Pollinator-mediated selection on Krameria oil flowers: A flower-pollinator fit adaptation to an atypical oil-collecting behaviour?

BACKGROUND AND AIMS: Spatial variation in plant-pollinator interactions is a key driver of floral trait diversification. A so far overlooked qualitative aspect of this variation is the behavioural component on flowers that relates to the pollinator fit. We tested the hypothesis that variation in pollinator behaviour influences the geographical pattern of phenotypic selection across the distribution range of the oil-producing Krameria grandiflora (Krameriaceae). This variation mainly involves the presence or absence of flag petal grasping, which is only performed by representatives of Centris (Centridini, Apidae), an oil-collecting bee group highly associated with Krameriaceae pollination. METHODS: We quantified variation in floral traits and fitness and estimated pollinator-mediated selection in five populations at a large geographical scale comprising the entire species range. In each population, we sampled individual pollen arrival and germination as a fitness measure, indicating pollination success and pollination performance, which was then relativized and regressed on standardized flower-pollinator fit (flag-stigma distance), advertisement (sepal length) and reward (oil volume) traits. This generated mean-scaled selection gradients used to calculate geographical selection dispersion. KEY RESULTS: Unexpectedly, stronger selection was detected on the flower-pollinator fit trait in populations highly associated to the absence of the flag petal grasping. Geographical variation in selection was mainly attributed to differential selection on the flag-stigma distance generating a selection mosaic. This may involve influences of a spatial variation in pollinator behaviour as well as composition and morphology. CONCLUSIONS: Our results show the adaptive significance of the specialized "flag" petals of Krameria in the absence of the grasping behaviour and highlight the contribution of geographical variation in pollinator behaviour on flowers in driving selection mosaics, with implications for floral evolution, adaptation to pollinator fit and phenotypic diversity in specialized systems.

Macroevolution of floral scent chemistry across radiations of male euglossine bee-pollinated plantsMacroevolución de olores florales a través de radiaciones de plantas polinizadas por abejas euglosinas machosMacroevolução dos voláteis florais em radiações de plantas polinizadas por machos de abelhas Euglossini.

Floral volatiles play key roles as signaling agents that mediate interactions between plants and animals. Despite their importance, few studies have investigated broad patterns of volatile variation across groups of plants that share pollinators, particularly in a phylogenetic context. The "perfume flowers," Neotropical plant species exhibiting exclusive pollination by male euglossine bees in search of chemical rewards, present an intriguing system to investigate these patterns due to the unique function of their chemical phenotypes as both signaling agents and rewards. We leverage recently developed phylogenies and knowledge of biosynthesis, along with decades of chemical ecology research, to characterize axes of variation in the chemistry of perfume flowers, as well as understand their evolution at finer taxonomic scales. We detect pervasive chemical convergence, with many species across families exhibiting similar volatile phenotypes. Scent profiles of most species are dominated by compounds of either the phenylpropanoid or terpenoid biosynthesis pathways, while terpenoid compounds drive more subtle axes of variation. We find recapitulation of these patterns within two independent radiations of perfume flower orchids, in which we further detect evidence for the rapid evolution of divergent floral chemistries, consistent with the putative importance of scent in the process of adaptation and speciation.

Data standardization of plant-pollinator interactions.

BACKGROUND: Animal pollination is an important ecosystem function and service, ensuring both the integrity of natural systems and human well-being. Although many knowledge shortfalls remain, some high-quality data sets on biological interactions are now available. The development and adoption of standards for biodiversity data and metadata has promoted great advances in biological data sharing and aggregation, supporting large-scale studies and science-based public policies. However, these standards are currently not suitable to fully support interaction data sharing. RESULTS: Here we present a vocabulary of terms and a data model for sharing plant-pollinator interactions data based on the Darwin Core standard. The vocabulary introduces 48 new terms targeting several aspects of plant-pollinator interactions and can be used to capture information from different approaches and scales. Additionally, we provide solutions for data serialization using RDF, XML, and DwC-Archives and recommendations of existing controlled vocabularies for some of the terms. Our contribution supports open access to standardized data on plant-pollinator interactions. CONCLUSIONS: The adoption of the vocabulary would facilitate data sharing to support studies ranging from the spatial and temporal distribution of interactions to the taxonomic, phenological, functional, and phylogenetic aspects of plant-pollinator interactions. We expect to fill data and knowledge gaps, thus further enabling scientific research on the ecology and evolution of plant-pollinator communities, biodiversity conservation, ecosystem services, and the development of public policies. The proposed data model is flexible and can be adapted for sharing other types of interactions data by developing discipline-specific vocabularies of terms.

