The Eucalyptus gall wasp, Leptocybe invasa (Hymenoptera: Eulophidae), has spread rapidly to all continents where Eucalyptus spp. are planted and is now one of the most important insect pests threatening global plantation forestry. In order to study the routes and extent of L. invasa introductions globally, we characterised the genetic diversity of populations from the purported origin and invaded regions of the wasp. From the 511 L. invasa specimens, 26 cytochrome oxidase I (COI) haplotypes were identified, of which three were found in the invaded range. Two of the three distinct lineages, which could represent cryptic species, appear to have been independently introduced into different parts of the world. One lineage (A) occurs throughout the invaded range, and is found exclusively in Europe, the Middle East, South America and most of Africa. The second lineage (B) co-occurs with lineage A in Laos, South Africa, Thailand and Vietnam. The third lineage (C) occurs only in Australia. Analyses using 13 newly developed simple sequence repeat (SSR) markers in sub-populations of L. invasa supported the distinction of the three lineages. These findings underpin the weakness of currently applied quarantine measures to halt the movement of plantation pests and question the suitability of measures being used to control L. invasa. Ongoing research using the SSR marker data should confirm the possible existence of cryptic species in the L. invasa populations, hybridization or admixture between the two lineages, and the reproductive mode of the pest in its invasive range.
XXV International Congress of Entomology (ICE), Orlando, United States 25-30 September 2016