Unraveling the Secrets of a Double-Life Fungus by Genomics: Ophiocordyceps australis CCMB661 Displays Molecular Machinery for Both Parasitic and Endophytic Lifestyles.

Ophiocordyceps australis (Ascomycota, Hypocreales, Ophiocordycipitaceae) is a classic entomopathogenic fungus that parasitizes ants (Hymenoptera, Ponerinae, Ponerini). Nonetheless, according to our results, this fungal species also exhibits a complete set of genes coding for plant cell wall degrading Carbohydrate-Active enZymes (CAZymes), enabling a full endophytic stage and, consequently, its dual ability to both parasitize insects and live inside plant tissue. The main objective of our study was the sequencing and full characterization of the genome of the fungal strain of O. australis (CCMB661) and its predicted secretome. The assembled genome had a total length of 30.31 Mb, N50 of 92.624 bp, GC content of 46.36%, and 8,043 protein-coding genes, 175 of which encoded CAZymes. In addition, the primary genes encoding proteins and critical enzymes during the infection process and those responsible for the host-pathogen interaction have been identified, including proteases (Pr1, Pr4), aminopeptidases, chitinases (Cht2), adhesins, lectins, lipases, and behavioral manipulators, such as enterotoxins, Protein Tyrosine Phosphatases (PTPs), and Glycoside Hydrolases (GHs). Our findings indicate that the presence of genes coding for Mad2 and GHs in O. australis may facilitate the infection process in plants, suggesting interkingdom colonization. Furthermore, our study elucidated the pathogenicity mechanisms for this Ophiocordyceps species, which still is scarcely studied.

Decay of homologous chromosome pairs and discovery of males in the thelytokous fungus-growing ant Mycocepurus smithii.

The prevalent mode of reproduction among ants is arrhenotokous parthenogenesis where unfertilized eggs give rise to haploid males and fertilized eggs develop into diploid females. Some ant species are capable of thelytokous parthenogenesis, a type of asexual reproduction where females develop from unfertilized diploid eggs. Thelytoky is well-documented in more than 20 ant species. Cytogenetic data are available for six species demonstrating that some thelytokous ant species are capable of producing males occasionally as well as maintaining their chromosome numbers and proper chromosome pairings. Mycocepurus smithii is a thelytokous fungus-growing ant species that inhabits large parts of Central and South America. Cytogenetic data are unavailable for M. smithii and male individuals were never documented for this species, although the presence of males is expected because genetic recombination was observed in a few sexually reproducing populations in Brazil and haploid sperm was documented from the spermathecae of M. smithii queens. This study aims at comparatively studying asexual and sexual populations of M. smithii using classical and molecular cytogenetic methods to test whether karyotype configuration is modified according to the mode of reproduction in M. smithii. Moreover, we report the discovery of M. smithii males from a sexually reproducing population in the Brazilian state Pará, diagnose the male of M. smithii, and morphologically characterize their spermatozoa. Karyotypic variation was observed within the asexual population (2n = 9, 10, or 11), whereas the chromosome number was fixed in the sexual population (2n = 14, n = 7). Identical karyotypes were maintained within individual M. smithii colonies and karyotype variation was only observed between colonies. In asexual individuals, the karyomorphs showed a decay of homologous chromosome pairs, especially in individuals with the karyomorph 2n = 11, which is potentially caused by relaxed natural selection on proper chromosome pairing. In contrast, females in the sexual population showed proper homologous chromosome pairings. In individuals of both asexual and sexual populations, we find that heterochromatin was localized in centromeric regions and on the short arms of the chromosomes, GC-rich regions were associated with heterochromatic regions, and 18S rDNA genes were located on the largest chromosome pair. This comparative cytogenetic analysis contributes to our understanding about the cytological mechanisms associated with thelytokous parthenogenesis in ants and suggests the decay of chromosome structure in the absence of meiosis and genetic recombination.

ATLANTIC ANTS: a data set of ants in Atlantic Forests of South America.

