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Are Snails Sexier Than Worms?

Published: November 17, 2014

Are snails sexier than worms? CSULB’s Bruno Pernet thinks so and he should know—his research involves both.

“Snails are a step up for me,” chuckled the biological sciences’ professor. “I also work on worms, and snails are way sexier than worms.”

Beginning his 11th year on campus, Pernet works with invertebrate animals which, according to him, include just about anything that moves.

“The only non-invertebrate animals are the vertebrates, like fishes and lizards and humans,” said Pernet. “There are something like a million described species of animals, and all but about 60,000 or so are invertebrates.”

Pernet, whose work focuses on the tiny embryos and larvae of invertebrates, finds the research to be not only interesting, but important work as well, particularly when it comes to marine reserves. While small in size, understanding snails has monumental effects on how we manage our coast’s natural resources.

“If we want to understand how a marine reserve works we need to understand how individual animals move in and out of reserves,” he said. “For many marine invertebrates the adults just sit on the bottom all the time, and the life stage that moves from site to site is the larvae that are up in the water column.

“How long those larvae spend up in the water column—which is determined, in part, by if and how they catch food particles—has a huge effect how far they move between sites. That’s important for the design of marine reserves,” he added. “How do you decide where on the coast you put reserves? Say you can establish five reserves. Where do you put them? How do you space them? To answer those kinds of questions, we need to know how larvae work, how long they spend drifting in ocean currents and how far they move while up in the water column.”

Pernet’s keen interest in inverterbrate animals grabbed hold at Cal State Stanislaus where he took invertebrate biology courses before going on to graduate school at the University of Washington (UW).

“I was generally interested in invertebrates, and at UW there were a ton of people who focus on the development of marine animals and the biology of their larvae and so I got interested in that and have been doing it ever since,” he said. “They’re really beautiful animals to look at.”

Since there are so many invertebrates, however, Pernet chose to focus on animals that undergo a particular kind of early development called spiral cleavage, where the cells tend to behave in the same manner. Those embryos, however, develop and give rise to animals that look really different from each other.

“So, for example, imagine a segmented worm (one of the many marine relatives of earthworms) and a snail. They don’t look anything alike as adults, but as embryos they’re indistinguishable,” said Pernet. “That’s the group I’m interested in, mostly because there is a huge amount that’s unknown about how their embryos and larvae work.”

When thinking of endangered species, snails do not usually come to mind, nor do any of the other animals Pernet and his students generally work with. But there is a concern for certain species.

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PHOTO BY MICHAEL SULLIVAN
Bruno Pernet

“There are several species of abalone in Southern California whose populations are incredibly small right now largely because of overfishing, but also because of disease,” said Pernet. “For example, black abalone are now extremely rare in the Southern California intertidal zone, but they used to be incredibly common, and, until about the 1970s, were harvested for food. They, as well as some other West Coast snails like white abalone, are listed as an endangered species.”

The concern is so great, according to Pernet, that research is taking place along the West Coast on how to restore abalone populations. For the white abalone in particular, there are scientists trying to breed abalone and rear their larvae in captivity so they can release juveniles back into the wild in an effort to increase the population.

“Whether or not populations of that species actually survive probably depends quite a bit on the success of that (captive breeding),” he said. “Because their populations are so low right now, it’s actually hard for the few remaining adults to find a mate because they are so sparse. Adult snails don’t move around much, and because they are so sparse, it’s hard for a male to find a female, so in the wild it seems like breeding is going to be a problem.”

Since Pernet and his students work on these very tiny embryos and larvae, most of their work is done in the lab. Still, there is a need for field trips to collect the adults that produce the embryos they work on, so they venture out to nearby sites such as the Palos Verdes Peninsula or Alamitos Bay, where the floating docks are a great source of animals.

“Lots of interesting snails and worms live on those docks,” said Pernet. “One good thing about Cal State Long Beach is that there is a huge diversity of animals really close to campus, so I’m really well positioned for the kind of work I’m interested in. I can actually stop by a field site on my way into work and pick up animals to work on that day.”