Keys to the Costa Rican species of paper wasps (Hymenoptera: Vespidae: Polistinae)

Paper wasps (subfamily Polistinae) are one of the four main groups of eusocial insects in the Neotropics. They are medically important for the frequent stings inflicted on humans, but at the same time are valuable predators of pest insects. Nonetheless, there are no updated keys for the identification of the Central American species. Here we provide keys to the 18 genera and 106 species known to occur in Costa Rica, illustrated with one hundred original line drawings.

Las avispas de la subfamilia Polistinae son uno de los cuatro grupos principales de insectos eusociales en el neotrópico, y son de importancia económica tanto por sus picaduras como por su papel en control biológico. Sin embargo, no existen claves actualizadas para la identificación de las especies de América Central. Aquí se proveen claves ilustradas para los 18 géneros y las 106 especies conocidas de Costa Rica y se incluyen cien dibujos originales.

Diversity of wasps (Hymenoptera: Aculeata: Vespidae) along an altitudinal gradient of Atlantic Forest in Itatiaia National Park, Brazil

ABSTRACT Surveying the diversity of stinging wasps (Hymenoptera: Aculeata) provides an important information base to assist in biodiversity conservation and the management of forest reserves, as wasps depend on and maintain the population balance of several other groups of insects. In accordance, this paper presents an altitudinal survey of wasps (Hymenoptera, Aculeata, Vespidae) in Itatiaia National Park, Brazil, which is a protected area covered by Atlantic Forest in a mountainous landscape, with altitudes ranging between 540 and 2791 metres above sea level. Six altitudinal zones were sampled with entomological net, and the abundance and diversity of the species were indicated by zones. Field sampling took 288 h of discontinuous activity, which was randomly conducted from December 2012 to December 2013. A total of 398 individuals belonging to 29 species and two subfamilies (Eumeninae and Polistinae) were sampled. Eight species are new records for the state of Rio de Janeiro. We found a monotonic decrease in wasp diversity in relation to altitude, and the number of captured individuals differed significantly between the low and high altitudes.

Variation of cuticular chemical compounds in three species of Mischocyttarus (Hymenoptera: Vespidae) eusocial wasps

Abstract The social wasps have a remarkable system of organization in which chemical communication mediate different behavioral interactions. Among the compounds involved in this process, cuticular hydrocarbons are considered the main signals for nestmate recognition, caste differentiation, and fertility communication. The aims of this study were to describe the cuticular chemical compounds of the species Mischocyttarus consimilis, Mischocyttarus bertonii, and Mischocyttarus latior, and to test whether these chemical compounds could be used to evaluate differences and similarities between Mischocyttarus species, using gas chromatography coupled to mass spectrometry (GC-MS). Workers from these three species presented a variety of hydrocarbons ranging from C17 to C37, and among the compounds identified, the most representative were branched alkanes, linear alkanes and alkenes. The results revealed quantitative and qualitative differences among the hydrocarbon profiles, as confirmed by discriminant analysis. This study supports the hypothesis that cuticular chemical profiles can be used as parameters to identify interspecific and intercolony differences in Mischocyttarus, highlighting the importance of these compounds for differentiation of species and populations.

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.

Guia de identificação dos ninhos de vespas sociais (Hymenoptera, Vespidae, Polistinae) na Reserva Ducke, Manaus, Amazonas, Brasil / Identification guide for nests of social wasps (Hymenoptera: Vespidae: Polistinae) in Reserva Ducke, Manaus, Amazonas, Brazil

