We found more jellyfish being born in our lab this week!
Rebecca Helm, a Dunn lab graduate student, left a couple of bowls of salt water and hydroids out on the table overnight, instead of the refrigerator where they usually live at around 50 or 60 degrees fahrenheit. The next day she came in and found them doing this:
This particular animal is called Podocoryna carnea. Like most jellies and close relatives of jellies, it has a pretty elaborate life cycle. This one involves a free swimming jellyfish, and a larva that swims around then lands on the back of a hermit crab’s shell. Then the larva metamorphoses into a polyp, which buds more polyps, growing into a whole colony on the crab’s back. The colony is made up of lots of polyps that are all connected and share fluid through a web of tubes that circulate partially digested food. Some members of this colony will eventually bud new swimming jellyfish.
The video at the top is of one of the colonies we have growing in our lab. These polyps were given to us by friends, but they can also be collected from hermit crabs at the beach, then grafted onto slides. They seem to grow well on slides, and slides are much easier to take care of then crabs.
Some of the polyps in the video have pink balls growing around the top. These are the buds that will mature to become free-swimming jellyfish. If you look closely, you can see jellies of all stages of maturity growing, including some that are ready to break free. After they swim off they will continue growing. We’ll try to follow up on how that goes.
Video by Sophia Tintori, life cycle drawing by Perrin Ireland, both released under a Creative Commons Attribution-Noncommercial-Share Alike license. Thanks to Diane Bridge and Neil Blackstone for the Podocoryna colonies. Check out this earlier post of the other polyps we saw budding jellyfish in our lab.