Nesting substrata, colony success and productivity of the wasp Mischocyttarus cassununga

Nesting substrata, colony success and productivity of the wasp Mischocyttarus cassununga. Colonies of the wasp Mischocyttarus cassununga (von Ihering, 1903) are easily found in urban areas. However, in spite of the massive presence of this species in cities, little is known about its nesting habits, colony success and productivity. The present study aimed at answering the following questions: What are the substrates used for nesting by M. cassununga? What is the main foundation strategy adopted by M. cassununga in urban areas: a solitary female or associative foundation? Is there a relationship between foundation strategies and colony success? Is the total number of cells per nest related to the number of adults produced? The study was conducted in Juiz de Fora, southeastern Brazil, from December 2006 to November 2007. Nesting in man-made substrata seems to be a common strategy in M. cassununga (90.9%), with preference for nest building with a horizontal comb facing north. The colonies were established mainly by groups of foundresses (67.6%), with a success of 84%. The number of brood cells produced per nest was 71.74 ± 45.25 (18-203), and it was positively correlated with the number of adults produced. Hence, we can say that the nests founded by M. cassununga are located mainly in man-made substrata and mostly founded by a group of females. The cell reuse behavior increases the number of adults produced, as it optimizes foraging. These characteristics together with its behavior and nesting habits promote the success of this species in thriving in urban environments.

Seasonal richness and composition of social wasps (Hymenoptera, vespidae) in areas of cerrado biome in Barroso, Minas Gerais, Brazil / Riqueza sazonal e composição de vespas sociais (Hymenoptera, vespidae) em áreas de cerrado em Barroso, Minas Gerais, Brasil

The study evaluated the seasonal richness and composition of social wasps in Cerrado transition areas and Atlantic Forest in the municipal district of Barroso (Cerrado Grassland, Semidecidual Forest and Anthropic Areas). Thirty-eight species of social wasps were recorded, distributed in 10 genera and 127 colonies. The phytophysiognomy of Cerrado Grassland had the highest number of species (35) and colonies (76), followed by Semidecidual Forest (26 species and 37 colonies) and Anthropic Areas (nine species and 14 colonies). Agelaia vicina (Saussure, 1854) showed the highest constancy, present in 57.7% of collections. The number of social wasp species and colonies was positively correlated with temperature and precipitation. The hot and humid season is the most favorable period for social wasp population growth.

A riqueza sazonal e composição de vespas sociais em áreas de transição Cerrado e Mata Atlântica no município de Barroso foram avaliadas (campo cerrado, mata semidecidual e áreas antrópicas). Foram registradas 38 espécies de vespas sociais, distribuídas em 10 gêneros, e 127 colônias. A fitofisionomia de campo cerrado teve o maior número de espécies (35) e de colônias (76), seguido da mata semidecidual (26 espécies e 37 colônias) e áreas antrópicas (nove espécies e 14 colônias). Agelaia vicina (Saussure, 1854) apresentou maior constância, presente em 57,7% das coletas. O número de espécies e colônias de vespas sociais correlacionou positivamente com a temperatura e a precipitação. A estação quente e úmida é o período mais favorável para o crescimento populacional de vespas sociais.

Spatial and temporal dynamics of coffee-leaf-miner and predatory wasps in organic coffee field in formation / Dinâmica espacial e temporal do bicho-mineiro do cafeeiro e da vespa predadora em plantação de café orgânico em formação

The coffee production is an economic mainstay for many countries in the world. Brazil is the world's largest producer and exporter of coffee, being responsible for about 25 percent of the world production. It is well known that coffee plantations are susceptible to more than 850 fungal and insect pests. Among these pests, the most important significant throughout Brazil is the coffee-leaf-miner, [Leucoptera coffeella (Guérin-Mèneville & Perrottet, 1842) (Lepidoptera: Lyonetiidae)]. It is estimated that the loss in yield due to infestation by L. coffeella moths can increase to as much as 80 percent in areas where the coffee-leaf-miner larvae are not controlled. Though it is effective, the chemical control of the pest substantially increases the cost of production and constitutes a risk to the environment. The knowledge about the spatial-temporal dynamics of coffee-leaf-miner and predatory wasps may provide valuable information about the biological management pest context. One way to investigate the spatial-temporal synchronism of predator and prey is to calculate and compare an index of spatial randomness within a sequence time. This paper advocates using the Morisita's index, coupled with the bootstrap method, in a temporal sequence to characterize the spatial- temporal dynamics of coffee-leaf-miner and predatory wasp (Hymenoptera: Vespidae) in one hectare of an organic coffee plantation. The results showed that coffee-leaf-miner and predatory wasps presented a seasonal behavior with a temporal synchronism. The results also showed that both new and preyed mines were aggregated during the peak population (dry season). There was little evidence for space-time interaction between coffee-leaf-miner and predatory wasps.

