Semiochemical strategies for sea louse control: host location cues.
The development of behavioural bioassays and electrophysiological recording techniques has enabled the role of semiochemicals to be investigated for the first time in Lepeophtheirus salmonis (Krøyer). Adult male sea lice L salmonis were activated by, and attracted to, salmon-conditioned water (SCW) and SCW extract. Non-host fish odours, turbot-conditioned water (TCW) and turbot-conditioned water extract (TCW extract), elicited activation but no attraction in the lice. Solid-phase extraction techniques were developed to extract low molecular weight components of fish odours, and biological activity was shown to be confined to these. Electrophysiological activity from aesthetascs in the first antennae was found and neural responses to odours were recorded from the antennal nerves. Preliminary experiments on individual chemicals (isophorone, 1-octen-3-ol) linked to salmon revealed behavioural activation and electrophysiological responses in adult male L salmonis. Isophorone was shown to be significantly attractive to sea lice when placed in a slow-release system in a perfused tank of seawater in a choice situation. Proof of concept has been established for successfully extracting odour cues from seawater, analysing their biological activity and applying these to slow-release technologies for field trapping of lice. Future work involving linked GC-MS techniques using behaviour, electrophysiological responses, and organolepsis will establish further host location cues specific to Atlantic salmon.
Department of Zoology, University of Aberdeen, Tillydrone Avenue, Aberdeen AB24 2TZ, UK.
Anna
A
Ingvarsdóttir
Michael A
MA
Birkett
Ian
I
Duce
Richard L
RL
Genna
William
W
Mordue
John A
JA
Pickett
Lester J
LJ
Wadhams
A Jennifer
AJ
Mordue
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D033342:Copepoda / Q000187:drug effects* / Q000502:physiology; D003463:Cues; D004594:Electrophysiology; D005393:Fish Diseases / Q000469:parasitology / Q000517:prevention & control; D008401:Gas Chromatography-Mass Spectrometry; D006790:Host-Parasite Interactions; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009812:Odorants; D010273:Parasitic Diseases, Animal / Q000517:prevention & control; D010571:Pest Control / Q000379:methods*; D010675:Pheromones / Q000032:analysis / Q000494:pharmacology*; D012474:Salmon / Q000469:parasitology*; D012623:Seawater / Q000737:chemistry; D013045:Species Specificity
D010675:Pheromones