Negative impacts of dominance on bee communities: Does the influence of invasive honey bees differ from native bees?

Invasive species can reach high abundances and dominate native environments. One of the most impressive examples of ecological invasions is the spread of the African subspecies of the honey bee throughout the Americas, starting from its introduction in a single locality in Brazil. The invasive honey bee is expected to more negatively impact bee community abundance and diversity than native dominant species, but this has not been tested previously. We developed a comprehensive and systematic bee sampling scheme, using a protocol deploying 11,520 pan traps across regions and crops for three years in Brazil. We found that invasive honey bees are now the single most dominant bee species. Such dominance has not only negative consequences for abundance and species richness of native bees but also for overall bee abundance (i.e., strong "numerical" effects of honey bees). Contrary to expectations, honey bees did not have stronger negative impacts than other native bees achieving similar levels of dominance (i.e., lack of negative "identity" effects of honey bees). These effects were markedly consistent across crop species, seasons and years, and were independent from land-use effects. Dominance could be a proxy of bee community degradation and more generally of the severity of ecological invasions.

Light intensity regulates flower visitation in Neotropical nocturnal bees.

The foraging activity of diurnal bees often relies on flower availability, light intensity and temperature. We do not know how nocturnal bees, which fly at night and twilight, cope with these factors, especially as light levels vary considerably from night to day and from night to night due to moon phase and cloud cover. Given that bee apposition compound eyes function at their limits in dim light, we expect a strong dependence of foraging activity on light intensity in nocturnal bees. Besides being limited by minimum light levels to forage, nocturnal bees should also avoid foraging at brighter intensities, which bring increased competition with other bees. We investigated how five factors (light intensity, flower availability, temperature, humidity, and wind) affect flower visitation by Neotropical nocturnal bees in cambuci (Campomanesia phaea, Myrtaceae). We counted visits per minute over 30 nights in 33 cambuci trees. Light intensity was the main variable explaining flower visitation of nocturnal bees, which peaked at intermediate light levels occurring 25 min before sunrise. The minimum light intensity threshold to visit flowers was 0.00024 cd/m2. Our results highlight the dependence of these nocturnal insects on adequate light levels to explore resources.

Accelerated landings in stingless bees are triggered by visual threshold cues.

Most flying animals rely primarily on visual cues to coordinate and control their trajectory when landing. Studies of visually guided landing typically involve animals that decrease their speed before touchdown. Here, we investigate the control strategy of the stingless bee Scaptotrigona depilis, which instead accelerates when landing on its narrow hive entrance. By presenting artificial targets that resemble the entrance at different locations on the hive, we show that these accelerated landings are triggered by visual cues. We also found that S. depilis initiated landing and extended their legs when the angular size of the target reached a given threshold. Regardless of target size, the magnitude of acceleration was the same and the bees aimed for the same relative position on the target suggesting that S. depilis use a computationally simple but elegant 'stereotyped' landing strategy that requires few visual cues.

Accelerated landing in a stingless bee and its unexpected benefits for traffic congestion.

To land, flying animals must simultaneously reduce speed and control their path to the target. While the control of approach speed has been studied in many different animals, little is known about the effect of target size on landing, particularly for small targets that require precise trajectory control. To begin to explore this, we recorded the stingless bees Scaptotrigona depilis landing on their natural hive entrance-a narrow wax tube built by the bees themselves. Rather than decelerating before touchdown as most animals do, S. depilis accelerates in preparation for its high precision landings on the narrow tube of wax. A simulation of traffic at the hive suggests that this counterintuitive landing strategy could confer a collective advantage to the colony by minimizing the risk of mid-air collisions and thus of traffic congestion. If the simulated size of the hive entrance increases and if traffic intensity decreases relative to the measured real-world values, 'accelerated landing' ceases to provide a clear benefit, suggesting that it is only a useful strategy when target cross-section is small and landing traffic is high. We discuss this strategy in the context of S. depilis' ecology and propose that it is an adaptive behaviour that benefits foraging and nest defence.

