An Experimental Analysis of the Behaviour ofLittorina Littorea(L.) Under Natural Conditions and in the Laboratory

Publisher Website
Google Scholar
Abstract
Winkles dwelling on horizontal surfaces orientate by means of a lightcompass reaction. As the tide recedes, most of the tracks in the sand are towards the sun but after a time each animal reverses its direction of crawling, so tracing out a roughly U-shaped path which leads it back, approximately, to its starting-point.When kept in an aquarium winkles tend to settle on the sides above the waterline and to become inactive. When stimulated, as by immersion, they crawl downwards, then horizontally and then upwards before settling above the waterline.Winkles collected from horizontal surfaces at first show no tendency to climb vertical surfaces in an aquarium. After a period which varies from a few hours up to 10 days they do climb the sides of the tank. Animals collected from vertical surfaces climb the sides of the aquarium at their first opportunity and then settle. It can be concluded that winkles have an inherent tendency to climb and settle in the head-up position on vertical or steeply sloping surfaces but that if this opportunity is denied them they become habituated to horizontal surfaces.The minimum angle to which winkles can react by gravitational responses is of the order of 10–20 degrees.In an aquarium starved winkles prolong their excursions below water when presented with suitable food but fully fed animals respond less strongly to the stimulus of immersion.Dark-adapted winkles from horizontal surfaces are at first positively phototactic, but after a time varying from 15 to 20 min, they become negatively phototactic. Tested with the ‘two-light’ experiment most animals disregard the second light (telotaxis).

This publication has 16 references indexed in Scilit: