Crabs. The invasive green crab C. maenas in fact. I spent this entire block working with crabs and one of the best research teams I've ever been a part: Jaimie (below), Ariel, and me. We did a series of training experiments that I'll get to later, but we spent 9-5 in a dark, cold room running trials on about 30 crabs for a month solid.
This is what our experimental design looked like, we sat side by side and ran individual trials in separate containers. (Don't worry, we rotated crabs to eliminate bias and any individual differences).
This is what we saw inside the buckets. We sectioned the buckets into 9 squares and selected at random which square we originally placed the crabs. The gist of the experiment was this: crabs do not like light. In fact, most stay in dark covered places for most of their lives. We also had access to this local invasive species. Knowing that 1. Crabs have shown learning capabilities in previous experiments and 2. Successful invasive species are usually very intelligent/can outcompete local species, we wanted to see if we could train this species of crab to approach a light in order to receive food. As the name of this class was chemosensory biology, we designed our trials by eliminating sensory cues one by one until the crabs made it to stage 4 successfully completing our experiment. The protocol went like this-
Stage 1-crabs see a piece of food dropped into the bucket, and we pipetted a flume of the scent at the crabs. Once the crabs retrieved the food we shone a light on them
Stage 2-same thing, except the light is on the food for the whole trial
Stage 3-food dropped in, no scent pipetted (so only visual cue) and continual light beam
Stage 4- shone only light beam into the container, once approached center of the beam we dispensed food
Our professor was very encouraging, but made it clear that he did not really expect anything from our experiment. Much to everyone's surprise we had a very high % complete our experimental design.
(be warned, we got excited while taping and talked some, our trials were always silent during experimentation)
Just some fun facts about crabs: to determine sex just look at the underside or abdomen! Male is on the left with the narrower shape, female on the right with the wider markings.
We compared the results between three different factors of the crabs; their sex M v. F, their background lab raised v. wild caught, and their size small carapace length v. large carapace length (below)
In the end we made some marine inspired cookies that we shared with the class.
And here is our award winning (well, peer voted best in class) poster :)
