The impact of an insecticide on insect flower visitation and pollination in an agricultural landscape

1 Pesticides are considered a threat to pollinators but little is known about the potential impacts of their widespread use on pollinators. Less still is known about the impacts on pollination, comprising the ecosystem service that pollinators provide to wildflowers and crops. 2 The present study measured flower visitation and pollination in an agricultural landscape, by placing potted flowering plants (Petunia sp.) in vine fields sprayed with a highly toxic insecticide (fenitrothion). During two sampling rounds, insect visitors to the petunias were observed and measures of pollination were recorded by counting and weighing seeds. 3 In the earlier sampling round, a lower species richness of insect visitors was observed in fields that had received an early application of insecticide. No negative impacts were found from later applications. The results obtained suggest a greater potential harm to insect pollinators and flower visitation as a result of insecticide application early in the season. 4 No reduction in pollination was found in fields that received an early insecticide application. Pollination was greater with two insecticide applications between sampling rounds rather than one application. 5 In the present study system, insecticide application had a negative effect on pollinators but a possible positive effect on pollination services. In some cases, it may be that actions for conserving biodiversity will not benefit pollination services to all plants.

Bacterial communities of the specialty crop phyllosphere: response to biological soil amendment use, rainfall, and insect visitation

Microorganisms in the plant rhizosphere, the zone under the influence of roots, and phyllosphere, the aboveground plant habitat, exert a strong influence on plant growth, health, and protection. Tomatoes and cucumbers are important players in produce safety, and the microbial life on their surfaces may contribute to their fitness as hosts for foodborne pathogens such as Salmonella enterica and Listeria monocytogenes. External factors such as agricultural inputs and environmental conditions likely also play a major role. However, the relative contributions of the various factors at play concerning the plant surface microbiome remain obscure, although this knowledge could be applied to crop protection from plant and human pathogens. Recent advances in genomic technology have made investigations into the diversity and structure of microbial communities possible in many systems and at multiple scales. Using Illumina sequencing to profile particular regions of the 16S rRNA gene, this study investigates the influences of climate and crop management practices on the field-grown tomato and cucumber microbiome. The first research chapter (Chapter 3) involved application of 4 different soil amendments to a tomato field and profiling of harvest-time phyllosphere and rhizosphere microbial communities. Factors such as water activity, soil texture, and field location influenced microbial community structure more than soil amendment use, indicating that field conditions may exert more influence on the tomato microbiome than certain agricultural inputs. In Chapter 4, the impact of rain on tomato and cucumber-associated microbial community structures was evaluated. Shifts in bacterial community composition and structure were recorded immediately following rain events, an effect which was partially reversed after 4 days and was strongest on cucumber fruit surfaces. Chapter 5 focused on the contribution of insect visitors to the tomato microbiota, finding that insects introduced diverse bacterial taxa to the blossom and green tomato fruit microbiome. This study advances our understanding of the factors that influence the microbiomes of tomato and cucumber. Farms are complex environments, and untangling the interactions between farming practices, the environment, and microbial diversity will help us develop a comprehensive understanding of how microbial life, including foodborne pathogens, may be influenced by agricultural conditions.

Floral resources used by insects in a grassland community in Southern Brazil

The goal of the present study was to identify plant species used as food source, the floral resources utilized, and the insects that visit flowers in a grassland community in southern Brazil. The study was carried out in an area of one hectare, located in a grassland formation in the Parque Estadual de Itapuã, State of Rio Grande do Sul, Brazil. The flowering pattern was seasonal, and richness and abundance of insects was higher during the period of high resource availability. Flowers of 106 species of angiosperms (73 genera and 34 families) were used as source of floral resources for 219 species (2,767 specimens) of insects. A total of 91.5% of plant species were visited by bees, 53.8% by flies, 34.9% by wasps, 22.6% by butterflies, and 12.3% by beetles. Nectar was the main resource consumed by the visitors (41.1%). Asteraceae was the richest (38 spp.) and most visited family, with 63.1% of the species and 49.5% of all specimens of recorded insects. Bees were the most representative insects (33.2% spp., 65% indiv.), followed by flies (26.9% spp., 16.5% indiv.), wasps, butterflies and beetles. 40 plant species were considered important resources for the floral visitors' community, due to high number of, both, species and individuals recorded in their flowers. The family Asteraceae as a species set was the main floral resource used by insect visitors through the year and has great importance for the maintenance of populations of many species of bees, flies, wasps and butterflies in the studied area.

