Incredibly another week has gone by. Work in the lab coming along but not much has changed from last week. We are still working on getting conditions right for the jellyfish.
In the mean time, I thought it would be interesting for you to learn a little bit about the hydrozoan jellyfish's life cycle. There is more to it than you might know.
The life cycle of the species I am studying, Phialidium gregarium, is typical of hydrozoans. The free swimming medusa, what you think of when you think jellyfish, is the sexually reproducing phase. Individuals produce have either ovaries or testes (although this week we found a hermaphroditic individual that had two ovaries and two testes). Light cues induce the medusa send sperm and eggs into the water. Fertilization is external and the embryo develops into a small larva called a planula. Now this is where it gets interesting. After some time swimming around as a non feeding planula, the jellyfish settles down and metamorphoses into a polyp. The polyp has a stalk and tentacles around its mouth, and it somewhat resembles a tall sea anemone. The polyp reproduces asexually by cloning itself and becoming a colony of polyps. After a while the colony will produce a specialized polyps that release medusae. Once the medusa mature, the cycle starts again.
My name is Philip Aspinall, and I am a student at Sierra College in Grass Valley, California. The first time I peered into a microscope and found an entire, complex, beautiful world below the visible, I was transfixed. I am thankful for George von Dassow and Svetlana Maslakova for allowing me to work in their lab, and to Geroge for his generosity with his time and for being my mentor this summer.