Experimental Tropical Marine Ecology

March 8: Day 5 – The Galeta Grind
by -- March 8th, 2011

Work. And then some…

 

Today was a major work day. We started out testing the naked hermit crabs in the arenas with targets that carried different odors. These odors ranged from aged seawater (the control) to conspecific and G. lateralisodors. We got a relatively large positive response from most of the crabs exposed to the conspecific  odor. Several of them climbed on top of the target, and a few even tried to huddle within it as if it were a shell. As for the predator odor, some fled away from the scent, while others tested the arena out timidly, rather than examining the dark sanctuary the target represented.

Around lunch time we searched for more brachyuran crabs, and finally collected a total of thirty G. lateralis–enough to run a Z Test on. We then placed two odors to attract hermit crabs in the field. We first placed a control, just to see if the crabs reacted to the odor of the plastic containers we were using. These did not attract any crabs. We then planted tubes of food odor (chopped up fish), which attracted a few, which we then collected. We resolved to plant the final two odors tomorrow.

Once we returned to the research station, we decided to experiment on the brachyurans. We first divided them into small cups, and then tested them with a variety of non-odorous targets in the arena, like our first hermit crab experiment. However, we did not observe the clear cut results we expected. These crabs were fast, frenzied, and foaming at the mouth, and often appeared to dart to random edges of the arena without noticing the target.

Then we analyzed data for a long time, and became confused.

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