Itabuna, Brazil
Itabuna, Brazil

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Rey O.,Montpellier SupAgro | Loiseau A.,Montpellier SupAgro | Facon B.,Montpellier SupAgro | Foucaud J.,Montpellier SupAgro | And 11 more authors.
Molecular Biology and Evolution | Year: 2011

The little fire ant, Wasmannia auropunctata, displays a peculiar breeding system polymorphism. Classical haplo-diploid sexual reproduction between reproductive individuals occurs in some populations, whereas, in others, queens and males reproduce clonally. Workers are produced sexually and are sterile in both clonal and sexual populations. The evolutionary fate of the clonal lineages depends strongly on the underlying mechanisms allowing reproductive individuals to transmit their genomes to subsequent generations. We used several queen-offspring data sets to estimate the rate of transition from heterozygosity to homozygosity associated with recombination events at 33 microsatellite loci in thelytokous parthenogenetic queen lineages and compared these rates with theoretical expectations under various parthenogenesis mechanisms. We then used sexually produced worker families to define linkage groups for these 33 loci and to compare meiotic recombination rates in sexual and parthenogenetic queens. Our results demonstrate that queens from clonal populations reproduce by automictic parthenogenesis with central fusion. These same parthenogenetic queens produce normally segregating meiotic oocytes for workers, which display much lower rates of recombination (by a factor of 45) than workers produced by sexual queens. These low recombination rates also concern the parthenogenetic production of queen offspring, as indicated by the very low rates of transition from heterozygosity to homozygosity observed (from 0% to 2.8%). We suggest that the combination of automixis with central fusion and a major decrease in recombination rates allows clonal queens to benefit from thelytoky while avoiding the potential inbreeding depression resulting from the loss of heterozygosity during automixis. In sterile workers, the strong decrease of recombination rates may also facilitate the conservation over time of some coadapted allelic interactions within chromosomes that might confer an adaptive advantage in habitats disturbed by human activity, where clonal populations of W. auropunctata are mostly found. © 2011 The Author.


Martins L.C.B.,State University of Maranhão | Della Lucia T.M.C.,Federal University of Viçosa | Goncalves W.G.,Laboratorio Of Mirmecologia | Delabie J.H.C.,Laboratorio Of Mirmecologia | And 2 more authors.
Microscopy Research and Technique | Year: 2015

Intramandibular glands have been poorly studied in polymorphic ants, where the differences between castes were unsufficiently scrutinized. Leaf-cutting ants possess one of the most complex systems of communication and labor division, which is polymorphic well as age polyethism, and makes them an ideal model for the study of intramandibular glands. This study has investigated the occurrence of intramandibular glands in female castes and subcastes of Atta laevigata. The mandibles of the queen, medium, and minor workers, and soldiers were submitted to histological, histochemical, ultrastructural, and morphometric analyses. The class-3 gland cells and the epidermal gland with a reservoir were found in all the castes. The queens and soldiers showed a higher number of class-3 gland cells, distributed within the mandible as well as a greater gland size in comparison to the workers. The histochemical tests, periodic acid-Schiff (PAS), mercury-bromophenol, and Nile blue, were similar for the class-3 gland cells and epidermal glands with a reservoir. However, the tests evidenced differences between the castes, with carbohydrates strongly positive in all of them, whereas neutral lipids were found in the queen and soldiers. The protein was weakly positive in the queen, whereas in the soldier, medium, and minor workers these reactions were strongly positive in the intramandibular glands. Our findings in A. laevigata suggest that intramandibular glands are directly involved in labor division and consequently in chemical communication between the castes. © 2015 Wiley Periodicals, Inc.


Martins L.C.B.,State University of Maranhão | Delabie J.H.C.,Laboratorio Of Mirmecologia | Serrao J.E.,Federal University of Viçosa
Tropical Zoology | Year: 2016

In social insects, secretions of the exocrine gland may modulate their behavior. Although many glands have their functions elucidated, this is absent for the intramandibular glands in ants. To study the function of intramandibular gland secretions in the ant Neoponera villosa, its compounds were subjected to behavioral analyses. These analyses revealed a significant increase in the walking time of ants exposed to the nestmate mandible extract. The results suggest that intramandibular gland compounds of N. villosa may play the role of alarm or scent trial pheromones. © 2016 Istituto per lo Studio degli Ecosistemi of the Consiglio Nazionale delle Ricerche, Firenze


Barros L.A.C.,Federal University of Viçosa | Mariano C.S.F.,Laboratorio Of Mirmecologia | Mariano C.S.F.,University Estadual Of Santa Cruz | Pompolo S.G.,Federal University of Viçosa
Caryologia | Year: 2013