Vespidae sociais utilizam principalmente material vegetal para a elaboração de seus ninhos. Embora existam alguns estudos referentes à fauna de vespas na região Amazônica, nenhum trabalho trata exclusivamente dos ninhos. Além disso, nas coleções biológicas poucos são os ninhos tombados, devido principalmente à fragilidade e difícil conservação dos mesmos. O objetivo desse trabalho foi o conhecimento de alguns ninhos encontrados na Reserva Ducke, apresentando informações a respeito dos mesmos e uma chave de identificação dos gêneros. Os ninhos foram coletados através da busca direta, percorrendo os transectos da grade do Programa de Pesquisa em Biodiversidade; locais como margens de igarapés, bordas de acampamentos e construções na sede da reserva também foram explorados. Para todos os ninhos obteve-se o registro fotográfico e a localização exata por GPS. Foram registrados 39 ninhos de vespas sociais alocados em 17 espécies de Polistinae: Agelaia constructor, A. pallipes, Angiopolybia pallens, Apoica pallens, Metapolybia unilineata, Mischocyttarus lecointei, M. saturatus, Polybia bistriata, P. dimidiata, P. jurinei, P. liliacea, P. occidentalis, P. procellosa, P. rejecta, Protopolybia bituberculata, P. chartergoides e Synoeca virginea. Cinco ninhos desabitados de Mischocyttarus, Polybia e Polistes também foram coletados.

Nests of social wasps are composed mainly out of plant material. Although there are some studies about the social wasp fauna in the Amazon region, there is no work exclusively about these wasps' nests. Also, there are few catalogued nests in biological collections, because of their fragility and difficult conservation. The purpose of this study was to evaluate the kinds of nests found at "Reserva Ducke", compiling information about them and developing a key to identify the nests of each genera. The nests were actively collected in tracks of the "Programa de Pesquisa em Biodiversidade" plot; areas such as "igarapés" margins, base camp's surroundings and buildings at the reserve headquarters were also explored. All the nests were photographed and their precise location was obtained by GPS. Thirty-nine wasp's nests from 17 species of Polistinae were recorded: Agelaia constructor, A. pallipes, Angiopolybia pallens, Apoica pallens, Metapolybia unilineata, Mischocyttarus lecointei, M. saturatus, Polybia bistriata, P. dimidiata, P. jurinei, P. liliacea, P. occidentalis, P. procellosa, P. rejecta, Protopolybia bituberculata, P. chartergoides and Synoeca virginea. Five uninhabited nests of Mischocyttarus, Polybia and Polistes were collected.

First report of Elasmus polistis Burks (Hymenoptera: Eulophidae) recovered from Polistes versicolor (Olivier) (Hymenoptera: Vespidae) nests in Brazil

The first record of Elasmus polistis Burks in Polistes versicolor (Olivier) nests in the Rio Grande do Sul state and in Brazil is provided. A total of 173 specimens of P. versicolor and 790 specimens of E.polistis were collected from two nests from Gramado and Santa Cruz do Sul, RS, Brazil.

Colony cycle of the social wasp Mischocyttarus consimilis Zikán (Hymenoptera, Vespidae)

Colony cycle of the social wasp Mischocyttarus consimilis Zikán (Hymenoptera, Vespidae). This study describes some aspects of the colony cycle of the Neotropical social wasp Mischocyttarus consimilis, from data obtained under field conditions. Our results showed that the colony cycle in M. consimilis is annual and asynchronous in relation to the months of the year. The colonies remained active for approximately eight months. Most of the abandonments were associated with natural causes, and were most frequent in the pre-emergence stage. The nests were constructed preferentially in man-made structures, especially in sites protected from direct sunlight and rain. Colony foundation was either by haplometrosis or pleometrosis, being the first form predominant.

Ciclo colonial da vespa social Mischocyttarus consimilis Zikán (Hymenoptera, Vespidae). Este estudo descreve alguns aspectos do ciclo colonial da vespa social Neotropical Mischocyttarus consimilis, sendo realizado em condições de campo. Os resultados desse estudo mostraram que o ciclo colonial em M. consimilis é anual, bem como assincrônico em relação aos meses do ano. Em geral, as colônias permanecem em atividade por aproximadamente oito meses. Os abandonos de colônia estão associados principalmente a causas naturais, e são mais freqüentes na fase colonial de pré-emergência. Os ninhos são estabelecidos preferencialmente em construções humanas, especialmente em locais protegidos da incidência direta de luz solar e água da chuva. Fundações de colônia ocorrem por uma ou outra forma haplometrose ou pleometrose, sendo a primeira predominante.

