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

Abstract

Plant biosecurity is increasingly challenged by emerging crop pests. The spider mite Tetranychus evansi has recently emerged as a new threat to solanaceous crops in Africa and the Mediterranean basin, with invasions characterized by a high reproductive output and an ability to withstand a wide range of temperatures. Mitochondrial (868 bp of COI) and nuclear (1,137 bp of ITS) loci were analyzed in T. evansi samples spanning the current geographical distribution to study the earliest stages of the invasive process. The two sets of markers separate the samples into two main clades that are only present together in South America and Southern Europe. The highest COI diversity was found in South America, consistent with the hypothesis of a South American origin of T. evansi. Among the invaded areas, the Mediterranean region displayed a high level of genetic diversity similar to that present in South America, that is likely the result of multiple colonization events. The invasions of Africa and Asia by T. evansi are characterized by a low genetic variation associated with distinct introductions. Genetic data demonstrate two different patterns of invasions: (1) populations in the Mediterranean basin that are a result of multiple cryptic introductions and (2) emerging invasions of Africa and Asia, each likely the result of propagules from one or limited sources. The recent invasions of T. evansi illustrate not only the importance of human activities in the spread of agricultural pests, but also the limits of international quarantine procedures, particularly for cryptic invasions.

Effects of <i>Wolbachia</i> on rDNA-ITS2 variation and evolution in natural populations of <i>Tetranychus urticae</i> Koch

“…The fact that there were just two haplotypes in the 80 individuals of T. urticae suggests that ITS2 is a poor marker for studies of population genetics. An analogous situation was observed in Tetranychus evansi (Boubou et al 2011). …”

Integrating ecology and genetics to address Acari invasions

“…These are some questions that molecular data and the associated data analyses can help to answer. The review by Navajas et al Exp Appl Acarol (2013) 59:1-10 5 (2012) in this issue, illustrates this approach based on the recent invasion of the red tomato spider mite T. evansi (see also Boubou et al 2011Boubou et al , 2012. Recent advances and improvements in optical technology have provided some very promising tools to study morphology, microstructures and feeding habits of mites in much greater detail.…”

Genetic traits leading to invasion: plasticity in cold hardiness explains current distribution of an invasive agricultural pest, Tetranychus evansi (Acari: Tetranychidae)

“…In this study we focus on the red tomato spider mite, Tetranychus evansi Baker & Pritchard 1960, an invasive pest of Solanaceous crops distributed from South to North America, Africa, Eastern Asia and the Mediterranean basin [see Dorkeld 2006-2013;Navajas et al 2013) for a complete review]. Tetranychus evansi was first reported from Brazil in 1915 (Caldas 1915;Paschoal 1971) and genetic studies show that this species originates in South America (Boubou et al 2011(Boubou et al , 2012. As an invasive species of tropical origin, the wide geographical area colonized by T. evansi is striking.…”

“…Two independent introduction events, corresponding to two well-separated genetic lineages (Boubou et al 2011(Boubou et al , 2012, have occurred during the colonisation of the mite outside its area of origin in South America. Mites belonging to one of them, hereafter lineage 1, are the most invasive, having been recorded from almost all parts of the world where the species is established.…”