Bee pollinator functional responses and functional effects in restored tropical forests.

Wild pollinators are necessary for ensuring plant reproduction, not only among crop fields but also remnant and restored ecosystems. Restoration activities should, therefore, lead to wild pollinator recovery, and thus be monitored to evaluate effects on pollinator diversity and functionality. We assessed bee pollinator functional responses in restoration plantings by creating functional groups (traits: body size, nesting location, sociality, and foraging strategy), comparing their abundance and diversity to that of other habitats (i.e., conserved and degraded primary forest fragments, anthropogenic wetlands, and sugarcane fields), and testing for an effect of source habitat (i.e., primary forest fragments) isolation. We analyzed functional effects on pollen transportation by identifying the pollen grains attached on the bodies of bees; creating plant functional groups with the identified species (traits: habit, successional class, geographic origin, and pollination mode); comparing their frequency, diversity, and interaction network structure among habitats; and searching for key interactions in network modules. In general, the abundance and diversity of bee communities and the frequency and diversity of the interacting plant species in restoration plantings were lower than those in primary forest fragments but higher than those in anthropogenic wetlands and sugarcane fields, suggesting that restoration plantings better enhance bee community recovery and functionality than other disturbed habitats. The interacting bees and plants were also negatively affected by habitat isolation, demonstrating the importance of primary forest fragments to supply bee populations to restored sites. The structure of interaction networks was little affected by habitat change and isolation, but the composition and diversity of functional groups varied significantly. There were more effects on larger bee species with more restricted nesting and floral requirements, and the woody species with which they interact most frequently. We identified key functional groups of bee pollinators that deserve priority for conservation because they play an important role in the pollen transportation of some the most relevant species in remnant forests and restoration plantings and also respond more negatively to habitat disturbances. Restoration efforts should include provisioning of nesting resources and management and conservation of primary forest remnant fragments that represent source habitats for them.

Nocturnal floral scent profiles of Myrtaceae fruit crops.

Communication between plants and nocturnal pollinators in low light conditions is mainly guided by floral scents, which is well documented for plants pollinated by bats, moths, and beetles. Just recently, nocturnal bees have been added to the list of pollinators known to respond to floral scents of their host plants. Little is known about the floral scent chemistry of plants visited and pollinated by nocturnal bees. Among these plants are economically important fruit crops of the family Myrtaceae. We aimed to analyze the nocturnal floral scent profiles of 10 species of Myrtaceae (only diurnal P. cattleianum was sampled after sunrise) and address the following questions: i) What are the main floral scent compounds emitted by the species? ii) Are the floral scent profiles similar to those described for other species pollinated by nocturnal bees? Floral scents were collected by dynamic headspace and analyzed by GC-MS (gas chromatography - mass spectrometry). The total amount of scent trapped ranged from 74 ng/flower/hour for Syzygium malaccense to 7556 ng/flower/hour for Eugenia dysenterica. A total of 46 floral scent compounds were detected in the samples with the most abundant compounds being the aromatics benzaldehyde, benzyl alcohol, 2-phenylethanol, methyl salicylate, 2-phenylethyl acetate, and benzyl acetate; the aliphatic compound 1-octanol; and the monoterpene linalool. The different species exhibited different relative scent patterns. Overall, the nocturnal scents of the studied species of Myrtaceae are dominated by aromatic compounds, which is in contrast to the scent profiles described for other plants pollinated by nocturnal bees.

Osmophores of Caryocar brasiliense (Caryocaraceae): a particular structure of the androecium that releases an unusual scent.

