Artigos
URI permanente para esta coleçãohttps://locus.ufv.br/handle/123456789/11845
Navegar
15 resultados
Resultados da Pesquisa
Item How predictable is the response of ant assemblages to natural forest recovery? Implications for their use as bioindicators(Ecological Indicators, 2013-01) Schmidt, Fernando A.; Ribas, Carla R.; Schoereder, José H.Environmental indicators can be used to evaluate natural recovery processes. Although several studies have used ant assemblage metrics as environmental indicators, few try to explain the response of these insect assemblages to forest recovery. Thus, we carried out a vertical ant sampling design to verify the sensitivity of ant assemblages from different microhabitats (epigeic, arboreal and hypogeic) to natural forest recovery. We also verified whether changes to the diversity measures (species richness, composition and evenness) of these assemblages could be predictable and explained by changes in the resource quantity and conditions, and structural and resource heterogeneity that also occur along the natural forest recovery gradient. Additionally, we verified the potential of ant species as indicators of forest recovery. We sampled ants in a pasture and seven forest remnants with different recovery times that represent a forest recovery gradient along a chronosequence. Although, the non response of species richness and evenness, species composition changed along the recovery gradient and the dissimilarity between the ant species composition of pasture and forest habitats increased with the age of the forest remnant. This was supported by ant species indicators of pasture and forest areas pointed out by the IndVal test. The variation of ant species composition of the two groups of habitat types (pasture and forest) could be explained by the different responses of open habitat and forest specialist ants to the increase in vegetation cover along the recovery gradient. Therefore, species composition and indicator species by habitat type seems to be the most predictable data for the use of ants in environmental monitoring programs.Item Sperm bundles in the seminal vesicle of the crematogaster victima (Smith) adult males (Hymenoptera: Formicidae)(Neotropical Entomology, 2014-06) Oliveira, C. M.; Lino-Neto, J.; Moreira, J.; Gomes, L. F.; Camargo-Mathias, M. I.This study establishes the presence of spermatodesm in the seminal vesicles of sexually mature males of Crematogaster victima (Smith). In this species, the spermatozoa are maintained together by an extracellular matrix in which the acrosomal regions are embedded. This characteristic has not yet been observed in any other Aculeata. However, the sperm morphology in this species is similar to that described for other ants. The spermatozoa measure on average 100 μm in length, and the number of sperm per bundle is up to 256. They are composed of a head formed by the acrosome and nucleus; this is followed by the flagellum, which is formed by the centriolar adjunct, an axoneme with a 9 + 9 + 2 microtubule pattern, two mitochondrial derivatives, and two accessory bodies. The acrosome is formed by the acrosomal vesicle and perforatorium. The nucleus is filled with compact chromatin with many areas of thick and non-compacted filaments. Both mitochondrial derivatives have the same shape and diameters. The presence of sperm bundles in sexually mature males differentiates C. victima from other ants; however, the similarities in the sperm ultrastructure support the monophyly of this insect group.Item Biotic and abiotic factors shaping ant (Hymenoptera: Formicidae) assemblages in brazilian coastal sand dunes: the case of Restinga in Santa Catarina(Florida Entomologist, 2014) Cardoso, Danon Clemes; Schoereder, José HenriqueSpecies inhabiting Brazilian coastal sand dunes (restingas) may feature a number of adaptations in their development and survival in these physical stressful environments. The present study determined the effect of biotic and abiotic factors on the assemblage of grounddwelling ants in a sand dune ecosystem of the Santa Catarina coastal plain in Brazil. Both linear and quadratic models were significant, but the quadratic model fitted the obtained data better. Furthermore, we also found a relationship between plant species richness and distance from the ocean only by using the quadratic model. Ant species richness was correlated with plant species richness, litter and vegetation coverage. Different environmental factors associated with plant species richness may have influenced the ant species richness by increasing the diversity and amount of available resources. The vegetation may also offer protection from higher temperatures by providing shade, a humid microclimate and a source of water, which is a limiting factor in sand dune environments. Our results showed the importance of plant species richness, and soil cover by litter and plants as local characteristics determining ant species richness in sand dunes. Further studies should explore additional habitat components, such as biotic interactions, as determinants of ant species richness.Item Multi‐scale ant diversity in savanna woodlands: an intercontinental comparison(Austral Ecology, 2011-04-27) Campos, Ricardo I.; Vasconcelos, Heraldo L.; Andersen, Alan N.; Frizzo, Tiago L. M.; Spena, Kelly C.Ecological patterns and processes are highly scale-dependent, but few studies have used standardized methodology to examine how scale dependency varies across continents. This paper examines scale dependency in comparative ant species richness and turnover in savannas of Australia and Brazil, which are well-matched climatically but