An investigative study on the effects of black fly (diptera: simuliidae) sugar meals on reproductive success and parasite transmission /

Black flies are opportunistic sugar-feeders. They take sugar meals from Homopteran honeydew secretions or plant nectars, depending on availability. Homopteran honeydew secretions contain both simple and complex carbohydrates while plant nectars contain primarily simple carbohydrates. In order to determine whether honeydew secretions offer more energy than plant nectars to their insect visitors a study of wild-caught black flies was undertaken in Algonquin Provincial Park, Canada during the spring of 1 998 and 1 999. It was hypothesized that female black flies maintained on honeydew sugars will survive longer, produce more eggs and have a greater parasite vectoring potential than those maintained on artificial nectar or distilled water. Results demonstrated that: (1) host-seeking female Prosimulimfuscum/mixtum and Simulium venustum maintained on artificial honeydew did not survive longer than those maintained on artificial nectar when fed ad libitum; (2) fiiUy engorged S. venustum and Simulium rugglesi maintained on artificial honeydew did not produce more eggs than those maintained on artificial nectar when fed ad libitum; and (3) S. rugglesi did not have a greater vectoring potential of Leucocytozoon simondi when maintained on artificial honeydew as opposed to artificial nectar when fed ad libitum. However, all flies maintained on the two sugars (artificial honeydew and artificial nectar) survived longer, produce more eggs and had greater vectoring potential than those maintained on distilled water alone.

Entomofauna visitante de Belamcanda chinensis (L.) DC (Iridaceae) durante o período de floração

A study of the reproductive biology of B. chinensis (L.) DC. (Iridaceae) was realized comprising floral biology and breeding systems. The floral biology studies included analyses of nectar production, occurence of osmophores, corolla pigments, ultraviolet reflexion and absortion patterns, viability of pollen, pollinators and flower visitors. The breeding systems were studied taking into account the results of manual pollinators tests. B. chinensis is self-compatible bul cross-pollination is more frequent. The effective pollinators are Plebeia droryana (Friese, 1906) (45,7%), Trigona spinipes (Fabricius, 1793) (27,3%), Tetragonisca angustula (Latreille, 1811) (9,3%). Others insects visitors are considered nectar and pollen thieves. The flowering begins generally in January and February. The complete reproductive cicle, as here considered, begining with floral bud production ending with development of mature fruits, lasts January to June. Seed dispersion is ornitocoric.

Entomophilous pollination in rape (Brassica napus L. var. oleifera) in Brazil

The most frequent insect visitors to the flower were: Apis mellifera, 80.6%; Trigona spinipes, 12.8% and Dialictus sp, 6.6%. -from Authors

Efeitos indiretos de predadores e de herbívoros florais e foliares no comportamento de visitantes florais e sucesso reprodutivo de Rubus rosifolius

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Polinização de Cacauí (Theobroma speciosum Willd. ex Spreng. - Sterculiaceae): implicações para conservação

