No abstract

This study examined subfamilial relationships within Braconidae, using 4 kb of sequence data for 139 taxa. Genetic sampling included previously used markers for phylogenetic studies of Braconidae (28S and 18S rDNA) as well as new nuclear protein‐coding genes (CAD and ACC). Maximum likelihood and Bayesian inference of the concatenated dataset recovered a robust phylogeny, particularly for early divergences within the family. This study focused primarily on non‐cyclostome subfamilies, but the monophyly of the cyclostome complex was strongly supported. There was evidence supporting an independent clade, termed the aphidioid complex, as sister to the cyclostome complex of subfamilies. Maxfischeria was removed from Helconinae and placed within its own subfamily within the aphidioid complex. Most relationships within the cyclostome complex were poorly supported, probably because of lower taxonomic sampling within this group. Similar to other studies, there was strong support for the alysioid subcomplex containing Gnamptodontinae, Alysiinae, Opiinae and Exothecinae. Cenocoeliinae was recovered as sister to all other subfamilies within the euphoroid complex. Planitorus and Mannokeraia, previously placed in Betylobraconinae and Masoninae, respectively, were moved to the Euphorinae, and may share a close affiliation with Neoneurinae. Neoneurinae and Ecnomiinae were placed as tribes within Euphorinae. A sister relationship between the microgastroid and sigalphoid complexes was also recovered. The helconoid complex included a well‐supported lineage that is parasitic on lepidopteran larvae (macrocentroid subcomplex). Helconini was raised to subfamily status, and was recovered as sister to the macrocentroid subcomplex. Blacinae was demoted to tribal status and placed within the newly circumscribed subfamily Brachistinae, which also contains the tribes Diospilini, Brulleiini and Brachistini, all formerly in Helconinae.

The hypothesis that eusociality originated once in Vespidae has shaped interpretation of social evolution for decades and has driven the supposition that preimaginal morphophysiological differences between castes were absent at the outset of eusociality. Many researchers also consider casteless nest-sharing an antecedent to eusociality. Together, these ideas endorse a stepwise progression of social evolution in wasps (solitary → casteless nest-sharing → eusociality with rudimentary behavioral castes → eusociality with preimaginal caste-biasing (PCB) → morphologically differentiated castes). Here, we infer the phylogeny of Vespidae using sequence data generated via anchored hybrid enrichment from 378 loci across 136 vespid species and perform ancestral state reconstructions to test whether rudimentary and monomorphic castes characterized the initial stages of eusocial evolution. Our results reject the single origin of eusociality hypothesis, contest the supposition that eusociality emerged from a casteless nest-sharing ancestor, and suggest that eusociality in Polistinae + Vespinae began with castes having morphological differences. An abrupt appearance of castes with ontogenetically established morphophysiological differences conflicts with the current conception of stepwise social evolution and suggests that the climb up the ladder of sociality does not occur through sequential mutation. Phenotypic plasticity and standing genetic variation could explain how cooperative brood care evolved in concert with nest-sharing and how morphologically dissimilar castes arose without a rudimentary intermediate. Furthermore, PCB at the outset of eusociality implicates a subsocial route to eusociality in Polistinae + Vespinae, emphasizing the role of mother–daughter interactions and subfertility (i.e. the cost component of kin selection) in the origin of workers.

Viral genome integration provides a complex route to biological innovation that has rarely but repeatedly occurred in one of the most diverse lineages of organisms on the planet, parasitoid wasps. We describe a novel endogenous virus in braconid wasps derived from pathogenic alphanudiviruses. Limited to a subset of the genus Fopius, this recent acquisition allows an unprecedented opportunity to examine early endogenization events. Massive amounts of virus-like particles (VLPs) are produced in wasp ovaries. Unlike most endogenous viruses of parasitoid wasps, the VLPs do not contain DNA, translating to major differences in parasitism-promoting strategies. Rapid changes include genomic rearrangement, loss of DNA processing proteins, and wasp control of viral gene expression. These events precede the full development of tissue-specific viral gene expression observed in older associations. These data indicate that viral endogenization can rapidly result in functional and evolutionary changes associated with genomic novelty and adaptation in parasitoids.

The invasive eucalyptus tortoise beetle, Paropsis charybdis, defoliates plantations of Eucalyptus nitens in New Zealand. Recent efforts to identify host specific biological control agents (parasitoids) from Tasmania, Australia, have focused on the larval parasitoid wasp, Eadya paropsidis (Braconidae), first described in 1978. In Tasmania, Eadya has been reared from Paropsisterna agricola (genus abbreviated Pst.), a smaller paropsine that feeds as a larva on juvenile rather than adult foliage of Eucalyptus nitens. To determine which of the many paropsine beetle hosts native to Tasmania are utilized by E. paropsidis, and to rule out the presence of cryptic species, a molecular phylogenetic approach was combined with host data from rearing experiments from multiple locations across six years. Sampling included 188 wasps and 94 beetles for molecular data alone. Two mitochondrial genes (COI and Cytb) and one nuclear gene (28S) were analyzed to assess the species limits in the parasitoid wasps. The mitochondrial genes were congruent in delimiting four separate phylogenetic species, all supported by morphological examinations of Eadya specimens collected throughout Tasmania. Eadya paropsidis was true to the type description, and was almost exclusively associated with P. tasmanica. A new cryptic species similar to E. paropsidis, Eadya sp. 3, was readily reared from Pst. agricola and P. charybdis from all sites and all years. Eadya sp. 3 represents the best candidate for biological control of P. charybdis and was determined as the species undergoing host range testing in New Zealand for its potential as a biological control agent. Another new species, Eadya sp. 1, was morphologically distinctive and attacked multiple hosts. The most common host was Pst. variicollis, but was also reared from Pst. nobilitata and Pst. selmani. Eadya sp. 1 may have potential for control against Pst. variicollis, a new incursion in New Zealand, and possibly Pst. selmani in Ireland. Our molecular data suggests that Pst. variicollis is in need of taxonomic revision and the geographic source of the beetle in New Zealand may not be Tasmania. Eadya sp. 2 was rarely collected and attacked P. aegrota elliotti and P. charybdis. Most species of Eadya present in Tasmania are not host specific to one beetle species alone, but demonstrate some host plasticity across the genera Paropsisterna and Paropsis. This study is an excellent example of collaborative phylogenetic and biological control research prior to the release of prospective biological control agents, and has important implications for the Eucalyptus industry worldwide.