title: Spread and global population structure of the diamondback moth Plutella xylostella (Lepidoptera: Plutellidae) and its larval parasitoids Diadegma semiclausum and Diadegma fenestrale (Hymenoptera: Ichneumonidae) based on mtDNA.
abstract: The diamondback moth (DBM) (Plutella xylostella) is one of the main pests of brassicaceous crops worldwide and shows resistance against a wide range of synthetic insecticides incurring millions of dollars in control costs every year. The DBM is a prime example of the introduction of an exotic species as a consequence of globalization. In this study we analyzed the genetic population structure of the DBM and two of its parasitic wasps, Diadegma semiclausum and Diadegma fenestrale, based on mitochondrial DNA sequences. We analyzed DBM samples from 13 regions worldwide (n = 278), and samples of the two wasp species from six European and African countries (n = 131), in an attempt to reconstruct the geographic origin and phylogeography of the DBM and its two parasitic wasps. We found high variability in COI sequences in the diamondback moth. Haplotype analysis showed three distinct genetic clusters, one of which could represent a cryptic species. Mismatch analysis confirmed the hypothesized recent spread of diamondback moths in North America, Australia and New Zealand. The highest genetic variability was found in African DBM samples. Our data corroborate prior claims of Africa as the most probable origin of the species but cannot preclude Asia as an alternative. No genetic variability was found in the two Diadegma species. The lack of variability in both wasp species suggests a very recent spread of bottlenecked populations, possibly facilitated by their use as biocontrol agents. Our data thus also contain no signals of host-parasitoid co-evolution.
authors: Research Institute of Organic Agriculture (FiBL),Ackerstrasse 21,5070 Frick,Switzerland.
authors: I
authors: I
authors: Juric
authors: Zoological Institute, University of Basel,Vesalgasse 1,4051 Basel,Switzerland.
authors: W
authors: W
authors: Salzburger
authors: Research Institute of Organic Agriculture (FiBL),Ackerstrasse 21,5070 Frick,Switzerland.
authors: O
authors: O
authors: Balmer
mesh_terms: D000818:Animals; D005075:Biological Evolution; D003576:Electron Transport Complex IV / Q000235:genetics; D014644:Genetic Variation; D019476:Insect Proteins / Q000235:genetics; D007814:Larva / Q000235:genetics / Q000469:parasitology / Q000502:physiology; D024101:Mitochondrial Proteins / Q000235:genetics; D009036:Moths / Q000235:genetics* / Q000254:growth & development / Q000469:parasitology; D010572:Pest Control, Biological; D010802:Phylogeny; D058974:Phylogeography; D017422:Sequence Analysis, DNA; D014863:Wasps / Q000235:genetics* / Q000254:growth & development / Q000502:physiology
chemical_list: D019476:Insect Proteins; D024101:Mitochondrial Proteins; D003576:Electron Transport Complex IV
keywords: COI; Cabbage pest; biocontrol; biological control; parasitic wasp; primers