Exposure to sublethal concentration of flupyradifurone alters sexual behavior and cuticular hydrocarbon profile in Heriades truncorum, an oligolectic solitary bee.

The aboveground oligolectic bee, Heriades truncorum, is a particularly good model for studying the impact of pesticides on sexual communication, since some aspects of its mating behavior have previously been described. We have tested (1) the interference of the pesticide flupyradifurone on male precopulatory behavior and male mating partner preferences, (2) the way that the pesticide interferes in male quality assessment by the female, and (3) the effects of the pesticide on the chemical compounds in the female cuticle. We exposed bees of both sexes to a sublethal concentration of flupyradifurone. Various behaviors were registered in a mating arena with two females (one unexposed and one exposed) and one male (either unexposed or exposed). Unexposed males were quicker to attempt to mate. Treatment also impacted precopulatory behavior and male quality assessment by females. Males approached unexposed females more quickly than insecticide-exposed ones. Females exposed to insecticide produced lower amounts of some cuticular hydrocarbons (sex pheromone candidates) and appeared less choosy than unexposed females. Our findings suggest that insecticide exposure affects sexual communication, playing a role both in male preference and in male quality assessment by the female.

Bioecological and Behavioral Interaction between Pollinating Bees and the Pioneer Shrub Ludwigia nervosa in Degraded Area Suggests an Exotic Bee as Its Major Pollinator.

The flowers of plants of the genus Ludwigia are an important source of food for several species of bees. In the current study, we conducted an experiment with the aim to describe the reproductive biology and phenology of L. nervosa; to identify the species of visiting bees; analyze the foraging behavior of bees; and to investigate whether the reproductive success of the species is related to the foraging activity of bees. We found that the flowers received visits from several native bee species (n = 7), in addition of the exotic honey bees which came to be the dominant species. During visits the majority of the bees foraged in both resources, pollen and nectar. The significantly higher production of fruits in open pollinated pollination experiment compared to artificial cross pollination, suggests honey bees as effective pollinator of this plant species in the study site. Pollen deposition occurs efficiently, given the absence of pollen limitation. Despite massive visitation of honey bees, Ludwigianervosa is attractive to native bees, and therefore it may help to sustain population of both native and exotic pollinators in fragmented humid areas.

Survival rate and changes in foraging performances of solitary bees exposed to a novel insecticide.

Solitary bees are among the most important pollinators worldwide however population declines especially in croplands has been noticed. The novel pesticide sulfoxaflor is a competitive modulator of nicotinic acetylcholine receptors (nAChR) in insects. While there is evidence of a negative impact of neonicotinoids on bees of several social organization levels, our overall knowledge on the impact of sulfoxaflor on bees is poor. Here we present for the first time a study showing effects of field realistic doses of sulfoxaflor on solitary bees. Bees submitted to long term exposure of field realistic doses of sulfoxaflor (5 µg dm-3, 10 µg dm-3, 50 µg dm-3) and control were observed regarding their survival rate. Moreover, we recorded metrics related to flower visitation and flight performance. We discover that the highest field realistic dose is lethal to Osmia bicornis along five days of exposure. The effect of sulfoxaflor reduces the outcome of foraging, important features for fruit and seed production of cross-pollinated plant species. Bees exposed to pesticide visited flowers mostly walking rather than flying. Flight performance was also impaired by the pesticide.

Environmental Display Can Buffer the Effect of Pesticides on Solitary Bees.

Environmental quality (e.g., diversity of resource availability, nesting sites, environmental display) plays an important role in an animal's life. While homogeneous environments can restrict organisms from developing activities such as food seeking (behavioral impairment), more complex environments allow animals to perform activities with learning and behavioral perfecting outcomes. Pesticides are known to affect the learning and foraging behaviors of bees; however, little is known about the counterbalance displayed by the environment. Herein, we conducted two experiments that simulated distinct environmental displays, in which the effects of a fungicide (IndarTM 5EW-febunconazole) on solitary bee foraging activities were tested. We found that the fungicide only impaired the activities of bees in one of the studied environments. The difference in visitation rates and flower exploitation of bees between the two different environmental displays led to changes in metrics of bee-flower networks across environments. Linkage density, a metric associated with pollination efficiency that is known to be impacted by different environments, differed across environments. Our results showed that ecological interaction network metrics can differ regarding the different environmental displays. This study indicates that environmental complexity helps balance the negative effects of pesticides on solitary bees and highlights the potential use of solitary bees as model organisms for experimental simulations of environmental change.

A botanic garden as a tool to combine public perception of nature and life-science investigations on native/exotic plants interactions with local pollinators.

Life-sciences are pointing towards an alarming worldwide pollinator decline. This decline proceeds along with overall biodiversity losses, even in the context of urban landscapes and human welfare. At the same time, social-sciences are arguing an increased distance from nature, experienced by citizens. The strong connection between the public good and pollinator sustainability, even in urban areas, is well-documented. However, usually basic and applied life-sciences tend to underestimate public perception of nature, which is better tackled by the fields of social-sciences. Therefore, more efforts are needed to link scientific questions and public 'perception' of nature. We designed a transversal project where research questions directly confront public concerns: i.e., even while addressing scientific knowledge gaps, our questions directly arise from public concerns. Social studies highlighted that appreciation of (exotic) plants is related to the impact they may have on the surrounding natural environment: therefore, we investigated links of native and exotic flowers to local pollinators. Other studies highlighted that scientific results need to link to everyday individual experience: therefore, we investigated pollination modes of the renown Salvia, native and exotic, largely used in cuisine and gardening. The botanic garden was the promoter of scientific questions addressed by the public, and also collated the results in a travelling exhibition. The exhibition, together with a dedicated catalogue, were especially designed to enlighten the wide public on the relationships that plants, native and exotic alike, establish with the surrounding world.

