QBL Goes to Busch Gardens

A few of us from the Quantitative Biology Lab (QBL) finally went to Busch Gardens last week on July 4th, because we had the day off from lab.  We rode all the major roller coaster, including the new one Verbolten, and did our very best not overheat.  The day resulted in some nice lab bonding, and a discussion of returning later this summer.  I concluded my day off by watching the fireworks and eating ice cream in Colonial Williamsburg with some other friends.

This past week, we’ve been attempting to add predation or competition terms to the zooplankton model.  The differential equations for the model include only linear terms, which really only gives us two options for the long term dynamics: unbounded growth or decay.  Neither of those options is very realistic or interesting. By adding non-linear terms in the form of predation or intra-specific competition, we hope to add another stable fixed point and see the population reach a steady-state.

We added a predator to the 2 stage class model, making the predation term a function of temperature, and we saw the population stabilize and show the oscillations you typically get with predator-prey interactions in addition to the cyclic behavior resulting from the temperature changes over the course of a year.   Everything was looking good, until we tried to add a predator to the condensed, 4 stage-class zooplankton model.  We could not get the model to match the data points, even after running error analysis several times.  We had been using a Holling type I response, so then we tried type II and III.  And well let’s just say the model didn’t get any better.  We were back to unbounded growth or decay.

So how do you put a bound on a population’s size? You limit the resource! Or in our case add intra-specific competition between the stage-classes.  That’s what we’ve been working on most recently.  We’ve only tried it out on the smaller models with just intra-specific competition and with competition and a predator. We’ve also made the competition a function of temperature, increasing it as temperature increases.  I hopeful this will work well for the zooplankton models, but we’ll have to try it out to see.

Also, my grant is for seven weeks of work, making this technically my last week, but I have decided to stay here for another two weeks to continue working on this project.

Oh,and I will be making cupcakes this weekend! I have a feeling they’re gonna be good 🙂