Pesticide Exposure Assessment Paradigm for Stingless Bees.

Although the importance of bees as the pollinators responsible for maintaining gene flow for many native and cultivated plants in ecosystems around the world is recognized, much of their biodiversity and behavior remains to be discovered. Stingless bees are considered key pollinators for several plant species in tropical and subtropical ecosystems and they also provide pollination services for economically important agricultural crops. Many countries are using the honey bee (Apis mellifera Linnaeus, 1758, Hymenoptera: Apidae) as a surrogate to evaluate the risk of pesticides to all species of bees. However, there is uncertainty regarding the extent to which honey bees can serve as surrogates for non-Apis bee species in the risk assessment for pesticides. This paper provides a short overview of the life history traits relevant in risk assessment of stingless bees. It summarizes what is known about stingless bee exposure to pesticides compared to that of honey bees and presents criteria for potential candidate species from Brazil for use in pesticide risk assessment in tropical environments. This paper also identifies gaps in knowledge of bee biology and pesticide exposure routes not covered by the current honey bee exposure assessment paradigm. Based on these gaps, research is needed on life history traits, estimates of nectar and pollen consumption, mud, resin, and water collection and available protocols to adequately assess toxic effects of pesticides to stingless bees. This review is part of a series of papers on the risk of exposure of non-Apis bees to pesticides.

Genetic Variability of Melipona subnitida (Hymenoptera: Apidae) in Introduced and Native Populations.

Melipona subnitida (Hymenoptera: Apidae) is a stingless bee native to Caatinga biome in Brazil, well adapted to hot and dry climate of that region and has been traditionally explored for honey production. Here, we evaluate the genetic structure of 173 colonies of M. subnitida in northeast Brazil by partially sequenced mitochondrial genes cytochrome oxidase I (COI) to compare an introduced population isolated for 30 yr into the Island of Fernando de Noronha (IFN) with the continental populations. We identified high haplotype diversity (0.8220) with 14 haplotypes on the continental populations, being three new ones, compared with the database GenBank. The haplotype H4 was present at the center of network, occurring in four localities on mainland and fixed as a single haplotype on IFN. We propose that the island populations originally introduced carried one haplotype (H4), even though IFN population is suffering pressure by island effect through changes on morphology. Studies on island populations could be a model to understand the dynamics of isolated populations and sustainable management of this biome to preserve M. subnitida.

Mutually beneficial pollinator diversity and crop yield outcomes in small and large farms.

Ecological intensification, or the improvement of crop yield through enhancement of biodiversity, may be a sustainable pathway toward greater food supplies. Such sustainable increases may be especially important for the 2 billion people reliant on small farms, many of which are undernourished, yet we know little about the efficacy of this approach. Using a coordinated protocol across regions and crops, we quantify to what degree enhancing pollinator density and richness can improve yields on 344 fields from 33 pollinator-dependent crop systems in small and large farms from Africa, Asia, and Latin America. For fields less than 2 hectares, we found that yield gaps could be closed by a median of 24% through higher flower-visitor density. For larger fields, such benefits only occurred at high flower-visitor richness. Worldwide, our study demonstrates that ecological intensification can create synchronous biodiversity and yield outcomes.

Honey bees (Apis mellifera) visiting flowers of yellow melon (Cucumis melo) using different number of hives / Visita de abelhas melíferas (Apis mellifera) em flores de melão amarelo (Cucumis melo) usando diferente número de colmeias

Honey bees (Apis mellifera) pollinate melon (Cucumis melo) and improve production and quality of fruits. However, little is known about bee behavior and number of hives required. The aims of this study were to compare bees visiting flowers in crop areas with different number of hives (0, 1, 2, and 3), and to evaluate which is the best number. Flowers were observed (n=78) from 5 am to 6 pm, for five consecutive days, in four experimental areas (0.5ha each). Comparisons were made for male (MF) and hermaphrodite (HF) flowers, number of hives and fruit production. The HF were always more visited than MF. Most comparisons made for three hives presented significant differences, since visits increased drastically, competition among bees for floral resources became stronger and reduced the production of commercial fruit (93.4%). On the other hand, the highest percentage of commercial fruit was obtained (99%) with two hives, setting the ideal number of hives as four hives ha-1.

