The effect of trail‐following on the locomotion of the marsh periwinkleLittorina irrorata(mesogastropoda: Littorinidae)¹

Abstract

The marsh periwinkle, Littorina irrorata, like many gastropods, can detect conspecific mucous trails and often follows them with polarity. Although trail-following is a common component of L. irrorata's behavioral repertoire, the adaptive significance of this behavior is not evident. This study examined some of the biomechanical and energetic advantages of tracking in L. irrorata.Mean crawling speeds of L. irrorata on artificial and natural substrata ranged from 0.615 to 1.74 mm/sec and tended to decrease with increasing substratum particle size. The presence of a conspecific's mucus did not affect snail speed over the substrata tested. Similarly, analysis of the foot morphology of marker and tracker snails revealed no significant differences between foot area, perimeter, maximum width, or shape (foot length/foot width). The maximum foot length of markers' feet were significantly greater than those of trackers. Laboratory tests showed that tracking over the trail of a conspecific required between 15% and 43% less force than marking or tracking over one's own mucus. The possibility that trail-following serves as a means of reducing metabolic cost is discussed.

Self-Organization of Intertidal Snails Facilitates Evolution of Aggregation Behavior

“…In this example investigating aggregation behavior in intertidal snails, self-organization of aggregation behavior occurs through behaviors that provide a direct selective advantage to each individual. Trail following reduces the amount of mucus deposited and so the cost of locomotion [10,46]. Crevice occupation can reduce desiccation and temperature stress in intertidal snails, regardless of whether they are in an aggregation or not [3,14].…”

Role of mucus trails and trail-following in the behaviour and nutrition of the periwinkle Littorina littorea

“…Hall (1973) found that marker L. irrorata were slower than tracker snails, though this was over a substratum of sand which might place constraints on movement. Tankersley (1989) and Dimock (1985) found no such relationship, but noted that the speed of L. irrorata and Ilyanassa obsoleta, respectively, was much reduced on sand in comparison to glass. These authors also noted no significant difference in speed between marker and tracker snails over a variety of substrata.…”

“…Trail-iollowing, then, might be a response to food availability rather than any other consideration (see discussion below). However, during the nonbreeding season winkles prefer to follow the trails of conspecifics over their own trails (described for other gastropods by : Townsend 1974, Trott & Dimock 1978, Tankersley 1989; this provides evidence (1) that snails can detect some component of 'self' in a trail and (2) that trail-following has evolved to facilitate aggregation and hence as a stress-reduction device. On the other hand, Littorina littorea can detect conspecifics through pheromones (Dinter & Manos 197 2), and trailfollowing in order to aggregate might only occur when the source of the pheromones is masked, e.g.…”

“…Townsend appears to regard increased coincidence indices as reflecting a n increased desire to aggregate, but this might be accounted for by snails searching for food in mucus trails. Tracking requires less force than marking in Littorina irrorata (Tankersley 1989) and has thus been suggested as an energysaving device.…”

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“…Gastropods sense many features about their environment and some can follow mucus trails and chemical odours in freshwater, marine and terrestrial systems (Chase et al 1978;Chase 1986;Tankersley 1989;Levri 1998;Davies and Knowles 2001). Gastropods can track odours in air using both tropotaxis and anemotaxis (Chase and Croll 1981;Lemaire and Chase 1998).…”