Termites are not ants. Yet, in also being eusocial, termites exhibit several behaviors that resemble ants, such as foraging for food via chemical trails. Termites and ants are also natural enemies, and several ant species are specialist predators of their distantly-related insect cousins. But how do the ants track their prey? A study recently published in the Proceedings of the Royal Society B reveals one sophisticated method: Exploiting the chemical trail laid by the termites.
Xiao-Lan Wen and colleagues conducted simple but effective field and lab experiments using the common predatory Ponerine ant Odontoponera transversa and three local termite species in southern Yunnan province in China. They found that the two primary trail pheromone components, DOE and DDE, were differentially abundant depending on the stage of foraging in the termites. In particular, DOE was more abundant at the onset of recruitment to a food source, while DDE became more abundant as more termites were recruited.
But what does this have to do with the ant predators? Well, Wen and colleagues also showed that O. transversa workers were more responsive to DDE, the pheromone component associated with a larger number of termites recruiting to a food source, strongly suggesting that the ants have evolved a chemical discrimination ability that increases the likelihood of the predators catching more prey. In other words, the ants have cracked the termite trail code!