Under the Sea — Predator and Prey Interactions

Chlorostoma Funebralis

Littorina littorea

When do you ever get to see star fishes, lobsters, crabs and snails all in the same place (besides in a supermarket of course)? Well you can in our lab! Today in Biology 326 we experimented with all these invertebrates including two species of snails; Chlorostoma funebralis from the Pacific Ocean and Littorina Littorea found in the Atlantic Ocean. We wanted to see how the different species of snails reacted with native versus non-native predators using their chemical senses. Our first experiment tested Chlorostoma funebralis with the water that smelt of Lucky the lobster, the Dungeness crab (Big Dan) and natural sea water. We then sat and waited to see how long it took the snails to crawl out of the bottles they were held captive. We then did this same experiment with L. Littorea and compared reaction times of both species. We expected that Chlorostoma would react faster when placed in the water of the crab versus Lucky the lobster since they co-evolved and fear crabs as predators. The opposite effect would be seen for L.littorea and no difference would be seen for both conditions of natural seawater. However, the results were slightly different. Chlorostoma indeed responded quicker when placed in Big Dans’ water versus L.Littorea however, both snails responded the same when place in Luckys’ water. Maybe snails just like lobsters more than crabs.

Our second experiment tested both snails’ tactile responses (response due to direct contact) by observing how the snails reacted when faced directly with predatory sea stars both native to the Pacific Ocean. Again, we predicted that Chlorostoma would have more of a response when touched with both sea stars (Pisaster ochraceus and Evasterias troschelii) as they co-evolved and likely have had more interactions with these predators. L.littorea on the other-hand we predicted would not have much of a response since they are not familiar with these same predators. We recorded the snails’ movement to see how far they ran to get away from these predators as well as if they had turned away or went straight through them. To tell you the truth, these snails are brave little creatures. I know personally if I was faced with a large scary predator regardless if I grew up with them around or not I would run for my life.

I know I’ve got you hooked for more information on predator-prey relationships so check out these awesome links:



All photos were taken from Google Images


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