Acute and oral exposure to imidacloprid does not affect the number of circulating hemocytes in the stingless bee Melipona quadrifasciata post immune challenge.

In the present work, the effects of the neonicotinoid imidacloprid formulation on the total hemocyte counts (THC) and differential hemocyte counts (DHC) were investigated in foraging workers of the stingless bee Melipona quadrifasciata under (or not) the challenge with the bacteria Escherichia coli. The THC was not altered with the insecticide exposure and/or bacterial infection. However, the DHC of the bees changed with the imidacloprid exposure and/or bacterial infection. The number of prohemocytes (stem cells) increased in bees exposed to imidacloprid, but it did not change after the bacterial infection. The number of plasmatocytes (phagocytic cells) increased in imidacloprid-exposed and uninfected bees and decreased in infected bees regardless of the exposure to imidacloprid. On the other hand, there was a reduction of granulocytes, the most active immune cells, after imidacloprid exposure and an increase of granulocytes after the infection. Previous studies have shown that the neonicotinoids exposure can impair the immune system of bees. Our findings showed that the relative number of granulocytes declined with imidacloprid exposure, but the overall capacity of hemocyte responses in terms of total numbers after bacterial infection persisted even after the insecticide exposure.

The antennal sensilla of Melipona quadrifasciata (Hymenoptera: Apidae: Meliponini): a study of different sexes and castes.

The sensilla of insects are integumental units that play a role as sensory structures and are crucial for the perception of stimuli and for communication. In this study, we compared the antennal sensilla of females (workers and queens), males (haploid (n) and diploid (2n)), and queen-like males (QLMs, resulting from 2n males after juvenile hormone (JH) treatment) in the stingless bee Melipona quadrifasciata. Images of the dorsal antenna surfaces were acquired using a scanning electron microscope. As reported for other hymenopterans, this species exhibits a heterogeneous sensillar distribution along the antennae. Thirteen different types of sensilla were found in the antennae of M. quadrifasciata: trichodea (subtypes I to VI), chaetica (subtypes I and II), placodea, basiconica, ampullacea, coeloconica, and coelocapitula. Sensilla trichodea I were the most abundant, followed by sensilla placodea, which might function in olfactory perception. Sensilla basiconica, sensilla chaetica I, sensilla coeloconica, and sensilla ampullacea were found exclusively in females. In terms of the composition and size of the sensilla, the antennae of QLMs most closely resemble those of the 2n male, although QLMs exhibit a queen phenotype. This study represents the first comparative analysis of the antennal sensilla of M. quadrifasciata. The differences found in the type and amount of sensilla between the castes and sexes are discussed based on the presumed sensillary functions.

The use of polliniferous resources by Melipona capixaba, an endangered stingless bee species.

Abstract Pollen types present in samples from corbiculae of Melipona capixaba (Moure and Camargo) (Hymenoptera: Apidae: Meliponina) worker bees were analyzed, as well as pollen samples from food pots inside the hives in three sites located at the bees' original habitat. The aim was to find out the sources used as a trophic resource by this species. The dominant pollen grains in the spectrum of the samples belonged to the families Myrtaceae and Melastomataceae. Eucalyptus was the most frequent pollen type in the corbiculae in Conceição do Castelo municipality; Eucalyptus, Myrcia, and Melastomatacea/Combretaceae in the Fazenda do Estado district; and Eucalyptus and Myrcia in the São Paulo de Aracê district, both in the Domingos Martins municipality. Eucalyptus and Melastomataceae/Combretaceae were the predominant pollen types in the food pots. Eucalyptus was the most prevalent type all year round or most of the year. The most common pollen types in the months that Eucalyptus was not present or dominant in the samples were of remaining native forest species, "ruderal" (field) plants, fruit-bearing plants, and introduced ornamental plants.

Buzz-pollination in Neotropical bees: genus-dependent frequencies and lack of optimal frequency for pollen release.

