Electrophysiological studies of olfaction in the whip spider Phrynus parvulus (Arachnida, Amblypygi)

The olfactory response of the whip spider Phrynus parvulus from Costa Rica was examined using a technique analogous to that used for insect electroant ennograms on the tarsi of the antenniform legs which bear multiporous sensi lla. Responses to 42 chemicals representing different chain lengths of alka nes, carboxylic acids, alcohols, aldehydes, and ketones, as well as some es ters, monoterpenes, and phenolics were examined. Fifty-four percent of the chemicals tested elicited responses. Concentration-response curves were gen erated for guaiacol, hexanal, methyl salicylate, benzaldehyde, octanoic aci d, and linalool. Guaiacol, benzaldehyde, and hexanol elicited the greatest responses and no differences were detected between the sexes. Compounds wit h chain lengths of six carbon atoms generated strong responses and most mon ocarboxylic acids and ring compounds elicited responses. Some compounds pro duced increases in potential believed to arise from a hyperpolarizing effec t on the neurons. The broad spectrum of chemicals to which these animals re spond is similar to results of other studies examining the general olfactor y sense of insects. It is possible that odor learning plays a significant r ole in the behavior of amblypygids. (C) 2000 Elsevier Science Ltd. All righ ts reserved.