Thursday, May 8, 2014

Using Model Species to Study Reproduction and Development in a Marine Lab

Because we study development in our lab, there is a lot of reproduction going on here! Currently, we are caring for hundreds of sea snails, carefully monitoring them for new babies.
The snail farm.  Crepidula snails hanging out while
they wait for new water to be added to their cups.
In biology, we like to use "model organisms" in our studies. Model organisms are those species that have several good qualifications for study. Naturally, our lab prefers to study animals whose reproduction can be monitored. We also like to study animals whose eggs and larvae can be maintained in the lab.

Crepidula marginalis fit my needs for my biology experiment! They are a marine snail that live in the rocky intertidal zone. And one place we can find them is a beach close to our lab, in the Veracruz area of Panama.

Crepidula are easy to collect, easy to maintain in a lab, and their reproduction can be monitored.

A female with eggs

As you can see from the photo, male snails will "climb aboard" a female snail. If the female chooses to mate, and to fertilize her eggs, then her egg "brood" will be visible through the sides of the clear cups. We use clear cups in our labs, which become the snail's new habitat, or home, while we study them.

When the eggs have developed, the brood sac will open and hundreds of veliger larvae will be released from their mama's care. For their first few days of life, they swim freely and quickly! Within a few days, their swimming slows down as their shell gets larger and heavier.

Upon hatching, we try to distribute the new larvae into new bowls with fresh, filtered sea water and algae to eat.

Of the many things I have learned under Dr. Collin's mentorship, I have learned how to choose an organism that suits your experimental needs. And for my thermal tolerance study, the Crepidula marginalis have been a good model organism for these reasons:

* They have been easy to collect in the field,
* They survive and reproduce in the lab,
* Their reproduction can be monitored, and
* Their larvae survive in the lab while we are studying them.

Nina Dropcho, Intern, Collin LabSmithsonian Tropical Research Institute

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