Stereotypic predation and size selection by gastropods on foraging Tivela mactroides (Born, 1778) (Bivalvia: Veneridae) Rafael Anaisce das Chagas, Werverton John Pinheiro dos Santos, Adriana da Cruz Melo, Ana Carla de Araújo Gomes, Mara Rúbia Ferreira Barros, Andrea Magalhães Bezerra

Abstract

The bivalve Tivela mactroides inhabits the intertidal zone of sandy beaches in the Atlantic Ocean (Mexico to Brazil), abundantly composing the benthic macrofauna. The present study aims to characterize the predation of marine gastropods on T. mactroides, through perforations in the shell, testing the hypothesis of foraging preference. For this purpose, 186 shells deposited in the Zoology Museum of the Federal Rural University of the Amazon (MZUFRA) were analyzed, performing: identification of the valve side (right or left), quantification of perforations, morphometric measurements of the shell, classification of foraging success (complete or incomplete) and identification of the position of the perforation. Perforations were evidenced in 10% of the analyzed shells, all with only a single incomplete perforation. Additionally, there was an incidence of perforations in the dorsal region of the shells regardless of the size of the prey, confirming the hypothesis of preference in a region of the shell by gastropods during foraging. It is concluded that there is no preference in the choice of the side of the valve during foraging by T. mactroides, however there is a stereotype in the choice of the region affected by the perforation, being significantly abundant in the dorsal region, close to the umbo.