A produção do café é, economicamente, muito importante para vários países do mundo. O Brasil é o maior produtor e exportador de café do mundo, sendo responsável por, aproximadamente, 25 por cento da produção mundial. Sabe-se que as plantações de café são suscetíveis ao ataque de mais de 850 tipos de fungos e insetos. Entre essas pragas, a mais importante em todo Brasil é o bicho mineiro do cafeeiro [Leucoptera coffeella (Guérin-Mèneville & Perrottet, 1842) (Lepidoptera: Lyonetiidae)]. Estima-se que a perda no rendimento devido à infestação do bicho mineiro pode chegar a 80 por cento em plantações onde não existe controle da praga. Embora o controle químico seja eficaz para combatê-la, ele acarreta um aumento no custo da produção e constitui um risco para o meio ambiente. O conhecimento da dinâmica espacial-temporal do bicho-mineiro e da vespa predadora (Hymenoptera: Vespidae) pode fornecer informações valiosas para o controle biológico da praga. Uma maneira de investigar o sincronismo espacial-temporal entre presa e predador é calcular algum índice para análise de completa aleatoriedade espacial e compará-lo ao longo do tempo. Este artigo sugere o uso do índice de Morisita, juntamente com o método bootstrap, em uma sequência temporal para caracterizar a dinâmica espacial-temporal do bicho-mineiro e da vespa predadora em um hectare de uma plantação orgânica de café. Os resultados revelaram que o bicho-mineiro e a vespa predadora apresentaram um comportamento sazonal com um sincronismo temporal. Além disso, observou-se que minas novas e predadas apresentavam agrupamentos durante a estação mais seca do ano. Existem poucas evidências de interação espaço-temporal entre minas predadas e vespas predadoras.

A diversificação da vegetação reduz o ataque do bicho-mineiro-do-cafeeiro Leucoptera coffeella (Guérin-mèneville) (Lepidoptera: Lyonetiidae)? / Does vegetational diversification reduce coffee leaf miner Leucoptera coffeella (Guérin-Mèneville) (Lepidoptera: Lyonetiidae) attack?

The effects of increasing plant diversity on the population of the coffee leaf-miner Leucoptera coffeella (Guérin-Mèneville) were investigated in two organic coffee production systems. One system consisted of coffee intercropped with banana trees (shaded system) and the other one of coffee intercropped with pigeon pea (unshaded system). The increase in plant diversity on both systems was achieved via introduction of green manures such a perennial pea nut, sunn hemp and Brazilian lucerne. The population of L. coffeella, predation and parasitism of L. coffeella mines were biweekly evaluated during eight months. The increase in plant diversity on both systems did not affect the attack of L. coffeella on coffee leaves and the mine parasitism rate. However, there was a positive and significant relationship between increasing plant diversity and coffee leaf mine predation by wasps on unshaded coffee system and a negative relationship on shaded coffee system.

Efeitos de variáveis ambientais, irrigação e vespas predadoras sobre Leucoptera coffeella (Guérin-Méneville) (Lepidoptera: Lyonetiidae) no cafeeiro / Effects of irrigation, environmental variability and predatory wasp on Leucoptera coffeella (Guérin-Méneville) (Lepidoptera: Lyonetiidae), in coffee plants

A densidade populacional do bicho-mineiro do cafeeiro Leucoptera coffeella (Guérin-Méneville) pode ser afetada por variáveis ambientais em agroecossistemas irrigados e vespas predadoras tais como Vespidae. Assim, objetivou-se neste trabalho avaliar os efeitos das variáveis ambientais, de lâminas de irrigação via gotejamento, e da predação por vespas na densidade populacional de L. coffeella. O experimento foi conduzido entre os anos de 2004 e 2005, em lavoura de Coffea arabica L. no município de Jaboticatubas, MG, Brasil. As diferentes lâminas de irrigação, aplicadas via gotejamento, foram estabelecidas tomando por referência a lâmina diária requerida pelo programa IRRIPLUS, que foi igual a 100 por cento e, duas outras abaixo, 51 por cento e 72 por cento, e acima, 124 por cento e 145 por cento, com a testemunha sem irrigação. Para a avaliação da densidade populacional do bicho mineiro e da predação determinou-se o número de minas ativas e predadas no quarto par de folhas do ramo mediano em dez plantas. Para estudar as interações entre as variáveis ambientais, lâminas de irrigação com as densidades de minas de L. coffeella e vespas predadoras foram realizadas análise multivariada, análises de regressão linear simples e trilha. Conclui-se que a maior precipitação pluvial, radiação solar e lâminas de irrigação reduzem a densidade populacional do bicho-mineiro. Além disso, o aumento na densidade das vespas predadoras foi dependente dos níveis populacionais de L. coffeella.

