Fungos melanizados associados a formigas cortadeiras (Formicidae: Tribo Attini)

Leafcutter ants are considered pests in agriculture for their impact in human crops, as they behave utilizing foliar fragments to raise their simbiont fungi (Agaricales: Lepiotaceae) inside their nest. Recent studies have noticed that other fungi may be associated to ants inside their nests, for instance, fungi with melanized wall, known by “dematiaceous”. Historically, many black fungi have been noticed as fitopathogens of many plant cultures with economic importance, highlighting dematiaceous ecological behavior importance in this study. This investigation had the purpose of amplifying ecological knowledge of this fungi, isolating and identificating dematiaceous fungi found in Attini nests, having the intention of understanding plant pathogens dispersion by ants. In this work, 66 isolates were characterized in the following genus: Aspergillus, Penicillium, Paecilomyces, Oxyporus, Rhodotorula, Bipolaris, Curvularia, Fusarium, Giberella, Paraphaeosphaeria, and Cladosporium. The genus Bipolaris, Curvularia, Fusarium and Giberella are known for their opportunistic behaviour, with some published human infections in literature. Fusarium is a notorious fitopathogen, with wide number of descriptions and studies involving pathogenicity development, biochemistry and genetics. The isolates outline is of phyto – associated (phytopathogens, endophytic or epiphitic), fulfilling this work intention in alarming fungi capacity of dispersal by ants. The comprehension of phytopathogenical processes may be clarified based on the knowledge of oportunistics fungi that may utilize ants bodies for their own dispersal. The identification of isolates with capacity of infecting humans brings out public health issues.

Associação entre mesoplasma sp e formigas da tribo Attini (Hymenoptera, formicidae)

As formigas da tribo Attini apresentam reconhecida simbiose com microrganismos: fungos mutualistas basidiomicetos nas famílias Lepiotaceae e Pterulaceae cultivados pelas formigas, bactérias actinomicetas ou no gênero Burkholderia produtoras de antibióticos contra fungos entomopatogênicos, fungos ascomicetos do gênero Escovopsis micófagos para o mutualista, e comensais como fungos, leveduras e bactérias que degradam celulose. Um novo mutualista é descrito no presente trabalho: uma espécie de bactéria no gênero Mesoplasma, detectada via PCR para 16S no DNA genômico de Attini derivadas (gêneros Acromyrmex, Atta, Serycomyrmex e Cyphomyrmex), intermediárias (Trachymyrmex) e basais (Apterostigma, Mycetarotes, Mycocepurus e Mycetagroicos). Uma única linhagem de Mesoplasma com baixíssima diversidade 16S esteve presente nas Attini, mas não em formigas de tribos filogeneticamente próximas a Attini, como Dolichoderini (Tapinoma sp), Camponotini (Camponotus sp), Cephalotini (Cephalotes sp), Crematogastrini (Crematogaster sp), Pheidolini (Pheidole sp) e Ponerini (Pachycondyla sp), indicando uma simbiose Mesoplasma-Attini recente e específica.

Sistemática e filogenia do fungo parasita Escovopsis associado às formigas Attini

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Caracterização transcriptômica de vias metabólicas na formiga Attini Atta sexdens rubropilosa Forel, 1908 (Hymenoptera, Formicidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Revision of the fungus-growing ant genera Mycetophylax Emery and Paramycetophylax Kusnezov rev. stat., and description of Kalathomyrmex n. gen. (Formicidae: Myrmicinae: Attini)

Based on the morphology of workers, gynes and males, we revise the taxonomy of nominal taxa traditionally included by authors in the fungus-growing ant genus Mycetophylax. Our results indicate that Mycetophylax Emery (Myrmicocrypta brittoni Wheeler, 1907, type species, by designation of Emery, 1913; junior synonym of Cyphomyrmex conformis Mayr, 1884 by Kempf, 1962) includes M. conformis, M. simplex (Emery, 1888), and M. morschi (Emery, 1888) new combination (formerly in Cyphomyrmex), with several synonymies. Mycetophylax bruchi (Santschi, 1916) does not belong to the same genus and is diagnosed, in addition to other characters, by a psammophore arising at the anterior margin of the clypeus. For this species we are resurrecting from synonymy Paramycetophylax Kusnezov, 1956 (Mycetophylax bruchi as type species, by original designation, with M. cristulatus as its new synonym). Myrmicocrypta emeryi Forel, 1907 is the only attine in which females lack the median clypeal seta and have the antennal insertion areas very much enlarged and anteriorly produced, with the psammophore setae arising from the middle of the clypeus and not at its anterior margin as in Paramycetophylax. Notwithstanding its inclusion in Mycetophylax by recent authors, it is here recognized as belonging to a hitherto undescribed, thus far monotypic genus, Kalathomyrmex new genus (Myrmicocrypta emeryi as its type species, here designated). We redescribe workers, gynes and males of all species in the three genera and describe for the first time gynes of Mycetophylax conformis and M. simplex, males of M. simplex and M. morschi, and gynes of P. bruchi. Furthermore we present a key to the workers of the taxa treated here (most formerly included under the name Mycetophylax), a key to workers of the Mycetophylax in the revised sense, SEM pictures and high resolution AutoMontage(C) photographs of the species, along with maps of collection records and a summary of biological observations.

