Crepidula Slipper Limpets Alter Sex Change in Response to Physical Contact with Conspecifics

Abstract

Abstract. Chemical signaling, especially signaling with waterborne cues, is an important mode of communication between conspecifics of aquatic organisms. Although conspecific associations play an important role in sex allocation of sequential hermaphroditic slipper limpets, the mode of signaling is unknown. We tested the hypothesis that the effects of conspecifics on animal size and time of sex change in the tropical slipper limpet Crepidula cf. marginalis are mediated by waterborne cues. In our experiment, pairs of snails (one small and one large) were kept in cups, either together or partitioned off with fine or coarse mesh, or partitioned, but switched from side to side to allow contact with the cup mate's pedal mucus. The larger snails that were allowed contact with the smaller companions grew faster, and generally changed sex sooner, than did the larger snails in the barrier treatments, which allowed no physical contact. The smaller snails that were allowed contact with the larger cup mate delayed sex change compared to those separated from their cup mates. We were, therefore, able to reject the hypothesis that waterborne cues mediate communication between these snails. Our results suggest that the cue that affects size and time to sex change requires some kind of physical interaction that is lost when the snails are separated. Furthermore, contact with another snail's pedal mucus does not compensate for the loss of physical contact. Since males often attach to the shell of larger females, direct contact may mediate this kind of physical interaction via positional information, physical stimulation, or contactbased chemical communication. Whatever the cue, contact with conspecifics influences both partners, resulting in, surprisingly, a higher growth rate in the larger animal and delayed sex change in the smaller animal.

The relationship between sex change and reproductive success in a protandric marine gastropod

“…Inhibition by the female could also explain the longer time to sex change observed for C. coquimbensis males in the 1F+1M treatment given the monopolization of the female by the only male present in the aggregation. Physical stimulation and chemical inhibition have been suggested by Carrillo-Baltodano & Collin 35 for C. cf. marginalis .…”

Beyond the sea: Crepidula atrasolea as a spiralian model system

“…Calyptraeids are protandrous hermaphrodites, i.e., all individuals change sex from male to female as they increase in age and size during their lifetime (Coe, 1936;. The timing of this transition is strongly influenced by social environment, in addition to size and feeding state (Coe, 1938;Collin, 1995;Hoagland, 1978), and is controlled by physical contact between individual animals (Cahill et al, 2015;Carrillo-Baltodano and Collin, 2015). Calyptraeid life history is diverse, and includes indirect development with planktotrophy (swimming and feeding larvae), lecithotrophy (swimming, non-feeding larvae), direct development that may include feeding on nutritive eggs or embryos (oophagy or adelphophagy) and poecilogony (transition between direct and indirect development in a single species) (Collin, 2003c;McDonald et al, 2014; see Table 1).…”

Fecundity of the invasive marine gastropodCrepidula fornicatanear the current northern extreme of its range

“…; Cahill et al. ; Carrillo‐Baltodano & Collin ). Following internal fertilization by the male, females encapsulate their fertilized eggs within a series of small, transparent, balloon‐like triangular egg capsules; this collection of capsules—the egg mass—is then maintained beneath the shell at the front of the mantle cavity (e.g., Richard et al.…”

“…Crepidula fornicata, however, is particularly well suited for such studies. This species, like other calyptraeid gastropods, is a protandric hermaphrodite, with males eventually transitioning to females (Coe 1936;Collin 1995;Henry et al 2010;Cahill et al 2015;Carrillo-Baltodano & Collin 2015). Following internal fertilization by the male, females encapsulate their fertilized eggs within a series of small, transparent, balloon-like triangular egg capsules; this collection of capsules-the egg mass-is then maintained beneath the shell at the front of the mantle cavity (e.g., Richard et al 2006;Mardones et al 2013) for several weeks until free-living veliger larvae emerge.…”