Kurt M. Pickett

The conflation of ignorance and knowledge in the inference of clade posteriors

The objective Bayesian approach relies on the construction of prior distributions that reflect ignorance. When topologies are considered equally probable a priori, clades cannot be. Shifting justifications have been offered for the use of uniform topological priors in Bayesian inference. These include: (i) topological priors do not inappropriately influence Bayesian inference when they are uniform; (ii) although clade priors are not uniform, their undesirable influence is negated by the likelihood function, even when data sets are small; and (iii) the influence of nonuniform clade priors is an appropriate reflection of knowledge. The first two justifications have been addressed previously: the first is false, and the second was found to be questionable. The third and most recent justification is inconsistent with the first two, and with the objective Bayesian philosophy itself. Thus, there has been no coherent justification for the use of nonflat clade priors in Bayesian phylogenetics. We discuss several solutions: (i) Bayesian inference can be abandoned in favour of other methods of phylogenetic inference; (ii) the objective Bayesian philosophy can be abandoned in favour of a subjective interpretation; (iii) the topology with the greatest posterior probability, which is also the tree of greatest marginal likelihood, can be accepted as optimal, with clade support estimated using other means; or (iv) a Bayes factor, which accounts for differences in priors among competing hypotheses, can be used to assess the weight of evidence in support of clades.u2028©The Willi Hennig Society 2009

Phylogeny and historical biogeography of the paper wasp genus Polistes (Hymenoptera: Vespidae): implications for the overwintering hypothesis of social evolution

The phylogeny of the paper wasp genus Polistes is investigated using morphological and behavioural characters, as well as molecular data from six genes (COI, 12S, 16S, 28S, H3, and EF1‐α). The results are used to investigate the following evolutionary hypotheses about the genus: (i) that Polistes first evolved in Southeast Asia, (ii) that dispersal to the New World occurred only once, and (iii) that long‐term monogyny evolved as an adaptation to overwintering in a temperate climate. Optimization of distribution records on the recovered tree does not allow unambiguous reconstruction of the ancestral area of Polistes. While the results indicate that Polistes dispersed into the New World from Asia, South America is recovered as the ancestral area for all New World Polistes: Nearctic species groups evolved multiple times from this South American stock. The final tree topology suggests strongly that the genus first arose in a tropical environment, refuting the idea of monogyny as an overwintering adaptation.

Phylogenetic relationships of yellowjackets inferred from nine loci (Hymenoptera: Vespidae, Vespinae, Vespula and Dolichovespula)

Eusociality has arisen repeatedly and independently in the history of insects, often leading to evolutionary success and ecological dominance. Eusocial wasps of the genera Vespula and Dolichovespula, or yellowjackets, have developed advanced social traits in a relatively small number of species. The origin of traits such as effective paternity and colony size has been interpreted with reference to an established phylogenetic hypothesis that is based on phenotypic data, while the application of molecular evidence to phylogenetic analysis within yellowjackets has been limited. Here, we investigate the evolutionary history of yellowjackets on the basis of mitochondrial and nuclear markers (nuclear: 28S, EF1α, Pol II, and wg; mitochondrial: 12S, 16S, COI, COII, and Cytb). We use these data to test the monophyly of yellowjackets and species groups, and resolve species-level relationships within each genus using parsimony and Bayesian inference. Our results indicate that a yellowjacket clade is either weakly supported (parsimony) or rejected (Bayesian inference). However, the monophyly of each yellowjacket genus as well as species groups are strongly supported and concordant between methods. Our results agree with previous studies regarding the monophyly of the Vespula vulgaris group and the sister relationship between the V. rufa and V. squamosa groups. This suggests convergence of large colony size and high effective paternity in the vulgaris group and V. squamosa, or a single origin of both traits in the most recent common ancestor of all Vespula species and their evolutionary reversal in the rufa group.

Phylogenetic tests reject Emery's rule in the evolution of social parasitism in yellowjackets and hornets (Hymenoptera: Vespidae, Vespinae)

Social parasites exploit the brood-care behaviour and social structure of one or more host species. Within the social Hymenoptera there are different types of social parasitism. In its extreme form, species of obligate social parasites, or inquilines, do not have the worker caste and depend entirely on the workers of a host species to raise their reproductive offspring. The strict form of Emerys rule states that social parasites share immediate common ancestry with their hosts. Moreover, this rule has been linked with a sympatric origin of inquilines from their hosts. Here, we conduct phylogenetic analyses of yellowjackets and hornets based on 12 gene fragments and evaluate competing evolutionary scenarios to test Emerys rule. We find that inquilines, as well as facultative social parasites, are not the closest relatives of their hosts. Therefore, Emerys rule in its strict sense is rejected, suggesting that social parasites have not evolved sympatrically from their hosts in yellowjackets and hornets. However, the relaxed version of the rule is supported, as inquilines and their hosts belong to the same Dolichovespula clade. Furthermore, inquilinism has evolved only once in Dolichovespula.

