Testing the Dutilleul syndrome: host use drives the convergent evolution of multiple traits in parasitic wasps

A new and unusual Digonocryptus Viereck (Hymenoptera, Ichneumonidae,Cryptinae), with notes on two other rare species

Digonocryptus magnus sp. nov., from French Guyana, is described and illustrated, and new records, morphological and morphometric data are presented for two other rare species, D. coloratus (Szpligeti, 1916), registered for the first time from Colombia, and D. zatheos Aguiar & Santos, 2012. The new species is characterized by having the apical margin of the clypeus straight, medially with a small tooth, propodeal apophyses stout, scale-shaped, fore wing with ramellus, areolet about as wide as high, nearly quadrate, 2r-m as long as the mostly spectral 3r-m, T1basally with a distinct lateral rounded flange, and the longest ovipositor of the genus. The study employs morphological character coding combined with a reanalysis of published molecular data to investigate the phylogenetic placement of D. magnus. The results suggest that it may represent a borderline species within Digonocryptus or potentially a new genus, although further investigation is required due to limited available material and inconclusive data.

Running in circles in phylomorphospace: host environment constrains morphological diversification in parasitic wasps

Understanding phenotypic diversification and the conditions that spur morphological novelty or constraint is a major theme in evolutionary biology. Unequal morphological diversity between sister clades can result from either differences in the rate of morphological change or in the ability of clades to explore novel phenotype ranges. We combine an existing phylogenetic framework with new phylogenomic data and geometric morphometrics to explore the relative roles of rate versus mode of morphological evolution for a hyperdiverse group: cryptine ichneumonid wasps. Data from genomic ultraconserved elements confirm that cryptines are divided into two large clades: one specialized in the use of hosts that are deeply concealed under hard substrates, and another with a much more diversified host range. Using a phylomorphospace approach, we show that both clades have experienced similar rates of morphological evolution. Nonetheless, the more specialized group is much more restricted in morphospace occupation, indicating that it repeatedly evolved morphological change through the same morphospace regions. This is in agreement with our prediction that host use imposes constraints in the morphospace available to lineages, and reinforces an important distinction between evolutionary stasis as opposed to a scenario of continual morphological change restricted to a certain range of morphotypes.