Settlement of crabs on reef habitats

Auckland University PhD student Jenni Stanley talks about her research with crab larvae and sound. She talks about where she got the idea to look at this phenomenon and why crab larvae might use sound to navigate.

Point of interest: Jenni’s research relied on a serendipitous discovery made almost by accident. These sorts of discoveries are very important in science and often show phenomena that are entirely new.

Transcript

JENNI STANLEY Right now, I’m looking at how ambient underwater reef sound affects the sediment behaviour and metamorphosis of larval crabs. Essentially what I’m researching is how crabs utilise reef sound – like sound created on a reef – how they utilise it to select a suitable habitat to grow up in.

Through the experiments, we have found that crabs do, in fact, use reef sound as a settlement and metamorphosis cue. This was previously not known. We also have found out that differences in the sound produced at different habitat types will affect the behaviour that we have seen.

I came across the idea to research whether crab larvae used sound from different habitat types to settle and metamorphose because I was actually investigating a completely different topic, and one night, I accidentally left a speaker on, playing reef sound next to an experimental tank. So I kind of gave up this experiment, cause things weren’t working my way.

So I decided to, you know, leave this one, and I came back a few days later and I noticed that they had completely changed behaviour. They had about 80% of them had settled to the substrate, which wouldn’t have happened normally. I really stumbled upon the phenomenon, that crabs use sound to mediate their settlement and metamorphosis. This unexpected result was quite exciting. I was kind of up against a dead end of my research where I just couldn’t get a lot of things to work correctly, so once I kind of had an idea that something funny was happening, it was very exciting.