Molecular phylogenetics and the evolution of wing reduction in the Baeini (Hymenoptera�:�Scelionidae): parasitoids of spider eggs

Studies of dispersal polymorphism in insects have played a pivotal role in advancing our understanding of population dynamics, life history evolution, and the physiological basis of adaptation. Comparative data on wing-dimorphic insects provide the most definitive evidence to date that habitat persistence selects for reduced dispersal capability. The increased fecundity of flightless females documents that a fitness trade-off exists between flight capability and reproduction. However, only recently have studies of nutrient consumption and allocation provided unequivocal evidence that this fitness trade-off results from a trade-off of internal resources. Recent studies involving wing-dimorphic insects document that flight capability imposes reproductive penalties in males as well as females. Direct information on hormone titers and their regulation implicates juvenile hormone and ecdysone in the control of wing-morph determination. However, detailed information is available for only one species, and the physiological regulation of wing-morph production remains poorly understood. Establishing a link between the ecological factors that influence dispersal and the proximate physiological mechanisms regulating dispersal ability in the same taxon remains as a key challenge for future research.

Partitioned Bayesian analyses of approximately 2.2 kb of nucleotide sequence data (mtDNA) were used to elucidate phylogenetic relationships among 30 scincid lizard genera. Few partitioned Bayesian analyses exist in the literature, resulting in a lack of methods to determine the appropriate number of and identity of partitions. Thus, a criterion, based on the Bayes factor, for selecting among competing partitioning strategies is proposed and tested. Improvements in both mean -lnL and estimated posterior probabilities were observed when specific models and parameter estimates were assumed for partitions of the total data set. This result is expected given that the 95% credible intervals of model parameter estimates for numerous partitions do not overlap and it reveals that different data partitions may evolve quite differently. We further demonstrate that how one partitions the data (by gene, codon position, etc.) is shown to be a greater concern than simply the overall number of partitions. Using the criterion of the 2 ln Bayes factor > 10, the phylogenetic analysis employing the largest number of partitions was decisively better than all other strategies. Strategies that partitioned the ND1 gene by codon position performed better than other partition strategies, regardless of the overall number of partitions. Scincidae, Acontinae, Lygosominae, east Asian and North American "Eumeces" + Neoseps; North African Eumeces, Scincus, and Scincopus, and a large group primarily from sub-Saharan Africa, Madagascar, and neighboring islands are monophyletic. Feylinia, a limbless group of previously uncertain relationships, is nested within a "scincine" clade from sub-Saharan Africa. We reject the hypothesis that the nearly limbless dibamids are derived from within the Scincidae, but cannot reject the hypothesis that they represent the sister taxon to skinks. Amphiglossus, Chalcides, the acontines Acontias and Typhlosaurus, and Scincinae are paraphyletic. The globally widespread "Eumeces" is polyphyletic and we make necessary taxonomic changes.

New taxonomic information is given on the identities, generic classification, morphology, relationships, and geographic distribution of several hundred species of proctotrupoid wasps. The paper is based on a study of primary types of 270 species of Scelionidae, many secondary types, and other important material in 40 world museums and private collections with approximately 300,000 specimens of Proctotrupoidea having been examined. Many genera are redefined, and generic diagnoses completed or corrected. The tribal classification is reviewed; four new tribes are proposed in the subfamily Scelioninae, viz. Nixoniini, Sparasionini, Cremastobaeini, and Doddiellini.