O cacauí (Theobroma speciosum) é uma fruteira típica da Região Norte, cujas flores sapromiofílicas atraem dípteros. Os recursos que os insetos utilizam são muito variados e entre eles estão as flores, as quais podem ser utilizadas como alimento e local para reprodução. Este trabalho visou fazer uma comparação do sistema de polinização de T. speciosum em duas áreas de preservação distintas, contribuindo para a avaliação das estratégias de conservação da espécie. O trabalho foi realizado nos anos de 2000 a 2002, no Centro de Pesquisa do Trópico Úmido da Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA/CPATU) e na Estação Científica Ferreira Penna (ECFPn/MPEG). Foram realizados estudos sobre estrutura populacional e fenologia de T. speciosum nas duas áreas de preservação, observação comportamental dos insetos no campo, coletas de insetos visitantes das flores de cacauí, análise de carreamento de pólen pelos insetos e verificação dos insetos emergentes no laboratório. As árvores de cacauí, em ambos os locais, florescem em períodos mais secos e frutificam em períodos mais úmidos. As populações de cacauí nas duas áreas diferem pela distribuição espacial e etária dos seus indivíduos. A falta de jovens e subadultos na área de preservação ex situ, mostra falha no "tum over' populacional, demonstrando fragilidade no sistema estabelecido. As inflorescências de T. speciosum são utilizadas por uma grande diversidade de invertebrados. Nove ordens de insetos, e pelo menos duas ordens de outros invertebrados, visitaram as flores de cacau'. As ordens com maior quantidade de indivíduos foram Hymenoptera, Thysanoptera, Diptera e Coleoptera. Os visitantes das flores de cacauí foram classificados como: oportunistas, predadores e polinizadores. Drosofilideos foram indicados como polinizadores de T speciosum, com a possibilidade da participação de alguns forídeos. As guildas dos drosofilídeos foram distintas nas duas áreas de preservação e mais diversa na área de preservação in situ. Quatro espécies foram comuns as duas áreas. A perda de diversidade e alteração na composição na guilda de polinizadores parece não ter afetado a população de T. speciosum na área de preservação ex situ. No caso em estudo o sistema de polinização apesar de profundamente alterado, ainda apresenta sinais de viabilidade.

Floral biology of Stachytarpheta maximiliani Scham. (Verbenaceae) and its floral visitors

This study describes the reproductive system of Stachytarpheta maximiliani (Verbenaceae), including its floral biology, nectar and pollen availability and insect foraging patterns, identifying whose species act as pollinators. It was carried out in a Brazilian Atlantic rain forest site. Observations on the pollination biology of the Verbenaceae S. maximiliani indicate that their flowering period extends from September through May. Anthesis occurs from 5:30 a.m. to 5:00 p.m. and nectar and pollen are available during all the anthesis. Many species of beetles, hemipterans, flies, wasps, bees and butterflies visit their flowers, but bees and butterflies are the most frequent visitors. The flowers are generally small, gathered in dense showy inflorescences. A complex of floral characteristcs, such as violet-blue color of flowers, long floral tubes, without scents, nectar not exposed, high concentration of sugar in nectar (about 32%), allowed identification of floral syndromes (melittophily and psicophily) and function for each visitor. The bees, Bombus morio, B. atratus, Trigonopedia ferruginea, Xylocopa brasilianorum and Apis mellifera and the butterflies Corticea mendica mendica, Corticea sp., Vehilius clavicula, Urbanus simplicius, U. teleus and Heraclides thoas brasiliensis, are the most important pollinators.

Variation in the proportion of flower visitors of Arum maculatum along its distributional range in relation with community‐based climatic niche analyses

Here, we investigate the geographical constancy in the specificity level of the specialized lure-and-trap pollination antagonism involving the widespread European Arum maculatum and its associated Psychodid pollinators. Until now, studies concurred in demonstrating that one single insect species, Psychoda phalaenoides, efficiently cross-pollinated plants; researches were, however, performed locally in western Europe. In this study we characterize for the first time the flower visitors' composition at the scale of the distribution range of A. maculatum by intensively collecting plants and insects throughout the European continent. We further correlate local climatic characteristics with the community composition of visiting arthropods.Our results show that flowers are generally visited by P. phalaenoides females, but not over the whole distribution range of the plant. In some regions this fly species is less frequent or even absent and another species, Psycha grisescens, becomes the prevailing visitor. This variability is geographically structured and can be explained by climatic factors: the proportion of P. grisescens increases with higher annual precipitations and lower precipitations in the warmest trimester, two characteristics typical of the Mediterranean zone. Climate thus seems driving the specificity of this interaction, by potentially affecting the phenology of one or both interacting species, or even of volatile and heat production in the plant. This result therefore challenges the specificity of other presumably one-to-one interactions covering wide distribution ranges, and provides an example of the direct effect that the abiotic environment can have on the fate of plant-insect interactions.

