural products of Nasutitermes corniger (Motschulsky 1855)

BackgroundSeveral species from Insecta are used as remedies. Among these species, the termite Nasutitermes corniger is commonly used in traditional medicine in Northeast Brazil. The present work tests the modifying antibiotic activity of Nasutitermes corniger, a termite used in folk medicine in Northeastern region of Brazil.MethodsChlorpromazine and decocts of N. corniger were collected from two different plant species used in the traditional medicine were tested for their antimicrobial activity against strains of Escherichia coli resistant to aminoglycosides. The growth of two bacterial strains of E. coli was tested using decocts and chlorpromazine alone or associeted with aminogycosides.ResultsThe MIC and MBC values were ≥1024 μg/ml for both strains of E. coli assayed. A significant synergism was observed between both decocts and chlorpromazine when assyed with neomycin. This synergism with neomycin indicates the involvement of an efflux system in the resistance to this aminoglycoside.ConclusionTherefore it is suggested that natural products from N. corniger could be used as a source of zoo-derived natural products with modifying antibiotic activity to aminoglycosides, being a new weapon against the bacterial resistance to antibiotics.

Edible and medicinal termites: a global overview

Termites are mainly known for damage caused to human beings, both in urban and rural areas. However, these insects play an important role in the decomposition of organic matter in tropical regions and are important natural resources, which are widely used in traditional medicine and are also consumed by human populations in several parts of the world. This study aimed to catalogue termite species used worldwide through a literature review, characterizing them by its human populations’ use. The results showed that at least 45 species of termites, belonging to four families, are used in the world, with 43 species used in human diet and/or in livestock feeding. Nine termite species are used as a therapeutic resource. There is an overlapping use of seven species. The use of termites was registered in 29 countries over three continents. Africa is the continent with the highest number of records, followed by America and Asia. The results suggest that, in addition to their ecological importance, termites are a source of medicinal and food resources to various human populations in various locations of the world, showing their potential for being used as an alternative protein source in human or livestock diets, as well as a source for new medicines.

Biomass and population structure of Constrictotermes cyphergaster (Silvestri) (Isoptera: termitidae) in the dry forest of caatinga, northeastern Brazil

Biomass and population structure of Constrictotermes cyphergaster (Silvestri) were studied in an area of dry forest of caatinga in the State of Paraiba, northeastern Brazil. Twelve nests of different sizes were randomly collected, being six during the dry season (November 2004 and 2005) and six during the wet season (March 2004). Soldier and worker populations varied between 4880 and 118800 individuals per nest. The ratio between soldiers and workers did not significantly vary between seasons. Biomass (measured as fresh weight) of individuals varied between 13.9 and 408.8 g per nest, and soldiers and workers had significantly greater biomass during the wet season. The estimated density of nests of C. cyphergaster was 59.0 +/- 22.53 active nests/ha. Quantitative data of the study colonies and data on the nest abundance showed that C. cyphergaster encompassed some 278.2 individuals/m(2), with approximately 0.9 g (fresh weight)/m(2). These data suggest that C. cyphergaster is an important consumer of vegetal matter and, therefore, an important species affecting the nutrient cycling and energy flow in the caatinga vegetation.

Seasonal variations in scorpion activities (Arachnida: Scorpiones) in an area of Caatinga vegetation in northeastern Brazil

Seasonal variations in scorpion activity were investigated during a 24 month period in an area of Caatinga (dryland) vegetation in the state of Paraiba, Brazil. The total number of scorpions captured was correlated with climatic variables and prey abundance. Scorpions were captured monthly using pitfall traps; their potential prey was captured using malaise, beating trays and pitfalls. A total of 104 scorpions were captured, representing four species: the bothriurids Bothriurus asper (Pocock, 1893) (n = 74; 71.2%) and B. rochai (Mello-Leitao, 1932) (n = 20; 19.2%), and the buthids Rhopalurus rochai (Borelli, 1910) (n = 4; 3.8%) and Tityus stigmurus (Thorell, 1876) (n = 1; 1.0%). The sex ratios (male:female) of the two most abundant species were 14:1 for B. asper and 7:1 for B. rochai. The abundance of scorpions captured was significantly correlated with precipitation, real evapotranspiration, and abundance of invertebrates (mainly insects). Scorpion activities, especially those of B. asper and B. rochai, may be closely related to their reproductive cycles. Reproduction apparently reaches its maximum when there is an abundance of food, which in the Caatinga is strongly associated with rainfall patterns.

