Colonization history of the Western Corn Rootworm (Diabrotica virgifera virgifera) in North America: insights from random forest ABC using microsatellite data

Abstract

First described from western Kansas, USA, the western corn rootworm, Diabrotica virgifera virgifera, is one of the worst pests of maize. The species is generally thought to be of Mexican origin and to have incidentally followed the expansion of maize cultivation into North America thousands of years ago. However, this hypothesis has never been investigated formally. In this study, the genetic variability of samples collected throughout North America was analysed at 13 microsatellite marker loci to explore precisely the population genetic structure and colonization history of D. v. virgifera. In particular, we used up-to-date Approximate Bayesian Computation methods based on random forest algorithms to test a Mexican versus a central-USA origin of the species, and to compare various possible timings of colonization. This analysis provided strong evidence that the origin of D. v. virgifera was southern (Mexico, or even further south). Surprisingly, we also found that the expansion of the species north of its origin was recent - probably not before 1100 years ago - thus indicating it was not directly associated with the early history of maize expansion out of Mexico, a far more ancient event.

Alien leaf beetles (Coleoptera, Chrysomelidae) of European Russia and some general tendencies of leaf beetle invasions

“…The western corn rootworm Diabrotica virgifera originates from the New World. The initial range is Mexico or Central America [ 100 ]. Now, the range in the Americas includes Canada, Costa Rica, Guatemala, Mexico, Nicaragua and the USA [ 4 ].…”

“…Man has greatly increased the range of this species in the Americas by the cultivation of corn [ 100 ]. In Europe, D .…”

Potential global distribution of Diabrotica species and the risks for agricultural production

“…The western corn rootworm is native to Mexico and incidentally followed the expansion of maize cultivation into North America thousands of years ago . More recently, the species was introduced in Europe and has continued to spread to several countries within central continental Europe.…”

Characterization of pyrethroid resistance in the western corn rootwormDiabrotica virgifera virgiferaLeConte

“…Later, this species was recognized as a maize pest and was divided into two subspecies: the WCR Diabrotica virgifera virgifera LeConte, and the Mexican corn rootworm Diabrotica virgifera zeae Smith (Gillette 1912, Krysan 1986). For over a century, the WCR was primarily confined to North America with its center of origin believed to be in Central America (Webster 1895, Krysan 1982, Lombaert et al 2018. However, in 1992 it was found in Serbia, and has been spreading through Europe since then (Berger 2001, Miller et al 2005, Wesseler and Fall 2010, Lemic et al 2015, Mrganić et al 2018).…”