Ants, an ecologically successful and numerically dominant group of animals, play key ecological roles as soil engineers, predators, nutrient recyclers, and regulators of plant growth and reproduction in most terrestrial ecosystems. Further, ants are widely used as bioindicators of the ecological impact of land use. We gathered information of ant species in the Atlantic Forest of South America. The ATLANTIC ANTS data set, which is part of the ATLANTIC SERIES data papers, is a compilation of ant records from collections (18,713 records), unpublished data (29,651 records), and published sources (106,910 records; 1,059 references), including papers, theses, dissertations, and book chapters published from 1886 to 2020. In total, the data set contains 153,818 ant records from 7,636 study locations in the Atlantic Forest, representing 10 subfamilies, 99 genera, 1,114 ant species identified with updated taxonomic certainty, and 2,235 morphospecies codes. Our data set reflects the heterogeneity in ant records, which include ants sampled at the beginning of the taxonomic history of myrmecology (the 19th and 20th centuries) and more recent ant surveys designed to address specific questions in ecology and biology. The data set can be used by researchers to develop strategies to deal with different macroecological and region-wide questions, focusing on assemblages, species occurrences, and distribution patterns. Furthermore, the data can be used to assess the consequences of changes in land use in the Atlantic Forest on different ecological processes. No copyright restrictions apply to the use of this data set, but we request that authors cite this data paper when using these data in publications or teaching events.

Ants of the State of Par, Brazil: a historical and comprehensive dataset of a key biodiversity hotspot in the Amazon Basin.

The state of Par in northern Brazil is located entirely within the Amazon Basin and harbors a great diversity of landscape and vegetation types that support high levels of biodiversity. Here, we provide a comprehensive inventory of ant species and their distribution in Par. This regional list is based on an extensive review of species records from published and unpublished sources covering a period of 134 years (18862020) and includes the five most representative ant collections in Brazil. In total, we documented 12 subfamilies, 90 genera and 753 ant species, including 97 species recorded for the first time in Par and 12 species newly reported in Brazil. Sampling effort across the state is highly uneven, and most records may be associated with research areas near the state capital, mining areas, hydroelectric dams, and research field stations run by the state or universities. In addition, our results suggest a strong bias in ant collection in Par in terms of proximity of sampled sites to access routes, such as roads and rivers. We also found that species records were highly unevenly distributed based on areas of endemism within the Amazon, vegetation type, and protected areas within the state. Ant surveys are still lacking from most protected areas of Par, and further sampling is urgently needed in view of the current trend of expansion of major infrastructure projects and natural resource harvesting within protected areas of Par. Our database represents an extremely valuable and rich source of information for further studies on ant biodiversity and conservation in the Amazon Basin.

Inhibition of HSP90 causes morphological variation in the invasive ant Cardiocondyla obscurior.

Canalization underlies the expression of steady phenotypes in the face of unsteady environmental conditions or varying genetic backgrounds. The chaperone HSP90 has been identified as a key component of the molecular machinery regulating canalization and a growing body of research suggests that HSP90 could act as a general capacitator in evolution. However, empirical data about HSP90-dependent phenotypic variation and its evolutionary impact is still scarce, particularly for non-model species. Here we report how pharmacological suppression of HSP90 increases morphological variation up to 87% in the invasive ant Cardiocondyla obscurior. We show that workers treated with the HSP90 inhibitor 17-DMAG are significantly more diverse compared to untreated workers in two of four measured traits: maximal eye distance and maximal propodeal spine distance. We further find morphological differentiation between natural populations of C. obscurior in the same traits that responded to our pharmacological treatment. These findings add support for the putative impact of HSP90 on canalization, the modularity of phenotypic traits, and its potential role in morphological evolution of ants.

