Browsing by Author "Cardoso, Danon Clemes"
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Item Agro-predation by Megalomyrmex ants on Mycetophylax fungusgrowing ants.(2016) Cardoso, Danon Clemes; Cristiano, Maykon Passos; Milanez, Cinthia Borges da Costa; Heinze, JürgenFungus-growing ants are a remarkable taxon of New World ants that engage in a mutualistic symbiosis with basidiomycete fungi. Their fungus-gardens are valuable resources and are exploited in countless ways by parasites and other beneficiaries outside of the ant-fungi mutualism. Here, for the first time, we report on the agro-predatory behavior of the ant Megalomyrmex incisus on Mycetophylax conformis and Mycetophylax morschi fungus-growers from sand dunes near Ilhe´us, Brazil. Me. incisus workers raided colonies of My. conformis and My. morschi and aggressively antennated, pulled, bit, and stung the fungus-growers, which played dead or retreated on the fungus. Me.incisus quickly usurped the fungusgarden and expelled all Mycetophylax workers. The usurpation closely resembled that described for raids of Me. wettereri on Cyphomyrmex longiscapus, in that the fungus-growers remained passive and avoided confrontation. This passive behavior suggests that Me. incisus uses chemical weapons that facilitate the exploitation of the host colony resources.Item Amoimyrmex Cristiano, Cardoso & Sandoval, gen. nov. (Hymenoptera: formicidae) : a new genus of leaf‐cutting ants revealed by multilocus molecular phylogenetic and morphological analyses.(2020) Cristiano, Maykon Passos; Cardoso, Danon Clemes; Sandoval Gómez, Vivian Eliana; Gomes, Flávia Carolina SimõesLeaf‐cutting ants (genera Acromyrmex and Atta) are the most important herbivores in the Neotropical region. Within the genus Acromyrmex, the species and subspecies Acromyrmex striatus, Acromyrmex silvestrii subsp. silvestrii and Acromyrmex silvestriisubsp. bruchi are morphologically similar to one another but differ from the rest of their congeners. Recent studies have suggested that Ac. striatus belongs to a currently undescribed leaf‐cutting ant genus. Herein, we propose a new phylogenetic hypothesis for leaf‐cutting ants based on five nuclear genes (wg, LW Rh, EF1αF1, EF1αF2 and Top1) and describe a new genus. We used colonies of Ac. striatus, Ac. silvestrii silvestrii and Ac. silvestrii bruchi collected from Brazil, Argentina, Uruguay and Bolivia, covering most of their known distribution. We constructed a molecular phylogenetic hypothesis for these three taxa using sequences from the mtDNA COI gene. The retrieved phylogenetic tree reveals that Ac. striatus, Ac. silvestrii silvestrii and Ac. silvestrii bruchi form a well‐supported clade (P.P. = 1). Through analyses of molecular phylogenetic and morphological data, we propose a new genus of leaf‐cutting ant, Amoimyrmex Cristiano, Cardoso & Sandoval, gen. nov., redescribe the species Amoimyrmex striatus (Roger, 1863) comb. nov. and Amoimyrmex silvestrii (Emery, 1905) comb. nov., and elevate Ac. silvestrii bruchi to the level of species as Amoimyrmex bruchi (Forel, 1912) comb. nov. et stat. rev.. We also provide information on the geographic distribution of Amoimyrmex, an illustrated identification key for its taxa and descriptions of all the known castes of each species, including diagnostic characteristics, high‐quality images and distribution maps. We believe that the results of this study contribute substantially to taxonomic knowledge of leaf‐cutting ants and reaffirm the complex evolutionary history of the group.Item Análise da resistência térmica e diversidade da comunidade de borboletas frugívoras.(2019) Silva, Vanessa Diniz e; Cardoso, Danon Clemes; Beirão, Marina do Vale; Cardoso, Danon Clemes; Cornelissen, Tatiana Garabini; Cordeiro, Marco Antônio AlvesCondições ambientais como temperatura, umidade do ar e disponibilidade de recursos, são condições que limitam os organismos aos habitats em que vivem, direcionando sua distribuição. Borboletas frugívoras são organismos dependentes das condições ambientais de seu habitat, por isso são sensíveis a qualquer variação nas condições abióticas. Assim, considerando as mudanças climáticas e seu efeito na temperatura média anual, as borboletas podem ser úteis no monitoramento das alterações ambientais. Testamos a composição e a diversidade das borboletas frugívoras presentes em dois ambientes contrastantes. Foram amostradas 50 espécies em indivíduos onde a abundância e a riqueza de espécies