The invasive Korea and Japan types ofVarroa destructor, ectoparasitic mites of the Western honeybee (Apis mellifera), are two partly isolated clones

Abstract

Varroa destructor , now a major pest of the Western honeybee, Apis mellifera , switched from its original host, the Eastern honeybee, A. cerana , ca . 50 years ago. So far, only two out of several known mitochondrial haplotypes of V. destructor have been found to be capable of reproducing on A. mellifera (Korea and Japan). These haplotypes are associated in almost complete cytonuclear disequilibrium to diagnostic alleles at 11 microsatellite loci. By contrast, microsatellite polymorphism within each type is virtually absent, because of a severe bottleneck at the time of host change. Accordingly, 12 mitochondrial sequences of 5185 nucleotides displayed 0.40% of nucleotide divergence between haplotypes and no intra haplotype variation. Hence, each type has a quasi–clonal structure. The nascent intratype variability is subsequent to the clone formation 50 years ago: in both types the variant alleles differ from the most common by one (in 10 cases), two (five cases) or three (one case) repeated motifs. In addition to individuals of the two ‘pure’ types, five F 1 hybrids and 19 recombinant individuals (Japan alleles introgressed into the Korea genetic background) were detected. The existence of F 1 and recombinant individuals in admixed populations requires that double infestations of honeybee cells occur in a high proportion but the persistence of pure types suggests a post–zygotic isolation between the two clones.

Impact of Varroa destructor on honeybee (Apis mellifera scutellata) colony development in South Africa

“…The European honeybee does not express these traits at a level at which they confer tolerance to the parasite ). This became obvious after the mite shifted host from A. cerana to A. mellifera L. (Rath and Drescher 1990;Solignac et al 2005) and became responsible for the mortality of a large number of honeybee colonies in several regions of the world where it has spread (see references in Dietemann et al 2012;van Dooremalen et al 2013;Spleen et al 2013;Steinhauer et al 2014). Apis mellifera colonies cannot survive without chemical treatment against Varroa mites and colonies usually die within one to three years if left untreated (Martin 1998;Rosenkranz et al 2010).…”

Natural Varroa mite-surviving Apis mellifera honeybee populations

“…It remains to be clarified whether the survival of the Arnot Forest bees and the Italian bees on Fernando de Noronha is due to an adaptive resistance by the host, host tolerance to mite infestation, or reduced virulence by the mite either by the mite's haplotype or adaptive reduced virulence. While many of these populations reviewed here clearly demonstrate adapted host resistance or at least tolerance, investigations have been very bee-centric, likely due to the common acceptance that the Varroa mite has a low genetic variation in Europe due to its clonal origin (Solignac et al 2005). A deeper understanding of the mite's passive or active role in the co-evolution among all of these populations would be insightful.…”

Recent emergence and worldwide spread of the red tomato spider mite, Tetranychus evansi: genetic variation and multiple cryptic invasions

“…A paradox often encountered in genetic studies of invasive species, is a colonization success of the introduced populations despite a strong reduction of genetic diversity (Frankham 2005; see also reviews by Dlugosch andParker 2008 andRoman andDarling 2007). Several studies to date have shown that founder effects and bottlenecks are not an obstacle for invasion success (Ahern et al 2009;Puillandre et al 2008;Solignac et al 2005), whereas plasticity in life history traits seems to be important for the successful expansion of an invasive species (Chen et al 2006;Valiente et al 2010;Wang et al 2005). Mites belonging to clade I have been found across a wide range of habitats and regions beyond the predicted geographical distribution as modeled based on climatic suitability T. evansi ).…”