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Instituto de Biologia Unicamp






ABSTRACTA IB (2) - 1999


P040-99 Population structure and fecundity of the hermit crab Clibanarius antillensis Stimpson 1862 (Anomura, Diogenidae) in southeastern Brazil

Turra A, Leite FPP*

The population structure and fecundity of Clibanarius antillensis Stimpson 1862 at the rocky shore of Praia Grande, São Sebastião, São Paulo State, Southeastern Brazil, was studied. Sexual dimorphism was verified, with males reaching larger sizes than females. Population sex ratio was skewed for females, which predominated in the smallest size classes, while males predominated in the largest ones. Size frequency distribution revealed a bimodal pattern correlated with seasonal differences in crab size. Reproductive season was continuous, with a peak of reproductive activity from November to March. Fecundity was positively correlated with crabs shield length and larger broods were found to be produced in relatively heavier (larger) shells. Thus, shells influenced both crab and, consequently, brood size, probably by regulating individual growth and reproductive activity of females. Bulletin of Marine Science 64: 281-289, 1999

041-99 Convergências entre controle químico, biológico e biotecnologia para o manejo de plantas invasoras: reflexões sobre ciência e tecnologia

Garcia MA*

Ciência e Sociedade, 2: 177-186, 1999.

P042-99 Ant-Homoptera interactions in a Neotropical savanna: The honeydew-producing treehopper Guayaquila xiphias (Membracidae) and its associated ant fauna on Didymopanax vinosum (Araliaceae)

Del-Claro K, Oliveira PS*

The ant fauna associated with the neotropical treehopper Guayaquila xiphias was studied on shrubs of Didymopanax vinosum in a cerrado savanna in SE Brazil. Treehoppers infested almost exclusively plants at the border of the cerrado and preferably fed near the apical meristem. During the reproductive phase of the host plant, however, the vast majority of the treehoppers aggregated on the inflorescences. Twenty one ant species were found to harvest honeydew at G. xiphias aggregations, the most frequent ones being Camponotus rufipes, Ectatomma edentatum, C. crassus and C. renggeri. Such a taxonomic diversity of ants tending G. xiphias aggregations in the cerrado is far greater than that reported for any other ant-homopteran system. Daily turnover of ant species at a given treehopper aggregation was observed on 64 out of 222 of the G. xiphias aggregations recorded on D. vinosum shrubs. Species replacements probably reflect distinct humidity and temperature ranges tolerated by the species, and may reduce interspecific competition at homopteran aggregations. Since predation and parasitism on G. xiphias can be severe, and tending ants protect the homopterans against predators and parasitoids, the round-the-clock activity by ants at G. xiphias aggregations is regarded as crucial for the survival of these treehoppers in the cerrado savanna. Biotropica 31: 135-144, 1999 IF= 0.542

P043-99 Isolation of magnetic nanoparticles from Pachycondyla marginata ants

Esquivel D, Wajnberg E, Acosta-Avalos D, Oliveira PS*, Leal IR, Farina M

Magnetic iron oxide particles were extracted from the head, thorax and abdomen of the migratory ant, Pachycondyla marginata, using magnetic precipitation methods. Electron spectroscopic images for iron and oxygen from the extracted particles were obtained, and histograms of size distribution were constructed from electronmicrographies. Selected area diffraction patterns were also determined for the particles, demonstrating mixtures of different iron oxides, including the magnetic ones, magnetite and maghemite. The size distribution of the particles in the abdomen was found to be different from that in the thorax and the head. Following the hypothesis of magnetic orientation based on magnetic material, two body regions (head and abdomen) could be suggested for detection of the geomagnetic field. Journal of Experimental Biology 202: 2687-2692, 1999 IF= 1.948

P044-99 Padrões sazonais de frutificação e germinação de sementes em cerrado, Minas Gerais

Varassin IG, Silva WR*

Boletim do Museu de Biologia Mello Leitão, Nova Série 10: 13-28, 1999

P045-99 Ecologia reprodutiva e distribuição espacial da colonia de Eudocimus ruber (Ciconiiformes: Threskiornithidae) na Ilha do Cajual, Maranhão

Hass A, Ribeiro RH, Machado LOM*

Breeding ecology and spatial nest distribuition of the Scarlet Ibis (Eudocimus ruber) in Cajual Island, Maranhão. The Scarlet Ibis breeds in large clusters on mangrove trees. To assess the spatial distribuition pattern of nests we studied a colony of 3500 individuals in Cajual Island (Maranhão), Brazil. Nests in 4800m2 of the colony area were mapped. No significant pattern of plant species or size selection was found. Nest nests, generating the aggregation pattern. The Scarlet Ibis selection of mangrove structures may be more associated with degree of human disturbance than with to the physical characteristics of the habitat. Ararajuba 7: 41-44, 1999
*Phone: xx-19-788-8476