Caryocar brasiliense is a flagship species of the Brazilian Cerrado. It produces flowers with a strong peculiar scent, which are pollinated by bats and occasionally moths with short mouthparts. However, the cues responsible for attracting these nocturnal pollinators remain unknown. We aimed to identify osmophores of C. brasiliense, describe the ultrastructure of the cells involved in the synthesis and release of floral odour, and identify the constituents of the floral bouquet. We performed field observations and histochemical and ultrastructural analyses of flowers focusing on the androecium. Gas chromatography-mass spectrometry was used to analyse the scents emitted. Filament epidermal cells were found to possess an unusual shape and be responsible for the main production and release of odour. These cells, called foraminous cells, are elongate and possess pores where their cell walls are abruptly thin. The cuticle is practically absent over the pores, which facilitates odour emission. The foraminous cells have conspicuous nuclei and organelle-rich cytoplasm where oil droplets can be seen prior to anthesis. The features of these cells remain similar during anthesis, but many vesicles fuse with the plasma membrane and the number of oil droplets in the cytosol decreases. Twenty-nine components were found in the scent, especially fatty acid derivatives and N- and S-bearing compounds. Our analyses revealed that the androecium of C. brasiliense has a particular structure that acts as an osmophore. The scent from the androecium resembles that of the entire flower, which is an unprecedented finding for a plant with single flowers as the pollination unit.

Spectral purity, intensity and dominant wavelength: Disparate colour preferences of two Brazilian stingless bee species.

Bees use floral colour as a major long distance orientation cue. While it is known for bumblebees and honeybees that dominant wavelength (≙ colour hue), colour contrast and spectral purity (≙ saturation) are crucial for flower detection and discrimination, only little is known about colour preferences in stingless bees (Meliponini). In this experiment freely flying workers of two Brazilian species of stingless bees-Partamona helleri and Melipona bicolor-were tested for colour preferences concerning the colour parameters dominant wavelength, spectral purity and intensity (≙ brightness). Each individual bee had to perform 57 tests, in which a definite series of dual choices between colour stimuli varying in intensity, spectral purity or dominant wavelength were presented. The results show that P. helleri chose colours of higher spectral purity and preferred bluish colours, while M. bicolor made generalized colour choices. Intensity did not influence the colour choice of any bee species. The results of P. helleri are consistent with findings for honeybees and bumblebees, while colour preferences in M. bicolor seem to be absent.

Nocturnal Bee Pollinators Are Attracted to Guarana Flowers by Their Scents.

Floral scent is an important component of the trait repertoire of flowering plants, which is used to attract and manipulate pollinators. Despite advances during the last decades about the chemicals released by flowers, there is still a large gap in our understanding of chemical communication between flowering plants and their pollinators. We analyzed floral scents of guarana (Paullinia cupana, Sapindaceae), an economically important plant of the Amazon, using chemical analytical approaches, and determined the attractiveness of the scent to its nocturnal bee pollinators using behavioral assays in the field. Pollen loads of attracted bees were also analyzed. Inflorescences of guarana emit strong scents, both during day and at night, with some semi-quantitative differences between day- and night-time scents. Synthetic scent mixtures containing some of the identified floral scent components, including the most abundant ones, i.e., linalool and (E)-ß-ocimene, successfully attracted the nocturnal Megalopta bee pollinators. Pollen analyses revealed that many of the attracted bees had pollen grains from previous visits to guarana flowers on their bodies. Overall, our data show that guarana flowers attract nocturnal bee visitors by their strong scents and suggest that the chemical communication between this plant and its pollinators is a key component in crop production of this economically important plant species.

Floral-oil-producing Plantaginaceae species: geographical distribution, pollinator rewards and interactions with oil-collecting bees

Floral oils as reward to pollinators occur in eleven plant families and appeared at least 28 times in the evolutionary history of flowering plants. They are produced in epithelial or tricomatic glands and collected by oil bee visitors. The present paper focuses on floral-oil-producing species of Plantaginaceae, a Neotropical group namely Angelonia clade. This group comprises around 40 described species in the genera Angelonia, Basistemon, Monttea, Monopera and the oil-less Melosperma. We present a revision of all species of the Angelonia clade, their geographical distribution, resources offered to pollinators and records of flower visitors, especially oil-collecting bees. These plants rely only on oil-collecting species in the tribe Centridini and Tapinotaspidini for a successful pollination, being the interaction between both partners an especial case of bee/flower adaptation in Neotropical region. Some bee species depend only on the oil of Plantaginaceae flowers to survive, while others can collect on several floral oil sources. The pollinating bees explore the oil glands located in sacs using specialized hairs in the forelegs. With this study, we hope to inspire further research relating to this fascinating group of plants, in which most species are rare and occur in highly endangered habitats in South American open vegetation biomes.