Arthropods associated with young orchard of pecan in southern Brazil / Artrópodes associados a um plantio jovem de nogueira-pecã no sul do Brasil

A produção mundial de noz-pecã Carya illinoinensis (Juglandaceae) é liderada pelos Estados Unidos. No Brasil, em especial no Rio Grande do Sul, houve uma expansão da área plantada com a cultura nos últimos anos. No entanto, faltam pesquisas relacionadas à entomofauna associada à noz-pecã, bem como práticas culturais que auxiliem no Manejo Integrado de Pragas, mesmo havendo uma expansão da cultura. Assim, o presente estudo objetivou avaliar a fauna de artrópodes na copa de plantas de C. illinoinensis, submetido a diferentes manejos de solo, em Santa Maria, Rio Grande do Sul, Brasil. Para tanto, utilizou-se delineamento experimental de blocos ao acaso, com cinco blocos e quatro tratamentos: plantio em cova pequena, com 20 × 60 cm (Sp); utilização de subsolador mais grade niveladora e cova pequena (Ssp); utilização de enxada rotativa e cova pequena (Tsp); e plantio em cova grande, com 40 × 60 cm (Lp). De novembro de 2014 a maio de 2015, foram coletadas 7.617 espécimes nas copas de árvores jovens de nogueira-pecã. Foram identificados 150 grupos taxonômicos, sendo Coleoptera a ordem com maior riqueza de espécies. Monellia caryella (Hemiptera: Aphididae) apresentou elevada densidade. Foram registrados os inimigos naturais himenópteros parasitoides e Coccinellidae. Conclui-se que a artropodofauna em copas de plantas jovens de nogueira-pecã apresenta diversidade similar entre os tratamentos e predomínio de M. caryella nas áreas avaliadas.(AU)

World production of pecan Carya illinoinensis (Juglandaceae) is led by the United States. In Brazil, especially in the Rio Grande do Sul State, there has been an expansion of the planted area in recent years. Despite this expansion of pecan culture, there is a lack of research on entomofauna associated with pecan and on cultural practices which aids in Integrated Pest Management. This study aimed to evaluate the arthropod fauna in the canopies of C. illinoinensis trees grown under different soil management practices in Santa Maria, Rio Grande do Sul, Brazil. A randomized design was used with five blocks and four treatments: planting in small pits of 20 × 60 cm (Sp) using a subsoiler with a leveling grader/shank, planting in small pits (Ssp) using a rotary tiller (Tsp), and planting in large pits of 40 × 60 cm (Lp). A total of 7,617 specimens were collected from November 2014 to May 2015 from the young pecan canopies. Among the 150 taxonomic groups identified, Coleoptera was the most taxonomically rich order. The blackmargined aphid Monellia caryella (Hemiptera: Aphididae) had the greatest abundance. Hymenopteran parasitoids and Coccinellidae spp. were among the natural pest enemies detected. We conclude that the arthropod fauna found in the young pecan canopies is similarly diverse among the different soil managements, with a predominance of pest species M. caryella in all the evaluated areas.(AU)

First checklist of the ants (Hymenoptera: Formicidae) of French Guiana.

We provide here a checklist of the ants of French Guiana, an overseas department of France situated in northern South America, with a very low human population density and predominantly covered by old-growth tropical rainforests. Based on 165 scientific papers, specimens deposited in collections, and unpublished surveys, a total of 659 valid species and subspecies from 84 genera and 12 subfamilies is presented. Although far from complete, these numbers represent approximately 10% of the ant diversity known to occur in the Neotropical realm. Additionally, three ant genera and 119 species are reported for the first time for French Guiana. Finally, five species are recognized as erroneous records for the the department in the literature. This checklist significantly expands the basic knowledge of the ants in the Guiana Shield, one of the world's most important biodiversity hotspots.

The Guild Concept: From Feudalism to Community Ecology / El concepto de gremio: del feudalismo a la ecología de comunidades

RESUMEN Se analiza el origen y evolución del término gremio, así como su aplicación en ecología, considerando las múltiples connotaciones que se le ha dado y la confusión que se ha generado por utilizarlo de forma indebida. De igual forma, se discute la importancia de homogenizar los términos y definir de manera clara a los gremios, a fin de tener un leguaje que permita entender los alcances del término sin ambigüedades. El uso del término, así como su persistencia en estudios ecológicos, sugiere que el mismo tiene relevancia considerable dependiendo de la forma y el modo en que es empleado. El uso inadecuado o derivado de este término es arriesgado y peligroso, dado que tiende a reducir el término a una palabra vacía con múltiples significados. Más que nada, esta trivialización constituye una amenaza al uso y significado adecuado del concepto de gremio en ecología.