whose ant faunas have contrasting biogeographic origins. The study was conducted in savanna woodland near Darwin in northern Australia and Uberlândia in central Brazil. The sampling design consisted of eight 400-m line transects, four in each continent, with eight pitfall traps located on and around each of 20 trees evenly spaced along each transect. Ant richness and species turnover were compared at three spatial scales: pitfalls associated with a tree, trees within a transect and transects within a savanna.The composition of the Australian and Brazilian savanna ant faunas was broadly similar at the subfamily level, despite the very low proportion of shared genera and species. The ground and arboreal ant faunas were very distinct from each other in both savannas, but especially in Brazil. Overall ant abundance was almost three times higher in Australia than in Brazil, both on the ground and on vegetation, but overall species richness was higher in Brazil (150 species) than in Australia (93). There was no significant difference in the mean number of species per pitfall trap, but the mean species richness was significantly higher in Brazil than in Australia at both the tree and transect scales. We attribute these scale-dependent intercontinental differences to biogeographical and historical factors in Brazil that have led to a large regional pool of arboreal species of rainforest origin. Our study underlines the importance of biogeographical context when conducting comparative analyses of community structure across biogeographical scales, and high- lights the importance of process acting at regional scales in determining species richness in ant communities.Item Ant community in natural fragments of the Brazilian wetland: species–area relation and isolation(Journal of Insect Conservation, 2015-05-08) Schmidt, Fernando A.; Cuissi, Rafael G.; Lasmar, Chaim J.; Moretti, Tamara S.; Fernandes, Wedson D.; Falleiros, Andreia B.; Schoereder, José H.; Ribas, Carla R.Biogeographic theory has been given much attention for its potential application to biodiversity conservation in areas fragmented through anthropic action. The objective of this study was to determine whether ant community structure established in natural woodland fragments immersed in a matrix of natural grasslands could be explained by this theory. We therefore investigated whether the relationship between species richness and both area and isolation that have previously been found in anthropogenically formed forest fragments are applicable to naturally formed forest fragments. The sampling consisted of eight natural woodland fragments with varying areas and degrees of isolation. Sampling was undertaken proportionally to the fragment size, and each sampling point was spaced at least 10 m apart. Ants were collected from each point through arboreal and epigeic “pitfall” traps. In addition, five epigeic traps were placed 100 m from each sampled fragment in the adjacent grassland. A total of 81 ant species were sampled. Total and epigaeic species richness increased with size of area and fragment isolation. However, arboreal ants responded positively only with respect to increasing area, but not with isolation. Moreover, specialist and generalist species richness had a positive relationship with area, but not with isolation. Biogeographic Theory can only be applied to some of the patterns found in the natural fragments in the present study. This positive relationship of ant richness and isolation suggests that these environments bear unique characteristics and therefore, must be regarded as conservation targets. The results obtained in this study suggest the need for further studies, to reinforce the importance of biodiversity conservation of this characteristic habitat in the Pantanal.Item Chemical composition of the intramandibular glands of the ant Neoponera villosa (Fabricius, 1804) (Hymenoptera: Ponerinae)(Chemoecology, 2014-10-11) Martins, Luiza Carla Barbosa; Nascimento, Fabio Santos do; Campos, Maria Cláudia Guidetti; Lima, Eraldo Rodrigues; Zanuncio, José Cola; Serrão, José EduardoProducts of exocrine glands modulate the behavior of social in sects. Among the exocrine glands, the function of intramandibular glands has not been well characterized in social Hymenoptera. To study the effects of exocrine gland secretions on the behavior of the ant, Neoponera villosa, identification of cuticular and intramandibular gland compounds was performed. Fifteen different compounds were identified in workers and queens of N. villosa. Linear alkanes C26, C27, C28, C30 and C36, as well as the methyl alkanes 13-, 11- MeC28, 3 MeC29, 13-, 11- MeC32, 13-, 11- MeC33, 13- MeC36, 13,17-; 15,19-DiMeC37 and 18-, 17-, 13-MeC38 and esters triacontyl acetate were found on the body and mandible surface of both workers and queens. The sterols, cholesterol and sitosterol were found only in the mandibles, with cholesterol present in both workers and queens, and sitosterol present only in queens. The results suggest that intramandibular gland compounds of N. villosa may play a role in worker activity. The presence of hydrocarbons and cholesterol in workers and sitosterol in the mandible of queens may be associated with caste profile.Item Karyotype differentiation among four Dinoponera (Formicidae: Ponerinae) species(Florida Entomologist, 2018-09) Barros, Luisa A. C.; Pompolo, Silvia G.; Santos, Igor S.; Delabie, Jacques H. C.; Silva, Janisete G.; Costa, Marco A.; Mariano, Cléa S. F.Ants in the genus Dinoponera (Hymenoptera: Formicidae: Ponerinae) are among the largest sized Formicidae of the World. In Brazil Dinoponera has an allopatric