910 resultados para entomological warfare
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Sexual dimorphism of green lacewings is discussed, citing previously known examples of this structural phenomenon on the frons, antennal scape, and forewings. Newly recognized dimorphism is cited in Ceraeochrysa cubana for the vertex and abdominal spiracles.
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Since palatable butterflies are more dependent on evasive flight to escape from predators, they should be more restricted in their flight-related morphology than unpalatable ones. We compared: the ratios between the (1) length of head plus thorax and the length of abdomen (A/B), (2) length of the tip of the head to wing base and the length of the wing base to end of the abdomen (C/D), (3) the variances of A/B and C/D, (4) the proportion between the thoracic and the body weight, and (5) the flight speed between palatable and unpalatable butterflies. A/B and thoracic/body weight were higher for palatable species, indicating higher body symmetry and muscular mass. However, flight speed did not differ. Unexpectedly, the variance of A/B was higher for palatable species while that of C/D did not differ. Therefore, corporal allometric measurements of Neotropical butterflies are good predictors of palatability, though not of flight speed.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The Culicidae composition of the Barra Grande Lake Situated between the Municipalities of Esmeralda (Rio Grande do Sul State) and Anita Garibaldi (Santa Catarina State) was assessed by monthly samplings. Twenty-four species were identified from a total of 1, 185 specimens (74.7% as adults and 25.3% as immatures), with Aedes fluviatilis Lutz as the most frequent species. Several species are new records, and some of them are of public health interest. It is suggested that local environmental changes may alter the relationship between humans and vector mosquitoes.
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In order to study the interactions of green lacewings toxocenosis on natural ecossystems, samplings were carried out in the Parque Ecologic Quedas do Rio Bonito, located in Lavras, Alto Rio Grande region, South of Minas Gerais, Brazil. The species inventory was accomplished in two vegetation types: semi-evergreen forest and open field formations, including areas of montane grassland, rocky montane grassland and "cerrado". Insects were captured with a butterfly net during 2h, walking through each vegetation formation. Sampling resulted in 1,948 specimens belonging to 30 species, of which 14 were Chrysopini and 16 Leucochrysini. Representatives of these tribes were observed both in forest and in open field formations. Species of the genera Ceraeochrysa, Chrysoperla, Chrysopodes, Plesiochrysa and Leucochrysa were found in forests and in open field formations, except for Plesiochrysa. The highest richness and diversity of species were observed in the forest. The similarity index among the communities of green lacewings in the studied areas was 27%.
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The social wasp nests were quantified in three different plant physiognomies (forested Caatinga, shrubby Caatinga, and agricultural systems) to analyze the effect of environmental seasonality and plant physiognomy on the richness, nest abundance, and species composition of social wasps in the region of tropical dry forest of Brazil. The forested Caatinga physiognomy had the greatest richness of species (S = 16), followed by shrubby Caatinga (S 13) and by agricultural system (S = 12). The first axis of detrended correspondence analysis (DCA) explained 67.8% of the variability and shows a gradient of the fauna from agricultural system and shrubby Caatinga to forested Caatinga. In the first axis, wet season scores were much higher than those for the dry season in forested Caatinga. The second axis explained 18.7% of the variability and shows a separation of samples collected during the wet or the dry periods in shrubby Caatinga. This separation was less evident in the agricultural system. Variations in nest abundance were more intense in arbustive caatinga (45% decrease in number of active nests in the dry period), moderate in forested Caatinga (24% decrease in number of active nests in the dry period), and low in agricultural systems (8% decrease in the dry period).
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Laboratory nests of the leaf-cutting ant Atta sexdens rubropilosa Forel fed daily with leaves of Ricinus communis showed a gradual decrease in fungal garden volume, a higher ant mortality rate, and fungal garden extinction after 6 weeks. The mean oxygen consumption rate of these ants was higher than that of control ants collected from nests fed with leaves of Eucalyptus alba (Myrtaceae) suggesting one or more components of the leaves of R. communis had a direct physiological effect on the ants, in addition to inhibiting fungal garden growth.
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Crematogaster cf. victima is a common inhabitant in the sheet web nests of the social spider Anelosimus eximius in the central Amazon basin near Manaus. A number of other ant species were found foraging on the non-sticky webs of A. eximius, but none of these reached the web occupation frequency found in C. cf. victima, nor, with the exception of an unidentified species of Pheidole, did they form satellite nests in the web, as did this species. Many prey which escaped the knock-down threads of the sheet web of A. eximius colonies were captured by ants in the lower web portions which they dominated. Furthermore, prey which were rejected by A. eximius, especially large, heavily sclerotized beetles, were also consumed by this ant. Repeated observations and experiments suggest that C. cf. victima is able to deter A. eximius activity through aerial venom release. Resources lost by A. eximius colonies to ants, especially C. cf. victima, in colonial web area and prey, may pose significant costs and may reduce colony growth.
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Two new species of the genus Eidmanacris are described (E. bidentata and E. corumbatai) and a new combination name ( E. alboannulata) is assigned for the species Arachnomimus alboannulatus Piza, 1960 (= E. bicornis Mesa & Mello, 1985). Morphological and karyologycal information are provided, and the structure of the genital sclerites is discussed. [KEY WORDS: Orthoptera, Grylloidea, Phalangopsidae, Eidmanacris, cricket, phallic sclerites, chromosomes].
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Morphological structures of male and female genitalia and the pars stridens of a population of Urogryllus toledopizai Mello (1988) as well as the karyotype of the species are illustrated. The characteristics of song signals and associated behavior are described and information on the seasonality of the species is provided. Disagreements with the results published by other authors are discussed.