Over 50 genera of bees release pollen from flower anthers using thoracic vibrations, a phenomenon known as buzz-pollination. The efficiency of this process is directly affected by the mechanical properties of the buzzes, namely the duration, amplitude, and frequency. Nonetheless, although the effects of the former two properties are well described, the role of buzz frequency on pollen release remains unclear. Furthermore, nearly all of the existing studies describing vibrational properties of natural buzz-pollination are limited to bumblebees (Bombus) and carpenter bees (Xylocopa) constraining our current understanding of this behavior and its evolution. Therefore, we attempted to minimize this shortcoming by testing whether flower anthers exhibit optimal frequency for pollen release and whether bees tune their buzzes to match these (optimal) frequencies. If true, certain frequencies will trigger more pollen release and lighter bees will reach buzz frequencies closer to this optimum to compensate their smaller buzz amplitudes. Two strategies were used to test these hypotheses: (i) the use of (artificial) vibrational playbacks in a broad range of buzz frequencies and amplitudes to assess pollen release by tomato plants (Solanum lycopersicum L.) and (ii) the recording of natural buzzes of Neotropical bees visiting tomato plants during pollination. The playback experiment indicates that although buzz frequency does affect pollen release, no optimal frequency exists for that. In addition, the recorded results of natural buzz-pollination reveal that buzz frequencies vary with bee genera and are not correlated with body size. Therefore, neither bees nor plants are tuned to optimal pollen release frequencies. Bee frequency of buzz-pollination is a likely consequence of the insect flight machinery adapted to reach higher accelerations, while flower plant response to buzz-pollination is the likely result of its pollen granular properties.

Bees and the Environmental Impact of the Rupture of the Fundão Dam.

The environmental consequences associated with the Fundão tailings dam failure in Mariana, Minas Gerais, Brazil on 5 November 2015 are still being investigated. Bees are the main pollinators believed to be most affected by the accident because they occur throughout the area affected by the dam rupture and build their nests in the soil. In this study, we evaluated the richness of different bee species in areas affected and not affected by the accident and measured the concentration of different metals on the pollen basket, or corbicula, located on the hind legs of Apis mellifera. Diversity indices were similar and there was no statistical difference in the diversity of bees sampled when comparing the sites affected and not affected by the tailings mud, either before or after the dam rupture. It is possible that the similarity is due to nearby forests that may be serving as areas of refuge. The levels of Al, Cu, Cd, Hg, and Pb in A. mellifera suggest no change in the level of metals in pollen collected by the bees that can be attributed to the rupture of the dam. Integr Environ Assess Manag 2020;16:631-635. © 2020 SETAC.

As consequências ambientais da ruptura da barragem de Fundão, ocorrida em Mariana, Minas Gerais, Brasil, em 5 de novembro de 2015, ainda estão sendo investigadas. As abelhas, principal grupo de polinizadores, podem ter sido afetadas direta e indiretamente, uma vez que a maioria das espécies constrói seus ninhos no solo. Neste estudo, avaliamos a riqueza de espécies de abelhas nas áreas afetadas e não afetadas e medimos a concentração de metais pesados nas corbículas de Apis mellifera, espécie que ocorre em toda a área afetada pela ruptura da barragem. Os índices de diversidade foram semelhantes e não houve diferença estatística na diversidade de abelhas amostradas quando comparamos locais afetados e não afetados pela lama de rejeitos após o rompimento da barragem. É possível que a semelhança se deva a florestas próximas que possam estar servindo como áreas de refúgio. Os resultados mostraram a presença de Al, Cu, Cd, Hg e Pb em A. mellifera. Nossos resultados indicam que não há efeito da contaminação de metais pesados nas abelhas devido à ruptura da barragem. Integr Environ Assess Manag 2020;16:631-635.

Karyotypic description of the stingless bee Meliponaquinquefasciata Lepeletier, 1836 (Hymenoptera, Meliponini) with emphasis on the presence of B chromosomes.