Os óleos florais como recompensa a polinizadores estão presentes em onze famílias e surgiram ao menos 28 vezes na história evolutiva das plantas floríferas. Estes são produzidos em glândulas tricomáticas ou epiteliais e coletados por abelhas coletoras de óleo. O presente trabalho foi focado nas espécies produtoras de óleo floral de Plantaginaceae, um grupo neotropical conhecido como clado Angelonia. Este grupo compreende cerca de 40 espécies nos gêneros Angelonia, Basistemon, Monttea, Monopera e Melosperma, que não produz óleo floral. Nós apresentamos uma revisão de todas as espécies no clado Angelonia, sua distribuição geográfica, recursos oferecidos e registros de visitantes florais, especialmente abelhas coletoras de óleo. Estas plantas dependem das abelhas coletoras de óleo das tribos Centridini e Tapinotaspidini para uma polinização bem-sucedida, sendo a interação entre ambos os parceiros um caso especial de adaptação abelha/planta na Região Neotropical. Algumas espécies dependem somente do óleo coletado em espécies do clado Angelonia, enquanto outras também podem coletar em várias fontes de óleos florais. Essas abelhas exploram as glândulas de óleo localizadas em bolsas utilizando pelos especializados nas pernas anteriores. Com o presente trabalho esperamos inspirar estudos futuros com este fascinante grupo de plantas, que são em sua maioria espécies raras e que ocorrem nos altamente ameaçados biomas de vegetação aberta da América do Sul.

As abelhas do gênero Xylocopa Latreille (Xylocopini, Apidae) do Estado de São Paulo, Brasil

This study contributes to the knowledge about the diversity of bees belonging to the genus Xylocopa Latreille, 1802 of the São Paulo State through a compilation of taxonomic and biological information. Identification keys are presented for the four subgenera (Dasyxylocopa Hurd & Moure, 1963; Neoxylocopa Michener, 1954; Schonnherria Lepeletier, 1841 and Stenoxylocopa Hurd & Moure, 1960) and for the 22 species recorded for the state, beyond the available data on its biology, plants visited and geographic occurrence.

Este estudo contribui para o conhecimento da diversidade das abelhas pertencentes ao gênero Xylocopa Latreille, 1802 do Estado de São Paulo através de uma compilação de informações taxonômicas e biológicas. São apresentadas chaves de identificação para os quatro subgêneros (Dasyxylocopa Hurd & Moure, 1963; Neoxylocopa Michener, 1954; Schonnherria Lepeletier, 1841 e Stenoxylocopa Hurd & Moure, 1960) e para as 22 espécies registradas para o Estado, além dos dados existentes sobre sua biologia, plantas visitadas e ocorrência geográfica.

Entering behavior of Gasteruption brachychaetum Schrottky (Hymenoptera, Gasteruptiidae) into a nest of Hylaeus Fabricius (Hymenoptera, Colletidae) / Comportamento de entrada de Gasteruption brachychaetum Schrottky (Hymenoptera, Gasteruptiidae) em um ninho de Hylaeus Fabricius (Hymenoptera, Colletidae)

Nests of Hylaeus aff. guaraniticus (Schrottky, 1906) were parasited by females of Gasteruption brachychaetum Schrottky, 1906 in trap nests in São Paulo (Brazil). This is thefirst host record of a Gasteruptiidae in the Neotropical Region. The behavior of a G.brachychaetum female entering a host's nest is described as follows: an inquiline female hovered near the host's nest, landed and detected that a female of H. aff. guaraniticus was inside the nest, waited for the host female to fly out, entered backwards into the nest, remained there for almost six minutes, and then went out the nest. The development time of immature stages of G.brachychaetum varied between 16 and 299 days.