ABSTRACT The origin and evolution of the term guild are analyzed, as well as its application in ecology, considering the multiple connotations that have been given and the confusion that has been generated by using it improperly. Likewise, the importance of homogenizing the terms and clearly defining the guilds is discussed, to have a language that allows understanding the scope of the term without ambiguities. The use of the term, as well as its persistence in ecological studies, suggests that it has considerable relevance depending on the form and the way it is used. The inappropriate or derivative use of this term is risky and dangerous since it tends to reduce the term to an empty word with multiple meanings. Also, this trivialization constitutes a threat to the proper use of the guild concept in ecology and its meaning as a whole.

Habitats shape taxonomic and functional composition of Neotropical ant assemblages.

Determining assembly rules of co-occurring species persists as a fundamental goal in community ecology. At local scales, the relative importance of environmental filtering vs. competitive exclusion remains a subject of debate. In this study, we assessed the relative importance of habitat filtering and competition in structuring understory ant communities in tropical forests of French Guiana. Leaf-litter ants were collected using pitfall and Winkler traps across swamp, slope and plateau forests near Saül, French Guiana. We used a combination of univariate and multivariate analyses to evaluate trait response of ants to habitat characteristics. Null model analyses were used to investigate the effects of habitat filtering and competitive interactions on community assembly at the scale of assemblages and sampling points, respectively. Swamp forests presented a much lower taxonomic and functional richness compared to slope and plateau forests. Furthermore, marked differences in taxonomic and functional composition were observed between swamp forests and slope or plateau forests. We found weak evidence for competitive exclusion based on null models. Nevertheless, the contrasting trait composition observed between habitats revealed differences in the ecological attributes of the species in the different forest habitats. Our analyses suggest that competitive interactions may not play an important role in structuring leaf-litter ant assemblages locally. Rather, habitats are responsible for driving both taxonomic and functional composition of ant communities.

Life history and reproduction of the neotropical caecilian Siphonops annulatus (Amphibia, Gymnophiona, Siphonopidae), with special emphasis on parental care

Due to their mainly fossorial way of life, caecilian amphibians are the least known order of terrestrial vertebrates. Here, we present new observations on the natural history and reproductive biology of the neotropical oviparous, siphonopid caecilian Siphonops annulatus from a long-term study of this species in the field and in captivity. In the studied population, mating occurs between the end of August and beginning of October, and oviposition between November and December, when rainfall peaks. Egg hatching occurs between the end of December and beginning of January. The complete cycle of maternal care, from oviposition to independent, self-sufficient offspring lasts about 3 months. After eclosion, the altricial young feed on the mother's specially modified skin (maternal dermatophagy) and are also supplied by a fluid released from coming from the maternal cloaca. Also presented are observations on the burrows, feeding and social behaviour of S. annulatus.

Life history and reproduction of the neotropical caecilian Siphonops annulatus (Amphibia, Gymnophiona, Siphonopidae), with special emphasis on parental care

Due to their mainly fossorial way of life, caecilian amphibians are the least known order of terrestrial vertebrates. Here, we present new observations on the natural history and reproductive biology of the neotropical oviparous, siphonopid caecilian Siphonops annulatus from a long-term study of this species in the field and in captivity. In the studied population, mating occurs between the end of August and beginning of October, and oviposition between November and December, when rainfall peaks. Egg hatching occurs between the end of December and beginning of January. The complete cycle of maternal care, from oviposition to independent, self-sufficient offspring lasts about 3 months. After eclosion, the altricial young feed on the mother's specially modified skin (maternal dermatophagy) and are also supplied by a fluid released from coming from the maternal cloaca. Also presented are observations on the burrows, feeding and social behaviour of S. annulatus.