Cytogenetic studies have been carried out on more than 750 ant taxa and are an important tool in evolutionary, taxonomic and phylogenetic studies. However, less than 10% of the species reported in the tribe Attini have been studied. The aim of the present study was to describe the chromosomes of five attine ants collected in Viçosa, Minas Gerais state, Brazil, at present unknown. The ant karyotypes reported are: Sericomyrmex sp. (2n = 50, 44m + 6sm, n = 25, 22m + 3sm); Trachymyrmex relictus (2n = 20m); Trachymyrmex sp. (2n = 22, 18m + 4sm); Apterostigma madidiense (n = 23, 7m + 10sm + 5st + 1a) and Apterostigma steigeri (2n = 22, 20m + 2sm). C-banding showed that heterochromatin was present in the centromeric region of all chromosomes of T. relictus. Future cytogenetic studies on members of the tribe Attini will provide important information to discuss chromosome evolution in this ant group. © 2013 Copyright Dipartimento di Biologia Evoluzionistica, Università di Firenze.


Azevedo D.O.,Federal University of Viçosa | Zanuncio J.C.,Federal University of Viçosa | Delabie J.H.C.,Laboratorio Of Mirmecologia | Serrao J.E.,Federal University of Viçosa
Journal of Insect Physiology | Year: 2011

Workers of the ant species Ectatomma tuberculatum (Ectatomminae) have active ovaries and lay eggs that are eaten by the queen and larvae (trophic eggs). Vitellogenins are the main proteins found in the eggs of insects and are a source of nutrients. The aim of this study was to characterize the period of vitellogenin production in workers of E. tuberculatum. The vitellogenin was identified from queen and worker eggs by SDS-PAGE. Anti-vitellogenin antibodies were obtained and used to detect this protein in the fat body and haemolymph of workers at different ages. Vitellogenin from E. tuberculatum consists of two polypeptides of 31 and 156. kDa. In the eggs of queens, the 156. kDa polypeptide is cleaved into two subunits of 36 and 123. kDa. The analysis of the haemolymph of workers showed that the secretion of vitellogenin varies with age. The secretion is initiated around the fifth day after emergence, with peak production from days 20 to 60, and stops around day 100. The variation in production is related to the different activities performed by the workers within the colony, suggesting that vitellogenin may have an important role in maintaining age polyethism. © 2011 Elsevier Ltd.


PubMed | Laboratorio Of Mirmecologia, Federal University of Espirito Santo, Federal University of Viçosa and Federal University of Amapá
Type: Comparative Study | Journal: Comptes rendus biologies | Year: 2015

The karyotype of the threatened ant species Atta robusta is described so as to establish the evolutionary relationships of this taxon with other leafcutter ants. Standard Giemsa staining, C-banding, NOR banding, fluorochromes CMA3/DAPI, Hsc-FA technique and Fluorescence in situ Hybridization (FISH) using 18S rDNA probe were conducted on a population from Aracruz, state of Esprito Santo, Brazil, allowing for comparisons with data available on Atta and other fungus-growing ant species. The diploid chromosome number observed for A.robusta was 2n=22, and the karyotypic formula was 18m+2sm+2st. Heterochromatic blocks were observed in the centromeric region of most chromosomes, where one pair of metacentric chromosomes is characterized by a GC-rich heterochromatic band in the interstitial region of its long arm. The detection of 18S rDNA using FISH confirmed the presence of single NOR for A.robusta. This is the first report of rDNA 18S detection using FISH for leafcutter ants. The cytogenetic results of this study confirm the information available for Atta and allow us to confirm the conserved chromosome number, morphology and banding pattern within the genus for the taxa studied to date, which included species from three out of the four groups of Atta indicated by molecular data. The accumulation of cytogenetic data on fungus-growing ants enhances the understanding of the genomic evolutionary patterns of Atta, since it belongs to a group of recent origin between the most well studied ants. Cytogenetic data does not indicate restrictions in relocation or reintroduction in areas where populations were extinct due to the conserved karyotype. This study allows for cytogenetic comparison of A.robusta with other ants of Atta, emphasizing the importance of chromosomal information for species conservation.


Guerrero R.J.,University of Magdalena | Guerrero R.J.,Central University of Venezuela | Delabie J.H.C.,Laboratorio Of Mirmecologia | Dejean A.,French National Center for Scientific Research
Journal of Hymenoptera Research | Year: 2010

We describe five new species in the aurita group of the genus Azteca: Azteca andreae sp. n. (French Guiana), Azteca diabolica sp. n. (Panama), Azteca laurae sp. n. (Brazil), Azteca linamariae sp. n. (Brazil and Colombia) and Azteca snellingi sp. n. (Panama). Four of these new species are based on gynes, while the last is based only on the worker caste. All of them bear the aurita group characteristics. The second taxon is remarkable, as it differs from all of the other members of the group in the exaggerated, horn-like extensions of the posterolateral vertex margins. Azteca snellingi sp. n. is named in honor of our colleague, Roy Snelling, in tribute to his life-long contribution to knowledge of the world of Hymenoptera. A key to all known species of the aurita group, based on gynes, is provided. We report also for the first time an intercast case for the genus Azteca, based on an Azteca schimperi specimen.