Morphological and physiological variation between queens and workers of Protonectarina sylveirae (de Saussure) (Hymenoptera, Vespidae, Epiponini) / Variações morfológicas e fisiológicas entre rainhas e operárias de Protonectarina sylveirae (de Saussure) (Hymenoptera, Vespidae, Epiponini)

Morphological and physiological variation between queens and workers of Protonectarina sylveirae (de Saussure) (Hymenoptera, Vespidae, Epiponini). The Neotropical swarm-founding wasps, Epiponini, range from the absence of morphological differentiation between castes to highly distinct castes. We measured eight body parts of females of two colonies of Protonectarina sylveirae (de Saussure, 1854). ANOVA and Discriminant Analysis evidenced significant differences between castes, as previously observed by other authors for other species of Epiponini. However, some females previously categorized as queens, were actually workers, supported by our statistic analyses. These individuals showed intermediate morphological features between queens and workers, having distinct patterns of hairs and clypeal spots. The castes of P. sylveirae are distinct, however intermediate individuals may be found in colonies promoting social flexibility.

As vespas enxameadoras neotropicais, Epiponini, apresentam desde ausência de diferenciação morfológica entre as castas até castas altamente distintas. Medimos oito partes corporais das fêmeas de duas colônias de Protonectarina sylveirae (de Saussure, 1854). ANOVA e Análise Discriminante evidenciaram diferenças significativas entre as castas, como observado anteriormente por outros autores em outros Epiponini. No entanto, algumas fêmeas, previamente categorizadas como rainhas, eram na verdade operárias, com base nas análises estatísticas. Esses indivíduos apresentaram características morfológicas intermediárias entre rainhas e operárias, tendo padrões distintos de pilosidade e da marca do clípeo. As castas em P. sylveirae são distintas, no entanto indivíduos intermediários podem ser encontrados nas colônias promovendo uma flexibilidade social.

Diversidade de vespas sociais (Hymenoptera: Vespidae) em áreas de cerrado na Bahia / Social wasps (Hymenoptera: Vespidae) diversity in a cerrado vegetation in Bahia State, Brazil

A diversidade de espécies de vespas sociais associadas à vegetação de cerrado no Oeste da Bahia foi analisada neste estudo. Dentre as dezenove espécies de vespas sociais encontradas, Chartergus globiventris de Saussure, Chartergellus communis Richards e Metapolybia cingulata (Fabricius) são registradas pela primeira vez para o estado. O cerrado arbóreo, apesar de apresentar maior riqueza (S = 19) e maior diversidade de espécies (H' = 2,33), apresentou níveis de abundância (N = 87 ninhos) inferiores aos sistemas agrícolas (N = 107 ninhos; S = 8 espécies; H' = 1,84). A fisionomia de cerrado campo sujo apresentou a menor abundância de colônias de vespas sociais (N = 61) e valores intermediários de riqueza (S = 13) e diversidade (H' = 2,20).

This study aimed to analyze the social wasps species diversity in a cerrado vegetation at the west region of the State of Bahia. Nineteen species of social wasps were found, with Chartergus globiventris de Saussure, Chartergellus communis Richards and Metapolybia cingulata (Fabricius) being recorded for the first time for the State of Bahia. The arboreous cerrado showed a higher species richness (S = 19) and diversity (H' = 2,33) than the agroecossistems (farms) (S = 8; H' = 1,84). However, nest abundance was higher at the agroecossystems (N = 107 nests) than at the arboreous cerrado (N = 87 nests). The physiognomy of "cerrado campo sujo" showed the lowest abundance of social wasps colonies (N = 61 nests) and intermediate values of species richness (S = 13) and diversity (H' = 2,20).