Genetic Characterization of Some Neoponera (Hymenoptera: Formicidae) Populations Within the foetida Species Complex.

The foetida species complex comprises 13 Neotropical species in the ant genus Neoponera. Neoponera villosa Fabricius (1804) , Neoponera inversa Smith (1858), Neoponera bactronica Fernandes, Oliveira & Delabie (2013), and Neoponera curvinodis (Forel, 1899) have had an ambiguous taxonomic status for more than two decades. In southern Bahia, Brazil, these four species are frequently found in sympatry. Here we used Bayesian Inference and maximum likelihood analyses of COI and 16S mtDNA sequence data and conventional cytogenetic data together with observations on morphology to characterize sympatric populations of N. villosa, N. inversa, N. bactronica, and N. curvinodis. Our results showed marked differences in the karyotype of these ants. Both N. curvinodis and N. inversa have chromosome number of 2n = 30. Their chromosome composition, however, is distinct, which indicates that N. curvinodis is more closely related to N. bactronica. These four species clustered into three distinct groups. The close relationship between N. bactronica and N. curvinodis deserves further investigation since it has not been fully resolved here. Our results confirm that N. inversa, N. villosa, N. bactronica + N. curvinodis indeed represent four distinct taxa within the foetida species complex.

Highly modular pattern in ant-plant interactions involving specialized and non-specialized myrmecophytes.

Because Tachia guianensis (Gentianaceae) is a "non-specialized myrmecophyte" associated with 37 ant species, we aimed to determine if its presence alters the ant guild associated with sympatric "specialized myrmecophytes" (i.e., plants sheltering a few ant species in hollow structures). The study was conducted in a hilly zone of a neotropical rainforest where two specialized myrmecophytes grow at the bottom of the slopes, another at mid-slope, and a fourth on the hilltops. Tachia guianensis, which occurred everywhere, had its own guild of associated ant species. A network analysis showed that its connections with the four other myrmecophytes were rare and weak, the whole resulting in a highly modular pattern of interactions with one module (i.e., subnetwork) per myrmecophyte. Three ant species parasitized three out of the four specialized myrmecophytes (low nestedness noted), but were not or barely associated with T. guianensis that therefore did not influence the parasitism of specialized myrmecophytes.

Methuselah's daughters: Paternal age has little effect on offspring number and quality in Cardiocondyla ants.

Male age may directly or indirectly affect the fitness of their female mating partners and their joint progeny. While in some taxa of insects, old males make better mates and fathers, young males excel in others. Males of most social Hymenoptera are relatively short lived and because of testis degeneration have only a limited sperm supply. In contrast, the wingless fighter males of the ant Cardiocondyla obscurior live for several weeks and produce sperm throughout their lives. Wingless males engage in lethal combat with rival males and the winner of such fights can monopolize mating with all female sexuals that emerge in their nests over a prolonged timespan. Here, we investigate if male age has an influence on sperm quality, the queen's lifespan and productivity, and the size and weight of their offspring. Queens mated to one-week or six-week-old males did not differ in life expectancy and offspring production, but the daughters of young males were slightly heavier than those of old males. Our data suggest negligible reproductive senescence of C. obscurior males even at an age, which only few of them reach. This matches the reproductive strategy of Cardiocondyla ants, in which freshly emerging female sexuals rarely have the option to mate with males other than the one present in their natal nest.

Hollow Internodes Permit a Neotropical Understory Plant to Shelter Multiple Mutualistic Ant Species, Obtaining Protection and Nutrient Provisioning (Myrmecotrophy).

The Neotropical understory plant Tachia guianensis (Gentianaceae)-known to shelter the colonies of several ant species in its hollow trunks and branches-does not provide them with food rewards (e.g., extrafloral nectar). We tested whether these ants are opportunistic nesters or whether mutualistic relationships exist as for myrmecophytes or plants sheltering ant colonies in specialized hollow structures in exchange for protection from enemies and/or nutrient provisioning (myrmecotrophy). We noted 37 ant species sheltering inside T. guianensis internodes, three of them accounting for 43.5% of the cases. They protect their host plants from leaf-cutting ant defoliation and termite damage because individuals devoid of associated ants suffered significantly more attacks. Using the stable isotope 15N, we experimentally showed that the tested ant species furnish their host plants with nutrients. Therefore, a mutualism exists. However, because it is associated with numerous ant species, T. guianensis can be considered a nonspecialized myrmecophyte.