Lopes D.T.,Servidao Reduzino Vergilino Teixeira | Lopes J.,State University Londrina | do Nascimento I.C.,State University of Southwest Bahia | Delabie J.H.,Laboratorio Of Mirmecologia
Iheringia - Serie Zoologia | Year: 2010

Considering the poor knowledge about the ant fauna of the state of Paraná, Brazil, this study aimed to compare the ant assemblages in three environments (primary forest, reforested area and secondary growth forest) of Mata dos Godoy State Park, municipality of Londrina. This study was carried out between December 2004 and March 2005. Ant collections were made using sardine baits and pitfall traps. We collected 102 ant species belonging to 38 genera of nine subfamilies. Myrmicinae was the richest subfamily (58 spp.) followed by Formicinae (20 spp.), Ponerinae (9 spp.), Ectatomminae, Heteroponerinae, Ecitoninae and Pseudomyrmecinae (3 species each), Dolichoderinae (2 spp.) and Proceratiinae (1 specie). The richest genera were Pheidole Westwood, 1839 and Camponotus Mayr, 1861, respectively with 14 and 11 species. The primary forest showed the highest richness values, number of exclusive species and diversity (92 spp., 20 spp. and H′ = 3.51, respectively), followed by the reforestation area (73 spp., 6 spp. And H′ = 3.47) and the secondary growth forest (67 spp., 4 spp. and H′= 3.34). The similarity values between the three environments were rather high. In each sample series, the observed richness was between 33 and 53 species and the estimated richness was between 35 and 86 species. The occurrence of seven guilds of ants was defined: omnivore species, specialist predators, generalist predator litter, armyants, vegetation dominant, soil dominant and fungus growers.


Nakano M.A.,Laboratorio Of Mirmecologia | Miranda V.F.,São Paulo State University | Feistosa R.M.,Federal University of Paraná | Morini M.S.C.,Laboratorio Of Mirmecologia
Sociobiology | Year: 2014

Arboreal ants of the genus Myrmelachista, which have ecologically important relationships with different vegetable species, are found exclusively in the Neotropical region. These ant species are difficult to identify, and their taxonomy remains controversial; moreover, little is known regarding their biology. The objective of the present work is to assess the genetic similarities and dissimilarities between and within Myrmelachista species, with the goal of expanding knowledge of the relationships among the taxa of this genus. Sample collection in selected regions of the dense ombrophile forest of southeastern Brazil yielded 256 nests, which were found in vegetation or among scattered twigs in the leaf litter; eight species were recorded. A total of 180 specimens were analyzed, producing 123 polymorphic fragments. Data analyses revealed similarity relationships that allowed the examined species to be classified into the following groups: (1) Myrmelachista sp. 4, M. nodigera, M. ruszkii and M. gallicola; (2) M. catharinae and M. arthuri; (3) M. reticulata; and (4) Myrmelachista sp. 7. The study results also revealed the existence of two morphological variants of M. catharinae; M. arthuri was more closely related to one of these M. catharinae variants than to the other variant. The present work provides important information regarding genetic variation among Myrmelachista species that may contribute to interpreting the complex morphology of this genus.


Neves F.S.,State University of Montes Claros | Neves F.S.,Federal University of Minas Gerais | Braga R.F.,Federal University of Lavras | Do EspiritoSanto M.M.,State University of Montes Claros | And 3 more authors.
Sociobiology | Year: 2010

In tropical systems, habitat heterogeneity and resource availability have been reported as important factors driving ant species richness and composition. For this reason, these variables have been widely used as indicators of forest disturbance. The aim of this study was to compare the composition and richness of arboreal ants between the dry and wet seasons in three successional stages of a tropical dry forest at the Parque Estadual da Mata Seca, northern Minas Gerais state, Brazil. Ant sampling was performed in 15 plots in three different forest secondary stages: early, intermediate and late. Ants were sampled during the wet and dry seasons, using five pitfall traps per plot. We collected 43 ant species, distributed in 19 genera. Our results indicated a change on ant species composition along the successional gradient (p < 0.05). However, ant species richness did not differ between stages and seasons (p > 0.05) and was not affected by the variables used here as surrogates to habitat heterogeneity (tree richness) and resource availability (tree density) (p > 0.05). Ant composition did not change significantly between the dry and wet seasons for the early successional stage, but plots from the intermediate and late stages were clearly segregated according to seasons. We suggest that it is likely that 25 years of forest regeneration are enough to restore most of the arboreal ant communities in tropical dry forests, strengthening the importance of secondary habitats to biodiversity maintenance.

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