meredith's feeding assay
The tube of a Diopatra cuprea made with Gracilaria.
OVERVIEW
Meredith ran a feeding assay with the decorator worm, Diopatra cuprea, to see how they respond to the chemistry of Gracilaria. Diopatra live in tubes that they build and "decorate" with what is in their environments. Usually bits of shell, Gracilaria, and Ulva are found attached to Diopatra tubes. Many seaweeds will produce chemicals that make them taste bad to herbivores and act as a defense. The worms love to eat Ulva, but they do not seem to like eating Gracilaria and we want to know why. To determine if Gracilaria has chemicals that keep Diopatra from wanting to eat it, we first extracted the chemicals from Gracilaria using Ethyl Acetate. Then, we set up a feeding assay to compare how much Ulva the worms will eat when it is coated with just Ethyl Acetate and how much Ulva the worms will eat when it is coated with Ethyl Acetate and Gracilaria chemicals. This method allows us to find out if the chemicals of Gracilaria deter feeding by Diopatra. Since it is known that the worms like to eat Ulva, if they eat less of the Ulva when it has chemicals from Gracilaria, this will indicate that the chemistry produced by Gracilaria is protecting it from herbivores such as Diopatra.
RESULTS
After breaking down the feeding assay with Diopatra, Ulva, and the chemical extracts of Gracilaria, no differences were found in the amount of Ulva the worms ate with Gracilaria chemicals painted on it and without Gracilaria chemicals. This tells us that the Gracilaria chemicals may not be preventing the worms from eating it. These results do not explain why the worms do not like to eat Gracilaria, so there are still questions to be answered!
Meredith ran a feeding assay with the decorator worm, Diopatra cuprea, to see how they respond to the chemistry of Gracilaria. Diopatra live in tubes that they build and "decorate" with what is in their environments. Usually bits of shell, Gracilaria, and Ulva are found attached to Diopatra tubes. Many seaweeds will produce chemicals that make them taste bad to herbivores and act as a defense. The worms love to eat Ulva, but they do not seem to like eating Gracilaria and we want to know why. To determine if Gracilaria has chemicals that keep Diopatra from wanting to eat it, we first extracted the chemicals from Gracilaria using Ethyl Acetate. Then, we set up a feeding assay to compare how much Ulva the worms will eat when it is coated with just Ethyl Acetate and how much Ulva the worms will eat when it is coated with Ethyl Acetate and Gracilaria chemicals. This method allows us to find out if the chemicals of Gracilaria deter feeding by Diopatra. Since it is known that the worms like to eat Ulva, if they eat less of the Ulva when it has chemicals from Gracilaria, this will indicate that the chemistry produced by Gracilaria is protecting it from herbivores such as Diopatra.
RESULTS
After breaking down the feeding assay with Diopatra, Ulva, and the chemical extracts of Gracilaria, no differences were found in the amount of Ulva the worms ate with Gracilaria chemicals painted on it and without Gracilaria chemicals. This tells us that the Gracilaria chemicals may not be preventing the worms from eating it. These results do not explain why the worms do not like to eat Gracilaria, so there are still questions to be answered!