Cytogenetic studies on populations of Camponotus rufipes (Fabricius, 1775) and Camponotus renggeri Emery, 1894 (Formicidae: Formicinae).

Two valid ant species, Camponotus rufipes and Camponotus renggeri, have recently been the subject of a broad discussion with reference to taxa synonymization. Both species are quite common among the Neotropical myrmecofauna and share some unique traits, such as the shape of the scape and the pilosity patterns of the tibiae and scapes. A single morphological trait can help distinguish these species; however, only a combination of different approaches can enlighten our view of the complex phylogenetic relationships prevailing in the different populations of these two taxa. Therefore, focusing on the taxonomic issues concerning these two species, a cytogenetic survey including 10 populations of C. rufipes and two populations of C. renggeri was performed. In order to better understand the extent of the relationship between C. rufipes and C. renggeri, two common Neotropical Camponotus species, C. atriceps and C. cingulatus were taken as outgroups. All four species of Camponotus that were studied had 2n = 40 chromosomes (4sm+34st+2t); however, the abundance of chromosome rearrangements observed, combined with several chromosome markers, suggest that C. rufipes and C. renggeri are two good distinct species although closely related. The already reported chromosome translocation 2n = 39 (1m+4sm+32st+2t) for C. rufipes has been found in different populations as in the unprecedented chromosome inversions found both in C. rufipes and in C. renggeri populations. Within the C. renggeri chromosome inversions, both the heterozygous state 2n = 40 (1m+3sm+34st+2t) and the homozygous state, 2n = 40 (2m+2sm+34st+2t) were identified. However, only heterozygous specimens for chromosome inversions were found among C. rufipes, with karyotype configurations distinct from those found in C. renggeri, with 2n = 40 (1m+4sm+34st+2t). None of the populations studied showed signs of mosaic individuals. With respect to rDNA clusters, the 18S rDNA seemed to be more restricted inside the genome, as C. renggeri showed four 18S rDNA clusters, whereas, C. rufipes, C. atriceps, and C. cingulatus showed only two clusters. The chromosome locations of the 5S rDNA clusters were pointed for the first time in Formicidae, and showed itself to be more widely spread over the genome. By combining different chromosome banding approaches it was possible to demonstrate the crucial importance that chromosome inversions played on the karyotype evolution within these ants. The results also showed that chromosome translocations might be a consequence of the chromatin dynamic condition observed among Camponotus species. The homozygosis condition found in a C. renggeri from a Brazilian savanna population for chromosome inversions and the contrasting heterozygous condition for a different kind of chromosome inversion in C. rufipes from the Brazilian coastal rainforest, opens the window for a chromosome race hypothesis within the group C. renggeri and C. rufipes. The wide distribution, rich ecological interactions, genetic diversity, and morphological variability among C. renggeri and C. rufipes justify questioning of the actual taxonomic status of these species. The answer of this puzzle is clear when observing the number of 18S rDNA clusters of these ants, as C. rufipes has only two clusters whereas C. renggeri has four.

Rediscovery and reclassification of the dipteran taxon Nothomicrodon Wheeler, an exclusive endoparasitoid of gyne ant larvae.

The myrmecophile larva of the dipteran taxon Nothomicrodon Wheeler is rediscovered, almost a century after its original description and unique report. The systematic position of this dipteran has remained enigmatic due to the absence of reared imagos to confirm indentity. We also failed to rear imagos, but we scrutinized entire nests of the Brazilian arboreal dolichoderine ant Azteca chartifex which, combined with morphological and molecular studies, enabled us to establish beyond doubt that Nothomicrodon belongs to the Phoridae (Insecta: Diptera), not the Syrphidae where it was first placed, and that the species we studied is an endoparasitoid of the larvae of A. chartifex, exclusively attacking sexual female (gyne) larvae. Northomicrodon parasitism can exert high fitness costs to a host colony. Our discovery adds one more case to the growing number of phorid taxa known to parasitize ant larvae and suggests that many others remain to be discovered. Our findings and literature review confirm that the Phoridae is the only taxon known that parasitizes both adults and the immature stages of different castes of ants, thus threatening ants on all fronts.

