Historical and Contemporary Population Genetics of the Invasive Western Corn Rootworm (Coleoptera: Chrysomelidae) in Croatia

Abstract

Classical population genetic analyses were used to investigate populations of the western corn rootworm, Diabrotica virgifera virgifera LeConte, in Croatia in 1996 and 2009. The number of alleles was low in both 1996 and 2009; however, more alleles were found in the putative populations surveyed in 2009. Croatia had only 51% of the alleles recorded from the United States and 69% from Europe. However, 10 private (unique) alleles were found in Croatia, which were not found previously in Europe. Most populations were out of Hardy-Weinberg equilibrium, although no linkage disequilibrium was found. Low to no genetic differentiation was found between population pairwise comparisons in 1996, with a greater level of differentiation found between populations sampled in 2009. Using the program STRUCTURE, a single genetic cluster was found for populations sampled in 1996 and 2009. However, two genetic clusters were detected when the 1996 and 2009 data were combined, indicating significant temporal differentiation. Isolation by distance pattern of gene flow characterized populations sampled in 2009 only when the most distant population of Ogulin (the head of the expansion front) was included in the analysis. When Ogluin was excluded from the 2009 analysis no isolation by distance pattern was found. The possible impact that control practices have had on the population genetics of D. v. virgifera in Croatia from 1996 to 2009 are discussed in light of the temporal genetics differences found.

Population structure of the expansive wasp spider (Argiope bruennichi) at the edge of its range

“…Similar results have been obtained for other populations of orb-weaving spiders (Ramirez & Fandino 1996;Ramirez & Haakonsen 1999;Lee et al 2004;Jung et al 2006), and indeed strong gene flow is frequently observed between populations of species with high dispersal abilities (Waples 1987;Bohonak 1999). However, significant genetic differences for species with high dispersal abilities have also been recorded (Sielezniew & Rutkowski 2012;Lemic et al 2013;Pentek-Zakar 2015).…”

Genetic Monitoring of Western Corn Rootworm (Coleoptera: Chrysomelidae) Populations on a Microgeographic Scale

“…Methods used to collect and process western corn rootworm for microsatellite genotyping are outlined in detail by Lemic et al (2013). A subset of the dataset of Lemic et al (2013) was used in this study and provided the genotypes for western corn rootworm sampled in 1996 and 2009 in Croatia and Serbia. In this study, 619 adult western corn rootworm were sampled from six locations in Croatia and one location in Serbia in 1996) and seven locations in the United States in 2011 (Fig.…”

“…That is, an understanding of western corn rootworm population genetic structure, gene ßow, and dispersal patterns has helped control the impact that they have on global agriculture and food resources. The use of population genetics to understand the invasion dynamics and genetics of insects includes the boll weevil Anthonomus grandis Bohemian (Kim and Sappington 2006), Linepithema humile Mayer (Holway et al 1998), Solenopsis invicta Buren (Tsutsui et al 2001), and western corn rootworm in Europe (Ciosi et al 2008(Ciosi et al , 2010Bermond et al 2012;Lemic et al 2013).…”

“…Population genetic principles and theory have been applied to the western corn rootworm to monitor the genetic variation present and the success of control measures used in Europe (Ciosi et al 2010, Lemic et al 2013). Using microsatellite markers, it was possible to demonstrate in central and southeastern Europe that crop rotation was effective in controlling the western corn rootworm.…”

“…Since the discovery of the western corn rootworm in Serbia, and the outbreaks that closely followed in Croatia, extensive physical monitoring of the invader using sticky traps and pheromone traps has taken place across Europe (for a discussion of this see Lemic et al 2013). However, more sophisticated monitoring techniques such as microsatellite and mitochondrial (mt) DNA-based genetic monitoring is required to identify the geographic source of a population and in doing so provides crucial information about the history of the invasion while allowing comparisons of the genetic diversity to be made between the source and invading population.…”