Natural products from the termite Nasutitermes corniger lowers aminoglycoside minimum inhibitory concentrations

Bacterial infectious agents present a risk to populations, as they are responsible for high morbidity and mortality. For combating these pathogens, our main line of defense is the use of antibiotics. However, indiscriminate use of these drugs develops resistant strains to these same drugs. The present study has tested the antibacterial and modifying antibiotic activity of natural products from Nasutitermes corniger (Termitidae) (Motschulsky), a termite used in folk medicine in Northeast Brazil, by the microdilution and checkerboard methods, respectively. In this study, the aqueous extract from the nest of N. corniger (ANCE) was prepared and tested with chlorpromazine (CPZ) for its antimicrobial activity, using the microdilution method. CPZ and ANCE were used independently and also in combination with aminoglycosides, against a strain of Escherichia coli resistant to these antibiotics, to determine the participation of efflux systems in resistance mechanisms. The fractional inhibitory concentration (FIC) index was calculated and evaluated for the occurrence of synergism, using the checkerboard method. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) values were ≥ 2048 μg/mL for both strains of E. coli assayed, indicating low antibacterial activity. However, synergism was observed with kanamycin when the decoction was used, but when chlorpromazine was used, synergism was observed with kanamycin, amikacin, and neomycin. This synergism with CPZ indicated the involvement of an efflux system in the resistance to these aminoglycosides. Therefore, it was suggested that the natural products from N. corniger could be used as a source of zoo-derived natural products with kanamycin-modifying activity, resulting in a new approach against bacterial resistance to antibiotics.

Phylogeny and micro-habitats utilized by lizards determine the composition of their endoparasites in the semiarid Caatinga of Northeast Brazil

Trophic networks can have architectonic configurations influenced by historical and ecological factors. The objective of this study was to analyze the architecture of networks between lizards, their endoparasites, diet, and micro-habitat, aiming to understand which factors exert an influence on the composition of the species of parasites. All networks showed a compartmentalized pattern. There was a positive relation between diet and the diversity of endoparasites. Our analyses also demonstrated that phylogeny and the use of micro-habitat influenced the composition of species of endoparasites and diet pattern of lizards. The principal factor that explained the modularity of the network was the foraging strategy, with segregation between the “active foragers” and “sit-and-wait” lizards. Our analyses also demonstrated that historical (phylogeny) and ecological factors (use of micro-habitat by the lizards) influenced the composition of parasite communities. These results corroborate other studies with ectoparasites, which indicate phylogeny and micro-habitat as determinants in the composition of parasitic fauna. The influence of phylogeny can be the result of coevolution between parasites and lizards in the Caatinga, and the influence of micro-habitat should be a result of adaptations of species of parasites to occupy the same categories of micro-habitats as hosts, thus favoring contagion.

Cupins de duas florestas de restinga do nordeste brasileiro

The structure of termite communities was evaluated at two restinga forests (a characteristic type of vegetation occurring on nutrient-poor sandy soils along the Brazilian coastline), located in the municipalities of Mataraca and Cabedelo, State of Paraiba. A standardised sampling protocol was used in both sites. Twenty-five species were found, 19 of them at Mataraca and 15 at Cabedelo, with just 9 species in common to both sites. Species of Nasutitermitinae and wood-feeding groups were dominant at both study sites. The low species richness and frequency of humus-feeders species, and species of the subfamily Apicotermitinae as well, seem to be related to the restinga soil properties. The conspicuous nest (all arboreal) builders were Armitermes holmgreni Snyder, 1926, Microcerotermes exiguus (Hagen, 1858), M. strunckii (Sorensen, 1884), Nasutitermes corniger (Motschulsky, 1855), N. ephratae (Holmgren, 1910), and N. macrocephalus (Silvestri, 1903). The termite fauna of the studied restinga was composed by typical species of other Brazilian ecosystems, such as Atlantic forest and Cerrado, being in agreement with the general pattern of distribution set up by the plant communities and the fauna of vertebrates described elsewhere for other Brazilian restingas.

