New records of megachilid bees (Hymenoptera: Megachilidae) for Colombia

The bee family Megachilidae consists of solitary species, some of which are important pollinators of cultivated plants. Although literature records indicate the existence of about 50 species of 10 genera of megachilid bees in Colombia, taxonomic studies are lacking and thus limited information is available on their identity as well as their distribution in the country. Herein, we provide new geographical records for the following ten species: Anthidium sanguinicaudum Schwarz, Chelostomoides otomita (Cresson), Hoplostelis bilineolata (Spinola), Megachile amparo Gonzalez, M. kalina Gonzalez et al., M. lorenziensis Mitchell, M. moderata Smith, M. simillima Smith, Pseudomegachile lanata (Fabricius), and Stelis costaricensis Friese. We report M. kalina for the first time for the country.

Las abejas de la familia Megachilidae son especies solitarias, algunas de ellas importantes polinizadores de cultivos. Aunque en la literatura se registran cerca de 50 especies de 10 géneros de abejas megachilidas en Colombia, faltan estudios taxonómicos y, por lo tanto, se dispone de información limitada sobre la identidad y la distribución de este grupo en el país. En este trabajo proporcionamos nuevos registros geográficos para 10 especies poco conocidas [Anthidium sanguinicaudum Schwarz, Chelostomoides otomita (Cresson), Hoplostelis bilineolata (Spinola), Megachile amparo Gonzalez, M. kalina Gonzalez et al., M. lorenziensis Mitchell, M. moderata Smith, M. simillima Smith, Pseudomegachile lanata (Fabricius), y Stelis costaricensis Friese]. Megachile kalina se registra por primera vez para Colombia.

Nesting biology of three Megachile (Hymenoptera: Megachilidae) species from Eastern Amazonia, Brazil

Abstract Megachile Latreille is a conspicuous genus of solitary bees distributed worldwide. However, the biology of tropical species is still little known. We present data on biology of Megachile brasiliensis Data Torre, Megachile sejuncta Cockerell and Megachile stilbonotaspis Moure found in two remnants of eastern Amazonian forest in northeastern Brazil. The study was conducted using the trap-nest methodology in two different areas during four periods. We collected a total of 24 nests of M. brasiliensis, 26 of M. sejuncta and 28 of M. stilbonotaspis. The differential abundance of collected nests may reflect the population size in each sampled place. The nesting activity was concentrated mainly between July and January and species presented a multivoltine pattern, except for M. sejuncta, which was partly univoltine. Assessed pollen use showed a predominant use of Attalea sp. (Arecaceae) and, for M. stilbonotaspis, Tylesia sp. and Lepidaploa sp. (Asteraceae). Babassu is a very common palm in the studied areas and the studied species seem to have a strong link with it. We also reported change of pollen use by M. sejuncta, probably due to competition with M. brasiliensis, which may have influenced the biased sex ratio observed in M. sejuncta toward males. Parasites reported here were also recorded for other Megachile species, such as Coelioxys, Brachymeria, Meloidae and Pyralidae species. Mites were observed in association with M. stilbonotaspis. The data presented here set up a background that encourages new studies on the ecology of these three Amazonian species, providing tools for proper biodiversity management and conservation.

Lack of correlation between micro fungi species and chemical control method of Atta treated with toxic baits / Ausência de correlação entre espécies de microfungos e método de controle químico de Atta tratadas com iscas tóxicas

ABSTRACT: Atta sexdens rubropilosa (leaf-cutter ants) has a symbiotic association with a fungus and has a negative interaction with other fungi due to parasitism of the fungus cultivated by ants; also, there are several other fungi with no exact known role occurring in their cultivated fungus garden. In the present study, we use the ITS region (internal transcribed spacer) to identify fungi in colonies treated with toxic baits. Experiments using two toxic baits were carried out: 0.75g of sulfluramid [0.3%] and 0.75g fipronil [0.003%]. Samples of fungi were collected and cultured in Czapek medium for seven days to allow fungal growth and subsequent identification. Total DNA was isolated from 100-150 mg of mycelium using the CTAB method and using PCR, with the universal primers (ITS4 and ITS5), to amplify the ITS region. Sequencing was performed using the Sanger method. Sequences were subjected to BLAST, allowing the identification of nine different species of the orders Agaricales, Eurotiales, Hypocreales, Pleosporales, Saccharomycetales and Tremellales showing a variation in identity of 96-100%. Using "The Automatic Barcode Gap Discovery" analysis, nine groups were identified, corresponding to species described in NCBI. The K2P distances were used to generate a tree using Neighbour-joining, demonstrating that the species were grouped according to phylogenetic groups. We concluded that leaf-cutter ant colonies exhibited a wide variety of fungi and this study suggested that there is no correlation between the species of fungi isolated with the control method used on the ant nest.

