Lyme disease bacterium does not affect attraction to rodent odour in the tick vector.
BACKGROUND
Vector-borne pathogens experience a conflict of interest when the arthropod vector chooses a vertebrate host that is incompetent for pathogen transmission. The qualitative manipulation hypothesis suggests that vector-borne pathogens can resolve this conflict in their favour by manipulating the host choice behaviour of the arthropod vector.


METHODS
European Lyme disease is a model system for studying this conflict because Ixodes ricinus is a generalist tick species that vectors Borrelia pathogens that are specialized on different classes of vertebrate hosts. Avian specialists like B. garinii cannot survive in rodent reservoir hosts and vice versa for rodent specialists like B. afzelii. The present study tested whether Borrelia genospecies influenced the attraction of field-collected I. ricinus nymphs to rodent odours.


RESULTS
Nymphs were significantly attracted to questing perches that had been scented with mouse odours. However, there was no difference in questing behaviour between nymphs infected with rodent- versus bird-specialized Borrelia genospecies.


CONCLUSIONS
Our study suggests that the tick, and not the pathogen, controls the early stages of host choice behaviour.
Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland. jeremy.berret@unine.ch.
Jérémy
J
Berret
Laboratory of Ecology and Evolution of Parasites, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland. maarten.voordouw@unine.ch.
Maarten Jeroen
MJ
Voordouw
D000818:Animals; D001070:Appetitive Behavior / Q000502:physiology*; D001096:Arachnid Vectors / Q000382:microbiology* / Q000502:physiology; D001898:Borrelia; D002633:Chemotaxis / Q000502:physiology*; D054884:Host-Pathogen Interactions; D018884:Ixodes / Q000382:microbiology* / Q000502:physiology; D008193:Lyme Disease / Q000382:microbiology*; D051379:Mice; D009758:Nymph / Q000502:physiology; D009812:Odorants; D013045:Species Specificity; D013557:Switzerland