Termite farmers fine-tune their weed control

Summary

The team added the termites to the dishes along with a bit of water to make sure the environment was hospitable. Finally, the dishes were covered up and placed in total darkness in an incubator that maintained a temperature that accurately emulated the conditions in a termite mound. "We observed what was going on in those dishes at regular time intervals and each time we took a peek, we took a photo," Raychoudhury says. The resulting timelapses gave us the first glimpse at the way termites handled weed infestation in their fungal gardens. Their actions were completely different from the simple, fixed behaviors scientists expected to see. Measured response The first experiment was designed to simulate the very onset of Pseudoxylaria infestation in the colony. After the team placed a small piece of the weed on one of the combs in each dish, the termites had a wide range of tactics to deal with these early-stage infections. The most frequently used strategy saw the termites take three steps: "First, they removed the weed—took it away from the comb," Raychoudhury says. After the weed was removed, the termites buried it in the soil away from the combs. In the next step, they scraped off some of the comb where the weed had been located. This allowed the termites to contain the infection in 94 percent of samples. "Then we said, ok, they can deal with early-stage infections—what about the scenarios where the infection gets through the initial stage and gets more severe?" Raychoudhury asked. To bump the difficulty level up, the team performed another experiment where the termites had two pieces of comb again, only this time one of them was fresh and the other one contained mostly weeds. "We learned that termites did not try to retrieve [the] severely infected combs; they probably could determine these were beyond saving," Raychoudhury claims. To deal with these heavily infected combs, termites, simply covered them with soil.