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Stingless bees (Meliponini) are expected to play a central role in structuring mutualistic networks in the Neotropics, as they are generalist and often abundant pollinators. Living in populous social colonies with a perennial life cycle, they require continuous large amounts of resources and often forage on abundant flowerings such as mass‐flowering throughout the year.In this field research, we seek to understand how temporal variations on foraging activity of stingless bees and abundance of mass‐flowering partner plants affect the topology of the plant–pollinator mutualistic networks. The networks were compared between spring and summer, periods of high and low abundances of flowerings and mass‐flowering, respectively.Bees were sampled on flowers, in replicates of floodplain fields in Atlantic Forest of southern Brazil. Interactions with partner plants were considered effective only when bees had pollen on their bodies (potential pollinators). Through analysis of pollen grains attached to their bodies, several topological metrics of networks and functional categories were obtained. The robustness or networks resistance to secondary species loss due to simulated focal species extinction was also measured.The networks maintained similar general structure throughout the year (high nestedness, moderate modularity and connectance, low community‐level specialisation and negative dependency asymmetry). Particularly, nestedness and dependency asymmetry did not change between the two seasons. Community‐level specialisation was higher in summer, contrary to expectations, when there was a collapse in the supply of floral resources and also a reduction in the abundance and foraging pressure of stingless bees. As there was also a greater number of specialist pollinators in summer, the hypothesis of temporal displacement due to foraging pressure from generalists was proposed. At the same time, stingless bees oscillated between network hubs in spring and connectors in summer, reflecting the variation in their abundance between these two seasons. In spring, the greater concentration of foraging by these generalists in the abundant mass‐flowering probably attenuated their diffuse competitive pressure on all other pollinators, even though the foraging overlap was higher in this period. In this period of high abundance of floral resources, specialist pollinators capable of expanding the realised niche are active.Based on recent theoretical conclusions of dynamic model of mutualistic networks structure that incorporated effects of inter‐specific competition and adaptive foraging, we argue that the adaptive foraging of generalist and abundant stingless bees contributes in an important way to the high nestedness and robustness of networks, which ultimately favour the coexistence of species in the long term. Particularly, taking the high intra‐annual turnover of bee and plant species between the two seasons, and the similar floral constancy of both generalist stingless bees and specialist pollinators, we also infer that stingless bees act as generalised pollinators in the networks rewiring throughout the year. [ABSTRACT FROM AUTHOR]

Context: Human disturbances are one of the main reasons for the recent deficit of pollinators, which can cause severe habitat loss, decreasing food availability and nesting resources for pollinators. However, few studies show how landscapes composition and configuration can impact the pollen foraging of bees. Objectives: We aimed to evaluate how landscape structure and local characteristics can influence the pollen foraging patterns of the stingless bee Melipona quadrifasciata anthidioides in agricultural landscapes of Chapada Diamantina, a region of the Bahia state in Brazil. Methods: Pollen samples were collected from fourteen M. quadrifasciata anthidioides colonies to evaluate how pollen collection varies according to different proportions of human land-use, landscape heterogeneity, plant richness and distance from crops. To explain the richness and diversity of pollen collected by bees, we used generalized linear models, and linear models, compared through the Akaike information criteria corrected for small samples (AICc). Results: Pollen richness can be explained by the distance from crops, plant richness and human land-use proportion. Bees will collect pollen from more plant species when they are in a natural and diverse landscape. Conclusions: Pollinator friendly crop areas must be planned to be surrounded by diverse natural nearby environments, guaranteeing yearlong pollen resources available for bees' maintenance. [ABSTRACT FROM AUTHOR]

Cities provide resources for the animals that live in them or their surroundings. There has been an increase in the number of ecological studies in urban areas, including interactions between plants and bees. Bees are pollinators that provide a vital ecosystem service to crops and wild plants. We assessed plant community structure in the campus of Universidade de São Paulo in Ribeirão Preto, Brazil, included in the neotropical Atlantic Forest biome, focusing on floristic composition, pollination syndromes, flowering phenology, and spatiotemporal distribution of floral resources for bees. Currently, the city is surrounded by sugar cane plantations. Once a month, from April 2011 to March 2012, we sampled plant species and individuals in bloom in an area with 500 m radius from the bee-rearing facilities of Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP), totaling 78 hectares. We sampled 289 plant species of 73 families; Leguminosae was the richest family. Plants pollinated by bees predominated (67%), followed by plants pollinated by hummingbirds (18%). Melittophilous species flowered throughout the year and, hence, food availability for bees was continuous. The flowering of plant individuals that provided pollen, nectar, and floral oil was seasonal in all vegetation (except for nectar in shrubs), with peaks in resource availability in the transition from the dry to the rainy season, and also in the rainy season. Our results show that the campus is able to maintain bee populations amid a monoculture matrix, acting as a refuge. In addition, it provides a list of several attractive native plants to different pollinator groups, coupled with a phenogram, that can be used in the design and planning of urban areas. [ABSTRACT FROM AUTHOR]

The article discusses a study that investigated plants used by the Centris tarsata bee species for its larval food supply in southern Brazil and determined if the bee is polylectic or oligolectic in the region. The study was conducted from March 2002 to December 2003 in the Parque Municipal das Araucárias, Guarapuava (PR) in southern Brazil. It was found that the Solanaceae plant family was visited most often, and that two members of the family were the primary pollen sources for the bees in the study area. The selective behavior of females of the bee species suggests that the bees are oligolectic in their larval provisioning.

Conchocarpus is the largest genus of Galipeinae (tribe Galipeeae), which is the most diverse group of Neotropical Rutaceae, with ca. 50 species. Recent phylogenetic analyses support a recircumscription of Conchocarpus to accommodate the species of Almeidea, a taxon from the Brazilian Atlantic Rainforest and Bolivia whose synapomorphy is the possession of pantocolporate pollen grains. Four species are recognized here: C. albiflorus, C. coeruleus, C. hendrixii, and C. ruber. A taxonomic revision of this group of four species of Conchocarpus is provided, with updates of their nomenclature, morphology, circumscription, geographic distribution, and preliminary conservation status, as well as a key to the species and illustrations. Conchocarpus limae and C. lilacinus are consigned to the synonymy of C. ruber. [ABSTRACT FROM AUTHOR]