Stingless bees are distributed widely in the tropics, where they are major pollinators of several plant species. In this study, the karyotype of Meliponaquinquefasciata Lepeletier, 1836 was analysed, with emphasis on the presence of B chromosomes. Post-defecating larvae were analysed using Giemsa staining, the C-banding technique, sequential staining with fluorochromes, and FISH. The chromosome number ranged from 2n = 18 to 22 (females) and from n = 9 to 13 (males) due to the presence of 0-4 B chromosomes. This result demonstrates that M.quinquefasciata has the same chromosomal number as other Melipona Illiger, 1806 species. Considering the A complement, heterochromatin was located only in the pericentromeric region of pair 1. Staining with chromomycin A3 (CMA3) and labelling with rDNA probe, indicated that this region corresponded to the nucleolus organising region. The B chromosomes of M.quinquefasciata could be found in individuals from different localities, they were completely heterochromatic (C-banding) and uniformly stained by 4',6-diamidino-2-phenylindole (DAPI). Variations in the number of B chromosomes were detected between cells of the same individual, between individuals of the same colony, and between colonies from different localities.

[The knowledge of the population of Viçosa, MG, about the ways of AIDS transmission]. / Conhecimento da população de Viçosa, MG, sobre as formas de transmissão da aids.

AIDS is a major public health problem reaching all social strata. Knowing about the ways of transmission is a way of preventing the disease. For evaluating the level of knowledge of the population of the city of Viçosa about AIDS transmission, a questionnaire about the ways of transmission of the disease based on studies made in Europe was applied to 376 individuals. The questionnaire consisted of eleven multiple-choice questions about the ways of AIDS transmission, sex, age and educational level of the interviewees. The results showed that the ways of transmission emphasized in health campaigns are well assimilated, while the questions about everyday situations that offer no risk received a high number of incorrect answers. The differences were not significant when data were stratified by sex. The same data stratified by age or educational level showed significant differences for some questions; people aged over 55 and with a lower educational level had a significantly higher number of incorrect answers. It can be concluded that the population of Viçosa knows the main ways of AIDS transmission, but a part of the population does not know that some everyday situations do not pose risk of transmission. These data can be useful for the preparation of elucidative campaigns for reducing prejudice.

Prediction of social structure and genetic relatedness in colonies of the facultative polygynous stingless bee Melipona bicolor (Hymenoptera, Apidae)

Stingless bee colonies typically consist of one single-mated mother queen and her worker offspring. The stingless bee Melipona bicolor (Hymenoptera: Apidae) shows facultative polygyny, which makes this species particularly suitable for testing theoretical expectations concerning social behavior. In this study, we investigated the social structure and genetic relatedness among workers from eight natural and six manipulated colonies of M. bicolor over a period of one year. The populations of M. bicolor contained monogynous and polygynous colonies. The estimated genetic relatedness among workers from monogynous and polygynous colonies was 0.75 ± 0.12 and 0.53 ± 0.16 (mean ± SEM), respectively. Although the parental genotypes had significant effects on genetic relatedness in monogynous and polygynous colonies, polygyny markedly decreased the relatedness among nestmate workers. Our findings also demonstrate that polygyny in M. bicolor may arise from the adoption of related or unrelated queens.

Comparative study on the use of specific and heterologous microsatellite primers in the stingless bees Melipona rufiventris and M. mondury (Hymenoptera, Apidae)

Due to their high degree of polymorphism, microsatellites are considered useful tools for studying population genetics. Nevertheless, studies of genetic diversity in stingless bees by means of these primers have revealed a low level of polymorphism, possibly the consequence of the heterologous primers used, since in most cases these were not specifically designed for the species under consideration. Herein we compared the number of polymorphic loci and alleles per locus, as well as observed heterozygosity in Melipona rufiventris and M. mondury populations, using specific and heterologous primers. The use of specific primers placed in evidence the greater frequency of polymorphic loci and alleles per locus, besides an expressive increase in observed heterozygosity in M. rufiventris and M. mondury, thereby reinforcing the idea that populational studies should be undertaken by preferably using species-specific microsatellite primers.

Genetic variability in five populations of Partamona helleri (Hymenoptera, Apidae) from Minas Gerais State, Brazil

Partamona is a Neotropical genus of stingless bees that comprises 33 species distributed from Mexico to southern Brazil. These bees are well-adapted to anthropic environments and build their nests in several substrates. In this study, 66 colonies of Partamona helleri from five localities in the Brazilian state of Minas Gerais (São Miguel do Anta, Teixeiras, Porto Firme, Viçosa and Rio Vermelho) were analyzed using nine microsatellite loci in order to assess their genetic variability. Low levels of observed (Ho = 0.099-0.137) and expected (He = 0.128-0.145) heterozygosity were encountered and revealed discrete genetic differentiation among the populations (F ST =0.025). AMOVA further showed that most of the total genetic variation (94.24 percent) in P. helleri was explained by the variability within local populations.

