Behavioral Responses of the Spiny Lobster (Panulirus argus) to Live Amphiporous angulatus and Its Bipyridyl Toxins
Nemertean worms have eversible proboscises that deliver pyridine compounds which paralyze their prey. Pyridine compounds have also been found in the skin of nemertean worms and they are thought to be effective in deterring the worms' predators. Two bipyridyl compounds, anabaseine and 2,3'-bipyridyl, have been purified from a nemertean worm species. The spiny lobster Panulirus argus is thought to be a potential predator of benthic living nemerteans. Live nemertean worms were delivered, via a glass tube, to the chemoreceptive dactylus segment of the spiny lobster's walking leg. Various doses of each bipyridyl were also delivered to the dactylus segment via a glass tube and saturated cotton swabs. Lobster's behavioral responses to the live worms and to the bipyridyls were compared and it was found that neither 2,3'-bipyridyl or anabaseine, at worm equivalent concentrations, act to deter lobster's consummatory behavior like a live nemertean worm deters consumption. Shortly following the delivery of the high concentrations of 2,3'-bipyridyl the lobsters were nonlocally paralyzed. Since worm equivalent concentrations of the bipyridyls do not elicit avoidance behavior there must be other chemicals present in the worm that work in conjunction with the bipyridyls in acting as a predator defense. Preliminary work, using dialysis tubing to separate a nemertean worm homogenate, was done in an attempt to find out what kind of mixture interaction is working to defend nemertean worms.