The alien and native pentastomids fauna of an exotic lizard population from Brazilian Northeast

Pentastomids are common parasites of reptiles’ respiratory tract with more than 130 species described (de Oliveira Almeida and Christoffersen 1999; Rego 1983). The knowledge on the infection by the pentastomid Raillietiella in Brazil is scarce. Few works has been reported: Raillietiella freitasi in the lungs of Thrachylepis atlanticus (formerly Mabuya punctata; Motta 1963; Motta and Gomes 1968; Rego 1983, 1984); larvae of Raillietiella sp. in the skink Mabuya agilis (Vrcibradic et al. 2002) and a likely new species of Raillietiella aff. furcocerca infecting Cnemidophorus abaetensis and Cnemidophorus ocellifer (Dias et al. 2005). The house gecko Hemidactylus mabouia Moreau de Jonnes, 1818, is a broadly distributed species in the tropics and has invaded the New World after accidental introductions, becoming a successful colonizer, widely represented in southern North America, in Central and South America (Federico and Cacivio 2000). Along its range, H. mabouia has harboured an extensive parasitic fauna composed of protozoans, platyhelminthes, acanthocephalans, nematodes, pentastomids, and mites (Ali et al. 1985; Simonsen and Sarda 1985; Lainson and Paperna 1999; Martinez-Rivera et al. 2003; Anjos et al. 2005). We collected the specimens of H. mabouia from January to April 2006 in human buildings (houses) in the municipality of Barbalha (7°18′S; 39°18′W), Ceara state, in Northeastern Brazil. The climate of the region is predominantly mild hot semi-arid (mean annual temperature varying from 24°C to 26°C) and an annual rainfall of 1,153 mm. The vegetation in the area is composed of plant species common to Caatinga, Cerrado, wet forest, and transitional zones between these adjacent biomes (IPECE 2005). Lizards were collected by hand, promptly euthanized with ether and fixed with formalin 10% and posterior preserved in ethanol 70%. Lizard snout–vent length (SVL) was measured with a ruler (to the nearest 1 mm). Voucher specimens were housed in the Zoological Collection of the Universidade Regional do Cariri (LZ-URCA): 323–332, 334, 336, 338, 339, 341–355, 368–375. The lungs of the geckos were removed and carefully checked under a stereomicroscope to search for pentastomids. After that, the body cavity was checked and no pentastomid was found in the body cavity. The pentastomids were either preserved in ethanol 70% or mounted on slides and treated with a Hoyer medium. All the pentastomids found were adults because we noticed that the uterus of the females were full of eggs and that their single hooks had no chitinous accessories, which make Parasitol Res (2007) 101:627–628 DOI 10.1007/s00436-007-0526-7

Termites in sugar cane in Northeast Brazil: ecological aspects and pest status

The spatial distribution, abundance, and feeding habits of termites in a sugar cane plantation in Northeast Brazil were studied, and based on these ecological parameters, the pest status of the species was evaluated. Four species were found: Amitermes nordestinus Melo & Fontes, Cylindrotermes nordenskioeldi Holmgren, Nasutitermes coxipoensis (Holmgren) and Syntermes nanus Constantino, which we reported by the first time in association to sugar cane. The abundance and spatial distribution (vertical and horizontal) of the termites were influenced mainly by the plant root biomass and soil organic matter. C. nordenskioeldi is harmful to sugar cane, A. nordestinus is a potential pest, while N. coxipoensis and S. nanus are not potential pests. The importance of termites for maintaining the fertility, aeration and porosity of tropical soils is an evidence that basic investigations on reproduction biology and population dynamics of C. nordenskioeldi and A. nordestinus must be encouraged aiming to develop pest control agents and species-specific management techniques.