Comparative genomics of mutualistic viruses of Glyptapanteles parasitic wasps

Comparative genome analysis of two endosymbiotic polydnaviruses from Glyptapanteles parasitic wasps reveals new insights into the evolutionary arms race between host and parasite

Biology and Life History of Balcha indica, an Ectoparasitoid Attacking the Emerald Ash Borer, Agrilus planipennis, in North America

Balcha indica Mani and Kaul (Hymenoptera: Eupelmidae) is a solitary ectoparasitoid attacking larvae, prepupae, and pupae of the emerald ash borer, Agrilus planipennis Fairmaire (Hymenoptera: Eupelmidae). Its fecundity, oviposition rate, longevity, and development time were determined in the laboratory under standard rearing conditions (25 ± 2° C, 65 ± 10% relative humidity, and 14:10 L:D). Adults lived a mean of 59 days with a maximum of 117 days. Lifetime adult fecundity averaged 36 eggs with a maximum 94 eggs per female. The egg stage lasted for a maximum of four days with ∼ 50% eggs hatched within two days. The development time of the first instars lasted for a maximum of nine days; 50% of the first instars completed their development (i.e., molted to the next instar) within five days. Instars of the intermediate and final stage larvae (after molting of the first instars occurred) could not be distinguished until they reached the pupal stage, and 50% of those larvae pupated ∼ 62 days after adult oviposition. Under the standard rearing conditions, 50% of B. indica took ∼ 83 days to complete the life cycle (from egg to adult emergence) ranging from 47 to 129 days. These results suggest that B. indica may not have more than two generations in the mid-Atlantic and Midwest regions of United States, where normal growing seasons—with average temperature above 25° C—are normally less than six months (May–October). Because of the long life span and oviposition period of adults, however, B. indica is likely to have overlapping generations

Parasitoid Guilds of Agrilus woodborers (Coleoptera: Buprestidae): Their diversity and potential for use in biological control. Psyche 2012

and the Korean peninsula) were reviewed to identify parasitoid guilds associated with Agrilus woodborers. There are at least 12 species of hymenopteran parasitoids attacking eggs of Agrilus beetles and 56 species (36 genera), attacking Agrilus larvae infesting various host plants in North America, Asia, and Europe. While most of the egg parasitoids (9 species) belong to the family Encyrtidae, a majority of the larval parasitoids are members of five families: Braconidae (24 species/11 genera), Eulophidae (8 species/4 genera), Ichneumonidae (10 species/9 genera), and Eupelmidae (6 species/5 genera). The highest rate of Agrilus egg parasitism (>50%) was exerted by encyrtid wasps (4 species) in North America, Asia, and Europe. In contrast, the highest rate of Agrilus larval parasitism (>50%) was caused by species in two genera of braconids: Atanycolus (North America) and Spathius (Asia), and one eulophid genus, Tetrastichus (Asia and Europe). Reported rate of Agrilus larval parasitism ichneumonids was frequent in North America, but generally low (<1%). Potential for success in biological control of emerald ash borer (Agrilus planipennis Fairmaire) in the USA with North American native parasitoids and old-association Asian parasitoids is discussed

Structure and evolution of a proviral locus of <it>Glyptapanteles indiensis </it>bracovirus

Abstract Background Bracoviruses (BVs), a group of double-stranded DNA viruses with segmented genomes, are mutualistic endosymbionts of parasitoid wasps. Virus particles are replication deficient and are produced only by female wasps from proviral sequences integrated into the wasp genome. Virus particles are injected along with eggs into caterpillar hosts, where viral gene expression facilitates parasitoid survival and therefore perpetuation of proviral DNA. Here we describe a 223 kbp region of Glyptapanteles indiensis genomic DNA which contains a part of the G. indiensis bracovirus (GiBV) proviral genome. Results Eighteen of ~24 GiBV viral segment sequences are encoded by 7 non-overlapping sets of BAC clones, revealing that some proviral segment sequences are separated by long stretches of intervening DNA. Two overlapping BACs, which contain a locus of 8 tandemly arrayed proviral segments flanked on either side by ~35 kbp of non-packaged DNA, were sequenced and annotated. Structural and compositional analyses of this cluster revealed it exhibits a G+C and nucleotide composition distinct from the flanking DNA. By analyzing sequence polymorphisms in the 8 GiBV viral segment sequences, we found evidence for widespread selection acting on both protein-coding and non-coding DNA. Comparative analysis of viral and proviral segment sequences revealed a sequence motif involved in the excision of proviral genome segments which is highly conserved in two other bracoviruses. Conclusion Contrary to current concepts of bracovirus proviral genome organization our results demonstrate that some but not all GiBV proviral segment sequences exist in a tandem array. Unexpectedly, non-coding DNA in the 8 proviral genome segments which typically occupies ~70% of BV viral genomes is under selection pressure suggesting it serves some function(s). We hypothesize that selection acting on GiBV proviral sequences maintains the genetic island-like nature of the cluster of proviral genome segments described herein. In contrast to large differences in the predicted gene composition of BV genomes, sequences that appear to mediate processes of viral segment formation, such as proviral segment excision and circularization, appear to be highly conserved, supporting the hypothesis of a single origin for BVs.</p