Behavior and microhabitat selection of the tortoiseshell limpet Testudinalia testudinalis in the northwest Atlantic intertidal zone

Abstract

Testudinalia testudinalis, the only species of intertidal limpet in the northwest Atlantic, feeds on the encrusting coralline alga Clathromorphum circumscriptum. We explored the behavior and habitat preference of this limpet in the intertidal zone of southern Maine and in laboratory experiments. We found T. testudinalis to be almost exclusively nocturnal, moving approximately 30-fold more during the night. This limpet did not home or display a consistent preference for any substrate as a resting site or preferred non-feeding habitat. However, they did show a significant preference for horizontal surfaces during feeding at night and vertical surfaces during the day. This behavior was observed at three intertidal sites along the Maine coast and in laboratory experiments, indicating a preference for a vertical resting site where heat stress, desiccation or predation may be less likely.