Isoenzyme variation in Melipona rufiventris (Hymenoptera: Apidae, Meliponina) in Minas Gerais State, Brazil.

The stingless bee Melipona rufiventris is an important pollinator in several Brazilian ecosystems. Originally widely distributed in Minas Gerais (MG) state, this species is becoming very rare. Therefore this species was included in the endangered species list of MG. We used isoenzyme data for a better understanding of the genetic structure of several M. rufiventris colonies. Samples of 35 colonies were collected from 12 localities and evaluated by nine enzymatic systems, which yielded 17 loci. M. rufiventris genetic variation was found to be low, typical of an endangered species. The proportion of polymorphic loci was 5.88% in both ecosystems. Only Est-4 was polymorphic in colonies from the Forest and Mdh-1 in colonies from the Cerrado. The expected heterozygosity ranged from 0.0068 in the Cerrado to 0.0078 in the Forest. Despite this, enzyme electrophoretic analyses provided a good idea of the diversity between samples from Cerrado and Forest which reinforce the existence of two different "forms" of M. rufiventris in MG, one present in the Cerrado and the other in Forest. This information is of great importance for the conservation of M. rufiventris in MG.

Cytogenetic characterization of Partamona cupira (Hymenoptera, Apidae) by fluorochromes

Four colonies of the stingless bee Partamona cupira (Hymenoptera: Apidae) were cytogenetically analyzed using conventional staining and the fluorochromes CMA3 e DAPI. The females have 2n = 34 chromosomes (2K=32+2). Some females, however, presented an additional large B acrocentric chromosome, to a total of 2n = 35. Chromosome B and the chromosomal pairs 2, 9 and 10 showed CMA3+ bands, indicating an excess of CG base-pairs. A clear association was verified between the P. helleri B chromosome SCAR marker and the presence of a B chromosome in P. cupira. The data obtained suggests that B chromosomes in P. helleri and P. cupira share a common origin.

DNA characterization and karyotypic evolution in the bee genus Melipona (Hymenoptera, Meliponini).

We analyzed patterns of heterochromatic bands in the Neotropical stingless bee genus Melipona (Hymenoptera, Meliponini). Group I species (Melipona bicolor bicolor, Melipona quadrifasciata, Melipona asilvae, Melipona marginata, Melipona subnitida) were characterized by low heterochromatic content. Group II species (Melipona capixaba, Melipona compressipes, Melipona crinita, Melipona seminigra fuscopilosa e Melipona scutellaris) had high heterochromatic content. All species had 2n = 18 and n = 9. In species of Group I heterochromatin was pericentromeric and located on the short arm of acrocentric chromosomes, while in Group II species heterochromatin was distributed along most of the chromosome length. The most effective sequential staining was quinacrine mustard (QM)/distamycin (DA)/chromomycin A3(CMA3)/4-6-diamidino-2-phenylindole (DAPI). Heterochromatic and euchromatic bands varied extensively within Group I. In Group II species euchromatin was restricted to the chromosome tips and it was uniformly GC+. Patterns of restriction enzymes (EcoRI, DraI, HindIII) showed that heterochromatin was heterogeneous. In all species the first pair of homologues was of unequal size and showed heteromorphism of a GC+ pericentromeric heterochromatin. In M. asilvae (Group I) this pair bore NOR and in M. compressipes (Group II) it hybridized with a rDNA FISH probe. As for Group I species the second pair was AT+ in M. subnitida and neutral for AT and GC in the remaining species of this group. Outgroup comparison indicates that high levels of heterochromatin represent a derived condition within Melipona. The pattern of karyotypic evolution sets Melipona in an isolated position within the Meliponini.

