Odontothermes obese – one of the types of termites on which fungi grow, called termitomycetes, in their mounds. Workers collect fallen leaves, wood and grass and place them in underground mushroom gardens called honeycombs. There, the fungi break down tough plant fibers, making them available to termites in a complex form of symbiotic farming.
However, like any other farmer, termites face a problem: weeds. “There have been a lot of studies suggesting that termites must have some sort of fixed response—that they always do the same thing when they detect a weed infestation,” says Rithoban Raichoudry, professor of biological sciences at the Indian Institute of Science Education, “but that’s not the case.” In a new Science study, Raychowdhury's team found that termites have quite advanced, remarkably human-like gardening techniques.
Go blind
At first glance, termites don't seem to be particularly good gardeners. They are essentially blind, which is not surprising given that they spend most of their lives in complete darkness, working in the endless corridors of their mounds. But termites compensate for the lack of vision with other senses. “They can sense their environment based on their developed sense of smell and touch, and I think that's what they use to identify weeds in their gardens,” says Raychowdhury. To find out how termites react when they detect a weed infestation, his team collected several Odontothermes obese and challenged them with various gardening tasks.
The experimental setup was quite simple. The team placed some autoclaved soil obtained from termite mounds into glass Petri dishes. With this in mind, Raychowdhury and his colleagues placed two mushroom combs in each cup. The first piece served as a control and was a fresh, uninfected comb with Termitomycetes. “Besides control, it also provided the termites with food because they find it very difficult to survive outside their mounds,” explains Raychowdhury. The second piece was deliberately contaminated Pseudocylariaa filamentous fungal weed that often invades Termitomycetes habitats in termite colonies.
