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| Hermit crab (Diogenes heteropsammicola) |
This relationship has proved to be mutually beneficial for both the hermit crab and the coral. By using coral as its protective armor the hermit crab no longer has to continue to search and search for new and better shells as it continues to grow. The space in the coral in which the hermit crab sits grows with the crab, so it does not need to search and compete among its species for new homes. In addition, the coral is able to sting, which helps to further protect the crab from predators such as starfish, larger crabs, and octopi.
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| A type of coral the hermit crab will use (Heteropsammia cochlea) |
This relationship is also able to be favorable for the coral as this species of coral is a solitary coral instead of a reef-building kind. Solitary corals are often found on shallow sandy seabeds. With this type of habitat, the solitary coral runs the risk of being buried by sediment and overturned by strong currents. To combat this, corals will develop a partnership with other animals to assist them out of the sand and do the ‘walking’ for them. This is usually seen with marine worms, but is now prevalent in this hermit crabs species as well.
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| Coral skeleton after being used by hermit crab |
Though more research needs to be done, it is thought this relationship with hermit crabs developed similarly to how the marine worms use the coral for protection. In the case of the marine worm, a young coral will settle on a small shell that has already been colonized by the marine worm. The coral then grows over and beyond the shell, providing a cavity for the marine worm, which is continuing to grow as well. These hermit crabs likely acquire coral shelter and develop this symbiotic relationship in a similar manner such as this one.
Mynott, S. (2017). Newly discovered hermit crab species lives in 'walking corals.' The Conversation, 12 March 2018.
This is a very interesting article! Something to look into may be the reasoning behind why the hermit crabs switched from using shells to using the corals? Was there a shortage of shells?
ReplyDeleteThis is very interesting! I guess I didn't realize that hermit crabs go from shell to shell, but I also am no expert on marine organisms! I think that it is very cool that the relationship between the coral benefits both the coral and the hermit crab! One thing to also consider, building off of Hayley's point, is: is the relationship between hermit crabs and shells symbiotic in any way, shape, or form?
ReplyDeleteI wonder if there are any downfalls to the hermit crabs using coral instead of shells. Based on the post, the relationship seems to have many benefits so it seems a little surprising that it was only recently discovered in this one species. It would be interesting if this strategy could be introduced to other species to see if it has the same benefits.
ReplyDeleteI thought this post was interesting because it reminded me of examples I have seen of hermit crabs using litter such as plastic containers as shells. It seems that competition for a shell is so great that hermit crabs may resort to using a variety of other forms of shelter. Being able to sting is a nice addition, but I wonder how well the coral holds up structurally compared to shells that the crab might use - is it just as strong? I also wonder how the size of hermit crabs using coral compares to other members of their species. Since they don't need to spend as much time competing for new shells, would this mean they therefore have more time to spend getting food and grow bigger as a result?
ReplyDeleteI wonder if the use of corals as shells is restricted to this area and this type of hermit crab alone? Perhaps more studies will show if it is an isolated happening or a more common practice? Also i wonder if rising sea temperatures and salinity have any impact on these interactions, perhaps they are working together to find the best way to handle the changing conditions.
ReplyDeleteI found this post extremely interesting. I have heard of hermit crabs exchanging shells and even adopting shells of various obscure objects, like glass bottles. However, I had not yet heard of a symbiotic relationship between the hermit crab and another organism it uses for a shell. Although on a different note, I found an interesting video and article that shows hermit crabs forming a "housing chain" as they wait for their ideal house. Essentially, as a large shell washes ashore, many hermit crabs gather around. After discovering the shell may be too big, the crabs start inspecting the shells currently worn by other crabs. Once a crab comes along that is big enough to fit into the shell, the "chain" starts and hermit crabs begin to exchange shells. Here is the link to the article and video for more details: http://www.bbc.com/earth/story/20141103-hermit-crab
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