Comparing nematocyst production in starved and well-fed sea anemones (Aiptasia pallida)

Background/Question/Methods

Resource availability can fluctuate in both space and time.  This patchy distribution of resources can act as an environmental stressor, resulting in acclimation within organisms. Like other resources, food availability can be variable over time and space, and the lack of food availability can be stressful for organisms. Symbiotic organisms such as some cnidarians receive nutrients both from their symbiotic dinoflagellates and through prey capture using specialized cells called nematocysts.  Symbiotic cnidarians can supplement heterotrophic feeding with photosynthate from their dinoflagellate symbionts.  Thus, some cnidarians can persist in relatively low food environments with extremely variable prey availability.  We tested the effects of feeding frequency on nematocyst production in Aiptasia pallida, a sea anemone. We hypothesized that A. pallida would up-regulate production of nematocysts when starved as a secondary mechanism for surviving low food availability. Five tanks of A. pallida were fed twice a week (well-fed) and another five were fed once a month (starved). We quantified nematocyst production by crushing A. pallida tentacles and counting the number of nematocysts in a known volume of solution, which we then standardized for total protein using a Bradford assay.

Results/Conclusions

Our results indicate a significant increase in nematocyst production in the starved anemones. We suggest that the starved A. pallida produce more nematocysts in order to capitalize on prey when available. Our study helps clarify how some organisms may cope with fluctuating resources, such as food availability.