não diferiram entre os habitats. A composição das espécies entre os habitats diferiu, esse fato pode ocorrer devido aos recursos vegetais disponíveis nos habitats. A distribuição das borboletas apresenta variação na diversidade temporal, e essa dissimilaridade ocorreu principalmente pela substituição de espécies. Os meses chuvosos são os meses mais abundantes e ricos, apresentando os meses de outubro e novembro como os meses de maior concentração de espécies. Esse fato pode ser explicado pelo aumento da produção de folhas e frutos devido ao aumento da precipitação. Ao analisar a diversidade das espécies de borboletas em diferentes habitats, nosso estudo abrange mais áreas e amostra maior número de espécies, contribuindo de forma mais completa para o conhecimento da comunidade local.Item "Baralho mutante” para o ensino das alterações cromossômicas numéricas Aneuploidias.(2018) Degrandi, Tiago Marafiga; Cordeiro, Alessandro Lick; Soares, Amanda de Araújo; Cardoso, Danon Clemes; Hass, IrisItem Caracterização do nicho térmico em comunidades de formigas de restinga.(2021) Guimarães, Pedro Henrique; Cardoso, Danon Clemes; Sobrinho, Tathiana Guerra; Cristiano, Maykon Passos; Cardoso, Danon Clemes; Moura, Mariana Neves; Carneiro, Marco Antonio AlvesA corrente teoria de nicho ecológico o define como o resumo das tolerâncias de necessidades de um organismo, onde essas são as dimensões por onde a ocorrência de um ser vivo é restringida. Dentre as dimensões que podem ser particionadas, a temperatura se constitui como uma das mais importantes, pois está na base dos processos de distribuição dos seres vivos. Tendo como base o aumento das médias globais de temperatura previsto para os próximos anos, os ambientes tropicais podem possuir maior vulnerabilidade, pois, considerando que são ambientes quentes e poucos sazonais, as comunidades biológicas vivendo nesses lugares tendem a apresentar nichos térmicos estreitos, segundo a hipótese de adaptação térmica. Pelo fato das restingas estarem inseridas em ambientes costeiros, sob forte tensores ambientais como a temperatura, elas se apresentam como excelentes ambientes para estudos desse tipo. Além disso, apresentam diversas comunidades de formigas, as quais são organismos que demonstram grande influência térmica na estruturação de suas comunidades. O presente estudo buscou elucidar os padrões térmicos da comunidade de formigas estudada através da construção de modelos de nicho térmico, com base em padrões de ocorrências. Construímos dois transectos de armadilhas de ‘pitfalls’ epigéicos ao longo de um gradiente de vegetação, um localizado nas dunas frontais e o segundo na fisionomia floresta de restinga, com temperatura e umidade sendo medidas durante um período de 24h. A cada três horas os ‘pitfalls’ eram trocados, totalizando, ao final de um dia, oito trocas. O processo foi repetido em três áreas diferentes, separadas por 500m umas das outras. A comunidade de formigas apresentou uma segregação temporal, que se projetou homogeneamente entre as fitofisionomias estudadas, formando um grupo de espécies majoritariamente diurno, e um outro majoritariamente noturno. Além disso, abundância e frequência foram significativamente maiores nos períodos quentes, evidenciando que a temperatura está intimamente ligada ao nível de atividade das formigas.Item Chromosomal dynamics in space and time : evolutionary history of Mycetophylax ants across past climatic changes in the Brazilian Atlantic coast.(2019) Micolino, Ricardo; Cristiano, Maykon Passos; Travenzoli, Natália Martins; Lopes, Denilce Meneses; Cardoso, Danon ClemesFungus-farming ants of the genus Mycetophylax exhibit intra and interspecific chromosome variability, which makes them suitable for testing hypotheses about possible chromosomal rearrangements that endure lineage diversification. We combined cytogenetic and molecular data from Mycetophylax populations from coastal environments to trace the evolutionary history of the clade in light of chromosomal changes under a historical and geographic context. Our cytogenetic analyses revealed chromosomal differences within and among species. M. morschi exhibited three distinct karyotypes and considerable variability in the localization of 45S rDNA clusters. The molecular phylogeny was congruent with our cytogenetic findings. Biogeographical and divergence time dating analyses estimated that the most recent common ancestor of Mycetophylax would have originated at about 30 Ma in