981 resultados para Neotropical rattlesnake


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The Nasutitermitinae species are the most diverse and derived of the Isoptera. The phylogeny of this subfamily has been a point of divergence. In an attempt to solve this problem, we propose the use of the morphological features of the head, frontal gland and its associated muscles as phylogenetic characters in some Nasutitermitinae genera. Results found about the head and frontal gland morphology are discussed and suggested to be used in future systematic studies of termites.

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Numerous nymphoid reproductives were found in three field nests of Armitermes euamignathus collected in Brazil. We report here a morphological description and a biometric study of these individuals. Nymphoid replacements displayed narrow wing buds when compared with those present in nymphs from the three last instars. Thorax morphology of the nymphoids was similar to the penultimate nymphal instar (N4) or to the ultimate nymphal instar (N5), and their origin from these instars of nymphs is discussed. All the nymphoids had eyes, ocelli, and 15 antennal segments. The nymphoid females from nest 1 had different grades of physogastry and royal fat body. The nymphoid females from nests 2 and 3, the nymphoid males from all nests, and the primary king from nests 2 acid 3 had a common fat body, which is similar to that present in alates. The ovaries and the testes of nymphoids were fully mature and the corpora allata larger than those in imagoes. The mandibular glands were also enlarged in nymphoids but the tergal glands were absent. (C) 1999 Wiley-Liss, Inc.

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Flowering phenology, breeding system and nectary structure of Corymborkis flava (Sw.) Kuntze were studied in a fragment of the Atlantic Forest in south-eastern Brazil. The flowering period extended from March (end of rainy season) to early June and seed dispersal occurred from June to September (dry season). Flowering peak occurred mainly in April, with up to 34 open flowers per plant being observed. The yellow, odourless and tubular flowers lasted similar to 7.8 days. The flowers present a perigonal nectary located in the basal lateral parts of the labellum; this is the first report on the nectary location and characterisation in the Tropidieae tribe. At the pre-anthesis stage, cells of both secretory parenchyma and epidermis of the nectary are filled with compound amyloplasts. However, starch grains were not observed in these tissues in senescent flowers, indicating that these starch grains are hydrolysed and used as source of sugars for nectar production. The nectar accumulates between the cuticle and the outer periclinal wall of the epidermal cells before. owing out into the nectar chamber. C. flava is a self-compatible species and spontaneous self-pollination does not occur because of hercogamy. The high pollinia removal (0.80) and insertion (0.82) per flower, as well as the high natural fruit-set indicate an efficient natural pollination system. The present study contributes for the knowledge of the diversity of reproductive strategies and nectary structures in Orchidaceae.

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Seven new genera of the Neotropical Lauxaniidae are described; all the type-species are also new and described here: Bacilloflagellomera gen. n. (type-species B. pectinicornis sp. n.), Baliopteridion gen. n. (type-species B. brevitarsus sp. n.), Gibbolauxania gen. n. (type-species G. elegans sp. n.), Minilauxania gen. n. (type-species M. bulbifacies sp. n.), Paraphysoclypeus gen. n. (type-species P. nigropleura sp. n.), Pseudominettia gen. n. (type-species P. platypeza sp. n.), Tauridion gen. n. (type-species T. shewelli sp. n.). With 37 original figures.

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Morphological caste differences and ovary conditions were analyzed in four colonies of Brachygastra augusti collected in different stages of the colony cycle. Differences between castes are distinct suggesting pre-imaginal determination. Many intermediates (non-inseminated ovary-developed females) were found. Because these intermediate females were morphologically similar to workers, it is suggested that they are young ovary-developed workers. Because there is a more evident overlap between queens and workers in the colony in pre-emergence of workers stage, and in three colonies in latter stages, especially in worker-production colonies, it is suggested that smaller queens are probably less viable than larger queens as observed in previously studied epiponines.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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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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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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In this paper the genus Cunaxoides Baker & Hoffmann, 1948, as delimited by Den Heyer (1979a, 1981b), is revised and divided into five genera, viz. Cunaxoides Baker & Hoffmann, Bunaxella gen. nov., Dunaxeus gen. nov., Funaxopsis gen. nov. and Qunaxella gen. nov.. Two new Neotropical species, Dunaxoides duosetosus and Qunaxella triasetosa are described and figured. Additional southern African material is reported. A key to the genera and species of the new genera of the subfamily Cunaxoidinae is provided.

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

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Species of Ceraeochrysa Adams are distributed from southeast Canada to Argentina. Larvae feed on aphids, thrips, white flies, mites, and neonatal larvae of Lepidoptera in varied agroecosystems. Seven species are known in Venezuela, viz. Ceraeochrysa achillea Freitas & Penny, C. angulata (Navas), C. bitacornua Freitas & Penny, C. caligata (Banks), C. cubana (Hagen), C. everes (Banks), and C. valida (Banks). In this study, three species are described as new to science, Ceraeochrysa melaenopareia sp. nov., Ceraeochrysa pittieri sp. nov., and Ceraeochrysa torresi sp. nov.