Ninhos de Hylaeus aff. guaraniticus (Schrottky, 1906)foram parasitados por fêmeas de Gasteruption brachychaetum Schrottky, 1906 em ninhos-armadilha em São Paulo (Brasil). Este é o primeiro registro de hospedeiro de um Gasteruptiidae na região Neotropical. O comportamento de uma fêmea entrando no ninho do hospedeiro é descrito: a fêmea inquilina pairou sobre o ninho do hospedeiro, pousou e detectou que a fêmea de H. aff. guaraniticus estava dentro do ninho, esperou a fêmea hospedeira voar para fora do ninho, entrou de costas no ninho, permanecendo no local por quase seis minutos, em seguida, partiu voando. O tempo de desenvolvimento dos imaturos de G.brachychaetum variou entre 16 e 229 dias.

Checklist das abelhas e plantas melitófilas no Estado de São Paulo, Brasil / Checklist of bees and honey plants from São Paulo State, Brazil

Para este trabalho, foram considerados os resultados de quatro estudos que amostraram abelhas nas flores nos dois principais biomas do Estado de São Paulo: Mata Atlântica (3 localidades) e cerrado (4 localidades). Foram coletadas 276 espécies de abelhas, pertencentes a 88 gêneros: 207 espécies e 78 gêneros na Mata Atlântica e 105 espécies e 40 gêneros no cerrado. Apidae foi a família mais representada nos dois biomas. Nas áreas amostradas, as abelhas visitaram 433 espécies de plantas: 361 na Mata Atlântica e 75 no cerrado.

For this work, we considered the results of four studies that sampled bees on flowers in the two main biomes of São Paulo State: Atlantic forest (3 locations) and 'cerrado' (4 locations). We found 276 species of bees belonging to 88 genera: 207 species and 78 genera in the Atlantic forest and 105 genera and 40 species in the 'cerrado' biome. Apidae family was the most represented in both biomes. In the sampled areas, bees visited 433 plant species: 361 in the Atlantic forest and 75 in the 'cerrado'.

Checklist das abelhas coletoras de óleos do Estado de São Paulo, Brasil / Checklist of oil bees from São Paulo State, Brazil

Neste trabalho uma lista atualizada das espécies de abelhas coletoras de óleo do Estado de São Paulo é apresentada, com suas ocorrências associadas aos grandes biomas do estado: Floresta Atlântica e Cerrado. Alguns dados sobre a biologia das espécies mais comuns são apresentados. Discutem-se as lacunas existentes em termos de amostragem no estado.

In this study a current list of the oil-collecting bees from São Paulo State is presented, with their occurrences associated to the mainly biomes of the state: Atlantic Rainforest and Cerrado. Some data on the biology of the common species are presented. We discuss about the sample gaps for the state.

[The use of different methods to sample the bee fauna (Hymenoptera: Apoidea), a study in the mixed temperate rainforest in Santa Catarina State]. / O uso de diferentes métodos para amostragem da fauna de abelhas (Hymenoptera: Apoidea), um estudo em floresta ombrófila mista em Santa Catarina.

A survey of the bee fauna of Araucaria Forest was performed in the border of a fragment in the district of Porto União, in Santa Catarina State. Samples were carried on monthly between October/2005 and October/2006 with hand nets directly on the flowers, besides three types of traps: chemical baits, trap nests and pantraps. A total of 1711 bees were captured belonging to 164 species, distributed in five families of bees that occur in Brazil. From the total 1339 bees of 130 species were sampled with the hand net, 346 individuals of 72 species were collected in pantraps, 24 bees of nine species were caught in the trap nests and two specimens of one species were sampled with baits. At most 48 species were common to two or more sample methods. Dialictus, with 27 species, was the most representative genus in the area. The exotic Apis mellifera L. was the most abundant species, representing 49.6% of the sampled bees, following by Dialictus sp.11 with 3.2%. The results show evidences of a seasonal pattern of activity of the bees and the importance of the use of complementary methods to survey the fauna. The composition of the bee fauna was similar to many inventories performed in the Araucaria Forest, being Halictidae the most diverse family followed by Apidae.

