KITTREDGE ET AL: CHEMICAL SIGNALS IN THE SEA 



present. We thus consider it likely that most 

 of the "natural products." not only of terrestrial 

 plants, but also of marine plants and inverte- 

 brates, function as allomones, kairomones, or 

 pheromones. Faulkner and Anderson (In press) 

 have provided a review of the chemistry of the 

 "natural products" of marine organisms. 



Conceptually, in such a "chemical environ- 

 ment" the most effective protection from a 

 predator would be a "cryptic odor," an irritant 

 that disrupts chemoreception. These cryptic 

 odors may be released into the environment, as 

 is the active component of octopus ink, they 

 may exist in the epidermal tissues or glands 

 where they would function at the inception of 

 attack, or they may be contained in the eggs or 

 larvae. Most sessile marine invertebrates re- 

 produce by epidemic spawning, the simultan- 

 eous release of the gonadal products of an entire 

 local population of a species. Most sessile 

 marine invertebrates are also filter feeders. The 

 prime advantage of epidemic spawning is the 

 enhancement of fertilization. However, in the 

 densely populated benthic environment, a heavy 

 loss of eggs or larvae to filter feeders may occur. 

 The presence of a "feeding inhibitor" in the eggs 

 or larvae would reduce such losses. Reiswig 

 (1970) reported that they observed epidemic 

 spawning of the sponge Neofibiilana iiolitaiigere 

 on a Jamaican reef. At the time they were 

 measuring the water pumping rate of other 

 sponges. When the epidemic spawning of A^ 

 nolitangere started, the pumping rate of the. 

 species under study, Vero)igia sp, abruptly 

 decreased and remained negligible for 2 days. 

 A', nolitangere is known to contain toxic sub- 

 stances. 



The evidence for chemical cooperation, from 

 gamones to sex pheromones, suggests a pattern 

 of increasing complexity in the function of 

 chemical cues. The behavioral response of even 

 a "simple" crustacean to a chemical gradient 

 appears to involve at least some short term 

 "memory" or a type of "chemical-spatial" 

 sense that we have not observed in such clear- 

 cut form in any other organism. 



The study of the chemical ecology of the 

 marine environment is scarcely in its infancy. 

 The chemical characterization of some of the 

 intraspecific and interspecific messages in the 

 sea and the physiology of their perception are 

 challenges. Solutions to these paired problems 



will provide insights into the evolution of 

 chemical transduction and perhaps expose a 

 hierarchy of perception from membrane 

 irritation to synaptic transmission. 



ACKNOWLEDGMENTS 



We wish to acknowledge the contribution of 

 Paul J. Scheuer, Department of Chemistry, 

 University of Hawaii, to the study of the "cryptic 

 odor" activity of natural marine naphtho- 

 quinones. He generously provided eight spino- 

 chromes and contributed observations on their 

 structure and occurrence. 



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