RESUMO: Atta sexdens rubropilosa (cortadeira de folha) possui associação simbiótica com fungos e interação negativa com outros fungos devido ao parasitismo do fungo cultivado pelas formigas. Quando colônias da formiga cortadeira de folhas são submetidas ao tratamento com iscas tóxicas, diversas espécies de fungos surgem dentro da colônia, podendo contribuir com a morte ou sobrevivência da colônia. Para entender os relacionamentos ecológicos em colônias de formigas, a identificação de espécie de fungos se torna muito importante e, o uso de DNA barcoding tem sido um método rápido e eficiente para identificação de espécies usando métodos moleculares. No presente trabalho, usamos a região ITS (internal transcribed spacer) para identificar fungos em colônias tratadas com iscas tóxicas. Dois experimentos com iscas tóxicas foram aplicados: 0.75g de Fipronil [0.003%] e 0.75g de Sulfluramid [0.3%]. As amostras, contendo os possíveis fungos, foram coletadas e cultivadas em meio Czaped durante sete dias para o crescimento do fungo e posterior identificação. O DNA total foi isolado de 100-150mg de micélio usando o método CTAB, usado para amplificar a região ITS por PCR empregando primers universais (ITS5 e ITS4). O sequenciamento foi realizado utilizando o método de Sanger. As sequências foram submetidas ao BLAST, permitindo identificar nove diferentes espécies das ordens Agaricales, Eurotiales, Hypocreales, Pleosporales, Saccharomycetales e Tremellales, mostrando variação 96-100% de identidade. Empregando a análise "The Automatic Barcode Gap Discovery", identificou-se nove grupos, correspondendo as espécies descritas no NCBI. As distâncias K2P foram usadas para gerar uma árvore usando Neighbour-Joining, apresentando que as espécies foram agrupadas de acordo com as filogenias dos grupos. Conclui-se que as colônias de formigas cortadeira de folhas apresentam grande diversidade de fungos e que DNA barcoding é eficiente para identificação destes.

Aflatoxins produced by Aspergillus nomius ASR3, a pathogen isolated from the leaf-cutter ant Atta sexdens rubropilosa

ABSTRACT Aspergillus spp. cause economic impacts due to aflatoxins production. Although the toxicity of aflatoxins is already known, little information about their ecological roles is available. Here we investigated the compounds produced by Aspergillus nomius ASR3 directly from a dead leaf-cutter queen ant Atta sexdens rubropilosa and the fungal axenic culture. Chemical analyses were carried out by high-resolution mass spectrometry and tandem mass spectrometry techniques. Aflatoxins B1 and G1 were detected in both the axenic culture and in the dead leaf-cutter queen ant. The presence of these mycotoxins in the dead leaf-cutter queen ant suggests that these compounds can be related to the insect pathogenicity of A. nomius against A. sexdens rubropilosa.

Biologia de nidificação e variação altitudinal na abundância de Megachile (Melanosarus) nigripennis Spinola (Hymenoptera, Megachilidae) em um inselberg na Mata Atlântica, Rio de Janeiro / Nesting biology and altitudinal variation in the abundance of megachile (melanosarus) nigripennis spinolla (hymenoptera, megachilidae) in an inselberg in the Mata Atlântica, Rio de Janeiro

