On April 29, 2014, sixth graders from Trinity Valley School (Ms. Julie Frey) in Fort Worth, Texas came to the Fort Worth Nature Center to learn about horned lizards and the ants they eat, mostly Pogonomyrmex ants, commonly called harvester ants because they mostly eat seeds. As part of their time with me, we set up tuna and pecan sandies cookie baits and made observations. At the conclusion, the students collected the ants for identification. I also recorded some video of the ants.
Although we attempted to set this up as a controlled study, it was a good preliminary investigation. The students explored their areas — limestone ridge, woods, or open prairie — and tried alternative ways of placing and using the baits. They did a good job of investigating.
I set them up with a data sheet to record location, weather, type of bait (tuna, cookie, or both), time of first arrival to the bait (and what this was), time for first ant arrival, observations (numbers of ants; rate of foraging, interactions, etc.), and how many ants on the baits after 5 minutes. (I did not get the data sheets so I cannot share that part.)
I recommend this kind of exercise for teaching about science method, forming hypotheses, investigating insects and foraging. It is easy to do and can be done anywhere. You can develop all kinds of ideas and possible experiments from this kind of work — myrmecologists do so all the time.
Here is a summary of the ants the students collected and some short clips from the video.
METHODS for Identification:
The students collected the ants from the baits and put the ants and bait into jars. In the Formanowicz lab at the University of Texas-Arlington, I separated the ants from the baits, rinsed them and placed them in 95% ethanol. They were identified to species using various on-line and published identification keys.
The lab bench: using a Nikon dissecting microscope with 40X magnification.
Sorting the ants from the baits
Some photos of the ants: Photos were taken using a dissecting microscope at 40X with a cell phone.
Camponotus americanus: This is a carpenter ant that nests in wood and is mostly found in woodland though they may wander into prairie. These ants are large, 1.5 cm.
Crematogaster sp.: Crematogaster is called an acrobatic ant because their gaster (part of the abdomen) is attached such that the ants can carry it above their heads — in a rather acrobatic posture.
Dorymyrmex flavus: Ants in the genus Dorymyrmex are easily recognized by a cone shaped structure on the their dorsal surface (just before the gaster). Their common name is cone or pyramid ants. The cones differ in size and shape. These differences are used to identify species.
Solenopsis invicta: This is the invasive, red imported fire ant. Note the antennae have a two-part club at the end and altogether there are 10 segments on each antennae. These features are diagnostic for the genus.
Video clip #1: “Bug and Ants”
This clip shows many Forelius ants on a tuna bait. An insect, perhaps a bug, lands on the bait and interacts with these ants, then leaves. It looks like the ants may be performing a cleaning service which has been suggested for Forelius ants in some situations.
Video clip #2: “Crematogaster Waggle”
This clip shows many Forelius ants on tuna bait. A Crematogaster forager is in the lower right hand side. As this forager leaves the bait, she waggles her gaster indicating that she is dispensing a pheromone.
Here are the two short clips from tuna baits that the Trinity Valley School of Fort Worth, Texas set out at the Fort Worth Nature Center.