DISTRIBUIÇÃO DE SUBSTRATOS NAS COLÔNIAS DE Atta laevigata (F. Smith, 1858) (HYMENOPTERA: FORMICIDAE)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Sobrevivência de operárias de Atta sexdens rubropilosa Forel (Hymenoptera: Formicidae) isoladas do formigueiro e alimentadas com dietas artificiais

Avaliou-se dietas artificiais, para operárias médias de Atta sexdens rubropilosa Forel isoladas de formigueiros de laboratório e de campo. Os bioensaios foram realizados com 6 formigas/placa de Petri, sendo 10 placas/tratamento, em câmara ambiental a 24 ± 1 °C e UR > 70%. Não houve diferença na sobrevivência entre as operárias de laboratório e de campo, quando tratadas com dieta artificial líquida. Ao se comparar as dietas artificiais líquida e sólida, pode-se constatar que não houve diferença na sobreviência das operárias de laboratório tratadas com as diferentes dietas. A dieta artificial sólida com troca a cada 48 h, até 25 dias, representa uma alternativa para se trabalhar com operárias médias de A. sexdens rubropilosa, isoladas do formigueiro, em bioensaios de laboratório.

Ovarian development in Meliponine bees (Hymenoptera: Apidae): the effect of queen presence and food on worker ovary development and egg production

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Purification, sequencing and structural characterization of the phospholipase A(1) from the venom of the social wasp Polybia paulista (Hymenoptera, Vespidae)

The biochemical and functional characterization of wasp venom toxins is an important prerequisite for the development of new tools both for the therapy of the toxic reactions due to envenomation caused by multiple stinging accidents and also for the diagnosis and therapy of allergic reactions caused by this type of venom. PLA(1) was purified from the venom of the neotropical social wasp Polybia paulista by using molecular exclusion and cation exchange chromatographies; its amino acid sequence was determined by using automated Edman degradation and compared to the sequences of other vespid venom PLA(1)'s. The enzyme exists as a 33,961.40 da protein, which was identified as a lipase of the GX class, liprotein lipase superfamily, pancreatic lipases (ab20.3) homologous family and RP2 sub-group of phospholipase. P. paulista PLA(1) is 53-82% identical to the phospholipases from wasp species from Northern Hemisphere. The use restrained-based modeling permitted to describe the 3-D structure of the enzyme, revealing that its molecule presents 23% alpha-helix, 28% beta-sheet and 49% coil. The protein structure has the alpha/beta fold common to many lipases; the core consists of a tightly packed beta-sheet constituted of six-stranded parallel and one anti-parallel beta-strand, surrounded by four alpha-helices. P. paulista PLA(1) exhibits direct hemolytic action against washed red blood cells with activity similar to the Cobra cardiotoxin from Naja naja atra. In addition to this, PLA(1) was immunoreactive to specific IgE from the sera of P. paulista-sensitive patients. (c) 2007 Elsevier Ltd. All rights reserved.

CYTOPHOTOMETRIC EVALUATION OF CORPORA ALLATA DNA DURING THE DEVELOPMENT OF LARVAE OF WORKERS AND QUEENS (APIS-MELLIFERA L, HYMENOPTERA, APIDAE)

Cytophotometric observation of corpora allata from workers and queens of A. mellifera showed significant variations in DNA content from the 2nd to the 4th instar of both castes, but the differences between castes are present only in the 2nd instar.The corpora allata are characterized by the presence of diploid, as well as polyploid cells, distributed in classes that are well established since the earliest developmental stages. However the frequency of cell nuclei in the higher classes of ploidy increases with development. This occurrence is responsible for the increase of the average DNA content in older larvae.

NEST REUSE AND COMMUNAL NESTING IN MICROTHURGE-CORUMBAE (HYMENOPTERA, MEGACHILIDAE), WITH SPECIAL REFERENCE TO NEST DEFENSE

Observations on the nesting activities of Microthurge corumbae, carried out at the University Campus of Ribeirao Preto, São Paulo, Brazil, from 1977 to 1981, indicated that 61.9% of nests were re-used by succeeding generations. Re-use by one generation was more frequent than by two generations, and re-use by a third was observed only once. Nests were re-used by one or several females. Single females were more frequently in the first re-use. In these cases nest re-use did not differ essentially from the solitary foundation of a new nest, except for the adoption of a pre-existing nest without excavation. In multifemale nests, analysis of relative age (wing wear), ovarian and spermathecal conditions of associated females and the content of nests at excavation indicated that the social pattern in such colonies is communal. There is some evidence that the associated females are relatives. The chalcidoid wasp Leucospis was the principal nest parasite, and ants of the genus Crematogaster were nest predators. In multifemale nests, the rate of parasitism was significantly lower than in solitary nests, indicating that nest-sharing resulted in improved nest defense. on the other hand. The absence of predation on immatures of the first generation of M. corumbue in multifemale nests suggests that such nests are also more resistant to attack by predators.

Ultrastructural evidences of the occurrence of digestion and absorption of organic solutes in bees ileum (Melipona quadrifasciata anthidioides - Hymenoptera, Apidae)

The ultrastructural aspects of the ileum of Melipona quadrifasciata anthidioides, a stingless bee whose workers obtain their protein requirements from pollen, present morphological evidences of digestion and absorption. These evidences are represented by special relationships between food particles and the bacterial nora present and between their assemblage and the ileum wall, mainly in the ileum three anterior fourths. The apical features of the epithelium also are indicative of organic material absorption.