Parabiosis between basal fungus-growing ants (Formicidae, Attini)

We describe the first observation of parabiosis between two Attini ants (Apterostigma urichii Forel and Cyphomyrmex faunulus Wheeler) found in northern Manaus, AM, Brazil. Complete, mature colonies of both species were found in a single cavity inside a rotten log, sharing and tending a single combined fungus garden, made up of two distinct halves, each cultivated by one species. Workers of one species often antennated workers of the other species and showed no aggression toward each other or toward each other`s workers, queens, or immatures. Laboratory observations suggest that immatures of both species feed on hyphae from either half of the fungus garden. We were not able to find other parabiotic pairs involving the same species in the same locality, although we found colonies of both species sharing trails and foraging territories.

Nesting biology of the fungus growing ants Mycetarotes Emery (Attini, Formicidae)

Fungus-growing ants of the genus Mycetarotes are among the least studied in the tribe Attini. This report documents nest architecture and worker population numbers for 19 nests of M. parallelus and 5 nests of M. acutus, including the first such report for M. acutus. This new information is integrated with the scant biological information reported on Mycetarotes to date. The resulting picture of Mycetarotes life history, as well as the relative ease with which large numbers of nests can be collected and observed in the field, suggest that Mycetarotes (particularly M. parallelus) is an ideal model system for the study of coevolution of lower-attine ants and their cultivated fungi.

Trophallaxis in Dehydrated Leaf Cutting Colonies of Atta sexdens rubropilosa (Hymenoptera: Formicidae)

Trophallaxis, the transfer of liquid among individuals by oral regurgitation or anal deposition, occurs in many insect groups including ants. The first indication that trophallaxis could occur in leaf cutting ants (Atta sexdens rubropilosa) was made by Autuori in 1942. He reported water collection by this ant species, and highlighted what in those days was an undescribed behavior for this species. In 2005, Da-Silva and Ribeiro presented preliminary results suggesting the existence of trophallaxis in A. sexdens rubropilosa. Here we report on a formal test of the hypothesis of trophallaxis in that species. Our approach was to test ant pairs in which only one individual (Group I) had access to blue-dyed water and the other individual (Group II), a nest-mate, came from a colony dehydrated by offering dry crushed corn for fungal growth. Positive results for trophallaxis were obtained in ants from four colonies and accounted for 33%-46% of all tests in which ants from Group I drank dyed water. These results indicate that trophallaxis occurs in this species.

Preliminary studies on the effects of d-limonene to workers of the leaf-cutting ant Atta sexdens rubropilosa and its implications for control

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Behavioral Repertoire of Basal Fungus-Growing Ant Sexuals (Hymenoptera: Formicidae) in the Parental Nest

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Susceptibility of the ant-cultivated fungus Leucoagaricus gongylophorus (Agaricales : Basidiomycota) towards microfungi

The aim of this study was to select virulent strains of microfungi against Leucoagaricus gongylophorus, a symbiotic fungus cultivated by leaf-cutting ants. The results from in vitro assays showed that microfungal strains had a variable and significant impact on the colony development of L. gongylophorus. Specifically, Trichoderma harzianum, Escovopsis weberi CBS 810.71 and E. weberi A088 were more effective, inhibiting the L. gongylophorus colonies by 75, 68 and 67%, respectively (P < 0.05) after 15 days. Strain E. weberi A086 and Acremonium kiliense were less effective: 43 and 26%, respectively (P < 0.05). In spite of the current negative perspective of a microbiological control approach for these ants, the present work discusses the possibility of using mycopathogenic fungi for the control of these insects, and points out the importance of encouraging more studies in this area.

Yeasts isolated from a fungus-growing ant nest, including the description of Trichosporon chiarellii sp nov., an anamorphic basidiomycetous yeast

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Growth of the Symbiotic Fungus of the Grass-cutting Ant Atta capiguara (Hymenoptera: Formicidae): Effect of Grass Extracts

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

Microscopic evidence supports the hypothesis of high cellulose degradation capacity by the symbiotic fungus of leaf-cutting ants

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Differentiation in Selection of Dicots and Grasses by the Leaf-Cutter Ants Atta capiguara, Atta laevigata and Atta sexdens rubropilosa

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