Investigating the poor performance of heather beetle, Lochmaea suturalis (Thompson) (Coleoptera: Chrysomelidae), as a weed biocontrol agent in New Zealand: Has genetic bottlenecking resulted in small body size and poor winter survival?

Publication date: Available online 29 April 2015 Source:Biological Control Author(s): Simon V. Fowler , Paul Peterson , D. Paul Barrett , Shaun Forgie , Dianne M. Gleeson , Helen Harman , Gary J. Houliston , Lindsay Smith Heather beetle (Lochmaea suturalis), has underperformed when compared with the damage it does to native heather in Europe. Mean heather beetle body size, measured by elytron area, was 10% smaller in NZ populations compared with beetles from northern UK where the NZ beetles originated. Previous research in Europe showed that small beetles suffer higher winter mortality. Field-collected heather beetles in NZ show a positive relationship between body size and the proportion of pre-overwintering food reserves (lipids) they contained. Beetles that died in an overwintering experiment had lower proportional lipid reserves, and a smaller mean body size, than surviving beetles. Smaller body size in NZ is probably mostly due to a severe founder effect: line-rearing of beetles in NZ to eliminate a microsporidian disease, and poor establishment success, resulted in NZ beetles being derived from one or two field-collected females from one UK site. Several measures of genetic variability in NZ beetles compared with beetles from the UK indicated severe genetic bottlenecking. In particular, reductions in heterozygosity in NZ versus UK beetles were a close match to theoretical heterozygosity after a severe bottleneck. Heather beetle populations from southern UK w...

Source: Biological Control - May 7, 2015 Category: Biology Source Type: research