Saturday, June 25, 2011

Will you take the path less traveled?

Well folks, sorry it's been a while since I've written, but I've been diligently crunching numbers and putting toads through trials in the arena. Long days and even longer nights! Let me give you a little breakdown of what a toad trial is like:

Step 1: Set up all of the equipment. This really just requires me to plug everything in and turn it all on. Not too hard. Remember that camera and infrared lights I have set up over the arena? 

The lights get plugged in, and the camera cord runs to a little room just beyond the dryer in the picture. In that room is a DVR box that transcribes the camera feed and plays the picture onto a computer monitor. I don't have a picture of the actual machines, but I'll take one tonight and post it later on. Here is a picture of what the arena looks like in the dark, from the camera's point of view:

Pretty neat, huh?! From here, I can watch the toads as they explore the arena. The video is in black and white, so it's a little hard to see, but I can get an idea of where they are going, what they are doing, and when then visit different areas of the trial arena. 

Step 2: Get the trials ready! Each night I have a schedule of which toads will be tested and in what order. We randomize the order in which toads get tested just in case there is any effect of toads going at the same time each night, or in the same order. What does that mean? Well, instead of toads going in order 1,2,3,4,5, they may go 3,5,2,4,1, or 2,4,3,5,1, etc. etc. There are lots of ways to randomly select what order you will do things, and some great random number generators online. 

I have 10 toads per set of trials, and 2 treatments : 10 toads / 2 treatments = 5 toads per treatment. Just to refresh your memory, my treatments are 'food' for toads that get mealworms in their bowls, and 'control' for toads that get empty bowls during trials. How do I decide which toads get which treatments? You guessed it - it's randomized! 

Note: Even though toads are randomly assigned their treatment group, they keep the same treatment group for the entire experiment. 

Now I look at the schedule, and decide if the next toad is in the food treatment. If so, I put a mealworm in each bowl in the arena. What's a mealworm?

Mealworms are the immature form of a darkling beetle, Tenebrio molitor. They are often used to feed reptiles, amphibians, birds and even fish that are kept in captive situations. We could also feed the cane toads crickets, but those are a little harder to get in Panama, and they have a tendency to escape out of the bowls! :)

Step 3: I press 'record' on the DVR box, and put the toad into the arena. Every toad gets moved in his own little flower pot, and is placed in the same spot to start:

Step 3: I wait for 60 minutes. During this time, the toads are (hopefully) exploring the arena and finding the food in the bowls. The toads that are in the control group will not find any food :(, so I'm not really sure what they do, but we'll find out when we.....

Step 4: Watch the video! Once the trial is done, I put the toad back in his happy home (or holding tank). If the toad was a control toad, then he gets a mealworm since he didn't have a chance to find any during the trial. I can download the video onto my computer and start to analyze it while I run the next trial. 

And voila! This is how it goes every night for 14 nights in a row. Tonight is night 12, so I am almost done with this group. When we're all finished, we'll feed them a nice big meal and send them on their way back to their original homes, like nothing ever happened!

Next time, I'll continue the saga and show you exactly how I analyze the videos. Stay tuned! :)

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