No abstract

No abstract

Newly hatched oyster drills, Urosalpinx cinerea (Say), that had not eaten prey and had no prior experience in prey detection, were used to screen 25 potential attractants. Of these, odors of intact, living barnacles, Semibalanus balanoides and Balanus eburneus were most effective, optimally causing upstream migration in over 90% of the snails and retaining detectable activity after 200 fold dilution. The odor of a mixed bryozoan culture evoked a 70% and Sabellaria vulgaris a 30% response, whereas responses to Crassostrea virginica, oyster valves containing Polydora \vebsteri, and Trypetesa lampas were low but still significant. Both rheotactic and chemotactic factors were involved in the upstream migration. Behavior reminiscent of trail search was observed in homogeneous dilute stimulus solutions. It is argued that the odor stimuli may be discrete molecules.

The gastropods Urosalpinx cinerea (Say) navigate through their habitat using chemical sensing to locate their prey. Major prey include barnacles, oysters, and mussels. This paper reports relationships of attractant concentration and flow as they affect snail discrimination of flow and chemical cues. Directionality, flow rate and concentration all affected snail responses to chemical attractant. Responses of snails to attractant alone or to flow alone were negligible. Responsiveness increased with increases in flow rate and attractant concentration until levels were reached above which responsiveness was constant. With equal flows, differences in concentration of attractants had to be 3-fold or greater before drills would discriminate between them. Flow rates and attractant concentrations in the range where neither alone had elicited drill response did not elicit response when combined.