Morphological function of autotomy in nudibranchs

Abstract

My goal for this project was to understand the morphological function of autotomy in nudibranchs. I began by exploring the structure and function of the cerata in nudibranchs that are capable of autotomy. I looked at two species of nudibranch: Melibe leonina and Dirona pellucida. I used micro-CT to look at the region where the cerata autotomized as well as the tissue present inside the cerata. An interesting fact about the cerata is that it functions as an extended gut in some nudibranchs, so I wanted to highlight the presence of digestive tissue inside the cerata. I stained the cerata in two different PTA (which stains all tissue) and silver nitrate (which specifically stains nervous tissue) in order to show the digestive tissue and nervous tissue separately. I used histology to identify the tissue present in the cerata. Surprisingly, digestive tissue seemed to be absent in the Dirona pellucida cerata. I also CT scanned entire nudibranchs in order to identify and observe the region at which autotomy occurs (the autotomous zone). I wanted to do a comparison of the autotomous zone before and after the cerata has been autotomized. I was able to accomplish this with the Melibe leonina. However, I was unable to show the autotomous zone in my CT scan of the Dirona pellucida because I didn’t allow enough time for PTA to penetrate and stain the inside of my specimen. I also feel that my research is incomplete. If I were to continue my research, the next step would be to dissect out the autotomous zones of the intact and autotomized cerata so that I can do an up-close CT scan of the region. This would show the structure of the autotomous zone in much finer detail. Additionally, histology could also be performed on the dissected autotomous zone to try and identify the tissue types in the region. Since my areas of interest are neuroscience and stem cell research, I wonder if research into autotomy could be used to improve current methods of organ/cell growth.