Many studies have already assessed how wave action may affect morphology of intertidal species among sites that vary in wave exposure, but few attempted to look to this issue in smaller scales. Using the most common limpet of the Brazilian coast, Lottia subrugosa, and assuming position on rocky boulders as a proxy for wave action at small scale, we tested the hypothesis that waves may also influence limpet morphology at a smaller spatial scale by investigating how individual size, foot area and shell shape vary between sheltered and exposed boulder sides on three shores in the coast of Ubatuba, Brazil. Limpets consistently showed a proportionally larger foot on exposed boulder sides for all shores, indicating that stronger attachment is an important mechanism to deal with wave action dislodgement at a smaller scale. Shell shape also varied in the scale investigated here, with more conical (dissipative) shells occurring in exposed boulder sides in one exposed shore across time and in the other exposed shore in one year. Shell shape did not vary regarding boulder sides across time in the most sheltered shore. Although we did not assess large spatial scale effects of wave action in this study, variations of the effect of waves at small spatial scale observed for shell shape suggest that it may be modulated by the local wave exposure regime. Our work highlights the importance of wave action at small spatial scales, and may help to understand the ecological variability of limpets inhabiting rocky shores.

Under the assumption that dislodged intertidal gastropods have developed some adaptations to return to their original habitat, we investigated the cues involved in the navigation ability of Littorina littorea, following a simulated wave-dislodgement. Return rates decreased by 2 and 4-fold in the absence of chemical cues at the surface of the sediment and the rock, respectively. The 19-fold decrease in return rates observed in the absence of both cues suggests their synergistic effect on L. littorea navigation. Chemoreception might be much more involved in the navigation and the survival of intertidal gastropods following wave dislodgement than previously thought.