Spawn city

A Crepidula fornicata larva. You can see its spiral shell, and
the lob hanging down is its velum.

After two weeks of successfully keeping Crepidula fornicata adults alive in the lab, I am happy to announce they have given me larvae! Now my experiment really takes off.

I'm investigating whether the conditions brooding mothers are kept in have carryover effects on the larvae. My mothers are in two different temperatures and only half of them are getting fed, so I can test those two crossed factors (high/low temperature and food/no food). To tell if there are any effects on the larvae, I'm measuring several variables - how big the larvae are when they're spawned, how quickly they grow, and how long it takes them to become competent to settle.

Crepidula larvae swimming in a dish under the microscope.
The clear lobes on each individual are the velum.

Measuring larval size is a tricky game. I collect a random sub-sample of individuals by sucking up some water from the larval culture jar, and then view them individually under the microscope. Crepidula larvae love to swim and move around almost constantly with two fleshy lobes called the velum. The edge of the velum is lined with cilia, so the rapidly beating micro-hairs create waves that propel the larvae through the water.

I'm able to make them stop swimming by cooling them down - basically sticking them in the freezer for a few minutes. Then I measure them using an ocular micrometer, which is a type of ruler built into the eyepiece of a microscope. I record the magnification and how many tick marks long the larva is so I can calculate their true size later. Voila - data!

It is very exciting for me to be collecting data for my experiment, and I hope I have good results!