Cytogenetic characterization of Melipona rufiventris Lepeletier 1836 and Melipona mondury Smith 1863 (Hymenoptera, Apidae) by C banding and fluorochromes staining

The stingless bees Melipona rufiventris and M. mondury were analyzed cytogenetically by conventional staining with Giemsa, C-banding and sequential staining with the fluorochromes CMA3/DA/DAPI. Both species presented 2n = 18 and n = 9, except for one colony of M. rufiventris, in which some individuals had 2n = 19 due to the presence of a B chromosome. After Giemsa staining and C-banding the chromosomes appeared very condensed and presented a high heterochromatic content, making it difficult to localize the centromere and therefore to visualize the chromosomes morphology. The constitutive heterochromatin was located in interstitial chromosome regions covering most of the chromosomes extension and consisted mainly of AT, as shown by DAPI staining. The euchromatin was restricted to the chromosome extremities and was GC-rich, as evidenced by CMA3 staining. The B chromosome was CMA3-negative and DAPI-positive, a heterochromatic constitution similar to that of the A genome chromosomes.

Conhecimento da população de Viçosa, MG, sobre as formas de transmissão da aids / The knowledge of the population of Viçosa, MG, about the ways of AIDS transmission

A aids é um dos mais graves problemas de saúde pública atuais e uma importante forma de prevenção reside no conhecimento, por parte da população, das formas de transmissão da doença. Com o objetivo de avaliar o grau de conhecimento da população da cidade de Viçosa em relação às formas de transmissão da aids, foram aplicados 376 questionários, com onze perguntas de múltipla escolha sobre as formas de transmissão da aids, bem como sexo, idade e escolaridade dos entrevistados. Os dados mostraram que as formas de transmissão enfatizadas pelas campanhas de saúde estão bem assimiladas, enquanto situações do cotidiano que não oferecem risco apresentaram elevado número de respostas incorretas. As diferenças encontradas entre os sexos não foram significativas. Quando os dados foram estratificados por idade e escolaridade, foram encontradas diferenças significativas para algumas perguntas em que as pessoas com mais de 55 anos e de menor escolaridade apresentaram maior número de respostas incorretas. Pode-se concluir que a população viçosense conhece as principais formas de transmissão da aids, mas uma parte desconhece a ausência de risco de algumas atividades cotidianas. Esses dados podem ser usados para a elaboração de campanhas de esclarecimento visando à redução do preconceito.

AIDS is a major public health problem reaching all social strata. Knowing about the ways of transmission is a way of preventing the disease. For evaluating the level of knowledge of the population of the city of Viçosa about AIDS transmission, a questionnaire about the ways of transmission of the disease based on studies made in Europe was applied to 376 individuals. The questionnaire consisted of eleven multiple-choice questions about the ways of AIDS transmission, sex, age and educational level of the interviewees. The results showed that the ways of transmission emphasized in health campaigns are well assimilated, while the questions about everyday situations that offer no risk received a high number of incorrect answers. The differences were not significant when data were stratified by sex. The same data stratified by age or educational level showed significant differences for some questions; people aged over 55 and with a lower educational level had a significantly higher number of incorrect answers. It can be concluded that the population of Viçosa knows the main ways of AIDS transmission, but a part of the population does not know that some everyday situations do not pose risk of transmission. These data can be useful for the preparation of elucidative campaigns for reducing prejudice.

Genetic variability in Partamona helleri (Hymenoptera: Apidae) populations with and without B chromosomes / Variabilidade genética em populações de Partamona helleri (Hymenoptera: Apidae) com e sem cromossomos B

Partamona helleri individuals have already been found with up to four B chromosomes. This study assessed whether these chromosomes would have any effect on the P. helleri genetic variability. Twenty colonies were selected and divided into three groups: 1) colonies in which no individual possessed B chromosomes; 2) colonies in which some, but not all, individuals possessed B chromosomes, and, 3) colonies in which all the individuals possessed Bchromosomes. The DNA from 8 individuals of each colony was analyzed using the PCR-RAPD technique. The heterozygosity values estimated were 0.168, 0.159 and 0.16643 for the three groups, respectively. The molecular analysis of variance showed that 94.16% of the genetic variability was due to differences within the groups, while only 5.84% was distributed among the groups. These data and the graphic dispersion analysis performed suggest that the B chromosomes have no significant effect on P. helleri genetic variability.