Taxones superiores de hormigas como sustitutos de la riqueza de especies, en una cronosecuencia de bosques secundarios, bosque primario y sistemas agroforestales en la Amazonía Oriental, Brasil / Ants' higher taxa as surrogates of species richness in a chronosequence of fallows, old-grown forests and agroforestry systems in the Eastern Amazon, Brazil

ResumenLa deforestación es una de las principales causas de pérdida de biodiversidad en todo el mundo. Las hormigas son clave como ingenieras del ecosistema, por lo tanto, la pérdida de la diversidad de hormigas puede indicar la pérdida de funciones cruciales de los ecosistemas. El objetivo de este estudio fue evaluar la riqueza de hormigas del suelo y estimar si los niveles superiores (Subfamilia y Género) pueden ser usados como sustitutos para estimar la riqueza de especies en diferentes estados de sucesión del bosque (bosque primario, bosque secundario y sistema agroforestal) en la Amazonía Oriental. Fueron muestreadas 65 parcelas en el estado de Maranhão y Pará entre 2011 y 2014. El esquema de muestreo siguió el procedimiento de Biología de Suelos Tropicales y Fertilidad (TSBF). Primero caracterizamos los tipos de vegetación de acuerdo con su edad y luego se estimó la riqueza de especies. Para evaluar si los taxones superiores pueden utilizarse como sustitutos utilizamos funciones lineales y exponenciales y correlación de Pearson. En total, se identificaron 180 especies distribuidas en 60 géneros. Los resultados mostraron que la riqueza fue superior en el bosque secundario intermedio (88) y avanzado (76) y fue menor en el sistema agroforestal (38) y bosque ribereño primario (35). El género fue el mejor sustituto para estimar la riqueza de especies de hormigas a través de los diferentes tipos de sucesión vegetal, explicando entre el 72-97 % (P < 0.001) de la variabilidad total de especies. Nuestros resultados confirman que el uso del nivel de género es un excelente sustituto para estimar la riqueza de especies de hormigas en la región y tanto los bosques en regeneración y sistemas agroforestales pueden contribuir en la conservación de la comunidad de hormigas en la Amazonía Oriental.

Abstract:Deforestation in Amazon forests is one of the main causes for biodiversity loss worldwide. Ants are key into the ecosystem because act like engineers; hence, the loss of ants' biodiversity may be a guide to measure the loss of essential functions into the ecosystems. The aim of this study was to evaluate soil ant's richness and to estimate whether higher taxa levels (Subfamily and Genus) can be used as surrogates of species richness in different vegetation types (fallows, old-growth forests and agroforestry systems) in Eastern Amazon. The samples were taken in 65 areas in the Maranhão and Pará States in the period 2011-2014. The sampling scheme followed the procedure of Tropical Soil Biology and Fertility (TSBF). Initially, the vegetation types were characterized according to their age and estimated species richness. Linear and exponential functions were applied to evaluate if higher taxa can be used as surrogates and correlated with the Pearson coefficient. In total, 180 species distributed in 60 genera were identified. The results showed that ant species richness was higher in intermediate fallows (88) and old secondary forest (76), and was lower in agroforestry systems (38) and mature riparian forest (35). The genus level was the best surrogate to estimate the ant's species richness across the different vegetation types, and explained 72-97 % (P < 0.001) of the total species variability. The results confirmed that the genus level is an excellent surrogate to estimate the ant's species richness in the region and that both fallows and agroforestry systems may contribute in the conservation of Eastern Amazon ant community. Rev. Biol. Trop. 65 (1): 279-291. Epub 2017 March 01.