Este trabalho descreve aspectos da biologia de nidificação de Megachile (Melanosarus) nigripennis e da abundância de ninhos em um gradiente de altitude (8 a 420 m), em um inselbergue, Morro do Itaoca (300 ha), Campos dos Goytacazes, RJ. Ninhos-armadilha em gomos de bambu e tubos de cartolina preta (n= 1.215, diâmetro de 0,6 a 2,7) foram instalados entre Mar/2009 e Abr/2011, em nove estações de amostragem localizadas em três altitudes: 50 m (P1, P2, P3); 200 m (P4, P5, P6) e 400 m (P7, P8, P9). As abelhas ocuparam ninhos-armadilha a 50m (n= 2), 200m (n= 24) e a 400 m (n= 5), onde construíram 4, 100 e 26 células, respectivamente. As abelhas construíram uma série de células em ninhos-armadilha com comprimento médio de 17.6 cm diâmetro médio de 1,1 cm; enquanto construíram de 2 a 6 série de células em ninhos com 19,3 cm de comprimento e 1,8 cm de diâmetro. A atividade de construção foi restrita à estação quente-chuvosa. A partir dos ninhos emergiram 64 abelhas, sete indivíduos de Coelioxys spp (Megachilidae) e dois Bombyliidae (Diptera). A razão sexual foi de 1: 0,52 tendenciado para machos. Em 20 ninhos emergiram somente machos (n= 15) ou fêmeas (n= 5), embora nenhum padrão espacial ou temporal tenha sido observado. M. nigripennis é uma espécie sazonal, nidificando preferencialmente de novembro a fevereiro.

This paper describes aspects of nesting biology of Megachile (Melanosarus) nigripennis and abundance of nests in a gradient of altitude (8 to 420m) in an inselberg, Morro do Itaoca (300 ha), Campos dos Goytacazes, RJ. Trap nests in bamboo canes and black cardboard tubes (n= 1.215, 0.6 to 2.7 diameter) were disposed from March/2009 to April/2011, in nine sampling stations located at three altitudes: 50 m (P1, P2, P3), 200 m (P4, P5, P6) and 400 m (P7, P8, P9). The bees occupied trap nests at 50 m (n= 2), 200 m (n= 24) and at 400 m (n= 5), where they built 4, 100 and 26 cells, respectively. Bees constructed one series of cells in trap nests with 17.6 cm average length and 1.1 cm average diameter ; whereas they constructed 2-6 series of cells in nests with 19.3 cm lenght and 1.8 cm diameter. Activity of nest construction was restricted to the warm-rainy season. From the nests emerged 64 bees, seven individuals of Coelioxys spp. (Megachilidae) and two Bombyliidae (Diptera). The sex ratio was 1: 0.52 biased to male. From 20 nests emerged only males (n= 15) or females (n= 5), although no temporal or spatial pattern has been observed. M. nigripennis is a seasonal species nesting in trap nests mainly from November to February.

Genetic variability and social structure of colonies in Acromyrmex heyeri and A. striatus (Hymenoptera: Formicidae)

The breeding structure of both colony and population of social insects can be examined by genetic analysis. Colonies of the leaf-cutting ants Acromyrmex heyeri and A. striatus (Myrmicinae, Attini) were thus analyzed for isoenzyme systems MDH, a-GPDH, and AMY to describe genotype variability and social structure. A total of five loci were investigated (three for amylase and one for each other system). Ninety-seven colonies of A. heyeri and 103 of A. striatus were sampled in different localities in Southern Brazil (State of Rio Grande do Sul). The genotypes found show the occurrence of monogyny and polygyny associated or not with polyandry, which indicates that the social organization is colony-specific. The polygyny and polyandry observed are likely to be responsible for the great genotypic diversity of the colonies. The average inbreeding coefficient per colony was higher in A. striatus than in A. heyeri, which may reflect the different patterns of production of sexual individuals and nuptial flight of those two species.

A estrutura de cruzamento de colônias e populações de insetos sociais pode ser observada por análise genética. Assim, colônias de formigas cortadeiras Acromyrmex heyeri e A. striatus (Myrmicinae, Attini) foram analisadas para os sistemas isoenzimáticos MDH, a-GPDH e AMY, a fim de descrever sua variabilidade genotípica e estrutura social. Foram investigados cinco locos (três para amilase e um para cada outro sistema), em 97 colônias de A. heyeri e 103 de A. striatus, amostradas em diversas localidades do Rio Grande do Sul. Os genótipos encontrados indicaram a ocorrência de monoginia e poliginia associadas ou não à poliandria, indicando que a organização social é colônia específica. Tanto a poliginia quanto a poliandria são responsáveis pela grande diversidade genotípica das colônias. O coeficiente de endocruzamento médio por colônia foi mais alto em A. striatus do que em A. heyeri e pode refletir os diferentes padrões de produção dos indivíduos sexuados e de vôo nupcial das duas espécies.