an area including the Amazon and Southern Grasslands, and several dispersion and vicariance events may have occurred before the colonization of the Brazilian Atlantic coast. Diversification of the psammophilous Mycetophylax first took place in the Middle Miocene (ca. 18–10 Ma) in the South Atlantic coast, while “M. morschi” lineages diversified during the Pliocene-Pleistocene transition (ca. 3–2 Ma) through founder-event dispersal for the Northern coastal regions. Psammophilous Mycetophylax diversification fits into the major global climatic events that have had a direct impact on the changes in sea level as well as deep ecological impact throughout South America. We assume therefore that putative chromosomal rearrangements correlated with increased ecological stress during the past climatic transitions could have intensified and/or accompanied the divergence of the psammophilous Mycetophylax. We further reiterate that “M. morschi” comprises a complex of at least three well-defined lineages, and we emphasize the role of this integrative approach for the identification and delimitation of evolutionary lineages.Item Chromosomal variation among populations of a fungus-farming ant: implications for karyotype evolution and potential restriction to gene flow.(2018) Cardoso, Danon Clemes; Heinze, Jürgen; Moura, Mariana Neves; Cristiano, Maykon PassosBackground: Intraspecific variation in chromosome structure may cause genetic incompatibilities and thus provides the first step in the formation of species. In ants, chromosome number varies tremendously from 2n = 2 to 2n = 120, and several studies have revealed considerable variation in karyotype within species. However, most previous studies were limited to the description of chromosome number and morphology, and more detailed karyomorphometric analyses may reveal additional, substantial variation. Here, we studied karyotype length, genome size, and phylogeography of five populations of the fungus-farming ant Trachymyrmex holmgreni in order to detect potential barriers to gene flow. Results: Chromosome number and morphology did not vary among the five populations, but karyotype length and genome size were significantly higher in the southernmost populations than in the northern populations of this ant. Individuals or colonies with different karyotype lengths were not observed. Karyotype length variation appears to result from variation in centromere length. Conclusion: T. holmgreni shows considerable variation in karyotype length and might provide a second example of centromere drive in ants, similar to what has previously been observed in Solenopsis fire ants. Whether this variation leads to genetic incompatibilities between the different populations remains to be studied.Item Comparative FISH-mapping of TTAGG telomeric sequences to the chromosomes of leafcutter ants (Formicidae, Myrmicinae) : is the insect canonical sequence conserved?(2020) Castro, Carini Picardi Morais de; Cardoso, Danon Clemes; Micolino, Ricardo; Cristiano, Maykon PassosTelomeric sequences are conserved across species. The most common sequence reported among insects is (TTAGG)n , but its universal occurrence is not a consensus because other canonical motifs have been reported. In the present study, we used fluorescence in situ hybridization (FISH) using telomeric probes with (TTAGG)6 repeats to describe the telomere composition of leafcutter ants. We performed the molecular cytogenetic characterization of six Acromyrmex Mayr, 1865 and one Atta Fabricius, 1804 species (Acromyrmex ambiguus (Emery, 1888), Ac. crassispinus (Forel, 1909), Ac. lundii (Guérin-Mèneville, 1838), Ac. nigrosetosus (Forel, 1908), Ac. rugosus (Smith, 1858), Ac. subterraneus subterraneus (Forel, 1893), and Atta sexdens (Linnaeus, 1758)) and described it using a karyomorphometric approach on their chromosomes. The diploid chromosome number 2n = 38 was found in all Acromyrmex species, and the karyotypic formulas were as follows: Ac. ambiguus 2K = 14M + 12SM + 8ST + 4A, Ac. crassispinus 2K = 12M + 20SM + 4ST + 2A, Ac. lundii 2K = 10M + 14SM + 10ST + 4A, Ac. nigrosetosus 2K = 12M + 14SM + 10ST + 2A, and Ac. subterraneus subterraneus 2K = 14M + 18SM + 4ST + 2A. The exact karyotypic formula was not established for Ac. rugosus. FISH analyses revealed the telomeric regions in all the chromosomes of the species studied in the present work were marked by the (TTAGG)6 sequence. These results reinforce the premise that Formicidae presents high homology between their genera for the presence of the canonical sequence (TTAGG)n.Item Could pseudogenes be widespread in ants? Evidence of numts in the leafcutter ant Acromyrmex striatus (Roger, 1863) (Formicidae: Attini).