distribution, and several species occur in threatened biomes. We characterized karyotypes of the following 4 species: Dinoponera australis Emery, Dinoponera gigantea Perty, Dinoponera lucida Emery, and Dinoponera quadriceps Santschi. Karyotype analysis found that all 4 species have high numbers of small-sized chromosomes (D. australis, 2n = 114; D. gigantea, 2n = 82; D. lucida, 2n = 118/120; D. quadriceps, 2n = 92). A moderate variation in chromosome number was observed among the 4 species, which suggests the occurrence of chromosome rearrangements during karyotype evolution in Dinoponera. An exclusive AMT chromosome pair was found to occur in all Dinoponera species studied thus far, which we conclude is a probable synapomorphy in Dinoponera.Item Ant assemblage and morphological traits differ in response to soil compaction(Insectes Sociaux, 2016-12-02) Schoereder, J. H.; Schmidt, F. A.; Caetano, M. D. N.Soil compaction, a process that decreases the free space among soil particles and hinders the underground movement of soil organisms, is one of the increasing impacts of mankind on the world’s ecosystems. We investigated the responses of subterranean ants to soil compaction by testing the following predictions: (i) soil from a trail is more compressed, leading to (ii) a decrease in species richness and a selective shift in ant assemblage composition, which is made up by (iii) species with a smaller body size that can apply a greater relative strength to move through soil particles. We carried out this study in and outside of a recreational ecology trail in a forest fragment in Viçosa, MG, Southeastern Brazil. The compaction was higher in the soil from the trail than outside of it. No change was observed in species richness, but soil compaction promoted a shift in ant assemblage composition, with ant size decreasing with an increase in soil compaction. However, ants did not appear to apply a greater strength to soil particles for moving in habitats with a high soil compaction. Overall, organisms at superficial soil layers appeared to be sensitive to even moderate human impacts that promote a filtering of the ant assemblage species composition, with small body size being a required trait.Item Biodiversity consequences of land-use change and forest disturbance in the Amazon: A multi-scale assessment using ant communities(Biological Conservation, 2016-05) Solar, Ricardo Ribeiro de Castro; Barlow, Jos; Andersen, Alan N.; Schoereder, José H.; Berenguer, Erika; Ferreira, Joice N.; Gardner, Toby AlanQuantifying and understanding the main drivers of biodiversity responses to human disturbances at multiple scales is key to foster effective conservation plans and management systems. Here we report on a detailed regional assessment of the response of ant communities to land-use change and forest disturbance in the Brazilian Amazon. We aimed to explore the effects of land-use intensification at both site and landscape scales, examining variation in ant species richness and composition, and asking which set of environmental variables best predict observed patterns of diversity. We sampled 192 sites distributed across 18 landscapes (each 50 km2) in Paragominas, eastern Brazilian Amazon, covering ca. 20,000 km2. We sampled from undisturbed primary forest through varyingly disturbed primary forests, secondary forests, pastures and mechanised agriculture, following a gradient of decreasing total aboveground biomass. Irrespective of forest disturbance class, ant species richness was almost twice as high in forests when compared to production areas. In contrast, ant species composition showed continuous variation from primary forest to intensive agriculture, following a gradient of aboveground biomass. Ant species richness at all spatial scales increased with primary forest cover in the surrounding landscapes. We highlight the limited value of species richness as an indicator of changes in habitat quality, reinforcing calls to consider species composition in assessments of forest disturbance. Taken together, our results reveal the unique biodiversity value of undisturbed primary forests, but also show that disturbed primary forests and secondary forests have high conservation value, and thus play an important role in regional conservation planning.Item Methodological remarks on rearing basal Attini ants in the laboratory for biological and evolutionary studies: overview of the genus Mycetophylax(Insectes Sociaux, 2011-03-29) Cardoso, D. C.; Cristiano, M. P.; Tavares, M. G.Some studies require fresh biological material for their development. Ant colonies have been reared under laboratory conditions for scientific purposes, and several methodologies for leafcutter ants have been reported in the literature. However, these methods are not well adapted for rearing basal Attini. In this study, we proposed a methodology for rearing basal Attini species in the laboratory based on the evaluation of colonies of the genus Mycetophylax. The complete system consists of two round translucent polypropylene containers inserted one inside the other, where one serves as a chamber proper and the other as a foraging area. Both containers are sealed with their lids, protecting the environment against desiccation. From a total of 29 colonies collected in the field, 22 colonies survived for at least 30 weeks, and Mycetophylax morschi was the most adapted for rearing under laboratory conditions. The main problem with rearing basal Attini in the laboratory is the loss of moisture. Thus, the method applied here may be adopted for rearing other basal Attini, as well as other ant species very sensitive to moisture variation.