ARS | Publication request: Microsatellite analysis of the Genetic Diversity of Asian Longhorned Beetles from an Invasive Population in Ontario, Canada

Submitted to: The Canadian Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 5, 2009
Publication Date: September 20, 2009
Citation: Carter, M.E., Smith, M.T., Turgeon, J., Harrison, R.G. 2009. Microsatellite analysis of the Genetic Diversity of Asian Longhorned Beetles from an Invasive Population in Ontario, Canada. The Canadian Entomologist.

Interpretive Summary: Asian Longhorned Beetles (ALB) were discovered in Ontario, Canada in 2003 at a commercial warehouse site, where they likely arrived on solid wood packing materials from China. Trees in the area showed numerous signs and symptoms of attack, including scars on the bark where adult beetles laid eggs, larvae feeding under the bark and adult beetles walking on the outer surface of the bark. Collectively, this indicates that the beetles have arrived and been attacking trees in Toronto for more than one to two years. Therefore, this study was conducted to determine how many years the infestation has been developing and to estimate the number of individual beetles that likely initiated the infestation. To conduct this study, genetic analysis was conducted on ALB collected across the ALB infestation in Toronto and at various heights within infested trees. Results indicate that beetles within the Toronto infestation are very closely related, and that either a small number of beetles initiated the infestation in Toronto or inbreeding has resulted in beetles that are increasingly more related. These results emphasize the importance of searching for natural enemies that have closely evolved with ALB in China.

Technical Abstract: Asian Longhorned Beetles (Anoplophora glabripennis Motschulsky) were discovered in Ontario, Canada in 2003 at a commercial warehouse site, where they likely arrived on solid wood packing materials from China. Trees in the area were heavily scarred with oviposition sites, and larvae and adult beetles were common, indicating that beetles had been there for more than one year. Sixteen microsatellite DNA markers were amplified from 326 specimens to examine the amount of genetic diversity in this population. Six of 16 loci were monomorphic, while 4 others were significantly out of Hardy-Weinberg equilibrium due to heterozygosity deficiency. Compared to other invasive populations in North America, most indicators of genetic diversity are lower, as are the proportion of unique genotypes. These results likely indicate either a small number of beetles founded the Canadian population, or that additional bottlenecks occurred at the site limiting the genetic diversity of the expanding population.