(2014) Cristiano, Maykon Passos; Cardoso, Danon Clemes; Salomão, Tânia Maria FernandesThe incorporation of fragments of mitochondrial DNA (mtDNA) in the nuclear genome, known as numts (nuclear mitochondrial pseudogenes), undermines general assumptions concerning the use of mtDNA in phylogenetic and phylogeographic studies. Accidental amplifications of these nuclear copies instead of the mitochondrial target can lead to crucial misinterpretations, thus the correct identification of numts and their differentiation from true mitochondrial sequences are important in preventing this kind of error. Our goal was to describe the existence of cytochrome b (cytb) numts in the leafcutter ant Acromyrmex striatus (Roger, 1863). PCR products were directly sequenced using a pair of universal primers designed to amplify the cytb gene of these insects. Other species of leafcutter ants were also sequenced. The sequences were analyzed and the numts were identified by the presence of double peaks, indels and premature stop codons. Only A. striatus clearly showed the presence of numts, while the other species displayed the expected amplification of the mtDNA cytb gene target using the same primer pair. We hope that our report will highlight the benefits and challenges of using mtDNA in the molecular phylogenetic reconstruction and phylogeographic studies of ants, while establishing the importance of numts reports for future studies.Item Could soil granulometry and permeability drive the occurrence of the dune‐dwelling ants from the genus Mycetophylax?(2021) Cardoso, Danon Clemes; Cristiano, Maykon Passos; Silva, Ana Beatriz Borges da; Carneiro, Marco Antonio AlvesSpecies distribution can be infuenced by several biotic and abiotic factors. Physical soil properties, such as granulometry and permeability, can, therefore, be key determinant factors of the occurrence of ground-dwelling species. Here, we evaluate whether the physical properties of soil, such as granulometry and the resulting soil permeability, could drive nesting occur- rence of the endemic psammophilous ants from the genus Mycetophylax and, in turn, their distribution. To accomplish this goal, we tested the hypothesis that variations in the granulometry and the resulting permeability (high or low D10 values) of beach soils contribute to explain the distribution pattern of dune endemic species from the genus Mycetophylax. We sampled sand soils from 26 beaches across the known distribution of the species along the Brazilian Atlantic coast. Sorting through seven mesh sieves, we determined the proportion of sand grain size of each sample and then calculated the efective diameter (D10). Therefore, we investigated the occurrence of the three ant species in relation to the soil permeability determined by D10. The spatial variation in sand grain size and its permeability across the beaches of the Atlantic coast is likely one of the contributors that infuence the pattern of distribution of psammophilous ants such as Mycetophylax simplex, M. conformis, and M. morschi.Item Cytogenetic analysis and chromosomal mapping of repetitive DNA in Melipona species (Hymenoptera, Meliponini).(2019) Travenzoli, Natália Martins; Lima, Bárbara Soares Amoroso; Cardoso, Danon Clemes; Santos, Jorge Abdala Dergam dos; Salomão, Tânia Maria Fernandes; Lopes, Denilce MenesesStingless bees of the genus Melipona are subdivided into 4 subgenera called Eomelipona, Melikerria, Melipona sensu stricto, and Michmelia according to species morphology. Cytogenetically, the species of the genus Melipona show variation in the amount and distribution of heterochromatin along their chromosomes and can be separated into 2 groups: the first with low content of heterochromatin and the second with high content of heterochromatin. These heterochromatin patterns and the number of chromosomes are characteristics exclusive to Melipona karyotypes that distinguish them from the other genera of the Meliponini. To better understand the karyotype organization in Melipona and the relationship among the subgenera, we mapped repetitive sequences and analyzed previously reported cytogenetic data with the aim to identify cytogenetic markers to be used for investigating the phylogenetic