More About Ants
Eating Habits
Ants are known for their diverse food preferences. While some species feed on a wide variety of food items, others have a more limited range of foods they prefer. Food preferences can also change significantly during the course of a season, especially for outdoor species or depending on the specific needs of the colony. For example, during periods of high egg production, foraging ants may need to bring back proteins for the queen or queens. At other times, foragers may prefer to gather sugars or greases for their own energy needs or to promote larval growth. These changing feeding preferences make it difficult to predict what type of insecticide bait base (protein, grease, sugar or grain) any particular ant species will prefer and respond to under specific field conditions that a pest management professional (PMP) faces. It’s also why the response to baits can switch suddenly and over the course of a foraging season.
Ant larvae have different feeding requirements depending on their age and species. The youngest larvae must be fed on liquids, while some species feed small food particles to all larva instars that they are able to ingest. Foraging ants bring food or water back to the colony and pass it to other nest-tending workers by a mouth-to-mouth process called trophallaxis. Nest-tending workers then pass the food to larvae or the queens. Workers may stimulate larvae to regurgitate liquid food for use within the colony. As a result, there is often a complex pattern of food transfer or flow within the colony, with the direction of this flow being basically toward the larvae and reproductives. Because of this food flow, ant baits that include a non-repellent and slow-acting CuAI ant can be passed along to other colony members, allowing complete colony kill.
Many ant species obtain energy-rich sugar by feeding on the sugary honeydew excreted by aphids, scale insects or other sucking insects from the order Homoptera on plants. Some ants tend and even defend these other insects as a food resource. Thus, controlling honeydew-producing insects on plants inside the home or around the foundation may be an important factor in decreasing the presence of such ants inside. Dead insects, earthworms and other organisms are frequently scavenged, while live insects may be preyed upon. Indoors, dead flies and gnats can be found on windowsills and in light fixtures, so these are good areas to place ant bait or to apply a residual insecticide spray or dust. Some ants, such as leaf-cutting ants, actually cut, strip and carry away plant leaf tissue. This leaf material is carried into the nest mound and used as a substrate to grow fungi, on which the ants feed. Other ants typically gather seeds as food.
To date, no universally effective ant bait has been developed due to the many pest species with variable food preferences and highly discriminating feeding behaviors. The feeding preferences of any particular colony infesting a premise will also vary depending on the season, the nature of the other food resources available and many other factors. Development of a truly universal ant bait is an unlikely prospect, but advances in bait formulation technology for ants have been made - and this is an active area of research for bait manufacturers and urban entomology researchers. Fortunately, there are now several non-repellent bait toxicants and residual sprays available that have the appropriate delayed toxicity properties that make them effective for controlling ant infestations.