On Friday, the Belden Lab went up to Mountain Lake Biological Station to catch and swab Red Efts (juvenile red-spotted newts), Redback Salamanders (Plethodon cinereus) and adult Red-spotted Newts (Notophthalmus viridescens viridescens). Red Efts are the terrestrial juvenile stage of the Eastern Newt. The life cycle of a red-spotted newt is more complex than most amphibian life cycles. After newt larvae are ready to metamorphose, they lose their gills and take to a life on land as a red eft. Red-spotted newts will live as efts for years before completing their transformation by turning green and returning to an aquatic life style. As an eft, the juvenile newts can be 10 times as toxic as when they are adults, although adults are also distasteful. The toxin that their skin contains is known as tetrodotoxin, and it has been shown to deter predators like largemouth bass and crayfish from eating the newts.
Because they go through a change in habitat as well as form, the skin bacteria of red-spotted newts probably changes throughout their life cycle. Swabs for bacteria of larval newts, red efts and adult red-spotted newts will be processed to determine if the species of bacteria on their skin do change throughout their life. A change of bacterial “species” on the skin of the newts could confer an advantage against the amphibian chytrid fungus for one life cycle stage versus another. This change may also be dependent on the habitat, meaning that amphibians might be less susceptible to chytrid in the water or on land due to the specific bacterial ecosystem of that habitat. The redback salamanders (Plethodon cinereus) were swabbed to help determine if there is a visible difference in skin bacteria communities on terrestrial species versus those that are more directly associated with water, such as American Bullfrogs (Lithobates catesbeianus) and adult Red-spotted Newts (N. viridescens viridescens).