Which pheromone attracts other termites to a food source?

The trail pheromone is the correct choice because it serves a vital function in the communication system of termites, specifically for foraging. When a termite discovers a food source, it leaves a chemical trail in its wake, comprised of these trail pheromones. Other termites, upon encountering this pheromone trail, are attracted to the source of food. This mechanism not only facilitates group foraging but also enhances the efficiency of locating and exploiting food resources within their environment.

While the other types of pheromones mentioned have their roles in termite behavior, they are not aimed at attracting others to food sources. The alarm pheromone alerts termites to danger, while sex pheromones are used in mating behaviors to attract partners. Aggregation pheromones can lead to group formation but are not specifically involved in directing termites to food. Thus, trail pheromones uniquely fulfill the critical role of guiding termites towards nutritional resources through an effective chemical communication process.