relationships and chromosome evolution in the genus. In general, Melipona species have 2n = 18 chromosomes, and the species of each subgenus share the same characteristics in relation to heterochromatin regions, DAPI/CMA3 fluorophores, and the number and distribution of 18S rDNA sites. Microsatellites were observed only in euchromatin regions, whereas the (TTAGG)6 repeats were found at telomeric sites in both groups. Our data indicate that in addition to the chromosome number, the karyotypes in Melipona could be separated into 2 groups that are characterized by conserved cytogenetic features and patterns that generally are shared by species within each subgenus, which may reflect evolutionary constraints. Our results agree with the morphological separation of the Melipona into 4 subgenera, suggesting that they must be independent evolutionary lineages.Item Cytogenetic data on the agro-predatory ant Megalomyrmex incisus Smith, 1947 and its host, Mycetophylax conformis (Mayr, 1884) (Hymenoptera, Formicidae).(2017) Cardoso, Danon Clemes; Pereira, Tássia Tatiane Pontes; Cordeiro, Alessandro Lick; Cristiano, Maykon PassosWe provide the first karyotype description of the agro-predatory ant species Megalomyrmex incisus Smith, 1947 (Myrmicinae, Formicidae), and chromosome counts of its host Mycetophylax conformis (Mayr, 1884) (Myrmicinae, Formicidae) from geographically distinct populations. Colonies of both species were sampled from coastal areas of Ilhéus, Bahia, Brazil, and transferred to the laboratory. Metaphase spreads were prepared from the cerebral ganglia of defecated larvae. The slides were examined and pictures of the best metaphases were taken. The chromosome number for M. incisus was 2n=50 and n=25. The karyotype of this species consists of 20 metacentric and 5 submetacentric pairs. Thus, the karyotype formula of the diploid set was 2K=40M + 10SM and a fundamental number FN=100. The host species M. conformis has 2n=30 and the karyotype consisting of 11 metacentric and 4 submetacentric pairs. The karyotype formula was 2K=22M + 8SM, and a fundamental number FN=60. M. incisus showed a slightly higher chromosome number, placed at the marginal range of the known distribution of haploid karyotypes of the Myrmicinae. The chromosome number and chromosomal morphology of M. conformis corresponded to those of previously studied populations, suggesting its karyotype stability.Item Daily dynamics of an ant community in a mountaintop ecosystem.(2020) Calazans, Eloá Gonçalves; Costa, Fernanda Vieira da; Cristiano, Maykon Passos; Cardoso, Danon ClemesAbiotic conditions have a great influence on the structure of biological communities, especially considering ectothermic organisms, such as ants. In this study, we tested whether the daily temporal dynamics of an ant community in a tropical mountainous ecosystem is driven by daily fluctuations of abiotic factors, such as temperature and humidity. We also investigated whether the strong oscillation in daily temperature leads to high heterogeneity in ant species thermal responses. We have found that air and soil temperatures positively influenced the richness and frequency of foraging ants, while air humidity caused the opposite effect. Ant activity followed daily temperature fluctuations, which resulted in subtle differences in foraging patterns featured by heat-tolerant and heat-intolerant species. Moreover, the studied ant community exhibited broad and highly overlapped thermal responses, suggesting a likely resilience under temperature oscillations. Lastly, identifying how species traits are linked to oscillations in abiotic conditions is a necessary step to predict the effects of future climatic changes on biological community dynamics and ecosystem functioning.Item Dinâmica temporal da comunidade de formigas em um ecossistema montanhoso : os efeitos das condições ambientais.