Predator effects on behavior and anaerobic capacity in the common acorn barnacle (Balanus glandula)

ABSTRACT   Differences in the stress experience of sessile organisms across the intertidal zone can differentially influence phenotype. For example, Balanus glandula barnacles from the low intertidal zone have higher lactate levels, greater lactate dehydrogenase (LDH) activity and reduced cirral activity compared to conspecifics from the high intertidal zone. We tested the hypothesis that enhanced anaerobic capacity in lower intertidal B. glandula results from increased predation and hypoxia-inducing shell closure. To investigate this hypothesis, we compared the density of whelk predators across the intertidal zone, and quantified the behavioral response and LDH activity levels of B. glandula exposed to predators in the lab. We consistently found more predators in the low intertidal zone, although the response of B. glandula to predators was short-term operculum closure (<1hr) which did not result in significant differences in LDH activity. Thus, increased predation is not the cause of high anaerobic capacity in lower intertidal B. glandula.