Stress and deviant reproduction in echinoderms

Ancestral characteristics in echinoderms are considered to include sexual reproduction with gonochorism, a planktonic feeding developmental stage, seasonal reproduction, and no protection of young. Deviants from these characteristics occur. Although many factors can affect reproductive characteristics, we suggest stress (a decreased capacity for production) is a important cause. Stress can result from a lower capacity to feed or to store production, a higher maintenance requirement, or a lower availability of food. We tested this by comparing echinoderms at taxa levels from subphylum to species to check for divergent evolution. In the examples used the deviant reproductive characteristics were in the direction predicted: they were correlated with conditions expected to increase stress.