O uso de diferentes métodos para amostragem da fauna de abelhas (Hymenoptera: Apoidea), um estudo em floresta ombrófila mista em Santa Catarina / The use of different methods to sample the bee fauna (Hymenoptera: Apoidea), a study in the mixed temperate rainforest in Santa Catarina State

A fauna de abelhas da Mata com Araucária foi inventariada no entorno de um fragmento no município de Porto União, SC. Foram realizadas coletas mensais entre outubro/2005 e outubro/2006, com rede entomológica diretamente nas flores, além de três tipos de armadilha: iscas de cheiro, ninhos-armadilha e pratos-armadilha. Foram amostradas 1.711 abelhas pertencentes a 164 espécies, distribuídas nas cinco famílias de abelhas ocorrentes no Brasil. Do total, 1339 abelhas de 130 espécies foram amostradas com rede entomológica, 346 indivíduos de 72 espécies foram coletados nos pratos-armadilha, 24 abelhas de nove espécies foram capturadas através dos ninhos-armadilha e dois indivíduos de uma espécie foram amostrados com iscas de cheiro. No máximo 48 espécies de abelhas foram comuns a duas ou mais metodologias. Dialictus, com 27 espécies, foi o gênero mais representativo na área. A exótica Apis mellifera L. foi a espécie mais abundante, correspondendo a 49,6 por cento dos indivíduos amostrados, seguida por Dialictus sp.11 com 3,2 por cento. Os resultados mostram evidências de um padrão sazonal de atividade das abelhas e a importância da utilização de metodologias complementares na realização de levantamentos de apifauna. A composição da fauna de abelhas foi similar a vários trabalhos realizados em Mata com Araucária, sendo Halictidae a família mais diversa seguida por Apidae.

A survey of the bee fauna of Araucaria Forest was performed in the border of a fragment in the district of Porto União, in Santa Catarina State. Samples were carried on monthly between October/2005 and October/2006 with hand nets directly on the flowers, besides three types of traps: chemical baits, trap nests and pantraps. A total of 1711 bees were captured belonging to 164 species, distributed in five families of bees that occur in Brazil. From the total 1339 bees of 130 species were sampled with the hand net, 346 individuals of 72 species were collected in pantraps, 24 bees of nine species were caught in the trap nests and two specimens of one species were sampled with baits. At most 48 species were common to two or more sample methods. Dialictus, with 27 species, was the most representative genus in the area. The exotic Apis mellifera L. was the most abundant species, representing 49.6 percent of the sampled bees, following by Dialictus sp.11 with 3.2 percent. The results show evidences of a seasonal pattern of activity of the bees and the importance of the use of complementary methods to survey the fauna. The composition of the bee fauna was similar to many inventories performed in the Araucaria Forest, being Halictidae the most diverse family followed by Apidae.

Abelhas nativas versus Apis mellifera Linnaeus, espécie exótica (Hymenoptera: Apidae) / Native bees versus Apis mellifera Linnaeus, exotic species (Hymenoptera: Apidae)

Este trabalho relata o comportamento agressivo de algumas espécies de abelhas nativas sobre Apis mellifera (espécie introduzida) durante visita as flores de plantas cultivadas no sul de Santa Catarina. Três espécies de Halictidae e Trigona spinipes atacam as abelhas do mel expulsando-as das flores de abóbora (Cucurbita maxima) ou investindo e perseguindo as antes de pousarem nas flores de brócolis (Brassica oleracea). Discute-se a disputa por recursos e a presença de A. mellifera no continente americano.

This work report the aggressive behavior of some native bees over Apis mellifera (exotic species) during the visit to flowers of cultivated plants in southern Santa Catarina. Three Halictidae species and Trigona spinipes attack the honeybee expelling them from the pumpkin flowers (Cucurbita maxima) and beating up or pursuing them before landing on flowers of broccoli (Brassica oleracea). The competition for resource and the presence of A. mellifera in the American continent are discussed.