Abstract
ABSTRACT: Dikerogammarus villosus, an invasive amphipod, has recently been detected in UK
freshwaters. To assess the potential for pathogen introduction with the invader, a year-long
histopathology survey of the D. villosus population inhabiting the initial site of detection (Grafham
Water, Cambridgeshire, UK) was conducted. Additional samples were collected from 2 other subsequently
identified populations within the UK (Cardiff Bay and Norfolk Broads), and from
established populations in France (River Rhine) and Poland (River Vistula). The data revealed a
range of pathogens and commensals. Several pathogens occurring within continental populations
were not present within the UK populations. Microsporidian parasites and a novel viral pathogen
were amongst those not observed in the UK. The absence of these pathogens at UK sites may therefore
impart significant survival advantages to D. villosus over native fauna, thereby increasing its
success as an invader. The contrast in pathogen profile between UK and continental-invasive populations
of D. villosus provides preliminary evidence for so-called ‘enemy release’ in UK populations
of D. villosus and is suggestive of single-point introductions, rather than continual incursion events
as previously observed throughout its continental invasive range. This baseline survey provides important
data on the pathogen and commensal profile of a high-impact, invasive species early in its
invasion history of the UK. It can be utilised to assess potential for temporal pathogen acquisition by
non-native invasive aquatic species and to investigate competitive advantages placed upon this invader
due to absence of important pathogens experienced within its native range.
freshwaters. To assess the potential for pathogen introduction with the invader, a year-long
histopathology survey of the D. villosus population inhabiting the initial site of detection (Grafham
Water, Cambridgeshire, UK) was conducted. Additional samples were collected from 2 other subsequently
identified populations within the UK (Cardiff Bay and Norfolk Broads), and from
established populations in France (River Rhine) and Poland (River Vistula). The data revealed a
range of pathogens and commensals. Several pathogens occurring within continental populations
were not present within the UK populations. Microsporidian parasites and a novel viral pathogen
were amongst those not observed in the UK. The absence of these pathogens at UK sites may therefore
impart significant survival advantages to D. villosus over native fauna, thereby increasing its
success as an invader. The contrast in pathogen profile between UK and continental-invasive populations
of D. villosus provides preliminary evidence for so-called ‘enemy release’ in UK populations
of D. villosus and is suggestive of single-point introductions, rather than continual incursion events
as previously observed throughout its continental invasive range. This baseline survey provides important
data on the pathogen and commensal profile of a high-impact, invasive species early in its
invasion history of the UK. It can be utilised to assess potential for temporal pathogen acquisition by
non-native invasive aquatic species and to investigate competitive advantages placed upon this invader
due to absence of important pathogens experienced within its native range.
| Original language | English |
|---|---|
| Pages (from-to) | 241-253 |
| Journal | Diseases of Aquatic Organisms |
| Volume | 106 |
| Publication status | Published - 2013 |