Dolichovespula

Abstract: . The phylogenetic relationships of the genera, subgenera and species-groups of the Vespinae are analysed using cladistic techniques. The results are used as the basis for a natural classification of these wasps. The cladogram for the four genera recognized is: Vespa+(Provespa + (Dolichovespula + Vespula)). No subgenera are recognized; all those previously described are synonymized with the appropriate genus. The synonymies of Nyctovespa with Vespa and Rugovespula with Vespula are new.

Abstract: In annual hymenopteran societies headed by a single outbred queen, paternity (determined by queen mating frequency and sperm use) is the sole variable affecting colony kin structure and is therefore a key predictor of colony reproductive characteristics. Here we investigate paternity and male production in five species of Dolichovespula wasps. Twenty workers from each of 10 colonies of each of five species, 1000 workers in total, were analysed at three DNA microsatellite loci to estimate paternity. To examine the relationship between kin structure and reproductive behaviour, worker ovary activation was assessed by dissection and the maternal origin of adult males was assessed by DNA microsatellites. Effective paternity was low in all species (D.media 1.08, D. maculata 1.0, D. sylvestris 1.15, D. norwegica 1.08 and D. saxonica 1.35), leading to the prediction of queen?worker conflict over male production. In support of this, workers with full-size eggs in their ovaries (four out of five species) and adult males that were workers? sons (all five species) were found in queenright colonies. However, workers were only responsible for a minority of male production (D.media 7.4%, D. maculata 20.9%, D. sylvestris 9.8%, D. norwegica 2.6% and D. saxonica 34.6%) suggesting that the queen maintains considerable reproductive power over the workers. Kin structure and reproductive conflict in Dolichovespula contrast with their sister group Vespula. Dolichovespula is characterized by low paternity, worker reproduction, and queen?worker conflict and Vespula by high paternity, effective worker policing and absence of worker reproduction. The trend revealed by this comparison is as predicted by kin selection theory suggesting that colony kin structure has been pivotal in the evolution of the yellowjacket wasps.

Abstract: Colonies of the European hornet, Vespa crabro, are typically founded by a single queen mated to a single male. From the resulting colony relatedness pattern we predicted strong worker-queen conflict over male production where both the workers and the queen attempt to produce the colony's males. To test for this conflict, male production was studied in 15 hornet nests using a combination of DNA microsatellite analysis (282 males), worker ovary dissections (500 workers from eight nests) and 50 h of observation (four nests). In contrast to our prediction, the data show that hornet males are queens' sons, that workers never attempt to lay eggs, rarely have activated ovaries, and that there is no direct aggression between the queen and the workers. This contrasts with other data for vespine wasps, which support relatedness predictions. Dolichovespula arenaria has the same kin structure as V. crabro and workers produce males in many colonies. The similarity between these two species makes it difficult to explain why workers do not reproduce in V. crabro. Self-restraint is expected if worker reproduction significantly reduces colony productivity but there is no obvious reason why this should be important to V. crabro but not to D. arenaria. Alternatively, queen control may be important. The absence of expressed queen-worker conflict rules out physical control. Indirect pheromonal control is a possibility and is supported by the occurrence of royal courts and queen pheromone in Vespa but not Dolichovespula. Pheromonal queen control is considered evolutionarily unstable, but could result from a queen-worker arms race over reproductive control in which the queen is ahead. The genetic data also revealed diploid males in one colony, the first example in the vespine wasps, and two colonies with double matrilines, suggesting that occasional usurpation by spring queens occurs.

Abstract: Queens of 12 species of yellowjackets (Vespula Thamson/Dolichovespula Rohwer), as well as Vespa crabro L., Polistes fuscatus (F.), and Mischocyttarus flavitarsis (Saussure), were dissected in a search for exocrine glands. Fourteen glands or gland systems were found, including 4 previously unreported glands associated with the mouth parts and an additional abdominal gland. Another unreported abdominal gland was found in males of Mischocyttarus flavitarsis. Most appear to be widely occurring in the social Vespidae. Some changes in gland development were documented in relation to season and colony development, suggesting possible functions. There were differences in the occurrence of certain glands among species groups and genera. The extensive exocrine gland systems found in vespid queens are probably associated with colony founding by queens as well as intensive use of chemical communication.