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.

Promotion of thermoregulatory insulation in nests of neotropical wasps by building extra-combs with empty cells / Promoção de isolamento térmico em ninhos de vespas neotropicais pela construção de favos com células vazias

We examined the hypotheses that the empty combs of Polybia occidentalis Olivier (Hymenoptera: Vespidae) nest insulate the inside of the nest. To examine this hypotheses, two kinds of temperature measurements were carried out: 1) with the outer comb of the nest intact (Control) and 2) removed (Treatment), using a large and a small nest. In the large nest, the daily nest temperatures (outer part, Tn1; inner part, Tn2) in Control were lower by 0.6°C (Tn1) and 1.2°C (Tn2) than those in Treatment, because of a higher ambient temperature (Ta) throughout temperature assessment in Treatment. However, the excess temperature (Tn - Ta) in Control was higher than that in Treatment. The value was higher by 0.7°C at Tn1 and 0.1°C at Tn2. In the small nest, the excess temperature in outer part was similar between experiments, while that in inner part of Control was lower than that of Treatment. The temperature fluctuation in the nests was lower in the Control than that in Treatment both the outer and inner part of the comb. We conclude that the unused comb is ecologically invaluable for raising and protecting the brood from extreme changes in ambient temperature during the winter period, because it helps not only keeping a higher nest temperature but also decreasing the temperature fluctuation around the brood combs. In addition, such a high temperature may influence the performance of adult wasps.

Examinou-se a hipótese de que os favos vazios dos ninhos de Polybia occidentalis Olivier (Hymenoptera: Vespidae) atuam como isolamento térmico dos elementos internos da colônia. Para avaliar essa hipótese dois tipos de medidas de temperatura foram tomadas: 1) com o favo externo intacto (Controle) e 2) removido (Tratamento), usando um ninho grande e um ninho menor. As temperaturas diárias no ninho grande (parte externa Tn1; parte interna Tn2), no Controle, foram 0,6°C (T n1) e 1,2°C (Tn2) mais baixas que aquelas do Tratamento, devido à temperatura ambiente (Ta) mais alta durante todo o período avaliado. Entretanto, a temperatura excedente (Tn - Ta) no Controle foi mais alta que no Tratamento. O valor foi 0,7°C mais alto em Tn1 e 0,1°C em Tn2. No ninho menor, a temperatura excedente na parte externa foi semelhante entre os experimentos, e na parte interna a temperatura do Controle foi inferior à do Tratamento. A flutuação térmica nos ninhos foi menor no Controle que no Tratamento, tanto na parte externa quanto interna dos favos. Conclui-se que o favo sem uso é ecologicamente muito importante para criar ou proteger a cria das alterações extremas de temperatura ambiente no inverno, uma vez que ele auxilia na manutenção de temperatura alta no ninho e também no decréscimo da flutuação de temperatura ao redor dos favos de cria. Além disso, essas temperaturas mais altas influenciam as atividades dos adultos.

Ultrastructure of the ectal mandibular gland of the paper-WASPPolistes versicolor (HYMENOPTERA: VESPIDAE)

The ultrastructural features of the ectal mandibular glands of the paper wasp Polistes versicolor are described. Theseglands contained a secretory portion and a sac-shaped reservoir. Muscle fibers were observed around the secretorycells close to where slender ducts arose to reach the reservoir sac. These fibers were probably involved in the releaseof secretion. The early secretory cells contained rough endoplasmic reticulum and Golgi complex with varying features,as well as the mitochondria necessary to sustain the energy requirements for the secretory activity. Smooth endoplasmicreticulum appeared only during the late stages of the secretion cycle. Synthesis and secretion occurred simultaneouslyand continuously within each cell, with the secretory cycle being essentially asynchronous throughout the gland. Thecells of the reservoir wall differed from those in other hymenopterans by their lack of a dense cuticle lining the lumen.These cells also produced lipids that probably will contribute to the ultimate composition of the secretion.