P046-99 The Family Histriobdellidae (Annelida, Polychaeta) Including Descriptions of Two New Species From Brazil and a New Genus

Steiner TM, Amaral AC*

We review the family Histriobdellidae and provide species descriptions and notes on geographical distribution based on data from the literature. The morphological structures used in the systematics of this family are defined. A new genus, Dayus, is proposed and two new species from Brazil, Stratiodrilus robustus and S. circensis, are described. Contributions to Zoology 68: 97-108 , 1999

P047-99 A Comparative Study of Intertidal Molluscan Communities in Sandy Beaches, São Sebastião Channel, São Paulo State, Brazil

Denadai MR, Amaral ACZ*

Molluscan communities were studied in two intertidal environments and their relationship with environmental variables were established. The study areas are located in São Francisco and Engenho d’Água beaches (São Sebastião Channel, São Paulo State, Brazil), sites which are structurally similar with sediment of coarse sand and pebbles, facilitating settlement of molluscan species. Temperature, salinity, grain size, organic matter, and calcium carbonate content were analysed as environmental variables. The high species diversity recorded in the study sites was due to the occurrence of organisms of consolidate and inconsolidate substrate. However, differences in the specific composition of the two areas were associated with local differences in sediment constitution and the presence of an urban waste water in São Francisco. In general, few species were common to both sites, with higher richness and number of individuals in Engenho d’Água. Differences in environmental variables and in species distribution between the two areas were indicated by Canonical Correspondence Analysis, which also revealed that grain size, salinity and calcium carbonate content played a more important role in species distribution than did organic matter content. Bulletin of Marine Science 65: 91-103, 1999

P048-99 Long-term nitric oxide inhibition and chronotropic responses in rat isolated right atria

Riado SR, Zanesco A, Barker LA, De Luca IMS*, Antunes E, De Nucci G

The long-term administration of nitric oxide synthesis inhibitors induces arterial hypertension accompanied by left ventricular hypertrophy and myocardial ischemic lesions. This study was performed to determine the potency of b -adrenoceptor agonists and muscarinic agonists on the spontaneous rate of isolated right atria from rats given long-term treatment with the nitric oxide inhibitor Nw -nitro-L-arginine methyl ester (L-NAME). Atrial lesions induced by long-term treatment with L-NAME were also evaluated. Long-term L-NAME treatment caused a time-dependent, significant increase in tail-cuff pressure. The potency of isoproterenol, norepineprhine, carbachol, and pilocarpine in isolated right atria from rats given long-term treatment with L-NAME for 7, 15, 30, and 60 days was not affected as compared with control animals. Addition of L-NAME in vitro affected neither basal rate nor chronotropic response for isoproterenol and norepinephrine in rat heart. Stereological analysis of the right atria at 15 and 30 days revealed a significant increase on amount of fibrous tissues in L-NAME treated groups as compared with the control group. Our results indicate that nitric oxide does not interfere with b -adrenoceptor-mediated and muscarinic receptor-mediated chronotropic responses. Hypertension 34 (part 2): 802-807, 1999 IF= 4.944

P049-99 Modulation of coronary flow and cardiomyocyte size by sensory fibers

Zanesco A, Costa SK, Riado SR, Nathan LP, de Oliveira CF, De Luca IMS*, Antunes E, De Nucci G

Cardiac tissue is densely innervated by sensory neurons that are believed to play important modulatory roles in cardiac functions. Here, the cardiomyocyte size and amount of fibrous tissue in left ventricles as well as in vitro coronary flow were evaluated in adult rats which had been treated with capsaicin when in the neonatal sate. The chronotropic and inotropic responses to beta-adrenoceptor agonists (norepinephrine and isoproterenol), muscarinic agonists (carbachol and pilocarpine), and calcitonin gene-related peptide (CGRP) were also investigated with the use of the isolated right atria preparation. Capsaicin pretreatment significantly reduced both basal coronary flow (18% reduction) and cardiomyocyte size (34% reduction) without affecting the amount of fibrous tissue in the left ventricles. The positive inotropic and chronotropic effects in response to norepinephrine in the isolated rat heart did not significantly differ between control and capsaicin-treated rats. Similarly, the positive chronotropic effects in response to norepinephrine, isoproterenol, and CGRP as well as the negative chronotropic responses to carbachol and pilocarpine in the isolated right atria were not affected by capsaicin pretreatment. The results suggest that reductions of both basal coronary flow and cardiomyocyte size seen in hearts from capsaicin-pretreated rats may be consequences of CGRP depletion. The cardiomyocyte size reduction produced by capsaicin treatment may be related to a modulatory role of CGRP as a growth factor. Hypertension 34 (part 2): 790-794, 1999 IF= 4.944


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