As abelhas melíferas (Apis mellifera) polinizam o melão (Cucumis melo) e melhoram a produção e qualidade dos frutos. Entretanto, pouco é conhecido sobre seu comportamento e o número de colmeias necessário. Os objetivos deste trabalho foram comparar a visitação das abelhas nas flores em áreas de cultivo com diferente número de colmeias (0,1, 2 e 3) e avaliar a produção de frutos em cada situação. Nas quatro áreas experimentais (0,5 ha cada), foram observadas flores (n=78), de 5 às 18h, por cinco dias consecutivos. Foram realizadas comparações para as flores masculinas (FM) e hermafroditas (FH), número de colmeias e produção de frutos. Os resultados mostraram que sempre as FH foram mais visitadas que as FM. A maioria das comparações feitas para três colmeias apresentaram diferenças significativas, já que as visitas aumentaram drasticamente. Provavelmente, a competição entre as abelhas pelos recursos florais foi maior e reduziu a produção de frutos comerciais (93,4%). Por outro lado, com duas colmeias, obteve-se a maior porcentagem de frutos comerciais (99%), indicando que o número ideal é de quatro colmeias ha-1.

Bees for development: Brazilian survey reveals how to optimize stingless beekeeping.

Stingless bees are an important asset to assure plant biodiversity in many natural ecosystems, and fulfill the growing agricultural demand for pollination. However, across developing countries stingless beekeeping remains an essentially informal activity, technical knowledge is scarce, and management practices lack standardization. Here we profited from the large diversity of stingless beekeepers found in Brazil to assess the impact of particular management practices on productivity and economic revenues from the commercialization of stingless bee products. Our study represents the first large-scale effort aiming at optimizing stingless beekeeping for honey/colony production based on quantitative data. Survey data from 251 beekeepers scattered across 20 Brazilian States revealed the influence of specific management practices and other confounding factors over productivity and income indicators. Specifically, our results highlight the importance of teaching beekeepers how to inspect and feed their colonies, how to multiply them and keep track of genetic lineages, how to harvest and preserve the honey, how to use vinegar traps to control infestation by parasitic flies, and how to add value by labeling honey containers. Furthermore, beekeeping experience and the network of known beekeepers were found to be key factors influencing productivity and income. Our work provides clear guidelines to optimize stingless beekeeping and help transform the activity into a powerful tool for sustainable development.

Impacto da precipitação pluviométrica sobre a atividade de vôo de Plebeia remota (Holmberg, 1903) (Apidae, Meliponini) / Rain effect on flight activity of Plebeia remota (Holmberg, 1903) (Apidae, Meliponini)

Através de um sistema automatizado, a atividade do vôo de forrageiras de quatro colônias de Plebeia remota foi registrada ao mesmo tempo, de dezembro de 1998 a dezembro de 1999. Havia uma quantidade grande de dados que permitiram uma análise quantitativa e sazonal do impacto da pluviosidade sobre a atividade de vôo. As colônias vieram de duas localidades diferentes: Cunha, Mata Atlântica de São Paulo e Prudentópolis, Mata Araucária no Paraná. Números percentuais referentes à atividade de vôo para o momento que antecedia em uma hora a chuva, como também durante e após a precipitação, são apresentados. Em todas as colônias observaram-se, predominantemente, decréscimos na atividade externa de P. remota, tanto antes como durante a precipitação. Após cessar a chuva, houve um predomínio de acréscimos, o que indica uma compensação da atividade de vôo em relação ao período chuvoso. De modo geral, o maior decréscimo de atividade de vôo, antes da chuva, ocorreu no outono e o maior acréscimo de atividade de vôo, depois da chuva, ocorreu na primavera. Alterações nesta atividade foram observadas com a variação da intensidade, freqüência e duração das precipitações pluviométricas. A atividade externa foi pouco alterada quando a precipitação foi de até 1,0 mm, mas com o aumento de intensidade, os valores de decréscimo nesta atividade aumentaram. Quando a precipitação ocorreu apenas uma vez por dia, os decréscimos na atividade de vôo foram maiores, comparados às chuvas intermitentes. Chuvas com duração maior que 1 hora causaram decréscimos maiores na atividade de vôo, do que precipitações de curta duração. A atividade do vôo foi bem diferente quando comparados dias com chuva e dias sem chuva, assim como a atividade do vôo foi influenciada diferentemente em dias chuvosos no verão e no inverno. Entretanto, este comportamento não permitiu discriminar as populações.

