Phenotypic
The shocking
variation
sex-lifeamongst
of Eastern
UK
European
amphipods
invaders
Adrian Love
Sparsholt College
Invasive Gammarid species
Dikerogammarus villosus – ‘Killer shrimp’
D. haemobaphes - ‘Demon Shrimp’
NNSS
Dobson, 2012
The Invasion
Sept
2010
Nov 2010
A habitat suitability map for D. haemobaphes, based
on current European distributions.
Graham, The
2014model is
based on climatic conditions, water chemistry and
altitude (Graham, 2014)
How bad is it?
Why so good at being bad?
 Opportunistic omnivore
Out competes native species
Directly consumes other invertebrates, fish eggs
and embryos
Very fecund
Less likely to be predated upon
Wide salinity tolerance (0-20‰)
Wide temperature tolerance (4-30°C)
Extremely aggressive – will kill without
consuming
Impact on
parasite
diversity
Feminising parasites
Etxabe et al., 2015
Intersex frequency
Upstream of STW
♂i
1%
♂
48%
♀
50%
♀i
1%
Downstream of STW
♂i
7%
♀
43%
♂
46%
♀i
4%
At STW discharge
♂i
3%
♂
42%
♀i
3%
♀
52%
What next?
• Response managed by National Task Group;
– Containment
– Surveillance
– High risk sites
– Research
– Communication
Dick and Platvoet (2000)
References
Bovy, H. C., Barrios-O’Neill, D., Emmerson, M. C., Aldridge, D. C., & Dick, J. T. (2014). Predicting the
predatory impacts of the “demon shrimp” Dikerogammarus haemobaphes, on native and
previously introduced species.Biological Invasions, 17(2), 597-607.
Dick, J. T., & Platvoet, D. (2000). Invading predatory crustacean Dikerogammarus villosus eliminates both
native and exotic species.Proceedings of the Royal Society of London B: Biological
Sciences, 267(1447), 977-983.
Dick, J. T., Platvoet, D., & Kelly, D. W. (2002). Predatory impact of the freshwater invader
Dikerogammarus villosus (Crustacea: Amphipoda).Canadian Journal of Fisheries and Aquatic
Sciences, 59(6), 1078-1084.
Dobson, M. (2012). Identifying invasive freshwater shrimps and isopods.Freshwater Biological
Association, Ambelside.
Etxabe, A. G., Short, S., Flood, T., Johns, T., & Ford, A. T. (2015). Pronounced and prevalent intersexuality
does not impede the ‘Demon Shrimp’invasion. PeerJ, 3, e757.
Graham, H. (2014) An investigation into the impacts of a non-native Gammarid, Dikerogammarus
haemobaphes, on the benthic macroinvertebrate community and ecosystem function of the River
Cherwell. MSc Thesis. University of Birmingham
Green Etxabe, A., & Ford, A. (2014). Do demon shrimp carry demon parasites?. Freshwater Biological
Association News, (62), 10-11.
MacNeil, C., Platvoet, D., Dick, J. T., Fielding, N., Constable, A., Hall, N., ... & Diamond, M. (2010). The
Ponto-Caspian'killer shrimp', Dikerogammarus villosus(Sowinsky, 1894), invades the British
Isles. Aquatic Invasions, 5(4), 441-445.
NNSS (Non-native Species Secretariat) Killer Shrimp Identification Sheet V.2.1. Available at
https://secure.fera.defra.gov.uk/nonnativespecies/downloadDocument.cfm?id=474
Rewicz, T., Grabowski, M., MacNeil, C., & Bacela-Spychalska, K. (2014, September). The profile of a
‘perfect’invader–the case of killer shrimp, Dikerogammarus villosus. In Aquatic Invasions (Vol. 9,
No. 3, pp. 267-288). Regional Euro-Asian Biological Invasions Centre (REABIC).
Thank you
Impact on ecosystem
G. pulex
Mature at 19
weeks
Mean brood
size 15 eggs
D. villosus
Mature at 48 weeks
Mean brood
size 50 eggs