Global spread of wheat curl mite by its most polyphagous and pestiferous lineages

Abstract

The wheat curl mite (WCM), Aceria tosichella, is an important pest of wheat and other cereal crops that transmits wheat streak mosaic virus and several other plant viruses. Wheat curl mite has long been considered a single polyphagous species, but recent studies in Poland revealed a complex of genetically distinct lineages with divergent host-acceptance traits, ranging from highly polyphagous to host-specific. This diversity of WCM genotypes and host-acceptance phenotypes in Europe, the presumed native range of WCM, raises questions about the lineage identities of invasive WCM populations on other continents and their relationships to European lineages. The goals of this study were to examine the global presence of WCM and determine the relatedness of lineages established in different continents, on the basis of phylogenetic analyses of mitochondrial and nuclear DNA sequence data. Host-range bioassays of a highly polyphagous WCM lineage were performed to supplement existing data on this lineage's ability to colonise graminaceous and non-graminaceous hosts. Invasive WCM populations in North and South America and Australia assorted with the only three known polyphagous and pestiferous WCM lineages ('MT-1', 'MT-7' and 'MT-8') from a total of eight currently described lineages. These results show that the most polyphagous lineages were more successful colonisers and reflect a need for extensive surveys for WCM on both crops and wild grass species in invaded continents. The most invasive lineage ('MT-1') was shown to successfully colonise all 10 plant species tested in three families and has spread to North and South America and Australia from its presumed origins in Eurasia.

Complex patterns of global spread in invasive insects: eco-evolutionary and management consequences

“…Here an incorrect name, 'Gonipterus scutellatus', has been applied to the invasive pest for decades, becoming a serious impediment to management, including the selection of specific biocontrol agents and understanding of invasion patterns. Invasive mites too, most notably eriophyoids, have regularly been found to comprise multiple cryptic lineages and/or species (Carew et al 2009;Skoracka et al 2014) with closely related, morphologically indistinguishable but molecularly distinct forms that differ in important ecological characteristics (particularly host range; Skoracka et al 2013), that co-occur in complex mosaics. The degree to which the cryptic species and/or lineages require more nuanced, targeted (or diversified) management strategies is largely unknown.…”

“…Similarly, some species of the wheat curl mite ("Aceria tosichella complex") are widely distributed with broad host range while others are restricted and specialized (Carew et al 2009;Skoracka et al 2013Skoracka et al , 2014. Other co-introduced lineages (e.g., Sirex noctilio, Thaumastocoris peregrinus) do not appear to differ markedly in host range, though more subtle differences in preference cannot be excluded.…”

Spatial and Host-Related Variation in Prevalence and Population Density of Wheat Curl Mite (Aceria tosichella) Cryptic Genotypes in Agricultural Landscapes

“…Therefore, their identification is currently based on DNA barcoding using the mitochondrial COI marker gene as well as nuclear regions, e.g. 28S rDNA D2 [25, 26]. Since the cryptic diversity of WCM is a relatively recent discovery [14–16], the majority of ecological data to date have been recorded for WCM sensu lato, rather than for individual genotypes.…”

The Effect of Temperature, Relative Humidity, and Virus Infection Status on off-host Survival of the Wheat Curl Mite (Acari: Eriophyidae)

“…The offhost survival times shown in this study would seem to be sufficient to enable this type of regional movement. Skoracka et al (2013Skoracka et al ( , 2014 indicate that wheat curl mite is a complex of lineages some of which have spread across multiple continents. The limits of off-host survival shown here demonstrate that intercontinental movement of mites will be very unlikely unless living plant material is transferred.…”

“…The limits of off-host survival shown here demonstrate that intercontinental movement of mites will be very unlikely unless living plant material is transferred. Skoracka et al (2014) indicates that those wheat curl mite lineages that have the largest worldwide spread are also polyphagous, including multiple grass species and Amaryllidaceae and Liliaceae bulbs. Considering wheat curl mite off-host survival limits, the potential for this type of movement seems more plausible, if associated with the transfer of these host bulbs.…”