We’ve been working on a few projects during the past couple weeks. One of these projects focuses on the fire ants themselves. We want to know if fire ant behavior differs across their range. Meaning, do fire ants in areas where they have recently invaded behave differently than fire ants that have been in an area for many years? To investigate this, we have been testing fire ants at a variety of sites across the south.
We use two different kinds of experiments to test ant behavior. The first compares how quickly fire ants recruit to baits compared to native ants. This involves setting up a grid of baits (hot dogs and mealworms) that we check every ten minutes for two hours. In little time, the baits look like this:
We record the number of each species every time we check the baits. Chris and I are getting very good at estimating ant numbers!
One hypothesis is that fire ants are better at finding tasty food (a lizard, perhaps?) at sites where they have been for many years. I’ll have to do some number crunching to see if our data actually support this idea.
The second experiment considers fire ant behavior on the mounds themselves. To see how good fire ants are at defending their mound, we record their responses to a novel object. Okay, so we poke a skewer into their mound. But by recording things like how many ants exit the mound and the time it takes to do so, we obtain valuable data on how aggressive fire ants are when defending. Are fire ants similarly aggressive across their invasive range?
The boys have been graciously recording data for me when I poke mounds. Our undergrad Mark (who flew into Solon Dixon last week) has been a great assistant.
We also video record these trials so we can gather further data (hooray slow motion!). This also means we have some cool footage of ants. You can even see some ants trying to bite and sting the skewer! Check it out:
I’m also collecting fire ants from these mounds for molecular analysis.
Another of our major projects this trip has focused on lizard behavior. Stay tuned for more details!