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.

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.

Phylogeny of wasps of the genus Mischocyttarus de Saussure (Hymenoptera, Vespidae, Polistinae) / Filogenia das vespas do gênero Mischocyttarus de Saussure (Hymenoptera, Vespidae, Polistinae)

A phylogenetic analysis is presented of subgenera and species-groups of Mischocyttarus de Saussure, the largest genus of social wasps. The analysis is based on 62 morphological and nest architecture characters, coded for 71 terminals representing much of the taxonomic diversity within the genus, plus three outgroup terminals representing other polistine tribes. The main conclusions about phylogenetic relationships within the genus are based on parsimony analysis under implied weights. Monophyly of Mischocyttarus is confirmed as well as that of most of the previously recognized subgenera: Mischocyttarus s. str., Clypeopolybia, Monogynoecus, Scytokeraia, Phi, Kappa, Megacanthopus and Omega sensu Richards (1978). Haplometrobius as conceived by Richards (1978) is not a monophyletic taxon, but some of its species-groups are monophyletic. The groups of M.artifex and M.cerberus are raised to subgenus level, and a new concept of Haplometrobius restricts it to the group of M.iheringi (the type species of this subgenus) in the sense of this work. The concept of subgenus Omega is widened to include the species-groups of M.surinamensis and M.prominulus. Besides the new subgeneric classification presented, limits and diagnoses of all species-groups of the subgenera Phi and Haplometrobius sensu Richards (1978) are discussed, and a new key for all subgenera and species-groups of Mischocyttarus is also presented.

O artigo apresenta um estudo filogenético dos subgêneros e grupos de espécies de Mischocyttarus de Saussure, o maior dos gêneros de vespas sociais. A análise é baseada em 62 caracteres morfológicos e de arquitetura de ninhos, codificados para 71 terminais representantes da diversidade taxonômica do gênero e mais três terminais correspondentes às outras três tribos de Polistinae. As conclusões principais sobre relações filogenéticas são extraídas de análises usando pesagem implícita de caracteres. O monofiletismo de Mischocyttarus é confirmado, assim como da maioria dos subgêneros previamente reconhecidos: Mischocyttarus s. str., Clypeopolybia, Monogynoecus, Scytokeraia, Phi, Kappa, Megacanthopus e Omega sensu Richards (1978). Haplometrobius tal como concebido por Richards (1978) não é um táxon monofilético, mas alguns de seus grupos de espécies são monofiléticos. Os grupos de M.artifex e M.cerberus são elevados à categoria de subgênero e um novo conceito mais restrito de Haplometrobius é adotado, circunscrito ao grupo de M.iheringi (a espécie tipo desse subgênero). O conceito do subgênero Omega é ampliado para incluir os grupos de espécies de M.surinamensis e M.prominulus. Além de uma nova classificação subgenérica, acompanhada de chave de identificação, discute-se também os limites e diagnoses de todos os grupos de espécies dos subgêneros Phi e Hamplometrobius sensu Richards (1978).

Morphological studies on castes of Protopolybia chartergoides (Hymenoptera, Vespidae, Epiponini) observed in colonies during male production stage

Social wasps are important for the study of social behavior evolution because their colonies present different degrees of caste differentiation, from morphologically similar to highly conspicuous, associated with the occasional presence of intermediate females, which bears developed ovaries but no insemination. In the Polistinae, depending on the taxon, such differentiation can be discreet or conspicuous. This work intended to study morphological and physiological differences between castes in Protopolybia chartergoides by using morphometric analyses associated with multivariate statistical analyses and physiological evaluations from females' ovarian development. Results evidence low morphological and physiological differences among the castes in P. chartergoides, indicating three groups of females: queens, workers and intermediates. In this way, it was possible to suggest that Protopolybia chartergoides presents post-imaginal caste differentiation (or a very subtle form of pre-imaginal determination).

Vespas sociais são importantes para o estudo da evolução do comportamento social devido suas colônias apresentarem diferentes graus de diferenciação de castas, de morfologicamente similares às altamente conspícuas, associadas com a presença de fêmeas intermediárias, as quais desenvolvem seus ovários, mas não estando inseminadas. Nos Polistinae, tais diferenciações podem ser discretas ou conspícuas. Este trabalho teve como objetivo estudar as diferenças morfológicas e fisiológicas entre as castas de Protopolybia chartergoides pelo uso de análises morfométricas associada com análises estatísticas multivariadas e avaliações fisiológicas do desenvolvimento ovariano das fêmeas. Os resultados mostraram baixa diferenciação morfológica e fisiológica entre as castas de P. chartergoides, indicando a presença de três grupos de fêmeas: rainhas, operárias e intermediárias. Assim, foi possível sugerir que Protopolybia chartergoides apresenta diferenciação de casta pós-imaginal (ou uma forma muito sutil de determinação pré-imaginal).

Colony membership is reflected by variations in cuticular hydrocarbon profile in a Neotropical paper wasp, Polistes satan (Hymenoptera, Vespidae)

Nestmate recognition is one the most important features in social insect colonies. Although epicuticular lipids or cuticular hydrocarbons have both structural and defensive functions in insects, they also seem to be involved in several aspects of communication in wasps, bees and ants. We analyzed and described for the first time the cuticular hydrocarbons of a Neotropical paper wasp, Polistes satan, and found that variation in hydrocarbon profile was sufficiently strong to discriminate individuals according to their colony membership. Therefore, it seems that small differences in the proportion of these compounds can be detected and used as a chemical-based cue by nestmates to detect invaders and avoid usurpation.

Observations on the social wasp Ropalidia montana from peninsular India.

Four colonies of Ropalidia montana collected in August in the Nilgiri Hills of southern India had adult populations of 32,000-61,000. Queens represented 0·46–1·40% of the populations. All colonies contained males, but in widely varying proportions (1·47– 27.00%). The large adult populations and the fact that the nests were largely filled with brood in all stages of development indicate that the colonies were in a stage of active growth in this season. In December, however, colonies have been reported to have smaller adult populations and little brood. Thus brood production appears to be seasonal in southern India. Predation by the hornet Vespa tropica was observed in 4 of 31 active colonies. Ropalidia montana adults were defenseless in the face of these depredations, which appear to continue at a low level for days or weeks on a given nest.