(2019) Calazans, Eloá Gonçalves; Cardoso, Danon Clemes; Costa, Fernanda Vieira da; Cristiano, Maykon Passos; Barão, Marina do Vale; Ribas, Carla Rodrigues; Cardoso, Danon ClemesAs condicoes abioticas tem grande influencia na estrutura das comunidades biologicas, especialmente em organismos termofilicos, como as formigas. Neste estudo, investigamos se a dinamica temporal de uma comunidade de formigas de solo em um ecossistema tropical montanhoso e regulada pela flutuacao das condicoes abioticas. Investigamos tambemse a alta oscilacao da temperatura diaria em campo rupestre prediz a diversidade termica das especies de formigas.Descobrimos que a temperaturainfluenciou positivamente a riqueza e a atividade de forrageamentodas 70 formigas, enquanto a umidade influenciou negativamente. A atividade de forrageamento da comunidade de formigasacompanhou as flutuacoes da temperatura diaria e detectamos especies de formigas especies tolerantes ao calor e especies intolerantes ao calor. Alem disso, as formigas exibiram nichos termicos amplos com alta sobreposicao nas respostas termicas, sugerindo uma alta resiliencia da comunidadeestudada as flutuacoes da temperatura.Por fim, identificar como as caracteristicas das especies estao ligadas as condicoes abioticase um passo necessario para avaliar os efeitos dasmudancas climaticas na dinamica e nos processos ecossistemicos das comunidasbiologicas.Item Genoma mitocondrial da formiga cultivadora de fungo Mycetophylax simplex Emery, 1888 : implicações filogenéticas, evolutivas e subsídios para conservação.(2019) Baldez, Brenda Carla Lima; Cardoso, Danon Clemes; Cristiano, Maykon Passos; Cardoso, Danon Clemes; Cruz, Izinara Rosse da; Svartman, MartaApesar da grande diversidade de formigas, ainda há poucos dados disponíveis de genomas mitocondriais. Em geral, tais estudos compreendem uma ou poucas espécies das principais subfamílias, sendo que dentro do grupo das formigas cultivadoras de fungos, sequências genômicas mitocondriais estão disponíveis apenas para as formigas cortadeiras do gênero Atta. O gênero Mycetophylax Emery, 1913, consiste em 21 espécies, sendo que possui três formigas endêmicas de ambientes de dunas arenosas da costa atlântica brasileira. Em particular, a espécie Mycetophylax simplex Emery, 1888 foi categorizada como vulnerável (VU) na lista das espécies da fauna brasileira ameaçadas de extinção vigente, em consequência da degradação e declínio da qualidade de seu habitat. Neste contexto, genomas mitocondriais (mitogenomas) são essenciais em estudos de evolução molecular, sistemática e conservação de espécies. Sendo assim, este trabalho teve como objetivo caracterizar o genoma mitocondrial da formiga M. simplex. Os dados moleculares gerados aqui serão utilizados para analisar variações genômicas e também contribuir para o conhecimento das relações filogenéticas e conservação dessa espécie. O genoma mitocondrial completo de M. simplex possui 16.367 pb de comprimento. Foram identificados 37 genes, dos quais, 13 são genes codificadores de proteínas (PCGs), 22 RNAs transportadores (tRNAs), 2 RNAs ribossomais (rRNAs), além de uma região controle (CR). As análises de composição nucleotídica indicam que o genoma dispõe de um forte desvio para os pares de base adenina e timina. Além disso, o viés do genoma mitocondrial de M. simplex para os nucleotídeos A-T também refletiu no uso de códons pelos PGCs. Em geral, os parâmetros AT-skew e GC-skew apresentaram valores negativos sugerindo que na sequência mitogenômica os nucleotídeos T são mais abundantes que A e C é mais abundante que G, com exceção do GC-skew dos tRNAs, o qual sugere que G é mais abundante que C. A estrutura gênica identificada aqui difere do arranjo ancestral em genes tRNAs, no entanto, é compartilhado com a maioria das espécies de Myrmicinae sequenciadas até o momento. Todos os PCGs utilizaram o códon de início típico, ATN, dos quais, nove iniciaram com ATA e os demais com ATG. Além disso, todos os códons finalizaram com TAA, com exceção dos genes cox1, atp6, cox3 e cytb que finalizaram com o códon de parada TAG. As estruturas secundárias dos genes tRNAs foram destacadas neste trabalho, sendo que todos os genes apresentaram a estrutura típica de trevo, com exceção de trnS1 e trnV. Além do mais, este trabalho 11 corrobora estudos filogenéticos anteriores, mostrando que M. simplex está intimamente relacionada com as demais espécies do grupo das formigas cultivadoras de fungos, evidenciando M. simplex como uma espécie basal em relação ao gênero Atta. Dessa forma, ressaltamos que a sequência genômica mitocondrial de M. simplex pode contribuir com a sistemática do grupo. Ainda, pode fornecer subsídios sobre o conhecimento da evolução de Formicidae e conservação da espécie M. simplex.Item Geographical distribution patterns and niche modeling of the iconic leafcutter ant Acromyrmex striatus (Hymenoptera: Formicidae).