Changes in social behavior are induced by pesticide ingestion in a Neotropical stingless bee.

Throughout evolutionary history bees have developed complex communication systems. For social bees, communication is important for both the individual and the development of the colony. Successful communication helps bees to recognize relatives, defend the colony, and promote recruitment to optimize foraging of floral resources. Bees' contribution to pollination is of broad environmental and economic importance. However, studies have reported that anthropogenic actions, such as the use of pesticides, negatively affect bee survival and behavior. We tested the effect of a commercially available pesticide mix containing two pesticide classes, a neonicotinoid and a pyrethroid, on the social behavior of the stingless bee, Melipona quadrifasciata (Lepeletier, 1863). After determining a sublethal dose of the pesticides, we tested the effect of an acute dose on antennation and trophallaxis behaviors of worker bees. Our results showed a drastic reduction in the communication and social interactions of bees.

Bees (Hymenoptera: Apoidea) and flowers in natural forest patches of southern Pantanal

This is the first systematic survey of bees in the Pantanal wetland, Brazil. We recorded bee species and their floral resources within grassland and natural forest edge habitats in the Pantanal. Surveys were conducted during two to four-days per month, for a total of 12 months. Overall, we recorded 56 bee species visiting a total of 63 flowering plants. Asteraceae and Fabaceae presented the highest number of visited species, however Hyptis suaveolens (Lamiaceae) was the plant most visited by different bee species (18). The most generalist native bee was Trigona fuscipennis visiting a total of 17 flowering plant species. Apis mellifera, an exotic bee, visited 27 species. We also report the overlap (37.5%) in the use of floral resources between the exotic bee Apis mellifera and native bee species. Our updated bee checklist here presented includes 10 new records for the State of Mato Grosso do Sul. These data will support management strategies targeting the conservation of plant-pollinator interactions in the Pantanal ecosystem.

Esta é a primeira amostragem sistemática de abelhas realizada no Pantanal, Brasil. Nós coletamos espécies de abelhas bem como as plantas que utilizaram como recurso floral em áreas de pastagens naturais e bordas de áreas florestadas. As coletas foram conduzidas durante dois a quatro dias a cada mês, durante 12 meses. Foram registradas 56 espécies de abelhas visitando um total de 63 espécies de plantas. As famílias Asteraceae e Fabaceae apresentaram o maior numero de espécies visitadas, entretanto Hyptis suaveolens (Lamiaceae) foi a espécie visitada pelo maior número de espécies diferentes de abelhas (18). A abelha nativa mais generalista encontrada foi Trigona fuscipennis, que visitou 17 espécies de plantas. Apis mellifera, uma espécie exótica, visitou 27 espécies. Reportamos também a sobreposição (37,5%) no uso de recursos florais entre A. mellifera e espécies de abelhas nativas. A listagem de abelhas aqui apresentada inclui 10 espécies ainda não mencionadas para o estado de Mato Grosso do Sul. Esses dados apoiarão estratégias de manejo focadas na conservação das interações entre plantas e polinizadores no ecossistema Pantanal.

Insetos visitantes de gomas exsudadas por Terminalia argentea Mart & Zucc (Combretaceae) / Visiting insects of exudated gums by Terminalia argentea Mart. & Zucc (Combretaceae)

One of the ephemeral food sources that insects may use is the exudated gums from plants. In May 2005, in an area of Cerrado from Campo Grande, Mato Grosso do Sul, Brazil, insects visiting an exudation structure of an individual of Terminalia argentea Mart & Zucc (Combretaceae) were observed. Nineteen species were identified, mainly Trigona branneri (Cockerel) and Mesembrinella bicolor (Fabricius). All visitors had been observed collecting or ingesting the gum. Visitation time and behavior of the most abundant species were reported. Samples of exudates showed a low concentration of proteins and reducing sugars and high concentration of complex carbohydrate, allowing infer that visitors of T. argentea seek the gum a food resource of high molecular weight that contributes to the storage of energy reserves.

Uma das fontes efêmeras de alimento que os insetos podem utilizar são as gomas exsudadas por plantas. No mês de maio de 2005, em uma área de cerrado no município de Campo Grande, Mato Grosso do Sul, foram observados insetos visitando as estruturas de exsudação em um indivíduo de Terminalia agentea Mart & Zucc (Combretaceae). Foram registradas 19 espécies, principalmente Trigona branneri (Cockerell) e Mesembrinella bicolor (Fabricius). Todos os visitantes foram observados coletando ou ingerindo a goma exsudada. Observações sobre o horário de visitação e comportamento das espécies mais abundantes são relatadas. As amostras de exsudatos apresentaram baixa concentração de proteínas e açucares redutores e alta concentração de carboidratos complexos, permitindo inferir que os visitantes de T. argentea buscam na goma um recurso alimentar de alta massa molecular que contribui para o armazenamento de reservas energéticas.