Do Balanus glandula consume brine shrimp cysts?

Abstract

The barnacle, Balanus glandula, is a good experimental organism for studying the impacts of both temperature and flow rate on filter feeding efficiency. Such knowledge has important implications for understanding the physiological constraints under which organisms operate, information necessary for predicting species’ responses to environmental changes. As a first step toward this larger goal, I tested the feasibility of using brine shrimp cysts as prey organisms for B. glandula feeding studies. Specifically, the experiment examined the ability of B. glandula to ingest brine shrimp cysts and pass them through its digestive tract. This experiment demonstrated that B. glandula do ingest cysts, but the number of cysts ingested per individual is highly variable. Approximately half of the individuals tested did not consume any cysts within the 24hr feeding period. Of the ones who did, the number of ingested cysts ranged from 2 to 207. With one exception, all cysts had passed through the guts of the animals within 24hr. These results suggest a reasonable strategy for analyzing feeding efficiency would be to examine the number of brine shrimp cysts in the feces of individual animals following feeding periods at different water flow rates and temperatures.