[Ants' higher taxa as surrogates of species richness in a chronosequence of fallows, old-grown forests and agroforestry systems in the Eastern Amazon, Brazil]. / Taxones superiores de hormigas como sustitutos de la riqueza de especies, en una cronosecuencia de bosques secundarios, bosque primario y sistemas agroforestales en la Amazonía Oriental, Brasil.

Deforestation in Amazon forests is one of the main causes for biodiversity loss worldwide. Ants are key into the ecosystem because act like engineers; hence, the loss of ants' biodiversity may be a guide to measure the loss of essential functions into the ecosystems. The aim of this study was to evaluate soil ant's richness and to estimate whether higher taxa levels (Subfamily and Genus) can be used as surrogates of species richness in different vegetation types (fallows, old-growth forests and agroforestry systems) in Eastern Amazon. The samples were taken in 65 areas in the Maranhão and Pará States in the period 2011-2014. The sampling scheme followed the procedure of Tropical Soil Biology and Fertility (TSBF). Initially, the vegetation types were characterized according to their age and estimated species richness. Linear and exponential functions were applied to evaluate if higher taxa can be used as surrogates and correlated with the Pearson coefficient. In total, 180 species distributed in 60 genera were identified. The results showed that ant species richness was higher in intermediate fallows (88) and old secondary forest (76), and was lower in agroforestry systems (38) and mature riparian forest (35). The genus level was the best surrogate to estimate the ant's species richness across the different vegetation types, and explained 72-97 % (P < 0.001) of the total species variability. The results confirmed that the genus level is an excellent surrogate to estimate the ant's species richness in the region and that both fallows and agroforestry systems may contribute in the conservation of Eastern Amazon ant community.

Cytogenetic data on six leafcutter ants of the genus Acromyrmex Mayr, 1865 (Hymenoptera, Formicidae, Myrmicinae): insights into chromosome evolution and taxonomic implications.

Cytogenetic data for the genus Acromyrmex Mayr, 1865 are available, to date, for a few species from Brazil and Uruguay, which have uniform chromosome numbers (2n = 38). The recent cytogenetic data of Acromyrmex striatus (Roger, 1863), including its banding patterns, showed a distinct karyotype (2n = 22), similar to earlier studied Atta Fabricius, 1804 species. Karyological data are still scarce for the leafcutter ants and many gaps are still present for a proper understanding of this group. Therefore, this study aimed at increasing cytogenetic knowledge of the genus through the characterization of other six species: Acromyrmex balzani (Emery, 1890), Acromyrmex coronatus Fabricius, 1804, Acromyrmex disciger (Mayr, 1887), Acromyrmex echinatior (Forel, 1899), Acromyrmex niger (Smith, 1858) and Acromyrmex rugosus (Smith, 1858), all of which were collected in Minas Gerais - Brazil, except for Acromyrmex echinatior which was collected in Barro Colorado - Panama. The number and morphology of the chromosomes were studied and the following banding techniques were applied: C-banding, fluorochromes CMA3 and DAPI, as well as the detection of 45S rDNA using FISH technique. All the six species had the same chromosome number observed for already studied species, i.e. 2n = 38. Acromyrmex balzani had a different karyotype compared with other species mainly due to the first metacentric pair. The heterochromatin distribution also showed interspecific variation. Nevertheless, all the studied species had a pair of bands in the short arm of the first subtelocentric pair. The fluorochrome CMA3 visualized bands in the short arm of the first subtelocentric pair for all the six species, while Acromyrmex rugosus and Acromyrmex niger also demonstrated in the other chromosomes. The AT-rich regions with differential staining using DAPI were not observed. 45S ribosomal genes were identified by FISH in the short arm of the first subtelocentric pair in Acromyrmex coronatus, Acromyrmex disciger and Acromyrmex niger. The uniform chromosome number in the genus Acromyrmex (2n = 38) suggests that Acromyrmex striatus (2n = 22) should be transferred to a new genus. Other aspects of the chromosome evolution in ants are also discussed.