Preservation of Field Samples for Enzymatic and Proteomic Characterization: Analysis of Proteins from the Trophallactic Fluid of Hornets and Yellowjackets

Proteomics is fast becoming one of the most interdisciplinary fields, bridging many chemical and biological disciplines. Major challenges, however, can limit the reach of proteomics to studies of model organisms. Challenges include the adequate preservation of field samples and the reliance of in-depth proteomics on sequenced genomes. Seeking to better establish the evolutionary relationships of hornets and yellowjackets comprising the subfamily Vespinae, we are combining classical morphological and genomic information with a functional genomics trait using proteomics. Vespine species form highly social colonies and exhibit division of labor in almost all aspects of colony life. An extreme digestive division of labor has been reported in Vespa orientalis, in which larvae but not adult workers exhibit the capacity to digest proteins fully. This makes the colony dependent upon the amino acid-rich trophallactic fluid released to adults by larvae and implies that the V. orientalis superorganism possesses larval-specific proteases. Identifying the proteases and the species exhibiting such extreme partitioning of digestive labor will allow for tracing the phylogenetic origins and elaboration of that digestive partitioning in the Vespinae. Herein we describe methods, generally applicable to field samples, showing the preservation of proteins and proteolytic activity from adult and larval vespine trophallactic fluid.

Taxonomic Notes on the Vespinae of Yunnan (Hymenoptera: Vespidae)

ABSTRACT In recent years, five new species of Vespinae have been described from Yunnan Province, China. A thorough assessment of these taxa, including study of color differences and compilation of measurements of specimens from six entomological collections, shows that the new taxa are merely variants of existing, nominal species. Thus, all five are synonymized here, as follows: Vespa hekouensis Dong and Wang, and Vespa maguanensis Dong = Vespa analis Fabricius; Vespula yulongensis Dong and Wang = Vespula flaviceps (Smith); Vespula nujiangensis Dong and Wang = Vespula orbata (du Buysson); and Vespula gongshanensis Dong = Vespula rufa (Linnaeus), all NEW SYNONYMY. The synonymies bring the current number of vespine species recognized worldwide to 67.

Dolichovespula albida (Sladen), a Valid Species, Not a Synonym of D. norwegica (Fabricius) (Hymenoptera: Vespidae, Vespinae)

Abstract Study of the male genitalia shows that Dolichovespula albida (Sladen) is not conspecific with D. norwegica (Fabricius).

Phylogenomic analysis of yellowjackets and hornets (Hymenoptera: Vespidae, Vespinae)

The phylogenetic relationships among genera of the subfamily Vespinae (yellowjackets and hornets) remain unclear. Yellowjackets and hornets constitute one of the only two lineages of highly eusocial wasps, and the distribution of key behavioral traits correlates closely with the current classification of the group. The potential of the Vespinae to elucidate the evolution of social life, however, remains limited due to ambiguous genus-level relationships. Here, we address the relationships among genera within the Vespinae using transcriptomic (RNA-seq) data. We sequenced the transcriptomes of six vespid wasps, including three of the four genera recognized in the Vespinae, combined our data with publicly available transcriptomes, and assembled two matrices comprising 1,507 and 3,356 putative single-copy genes. The results of our phylogenomic analyses recover Dolichovespula as more closely related to Vespa than to Vespula, therefore challenging the prevailing hypothesis of yellowjacket (Vespula+Dolichovespula) monophyly. This suggests that traits such as large colony size and high paternity arose in the genus Vespula following its early divergence from the remaining vespine genera.

“Basal” but not primitive: the nest of Apoica arborea de Saussure, 1854 (Insecta, Hymenoptera, Vespidae, Polistinae)

Pickett K. M., Carpenter J. M. & Dejean A. 2009. — “Basal” but not primitive: the nest of Apoica arborea de Saussure, 1854 (Insecta, Hymenoptera, Vespidae, Polistinae). Zoosystema 31 (4): 945-948. ABSTRACT The first nest of Apoica arborea ever collected is reported. Characteristics of the unusual nest design are discussed relative to other members of the genus Apoica and other epiponine genera. The characteristics of its nest architecture are a mosaic of primitive and derived features for the Polistinae, and thus the nest design is not properly interpreted as the primitive condition from which other swarm-founding wasp nest designs are derived. The frequent conflation of “basal” and primitive is discussed.

Paper Wasps ( Polistes spp.) Attacking Fall Armyworm Larvae ( Spodoptera frugiperda ) in Turfgrass

The objective of this paper is to identify common species of paper wasps (Polistes spp.) attacking fall armyworm (Noctuidae: Spodoptera frugiperda) larvae and to investigate foraging activity in turfgrass. Three species — Polistes exclamans, P. dorsalis, and P. metricus — were collected while they foraged in bermudagrass turf. Polistes wasps forage in turf for about 10 h a day beginning a few hours after sunrise (0830 h), waning near midday, and increasing again in the late afternoon. Wasps were more abundant in plots infested with fall armyworms although these differences were statistically significant in one of three trials. The benefits of Polistes wasps may be conserved by scheduling insecticide applications in the early evening (0700 h or later) or by using reduced-risk insecticides.