(2017) Gomes, Flávia Carolina Simões; Cardoso, Danon Clemes; Cristiano, Maykon PassosAnts are considered one of the most successful groups in the planet’s evolutionary history. Among them highlights the fungus-farming ants of the genera Atta and Acromyrmex that occur throughout most of the Americas. Within the Acromyrmex genus, the species A. striatus distinguishes from other Acromyrmex species as its morphology and karyotype differ from its congeners. This species is found in open environments of dry climate in the southern States of Brazil, Argentina, Paraguay and Uruguay; however, little is known about the current distribution of the species. This article aimed to investigate the current distribution of the species by compiling its known distribution and discussing its distributional range. To achieve this, published and unpublished data obtained through a literature search and active collections in various locations were compiled. Published and unpublished data revealed that 386 colonies were recorded, distributed across four countries where its occurrence is known. Environmental factors, such as temperature, humidity, soil type and vegetation, as well as historical geological and climate events that have modified Earth’s surface may have influenced species distribution patterns. In the Neotropics, the environmental factors that most impacted the distribution of species were the glaciation periods that occurred in the Quaternary, leading to a great migratory process. These factors may have contributed to the current geographical distribution of A. striatus.Item Integrating paleodistribution models and phylogeography in the grass-cutting ant Acromyrmex striatus (Hymenoptera: Formicidae) in southern lowlands of South America.(2016) Cristiano, Maykon Passos; Cardoso, Danon Clemes; Salomão, Tânia Maria Fernandes; Heinze, JürgenPast climate changes often have influenced the present distribution and intraspecific genetic diversity of organisms. The objective of this study was to investigate the phylogeography and historical demography of populations of Acromyrmex striatus (Roger, 1863), a leaf-cutting ant species restricted to the open plains of South America. Additionally, we modeled the distribution of this species to predict its contemporary and historic habitat. From the partial sequences of the mitochondrial gene cytochrome oxidase I of 128 A. striatus workers from 38 locations we estimated genetic diversity and inferred historical demography, divergence time, and population structure. The potential distribution areas of A. striatus for current and quaternary weather conditions were modeled using the maximum entropy algorithm. We identified a total of 58 haplotypes, divided into five main haplogroups. The analysis of molecular variance (AMOVA) revealed that the largest proportion of genetic variation is found among the groups of populations. Paleodistribution models suggest that the potential habitat of A. striatus may have decreased during the Last Interglacial Period (LIG) and expanded during the Last Maximum Glacial (LGM). Overall, the past potential distribution recovered by the model comprises the current potential distribution of the species. The general structuring pattern observed was consistent with isolation by distance, suggesting a balance between gene flow and drift. Analysis of historical demography showed that populations of A. striatus had remained constant throughout its evolutionary history. Although fluctuations in the area of their potential historic habitat occurred during quaternary climate changes, populations of A. striatus are strongly structured geographically. However, explicit barriers to gene flow have not been identified. These findings closely match those in Mycetophylax simplex, another ant species that in some areas occurs in sympatry with A. striatus. Ecophysiological traits of this species and isolation by distance may together have shaped the phylogeographic pattern.Item Intraspecific variation in the karyotype length and genome size of fungus-farming ants (genus Mycetophylax), with remarks on procedures for the estimation of genome size in the Formicidae by flow cytometry.