STIMULUS-SPECIFIC AND RESPONSE-SPECIFIC HABITUATION IN COURTING STICKLEBACK: DEVELOPMENTAL AND FUNCTIONAL CONSIDERATIONS

Abstract

AbstractMale threespine stickleback, Gasterosteus aculeatus, from a marine population on Long Island, New York were presented simultaneously with two dummies, one simulating a normally distended ('thinner') gravid female and the other a highly distended ('fatter') one. Males initially courted the dummies much as they do real females, but showed stimulus-specific and response-specific habituation to the dummies. Males initially courted the fatter dummy slightly more than the thinner one but showed clear signs of habituation toward the thinner dummy after about 4 min while courtship to the fatter one continued throughout the 1 hr presentation period. Thus, within 12 min males were directing a much greater proportion of courtship to the fatter dummy, and this difference increased over time. Males also attacked both dummies and, in contrast to their courtship response, divided biting equally between the two dummies. Moreover, bite rates to the thinner and the fatter dummy doubled within the first 12 min and then fluctuated around that level for the remainder of the trial. The stimulusspecific and response-specific nature of habituation may be adaptive for male mating success because it leads the male to focus courtship on the preferred female and to direct attack against the fish presenting a greater threat to the nest but a lower potential reproductive payoff.