Neotropical swarm-founding wasps are divided into 19 genera in the tribe Epiponini (Vespidae, Polistinae). They display extensive variation in several colony-level traits that make them an attractive model system for reconstructing the evolution of social phenotypes, including caste dimorphism and nest architecture. Epiponini has been upheld as a solid monophyletic group in most phylogenetic analyses carried out so far, supported by molecular, morphological and behavioural data. Recent molecular studies, however, propose different relationships among the genera of swarm-founding wasps. This study is based on the most comprehensive epiponine sampling so far and was analyzed by combining morphological, nesting and molecular data. The resulting phylogenetic hypothesis shows many of the traditional clades but still impacts the way certain behavioural characters, such as nest structure and castes, evolved, and thus requires some re-interpretations. Angiopolybia as sister to the remaining Epiponini implies that nest envelopes and a casteless system are plesiomorphic in the tribe. Molecular dating points to an early tribal diversification during the Eocene (c. 55-38 Ma), with the major differentiation of current genera concentrated in the Oligocene/Miocene boundary.

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Swarm-founding wasps are endemic and common representatives of neotropical fauna and compose an interesting social tribe of vespids, presenting both complex social characteristics and uncommon traits for a eusocial group, such as the absence of castes with distinct morphology. The paper wasp Protonectarina sylveirae (Saussure) presents a broad distribution from Brazil, Argentina and Paraguay, occurring widespread in the Atlantic rainforest and arboreal Caatinga, being absent in the Amazon region. Given the peculiar distribution among swarm-founding wasps, an integrative approach to reconstruct the evolutionary history of P. sylveirae in a spatial-temporal framework was performed to investigate: the presence of genetic structure and its relationship with the geography, the evolution of distinct morphologic lineages and the possible historical event(s) in Neotropical region, which could explain the observed phylogeographic pattern. Individuals of P. sylveirae were obtained from populations of 16 areas throughout its distribution for DNA extraction and amplification of mitochondrial genes 12S, 16S and COI. Analysis of genetic diversity, construction of haplotype net, analysis of population structure and dating analysis of divergence time were performed. A morphometric analysis was also performed using 8 measures of the body of the adult (workers) to test if there are morphological distinction among populations. Thirty-five haplotypes were identified, most of them exclusively of a group and a high population structure was found. The possibility of genetic divergence because of isolation by distance was rejected. Morphological analysis pointed to a great uniformity in phenotypes, with only a small degree of differentiation between populations of south and the remaining. Divergence time analysis showed a Middle/Late Miocene origin, a period where an extensive marine ingression occurred in South America. Divergence of haplogroups began from the Plio/Pleistocene boundary and the last glacial maximum most likely modeled the current distribution of species, even though it was not the cause of genetic breaks.

The State of Acre, in the southwestern Brazilian Amazon, harbors high biodiversity and a high degree of endemisms. Nevertheless, there are few studies on the diversity of social wasps occurring in this region. This study presents a list of social wasps (Hymenoptera, Vespidae, Polistinae) collected actively with attractive bait in three rainforest fragments in Acre. A total of 758 wasps belonging to 11 genera and 36 species were collected. Nineteen species were new distribution records for Acre and three others were new records for Brazil. Based on our results, further investigations should lead to a significant increase in Polistinae diversity in this region, producing information for biogeographic studies and management of natural areas.KEYWORDS: distribution records, Neotropical Region, swarm-founding wasps, Western Amazon Levantamento de vespas sociais (Hymenoptera, Vespidae, Polistinae) em fragmentos de floresta Amazônica no Acre, Brasil RESUMO O estado do Acre é parte da Amazônia Ocidental brasileira, uma área que abriga uma grande biodiversidade e alto grau de endemismos. Contudo, poucos estudos investigaram a diversidade de vespas sociais nesta região. Este trabalho apresenta os resultados de uma amostragem de vespas sociais (Hymenoptera,Vespidae, Polistinae) em três fragmentos de floresta primária no estado do Acre. As vespas foram coletadas ativamente com o uso de solução atrativa. Um total de 758 vespas, pertencentes a 11 gêneros e 36 espécies, foi amostrado, sendo 19 dessas espécies novos registros de distribuição para o Acre e três novos registros para o Brasil. Nossos resultados indicam que novas investigações devem levar a um aumento significativo da diversidade de espécies de vespas Polistinae conhecida para a região. Nosso estudo produziu subsídios de grande utilidade para estudos biogeográficos e fornece informações importantes para a tomada de decisões sobre o manejo de áreas naturais.

