January 1, 2019.
Botrylloides diegensis is among the most common colonial ascidian invaders with the ability to undergo whole body regeneration (WBR), as do other botryllid ascidians. This phenomenon allows entire adult zooids to arise from minute fragments of vascular tissue including single ampullae. With the global spread and unknown environmental range of B. diegensis this study focuses on the ecological component in the process of WBR, particularly the influences of temperature and salinity on the rate of regeneration. Six adult colonies were collected and clonal replicates were established allow comparison of regeneration at a variable field site (16-19 ¬∞C;28-31 salinity) and a fixed lab setting (14 ¬∞C; 33 salinity). Using clonal replicates, each genotype was subjected to four ampullar isolation treatments : 1- Single, one ampulla; 2- Double, two ampullae; 3- Triple, three ampullae; 4- Quad, four ampullae. Daily microscope photographs were taken to track the process of WBR. Preliminary results showed an unanticipated and clear difference in mortality between field and lab replicates. Field replicates showed a loss of ampullae across all four treatments at a more rapid rate than those in the lab setting. Observations suggest other environmental stressors also influenced field individuals, such as more predators and marine invertebrate settlers in competition for space. This data contributes knowledge on the importance of environmental conditions and on what the most suitable conditions are in the process of regeneration. Further work will provide guidelines towards management of B. diegensis in identifying conditions inhibiting WBR. Ongoing genetic analysis will additionally assist in defining the unknown distribution and native region of B. diegensis in order to conserve invaded habitats.
San Francisco State University (SFSU)
The 2018 STEM Teacher and Researcher Program and this project have been made possible through support from Chevron (www.chevron.com), the National Marine Sanctuary Foundation (www.marinesanctuary.org), the National Science Foundation through the Robert Noyce Program under Grant #1836335 and 1340110, the California State University Office of the Chancellor, and California Polytechnic State University in partnership with San Francisco State University. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the funders.