Em Partamona helleri já foram encontrados indivíduos com até quatro cromossomos B. Neste trabalho, avaliou-se se estes cromossomos teriam algum efeito sobre a variabilidade genética de P. helleri. Vinte colônias foram selecionadas e divididas em três grupos: 1) colônias nas quais nenhum indivíduo possuía cromossomos B; 2) colônias nas quais alguns indivíduos possuíam cromossomos B e outros não e, 3) colônias nas quais todos os indivíduos possuíam cromossomos B. O DNA de 8 indivíduos de cada colônia foi analisado através da técnica de PCR-RAPD. Os valores da heterozigosidade estimada foram 0,168, 0,159 e 0,166 para os três grupos, respectivamente. A análise molecular de variância demonstrou que 94,16 % da variabilidade genética foi devida a diferenças dentro dos grupos, enquanto apenas 5,84% estava distribuída entre os mesmos. Estes dados e a análise de dispersão gráfica realizada sugerem que os cromossomos B não têm nenhum efeito significativo sobre a variabilidade genética de P. helleri.

Melípona: seis décadas de citogenética / Melípona: six decade of cytogenetic

São 59 anos de estudos citogenéticos no gênero Melipona e esse artigo é uma revisão dessa história, que vai desde trabalhos com apenas a determinação do número cromossômico até os trabalhos de citogenética molecular. Os principais focos do artigo são: o número e morfologia dos cromossomos, conteúdo heterocromático e a natureza da cromatina. Fundamentadas nesses dados são feitas inferências sobre a evolução cariotípica do gênero.

They are 59 years of cytogenetics study in Melipona genus and this paper has a review about this history, going to the works only with the chromosome number determination, up to molecular cytogenetic. The mainly focuses of this paper are: chromosome number and morphology, heterochromatin content and the chromatin nature. With base of this data they are realized inferences about the karyotype evolution of this genus.

Genetic divergence between populations of the stingless bee uruçu amarela (Melipona rufiventris group, Hymenoptera, Meliponini): is there a new Melipona species in the Brazilian state of Minas Gerais?

Allozyme, microsatellite and random amplified polymorphic DNA (RAPD) molecular markers were used to investigate the within and between population genetic variability and between population genetic differentiation of the Brazilian stingless bee uruçu amarela (nominally Melipona rufiventris Lepeletier, 1836) present in savanna and Atlantic forest habitats of the Brazilian state of Minas Gerais (MG). We found low levels of within population variability, although there were a large number of private alleles that specifically characterized these populations. The F ST values indicated a high level of genetic diversity between populations. Analysis of molecular variance (AMOVA) showed a high degree of population differentiation between the savanna and Atlantic forest habitats, confirmed by population pairwise F ST data. Principal coordinates analysis and unweighted pair-group method using an arithmetic average (UPGMA) dendrograms also confirmed that in Minas Gerais the savanna populations (M. rufiventris) were genetically distinct from those present in the Atlantic forest (M. mondury). In addition, populations from locations near the towns of Dom Bosco and Brasilândia de Minas were genetically different from those collected in other localities in the savanna. Our data indicate that populations of uruçu amarela found in the savanna and Atlantic forest habitats of Minas Gerais state should be treated separately for conservation purposes and that special attention should be given to the populations found in the region of Dom Bosco and Brasilândia de Minas until their taxonomic status is clarified.

Correlation between honey production and some morphological traits in africanized honey bees (Apis melifera)

This study focused on the correlation between honey production length and width of the tibia of the third pair of legs, corbicular area, pupal weight, and glossal length, in Africanized honey bees in Viçosa/MG, Brazil. Correlation values were relatively low, though always positive. The traits glossal length and pupal weight presented the lowest correlation to honey production: 0.225 and 0.410, respectively. The highest correlations were observed between length of the tibia and corbicular area and honey production: 0.587 and 0.549, respectively. In all cases, except pupal weight, correlation was significant. These findings support the notion that worker bees with larger corbicular areas may have a better ability to carry larger quantities of pollen to their hives, so that it is possible to improve honey production through indirect selection of this trait