Phylogenetic analysis of the neotropical pseudopolybia de saussure, 1863, with description of the male genitalia of pseudopolybia vespiceps (Hymenoptera : Vespidae, epiponini)

The male genitalia of Pseudopolybia vespiceps are described and compared to congeners. Characters of the male genitalia are combined with morphological characters of the females and nests and used in a phylogenetic analysis. The single cladogram resulting supports monophyly of the genus Pseudopolybia and interrelationships among the species as: P. langi + (P. difficilis + (P. compressa + P. vespiceps)). A new, illustrated identification key is presented.

THAUMATOMYRMEX STRIPS MILLIPEDES FOR PREY - A NOVEL PREDATORY BEHAVIOR IN ANTS, AND THE 1ST CASE OF SYMPATRY IN THE GENUS (HYMENOPTERA, FORMICIDAE)

We describe, for the first time, the predatory behaviour of Thaumatomyrmex ants on millipedes of the family Polyxenidae, based on field observations of T. atrox and a field and laboratory study of T. contumax. The capture of the prey and the removal process of its body-covering setae by the ants before they eat the millipede are described. This specialized behaviour in at least two species of the genus, belonging to two distinct groups of species, indicates a general trend in Thaumatomyrmex. We coupled this study with a comparative morphological analysis of the mouthparts and digestive tube of these and other Thaumatomyrmex species. Also, we report the first case of sympatry in the genus, which suggests that Thaumatomyrmex includes several species. and not only one highly variable taxon, as hypothesized earlier.

HOST-SPECIFICITY OF SEVERAL PSEUDACTEON (DIPTERA, PHORIDAE) PARASITES OF FIRE ANTS (HYMENOPTERA, FORMICIDAE) IN SOUTH-AMERICA

We tested the host specificity of several parasitic Pseudacteon scuttle flies in South America with 23 species of ants in 13 genera. None of these ant species attracted Pseudacteon parasites except Solenopsis saevissima (F. Smith) and to a lesser extent Solenopsis geminata (Fab.). This result is encouraging because it indicates that the Pseudacteon flies tested in this study would not pose an ecological danger to other ant genera if these flies were introduced into the United States as classical biological control agents of imported fire ants. This prediction of host specificity will, of course, need to be validated with potential hosts in the United States before these flies can be released.

THE POPULATION STATUS OF THE ENDANGERED BRAZILIAN ENDEMIC LEAF-CUTTING ANT ATTA-ROBUSTA (HYMENOPTERA, FORMICIDAE)

The population status of the endemic leaf-cutting ant Atta robusta was assessed using extensive field surveys. In the coastal plain of the state of Rio de Janeiro, we found localized populations of A. robusta, bur no evidence of population recruitment. In disturbed habitats, A. robusta is apparently being displaced by Atta sexdens rubropilosa.

Comparative study of digestive cells in different midgut regions of stingless bees (Hymenoptera: Apidae: Meliponinae)

Ultrastructure of the digestive cells was analyzed in three midgut regions (anterior, middle and posterior) of stingless bees. Variations occurs in the presence of lipid inclusions in the cells from posterior midgut and presence of double-membraned vesicles associated to microvilli in the anterior midgut. However, basal plasmic membrane infoldings and augmentation of surface area achieved by microvilli ale very similar in all midgut regions. These results not supported the existence of fluid fluxes in the ectoperitrophic space and suggest that digestive cells in stingless bees are polifunctional, that is, there is not midgut region specialized in secretion ol absorption as observed in other insects.

SOLENOPSIS (HYMENOPTERA, FORMICIDAE) FIRE ANT REACTIONS TO ATTACKS OF PSEUDACTERON FLIES (DIPTERA, PHORIDAE) IN SOUTHEASTERN BRAZIL

We studied the responses of Solenopsis fire ants to Pseudacteon phorid fly attacks in southeastern Brazil. The presence of these phorid parasites triggered a suite of phorid-specific defense responses including reduced foraging, bait guarding, a curled defensive posture, and general colony immobility. The existence of these phorid-specific defenses indicates that Pseudacteon phorids exert substantial evolutionary pressure on South American fire ant populations.

Fugitive species in a harlequin environment: Ants (Hymenoptera : Formicidae) and banana baits in the Amazon

A total of 9 ant species were sampled from four sites covering 2000 km in the Amazon Basin using banana fruit baits: two sites on the Jurua River, one site on the Xingu River and in a dry forest of eastern Amazon, Paragominas. Camponotus abdominalis was present in all sites, and Camponotus sericeiventris, Camponotus sp. and Crematogaster sp. were present in two sites. All other species were present in only one site. Paragominas had the highest species richness because of a higher number of site restricted species. However, Jaccard faunas similarities among sites were not significantly related with distance between sites. Mosaic diversity showed a relatively simple taxonomic composition. The strong differences of the fauna sampled at banana fruit baits from other reported Neotropical ant faunas suggests that the fauna represents widespread fugitive species in an apparently complex environment.