Enemy release and genetic founder effects in invasive killer shrimp populations of Great Britain

Abstract

Arundell, K., Dunn, A., Alexander, J. L., Shearman, R., Archer, N., Ironside, J. (2015). Enemy release and genetic founder effects in invasive killer shrimp populations of Great Britain. Biological Invasions, 17 (5), 1439-1451. Document embargo until 04/11/2015The predatory ?killer shrimp? Dikerogammarus villosus invaded Britain from mainland Europe in 2010. Originating in the Ponto-Caspian region, this invader has caused significant degradation of European freshwater ecosystems by predating and competitively excluding native invertebrate species. In contrast to continental Europe, in which invasions occurred through the migration of large numbers of individuals along rivers and canals, the invasion of Great Britain must have involved long distance dispersal across the sea. This makes the loss of genetic diversity and of debilitating parasites more likely. Analysis of nuclear microsatellite loci and mitochondrial DNA sequences of D. villosus samples from the four known populations in Britain reveal loss of rare alleles, in comparison to reference populations from the west coast of continental Europe. Screening of the British D. villosus populations by PCR detected no microsporidian parasites, in contrast with continental populations of D. villosus and native amphipod populations, most of which are infected with microsporidia. These findings suggest that the initial colonisation of Great Britain and subsequent long distance dispersal within Britain were associated with genetic founder effects and enemy release due to loss of parasites. Such effects are also likely to occur during future long-distance dispersal events of D. villosus to Ireland or North America.authorsversionPeer reviewe

Invaders, natives and their enemies: distribution patterns of amphipods and their microsporidian parasites in the Ruhr Metropolis, Germany

“…Among the ten microsporidians found in the present study, the D. duebenum- / D. muelleri- complex seems to be the most common in European amphipods. It was found in a variety of host species and shows the widest distribution among all amphipod-infecting microsporidians investigated [ 35 , 38 , 40 , 59 – 63 ]. This species complex was also most abundant in the present study and our data can add G. pulex clade C, E and G. fossarum type B as new hosts to this parasite group.…”

The killer shrimp, Dikerogammarus villosus, invading European Alpine Lakes: A single main source but independent founder events with an overall loss of genetic diversity

“…A mechanism explaining such patterns could be a purge of recessive deleterious alleles, which fuelled further population expansion, as evidenced in the ladybird Harmonia axyridis (Facon et al., ). Reduction in genetic diversity was also observed in populations of D. villosus after the colonisation of waterbodies in the U.K. (Arundell et al., ; Rewicz et al., ). Since the first initial population was discovered in 2010, the killer shrimp was detected in further four localities (Macneil et al., ).…”

“…Since the first initial population was discovered in 2010, the killer shrimp was detected in further four localities (Macneil et al., ). Its surprisingly slow spread in U.K. compared to the Alpine Lakes can be explained by the effective implementation of ‘check, clean and dry’ procedure (Arundell et al., ).…”

Enhanced fecundity and parasite release in the first amphipod invader on the Iberian Peninsula

“…Similarly, histopathology (Bojko et al, 2013) and PCRbased (Arundell et al, 2015) studies of UK populations of the invasive amphipod Dikerogammarus villosus showed a distinct lack of pathogens and parasites when compared in invasive range across central (Etxabe et al, 2015) populations of D. villosus is suggestive of single-point introductions, rather than continual incursion events as previously observed throughout its continental invasive (Bojko et al, 2013). In contrast, Dikerogammarus haemobaphes, presents UK populations with high prevalence of parasites, such as the Microsporidia Dictyocoela berillonum and Cucumispora ornate (Bojko et al, 2015) or the Nematoda Hysterothylacium deardorffoverstreetorum (Etxabe et al, 2015).…”