Aquatic Sciences Meeting, Albuquerque 2001

SS23 In Transition: Biomechanics of Sensory Perception (Disciplinary Connections)

Date: Thursday, February 15, 2001, Time: 10:45:00 AM

Location: Acoma/Zuni/Tesuque

Schar, D, W, UCLA, Dept of OBEE, Los Angeles, USA, dws@protos.lifesci.ucla.edu

Krug, P, J, UCLA, Dept of OBEE, Los Angeles, USA, pkrug@protos.lifesci.ucla.edu

Zimmer, R, K, UCLA, Dept of OBEE, Los Angeles, USA, z@protos.lifesci.ucla.edu

TTX, a potent neurotoxin, is an alarm pheromone in the California newt

Larvae of the California newt exhibit a chemically-mediated antipredator defense, demonstrating escape behavior and increased refuge use after detecting a cue from cannibalistic adult conspecifics. Bathwater solutions collected from adults in the field were tested in non-recirculating flow-through chambers, and induced defensive responses in 80-100% of larvae. Blockage of the adult cloaca with inert gel did not diminish bathwater bioactivity, indicating the alarm pheromone is not an excretory product. Swabs of adult backs, sides, and bellies were all highly active in solution, indicating the chemical cue is released from adult skin. Adult newts contain tetrodotoxin (TTX) and/or up to 5 related isomers; reversed-phase HPLC analysis revealed a TTX isomer was present in skin swabs, and in bathwater at a 10-7 M concentration. A TTX standard was tested in the behavioral assay at concentrations from 10-7 to 10-9 M, along with equivalent dilutions of bathwater. At each concentration, bathwater and the corresponding TTX solution triggered an escape response from the same number of larvae, with no subsequent sublethal toxicity effects. The larval escape response is thus triggered by adult defensive toxins.

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Aquatic Sciences Meeting, Albuquerque 2001

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