Through an automated system, foragers' flight activity of four colonies of Plebeia remota was registered simultaneously from December 1998 to December 1999. The large amount of data obtained has allowed a quantitative and seasonal analysis of the rain impact on the bees' flight activity. The colonies came from two different localities: Cunha, Atlantic Rainforest in São Paulo State and Prudentópolis, Araucaria Forest in Paraná State. Percent numbers related to the flight activity for the moment that preceded the rain in one hour, as well as during and after the precipitation are presented. In all colonies, it was observed that the flight activity of P. remota has predominantly decreased before and during the precipitation. After it stopped raining, there was a predominance of increases, what indicates a compensation of flight activity in relation to the rainy period. In general, the greatest decrease of flight activity before rain, occurred in the autumn and the greatest increase of flight activity after rain, occurred in the spring. Alterations in this activity were observed with the variation of intensity, frequency and duration of precipitation. The external activity was little modified when the precipitation was up to 1.0 mm. However, when the rain intensity increased, the bees reduced strongly their flight activity. When the rain occurred only once per day, the decreases in the flight activity were greater, when compared to intermittent rain. Rains that lasted more than one hour caused larger decreases in the flight activity than precipitations of short duration. Flight activity was quite different when we compared days with rain and days without rain, as well as, flight activity was differently influenced in rainy days in the summer and in the winter. However, this behavior (response of flight activity to rain) did not allow to discriminate both populations.

Efeito do vento sobre a atividade de vôo de Plebeia remota (Holmberg, 1903) (Apidae, Meliponini) / Wind effect on flight activity of Plebeia remota (Holmberg, 1903) (Apidae, Meliponini)

Através de um sistema automatizado, a atividade do vôo de forrageiras de quatro colônias de Plebeia remota foi registrada, simultaneamente, de dezembro de 1998 a dezembro de 1999. A grande quantidade de dados obtidos permitiu uma análise quantitativa e sazonal do efeito da velocidade e direção do vento sobre a atividade de vôo. Nas quatro estações, a menor atividade de vôo de Plebeia remota ocorreu quando não houve vento ou quando a velocidade média do vento esteve abaixo de 0,5 m/s. Os picos de atividade de vôo ocorreram em velocidades de vento maiores e variaram segundo as estações e as colônias. No verão, os picos de atividade de vôo estiveram entre 3,5 e 5,5 m/s de velocidade, no outono, na classe 4,0-4,5 m/s, e na primavera entre 4,5 e 6,0 m/s. Entretanto, no inverno, houve clara restrição da atividade externa sob velocidades de vento superiores a 5,5 m/s. As forrageiras de P. remota orientaram preferencialmente seus vôos para certas direções de vento. Exceto no verão, as direções predominantes de vôo foram similares entre as quatro colônias. Estas direções também coincidiram com a posição dos recursos florais mais utilizados pelas colônias. Quando as forrageiras tinham que sair da colônia com vento contra, se registrou menor atividade de vôo.

Through an automated system, foragers' flight activity of four colonies of Plebeia remota was registered at same time from December 1998 to December 1999. The large amount of data obtained allowed a quantitative and seasonal analysis of the effect of speed and direction of wind on their flight activity. In all four seasons, the smallest flight activity of Plebeia remota occurred when there was no wind or when the wind speed average was below 0.5 m/s. The flight activity peaks occurred in higher measured wind speeds and varied according to the seasons and the colonies. In the summer, the flight activity peaks occurred between 3.5 and 5.5 m/s of speed, in the autumn, in the series 4.0-4.5 m/s, and in the spring between 4.5 and 6.0 m/s. In the winter, clear restriction upon flight activity occurred in wind speeds above 5.5 m/s. Plebeia remota foragers guided preferentially their flights for certain wind directions. Except summer, the directions were similar to the four colonies. These directions matched with the locations where the most used floral resources are. On the other hand, lowest flights number coincided with conditions when the foragers would left their colonies upwind.