Student Research Projects

Spiculation in Doriopsilla pharpa (Mollusca: Gastropoda: Opisthobranchia: Nudibranchia) and its sponge prey

Student Ashley Byers, '16
Faculty Mentor(s)
Department Biology
Course Biology 489: Research in the Natural Sciences

Abstract

Opisthobranch mollusks are an ecologically important group of gastropods with a reduced or absent shell. As a result of their shell loss, many opisthobranchs exhibit unique adaptations for defense that include rod-like structures known as spicules in their integument. These spicules could be for either defensive or structural purposes and may distinguish certain genera. Sponges, of the Phylum Porifera also produce spicules. These spicules come in a variety of shapes and forms and link together to form a network throughout its integument. The focus of this study is on oriopsilla pharpa, a yellow-orange nudibranch with a network of calcareous spicules in its integument and specialist feeder on the sponge Cliona celata. Previous research at VWC postulated that the morphological similarities observed between D. pharpa and C. celata spicules indicated that D. pharpa may sequester spicules from its prey. However, five spicule types were observed from D. pharpa, and only one from C. celata. If the remaining four spicule types are observed in other sponge species this could indicate that D. pharpa is sequestering spicules from multiple hosts. We isolated the spicules from 5 species of porifera including C. celata and found 5 different types of spicules present: tylostyle (C. celata), tylote (Lissodendoryx isodictyalis), style (L. isodictyalis), acanthostyle (Microciona prolifera), and oxea (Halichondria bowerbanki). We found morphological similarities between one set of spicules found in both D. pharpa and C. celata. This may indicate that nudibranch species could both sequester and produce spicules.

Grants

Virginia Foundation for Independent Colleges (VFIC), summer 2015.
Virginia Wesleyan Undergraduate Research Conference Grant, 2015-16.

Conferences

Association of Southeastern Biologist Meeting, 2016