Meeting Abstract
Intertidal areas are highly variable environments imposing selective forces unevenly on organisms, potentially leading to divergence in behavior and morphology in closely related taxa. Leptasterias is a species complex of small, direct-developing sea stars living across intertidal habitats and experiencing different degrees of abiotic stresses, including wave impacts. We compared attachment strength and mobility in Leptasterias spp. from microhabitats inferred to be more or less wave-impacted. Attachment strength, the force required to dislodge a star from its substrate, was quantified by a direct pulling test in field and laboratory using a flexible, piano-wire clamp connected to a spring scale. Additionally, resistance to dislodgement by controlled water surge was measured in field and lab environments. And, righting time of sea stars placed oral side up (“flip time”) was recorded as a measure of mobility, in the field and lab. We analyzed results of these tests using Mann-Whitney U tests and showed that the attachment strength of Leptasterias spp. in more wave-impacted microhabitats is greater than in less wave-impacted microhabitats, whereas the mobility of more wave-impacted sea stars was lower than that of less wave-impacted sea stars. The difference in attachment strength and mobility of Leptasterias spp. may be a local adaptation to wave-stressed environments and is being further explored using genetic methods.