A survey of social wasps (Vespidae, Polistinae), common insects of Neotropical fauna, which performs a great variety of important ecosystemic services, was conducted for the first time in areas of the Amazon forest in Rondônia state. The state is part of the western Amazon, a region harboring high biodiversity, but which has been suffering from constant deforestation. Three areas were sampled, and the wasps were actively collected, and an attractive liquid was sprayed onto the vegetation to bait the wasps. A total of 2961 wasps were sampled in all three areas, distributed in 72 species of 15 genera. Thirty-nine species were recorded for the first time in the state and three others (Agelaia melanopyga Cooper, Brachygastra cooperiAndena and Carpenter and Polybia diguetana du Buysson)represents the first record for Brazil.AgelaiaLepeletier was the most abundant genus in all areas, which is congruent with results of other surveys, and the greatest species richness was found for Polybia Lepeletier. The highest number of species was sampled in Floresta Nacional do Jamari (51), followed by Estação Ecológica de Cuniã (46) and forest fragment of Universidade Federal de Rondônia (39). The latter also presented the highest number of different genera sampled. The great diversity sampled, mainly for Epiponini, which represented 64 of the 72 species collected, can be attributed to various factor as the location of the areas and also to the methodology used.

Aim The aim of this study was to understand the biogeography of Brachygastra. As the spatial component of evolution is of fundamental importance to understanding the processes shaping the evolution of taxa, the known geological history of the Neotropical region was used together with the current phylogeny and distribution of species to investigate questions concerning the biogeography of Brachygastra: the ancestral ranges of Brachygastra species; their areal relationships and their congruence with previously published hypotheses; the possible associated vicariance events and the influence of land bridges between North and South America, and the split between the Amazon and Atlantic forests.Location Neotropical region, from Mexico to central Argentina and southern USA.Methods Statistical dispersal-vicariance analysis (S-DIVA) was used to reconstruct the possible ancestral ranges of Brachygastra species based on their phylogeny (divided into three groups, lecheguana, scuttelaris and smithii). A Brooks parsimony analysis (BPA) and component analysis were performed to reconstruct the areal relationships of these species within the Neotropics.Results S-DIVA suggested a widespread, South American ancestral region for Brachygastra. The ancestral B. azteca probably reached the Nearctic before a posterior vicariance event separated it from the species groups ((lecheguana (scutellaris + smithii))), that stayed in the Atlantic forest. The ancestral (scutellaris + smithii groups) possibly reached the Amazon by dispersal, and the subsequent vicariance event splitting the Atlantic forest and Amazon separated the groups into scutellaris in the Atlantic forest and smithii in the Amazon. BPA and component analyses suggested that the Nearctic was a sister area to other regions, the Andes and Mesoamerica was a sister area to the Neotropical regions and the Amazon was closely related to the Atlantic forest. Main conclusionsThe phylogeny and distribution of Brachygastra suggest the influence of a land bridge between the Northern and Southern Hemispheres affecting the cladogenesis of B. azteca and the importance of the formation of the two blocks of forests in South America to the cladogenesis of the main groups of Brachygastra. Future comparisons between the distribution patterns of other taxa should enable a more precise identification of the possible events and outcomes, adding robustness to the hypothesized areal relationships.

da Silva, M., Noll, F. B. and Billen, J. 2015. Morphology of Richards' gland in the swarm-founding wasp Protonectarina sylveirae (Hymenoptera, Vespidae). -Acta Zoologica (Stockholm) 96: 530-533.Richards' gland is known for the majority of Epiponini wasps, and despite few experimental evidences, the taxonomic distribution in swarm-founder species and the function of this gland remain rather unclear. This work presents a morphological description of Richards' gland in Protonectarina sylveirae. The gland is formed by a cluster of class 3 cells underneath the anterior margin of the fifth metasomal sternite, and a reservoir formed by the intersegmental membrane between the fourth and fifth metasomal sternites where the secretion can be stored. The secretory cells contain a branched end apparatus that carries the secretory products towards the duct cell. Externally, the cuticle of the sternite, where the duct cells penetrate, is characterized by modifications as scales with very numerous pores. The presence of Richards' gland according to the model proposed by Samac a et al. 2013 in Protonectarina corroborates the single origin of this gland in Epiponini. The occurrence of a Golgi apparatus and smooth endoplasmic reticulum suggests pheromone production.

In  colonies  of  Neotropical  swarm-founding  wasps  (Epiponini),  males  are  thought  to be produced only in periods when there are many queens present. Little information is available regarding male behavior in and out of the nest, and male mating strategies are poorly understood. Here, a behavioral study of males of Synoeca  surinama is provided and copulation behavior inside a nest is described for the first time. A description of an aggregation of non-natal males at a nest is also provided. The behavior of males was observed in three colonies subjected to removal of queens for another study. Nest envelope was partially removed, and the observations were made directly (seen by “the naked eye”) and indirectly (through camcorder recordings), daily. Production of males occurred in large colonies with number of workers being more relevant than the number of the queens. Males of the aggregation were marked and filmed. The aggregation of non-natal males was observed for seven consecutive days next to the largest colony; some of the males attended the aggregation on consecutive days. The males were observed accessing the comb by the opening in the envelope and courting new queens. One successful copulation on the comb of the nest was observed. In the colony where the male aggregation was observed, 47.6% of the new queens were inseminated while in the other two colonies, no new queens were inseminated. These observations suggest males are attracted to, aggregate and seek mating opportunities at non-natal colonies that are producing young adult queens.