Hacking spring: what to do when things are slow in the field

Spoiler: spring progress this year is slow. The cyprids continue to settle.

An oyster shell (Crassostrea virginica) covered with newly settled barnacles.
The redder dots are the younger larvae, and the gray ones are slightly older. 

A cement wall at my field site. It's hard to tell in this picture, but the reddish tint that you see between the large white pebbles is entirely due to a dense covering of newly settled barnacles.

The snails are just starting to come out in the field, and the water is warm enough that the Crepidula are finally brooding eggs. That means that they should be ready for experiments in a few weeks. Until I can reliably collect larvae in the field, I've been making do with what I can farm in the lab. That has meant collecting animals and bringing them up to room temperature, which triggers them to lay eggs. If I keep the females in clear plastic cups, I can watch the embryos develop and collect the larvae when they are ready to hatch.

Developing C. fornicata egg mas in a plastic lab cup. The female is probably about 30 mm long, and you are looking at her underside (ventral side). The solid arrow indicates the egg mass, which is full of little yellow dots. Those are the individual eggs. They are just laid, and have not really started developing yet. As the embryos develop and grow into little larvae, they will change color -- that's the signal I'm looking for to indicate their readiness to hatch. The dashed arrow is the foot of the animal. The egg mass is obscuring the head of the animal; she is brooding the eggs between her neck and the cup. 

This is a nice, convenient way to get lots of larvae for experiments year-round. The animals require extra care in the cups (each one needs to be fed daily and given clean water every 2-3 days), but sometimes this also means that I can get developing larvae as a side effect when working on other experiments with these adults in cups.