The population density of the coffee leaf miner Leucoptera coffeella (Guérin-Méneville) can be affected by environmental variables in irrigated agroecosystems and the occurrence of predatory wasps such as Vespidae. In here, we aimed to evaluate the effects of environmental variables, drip irrigation depths and predation by wasps on the population density of L. coffeella. The experiment was carried out during 2004 and 2005 in a Coffea arabica plantation cultivated in the county of Jaboticatubas, Minas Gerais State, Brazil. The different irrigation depths set through drip were established considering the daily depth required by the IRRIPLUS program, which was equal to 100 percent, and two other lower (51 percent and 72 percent) and higher (124 percent and 145 percent) values, having the control without irrigation. In order to evaluate the coffee leaf miner population density and predation, the number of active and preyed mines was determined on the fourth pair of leaves in a group of ten plants. For the study of interactions among the environmental variables, irrigation depths with the mine density of L. coffeella and predatory wasps, the following methods were used: multivariated analysis, simple linear regression and trail. We concluded that higher pluvial precipitation, solar radiation and irrigation depths would reduce population density of the coffee leaf miner. Furthermore, the increase in density of the predatory wasps was dependent on the population level of L. coffeella.

Diversity of social wasps (Hymenoptera, Vespidae, Polistinae) in three fragments of semideciduous seasonal forest in the northwest of São Paulo State, Brazil / Diversidade de vespas sociais (Hymenoptera, Vespidae, Polistinae) em três fragmentos de floresta estacional semidecidual no noroeste do Estado de São Paulo, Brasil

Human exploitation of the forest in the northwest of São Paulo State has generated enormous fragmentation of that forest. Such disturbance has reduced the populations of insects in general. This work was a survey of social wasps (Hymenoptera, Vespidae; Polistinae) in three areas in different stages of regeneration: Paulo de Faria - SP (435 ha), Pindorama - SP (128 ha) and Neves Paulista - SP (1 ha). These three areas were chosen for comparative purposes. To capture the wasps, it was used: active collecting with attractant liquid (solution of water, salt and sugar) with the aid of a dorsal spray bag. During the period from July to December 2006, 414 social wasps were collected in Paulo de Faria, constituting seven species belonging to four genera; 111 social wasps were collected in Pindorama, constituting six species belonging to four genera, and 129 social wasps were collected in Neves Paulista constituting 12 species belonging to seven genera. In order to compare these three areas ecological indexes were calculated. Neves Paulista had the greatest diversity, and Paulo de Faria presented greater abundance. These factors were probably caused by neighboring areas and ecological corridors, which were limited in Paulo de Faria and Pindorama.

A ação antrópica no noroeste do Estado de São Paulo tem gerado grande fragmentação florestal. Tais perturbações reduziram as populações de insetos em geral. Neste trabalho foi realizado um levantamento de vespas sociais (Hymenoptera, Vespidae; Polistinae) em três áreas em diferentes estágios de regeneração, em Paulo de Faria - SP (435 ha), Pindorama (128 ha) e em Neves Paulista (1 ha), escolhidas para fins comparativos. Para capturar as vespas, foi utilizada: coleta ativa com utilização de líquido atrativo (solução de água, sal e açúcar) com auxílio de um borrifador dorsal de alavanca. Durante o período de Julho a Dezembro de 2006 foram capturados 414 vespídeos sociais em Paulo de Faria, sendo estes distribuídos em sete espécies pertencentes a quatro gêneros; em Pindorama, foram coletadas 111 vespas sociais distribuídos em seis espécies pertencentes a quatro gêneros, e em Neves Paulista, um total de 129 vespídeos sociais distribuídos em 12 espécies pertencentes a sete gêneros. A fim de comparar as três áreas foram utilizados índices ecológicos. A área de Neves Paulista obteve a maior diversidade e Paulo de Faria a maior abundância de vespas. Tais fatores provavelmente foram causados pela influência das áreas vizinhas e pelos corredores ecológicos, que eram limitados na área de Paulo de Faria e Pindorama.