The foraging range of bees determines the spatial scale over which each species can provide pollination services. In agricultural ecosystems, productivity is related not only to the taxonomic diversity of bees per se, but also to the location of their nesting sites, which reflects on their flying range. Within this context, the present study sought to assess how wild bee assemblages affect the yield of Brassica napus at three different distances (25 m, 175 m, 325 m) from forest remnants in Southern Brazil. Bees were sampled by means of pan traps and findings were analyzed using the Shannon diversity index and generalized linear models. We identified 11 species of native bees, both solitary and social, as well as the exotic species Apis mellifera, which was most abundant. Our findings show that canola crop yield were positively influenced by the diversity of bee species. This demonstrates that native bees, not only A. mellifera, can contribute significantly to the productivity of canola crops. In addition, we found that bee body size is significantly associated with flight distance traveled within the canola fields, and demonstrated a relationship with nesting sites. Thus, we hypothesize that canola yields are associated with the presence of wild bee species, both social and solitary, and that maintenance of these pollinators is directly dependent on practices adopted in rural areas, whether within plantation fields per se or in forest remnants used as nesting sites by wild bees.

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High genetic diversity is important for the functioning of large insect societies. Across the social Hymenoptera (ants, bees, and wasps), species with the largest colonies tend to have a high colony-level genetic diversity resulting from multiple queens (polygyny) or queens that mate with multiple males (polyandry). Here we studied the genetic structure of Trigona spinipes, a stingless bee species with colonies an order of magnitude larger than those of polyandrous honeybees. Genotypes of adult workers and pupae from 43 nests distributed across three Brazilian biomes showed that T. spinipes colonies are usually headed by one singly mated queen. Apart from revealing a notable exception from the general incidence of high genetic diversity in large insect societies, our results reinforce previous findings suggesting the absence of polyandry in stingless bees and provide evidence against the sperm limitation hypothesis for the evolution of polyandry. Stingless bee species with large colonies, such as T. spinipes, thus seem promising study models to unravel alternative mechanisms to increase genetic diversity within colonies or understand the adaptive value of low genetic diversity in large insect societies.

Bees are important for the world biodiversity and economy because they provide key pollination services in forests and crops. However, pesticide use in crops has adversely affected (decreased) queen production because of increased mortality among larvae. Here, we demonstrated that in vitro-reared queens of a neotropical social bee species (Plebeia droryana) also showed high larval mortality after exposure to an organophosphate pesticide (chlorpyrifos) via larval food. Moreover, most of the surviving larvae that were destined to develop into queens became workers more likely because they ate less food than expected without pesticide skewing thus caste differentiation in this bee species. This adverse effect has not been previously reported for any other social insects, such as honeybees or bumblebees. Queens are essential for breeding and colony growth. Therefore, if our data are applicable to other pantropical social bee species across the globe, it is likely that these bees are at a serious risk of failure to form new colonies.

Pollination by bees improves agricultural crop yields and improves the financial outlook of beekeepers because it increases honey production and hive rental revenues. However, in Brazil, with a few exceptions, these benefits have been neglected in recent years because beekeepers are more interested in honey production than in agricultural pollination. The excessive and indiscriminate use of insecticides on agricultural fields in Brazil appears to be one of the principal obstacles preventing partnership between farmers and beekeepers. The goal of this study was therefore to evaluate the most recent situation in Brazil in relation to the use of insecticides, agriculture and to honey production in comparison with other countries. Our results show that Brazil is the largest consumer of insecticides in the world and that consumption has increased by > 150% over 15 years. While countries with a high Human Development Index (i.e., a measure that can also be used to question national policy choices) are reducing their levels of insecticide use in agriculture, Brazil is going in the opposite direction. It is highly likely the increase seen in other countries is a result of alternative methods for pest control rather than a result of the amount of area under agricultural cultivation and their capability to shift their economies from agriculture to other sectors. The number of hives (23%) and the volume of honey production (72%) in Brazil have, however, increased over the same period, raising Brazil to the ninth highest honey producer in the world. Although the data on apiculture are promising, the growth in use of insecticides in Brazil is a cause for concern because they leave residuals on bee products, on crops, and in the environment. Civil society and government in Brazil should encourage reductions in insecticide use and better relations between agricultural farmers and beekeepers.

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1. Animal trade, such as birds, mammals and reptiles, is a common human activity.Among insects, few are as charismatic as bees. Their hives are commonly commercialized for multiple purposes, such as honey production, crop pollination and leisure. However, hive trade has the potential to adversely introduce species into novel places in a widespread way. 2. Our main objectives were to evaluate the trade flow of stingless beehives in Brazil by comparing the geographical distances and climatic features between origin and destination as well as by determining the potential impact on endangered (EN) native bee species.3. We performed species distribution modelling to estimate their respective natural habitats. After that, we carried out a principal component analysis characterizing the climatic features found within their natural habitats and those where bees were negotiated. Subsequently, we applied hierarchical clustering followed by a Procrustes analysis to evaluate the contrast between the climatic niches of original and destination places. We also checked the conservation status of each species being commercialized and whether exotic species could be introduced within their areas. 4. At least nine species of stingless bees were negotiated during the surveyed period. The hives were requested for almost 100 different localities. Over 40% of sellers and buyers were located outside the natural range of the stingless bee species being negotiated, and half of interested people were as far as 320 km. Climatic features vary considerably between natural habitat and traded regions.This implies that some species might suffer and perish due to intolerance to new climatic features. Nonetheless, species can be taken to new areas that are climatically suitable, creating a risk of biological introduction and invasion events.

Very little is known about stingless bee reproductive biology or male behaviour. In this note we provide the first observations on the male aggregations (congregation sites and roosting sites) of some stingless bee species. Our observations show that males of two stingless bee species can congregate on the same site. We also report for the first time the substrates used by stingless bee males for resting at night, that at least one species forms large sleeping roosts composed of hundreds of individuals, and that sleeping roost locations are not reused on subsequent nights.