(2020) Moura, Mariana Neves; Cardoso, Danon Clemes; Baldez, Brenda Carla Lima; Cristiano, Maykon PassosAnts (Formicidae) present considerable diversity in chromosome numbers, which vary from n = 1 to n = 60, although this variation is not proportional to that in genome size, for which estimates range from 0.18 pg to 0.77 pg. Intraspecific variation in the chromosome number and karyotype structure has been reported among species, although the variation among populations of the same species has received much less attention, and there are few data on genome size. Here, we studied the karyotype length and genome size of different populations of the fungus-farming ants Mycetophylax conformis (Mayr, 1884) and Mycetophylax morschi (Emery, 1888). We also provide remarks on procedure for the estimation of ant genome size by Flow Cytometry (FCM) analysis. Chromosome number and morphology did not vary among the populations of M. conformis or the cytotypes of M. morschi, but karyotype length and genome size were significantly distinct among the populations of these ants. Our results on the variation in karyotype length and genome size among M. morschi and M. conformis populations reveal considerable diversity that would be largely overlooked by more traditional descriptions of karyotypes, which were also supported by the estimates of genome size obtained using flow cytometry. Changes in the amount of DNA reflect variation in the fine structure of the chromosomes, which may represent the first steps of karyotype evolution and may occur previously to any changes in the chromosome number.Item Karyotype and putative chromosomal inversion suggested by integration of cytogenetic and molecular data of the fungus-farming ant Mycetomoellerius iheringi Emery, 1888.(2020) Micolino, Ricardo; Cristiano, Maykon Passos; Cardoso, Danon ClemesComparative cytogenetic analyses are being increasingly used to collect information on species evolution, for example, diversification of closely related lineages and identification of morphologically indistinguishable species or lineages. Here, we have described the karyotype of the fungus-farming ant Mycetomoellerius iheringi Emery, 1888 and investigated its evolutionary relationships on the basis of molecular and cytogenetic data. The M. iheringi karyotype consists of 2n = 20 chromosomes (2K = 18M + 2SM). We also demonstrated that this species has the classical insect TTAGG telomere organization. Phylogenetic reconstruction showed that M. iheringi is phylogenetically closer to M. cirratus Mayhé-Nunes & Brandão, 2005 and M. kempfi Fowler, 1982. We compared M. iheringi with other congeneric species such as M. holmgreni Wheeler, 1925 and inferred that M. iheringi probably underwent a major pericentric inversion in one of its largest chromosomes, making it submetacentric. We discussed our results in the light of the phylogenetic relationships and chromosomal evolution.Item Karyotype diversity, mode, and tempo of the chromosomal evolution of Attina (Formicidae: Myrmicinae: Attini) : is there an upper limit to chromosome number?(2021) Cardoso, Danon Clemes; Cristiano, Maykon PassosAnts are an important insect group that exhibits considerable diversity in chromosome numbers. Some species show only one chromosome, as in the males of the Australian bulldog ant Myrmecia croslandi, while some have as many as 60 chromosomes, as in the males of the giant Neotropical ant Dinoponera lucida. Fungus-growing ants are a diverse group in the Neotropical ant fauna, engaged in a symbiotic relationship with a basidiomycete fungus, and are widely distributed from Nearctic to Neotropical regions. Despite their importance, new chromosome counts are scarcely reported, and the marked variation in chromosome number across species has been poorly studied under phylogenetic and genome evolutionary contexts. Here, we present the results of the cytogenetic examination of fungus-farming ants and compile the cytogenetic characteristics and genome size of the species studied to date to draw insights regarding the evolutionary paths of karyotype changes and diversity. These data are coupled with a fossil-calibrated phylogenetic tree to discuss the mode and tempo of chromosomal shifting, considering whether there is an upper limit for chromosome number and genome size in ants, using fungus-farming ants as a model study. We recognize that karyotypes are generally quite variable across fungus-farming ant phylogeny, mostly between genera, and are more numerically conservative within genera. A low chromosome number, between 10 and 12 chromosomes, seems to present a notable long-term evolutionary stasis (intermediate evolutionary stasis) in fungus-farming ants. All the genome size values were inside a limited spectrum below 1 pg. Eventual departures in genome size occurred with regard to the mean of 0.38 pg, indicating that there is a genome, and likely a chromosome, number upper limit.