EDITOR'S CHOICE: REVIEW: Trait matching of flower visitors and crops predicts fruit set better than trait diversity

Understanding the relationships between trait diversity, species diversity and ecosystem functioning is essential for sustainable management. For functions comprising two trophic levels, trait matching between interacting partners should also drive functioning. However, the predictive ability of trait diversity and matching is unclear for most functions, particularly for crop pollination, where interacting partners did not necessarily co-evolve. World-wide, we collected data on traits of flower visitors and crops, visitation rates to crop flowers per insect species and fruit set in 469 fields of 33 crop systems. Through hierarchical mixed-effects models, we tested whether flower visitor trait diversity and/or trait matching between flower visitors and crops improve the prediction of crop fruit set (functioning) beyond flower visitor species diversity and abundance. Flower visitor trait diversity was positively related to fruit set, but surprisingly did not explain more variation than flower visitor species diversity. The best prediction of fruit set was obtained by matching traits of flower visitors (body size and mouthpart length) and crops (nectar accessibility of flowers) in addition to flower visitor abundance, species richness and species evenness. Fruit set increased with species richness, and more so in assemblages with high evenness, indicating that additional species of flower visitors contribute more to crop pollination when species abundances are similar. Synthesis and applications. Despite contrasting floral traits for crops world-wide, only the abundance of a few pollinator species is commonly managed for greater yield. Our results suggest that the identification and enhancement of pollinator species with traits matching those of the focal crop, as well as the enhancement of pollinator richness and evenness, will increase crop yield beyond current practices. Furthermore, we show that field practitioners can predict and manage agroecosystems for pollination services based on knowledge of just a few traits that are known for a wide range of flower visitor species.

A preliminary study of insect fauna on pig carcasses located in sugarcane in winter in southeastern Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Insect mortality in Spathodea campanulata Beauv. (Bignoniaceae) flowers

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Insect feeding preferences on Piperaceae species observed in São Paulo city, Brazil

Piperaceae species have been placed among the basal angiosperm and are adapted to a variety of habitats including moist forests, secondary vegetation and dry high lands. The major anatomical/morphology features are of small trees, vines, and shrubs for Piper species, while the epiphytic and succulent characteristics are predominant forms among Peperomia species. Their secondary chemistry can be mostly represented by amides, phenylpropanoids/lignoids, and chromenes in addition to a phletoria of biosynthetically mixed-origin secondary compounds. Although several amides and lignans are known as insecticides, several phytophagous insects, among which some considered pests of economic importance, have been observed feeding vigorously on Piperaceae species. Herein we describe the feeding preferences of fourteen phytophagous species of Coleoptera, Lepidoptera and Hemiptera over approximately fifty Piperaceae species observed in São Paulo, SP, Brazil, in a long-term basis.

Expression of recombinant Araraquara Hantavirus nucleoprotein in insect cells and its use as an antigen for immunodetection compared to the same antigen expressed in Escherichia coli

Background: Antigens for Hantavirus serological tests have been produced using DNA recombinant technology for more than twenty years. Several different strategies have been used for that purpose. All of them avoid the risks and difficulties involved in multiplying Hantavirus in the laboratory. In Brazil, the Araraquara virus is one of the main causes of Hantavirus Cardio-Pulmonary Syndrome (HCPS). Methods: In this investigation, we report the expression of the N protein of the Araraquara Hantavirus in a Baculovirus Expression System, the use of this protein in IgM and IgG ELISA and comparison with the same antigen generated in E. coli. Results: The protein obtained, and purified in a nickel column, was effectively recognized by antibodies from confirmed HCPS patients. Comparison of the baculovirus generated antigen with the N protein produced in E. coli showed that both were equally effective in terms of sensitivity and specificity. Conclusions: Our results therefore indicate that either of these proteins can be used in serological tests in Brazil.