Tripneustes ventricosus covering itself in natural and bendable materials.

Tripneustes ventricosus and Lytechinus variegatus have been known to cover themselves for a few reasons; avoidance of predation and protection from UV rays. It is thought that there may be a correlation between the use of materials that conform to the urchins’ body and its preferences for that material. For this paper, it was hypothesized that urchins are more likely to use a bendable natural material over materials that are not able to conform to their body shape. Samples of both these species were collected from two sites, mangroves and turtle grass, in Discovery Bay. Of these samples two were large for both species and two were smaller in size for each species collected. A total of 16 individuals were used to conduct this experiment. There were seven different conditions they were tested under; the use of natural bendable material, natural unbendable, unnatural bendable, unnatural unbendable, unnatural and natural bendable, unnatural and natural unbendable, and bendable and unbendable materials. Although the majority of the data was not statistically significant, there were some noted correlations. On average the larger sized urchins, of both species, used more material to cover themselves than the smaller sized urchins. T. ventricosus covered itself more than L. variegates, with a statistically significant difference when using unnatural, bendable materials (p=0.0095). The urchins collected from the mangroves used more materials for coverage than those from the turtle grass; statistically significant difference when using natural, bendable materials (p=0.008176). Although there is no statistical significance natural, bendable materials were used the most, while unnatural, unbendable materials were used to least.