Ants are highly social insects that form complex colonies, and their foraging habits are a reflection of the nutritional demands of their society. The answer to whether ants consume other insects is yes; arthropods form a fundamental part of the diet for the vast majority of species. While ants are often observed moving across sidewalks or into pantries, their primary food source in the wild is frequently other invertebrates. This predatory and scavenging behavior provides the specific nutrients necessary to sustain the growth and reproductive capacity of the colony. The methods they use to acquire this food, and the degree to which they specialize, are diverse across the ant family tree.
Insects as a Primary Protein Source
The consumption of other insects is driven by a biological necessity for protein, which is not evenly distributed across the ant colony’s population. Adult worker ants primarily rely on carbohydrates, such as sugars from nectar or honeydew, to fuel high-energy activities like foraging and nest maintenance. These sugars provide the quick energy needed for the rapid metabolism of a small, active insect.
Protein supplies the essential amino acids required for growth and reproduction, making it indispensable for the colony’s developing members. The queen needs a steady supply of protein to support the continuous production of eggs, which represent the future workforce of the colony. The larvae, which are the only life stage in the colony that grows substantially, require the bulk of the protein intake to develop into adult ants.
Worker ants retrieve insect prey and process it, often by tearing it apart, before feeding the protein to the larvae and the queen. This protein is frequently converted into a liquid or semi-liquid form, as adult ants are generally unable to ingest solid food particles due to the structure of their mouthparts. The colony’s health and ability to grow depend directly on the consistent delivery of these protein resources, often sourced from other arthropods.
Methods of Acquisition
Ants employ two main strategies to obtain protein from insects: active predation and scavenging. Predation involves the hunting and capture of live prey, which can range from small springtails to much larger insects and spiders. This active hunting can be carried out by a single ant (solitary hunting) or through coordinated group attacks.
Many predatory species utilize a sting and venom to quickly immobilize their victims, targeting vulnerable areas like the ventral nerve cord. For instance, weaver ants (Oecophylla species) use coordinated group attacks, physically overwhelming larger prey items with sheer numbers. Army ants are famous for their massive, coordinated raids that function like a moving swarm, allowing them to subdue a wide variety of prey, including other social insects.
Scavenging involves finding and retrieving arthropod carrion, which is a less energetically costly method of acquisition. Many species are generalist feeders and readily take advantage of any dead organism they encounter, as it represents a protein source with no risk. Ants are highly efficient scavengers, often discovering and removing insect carcasses much faster than other detritivores. The size of the colony and the number of available workers directly influence the success of both predatory and scavenging efforts, particularly when dismantling or transporting a large food item.
Dietary Specialization Among Ant Species
While most ants are generalist omnivores that consume both insects and plant-based sugars, certain species have developed highly specialized diets. Harvester ants (Pogonomyrmex and Messor genera) are a notable example, focusing on granivory. They collect and store seeds and grains, which provide significant carbohydrates and fats, though the colony still needs protein for the brood.
Another distinct specialization is seen in the fungus-farming leafcutter ants (Atta and Acromyrmex). They dedicate their efforts to cultivating a specific fungus within their nests. They feed this fungus with pieces of leaves they cut and transport, and the colony then consumes the fungus as its main food source. This cultivated food provides the necessary nutrients for the entire colony, including the developing larvae.
Other ants engage in a mutualistic relationship called trophobiosis, particularly with aphids or scale insects. They ‘farm’ these insects for the sugary liquid they excrete, known as honeydew, which is rich in carbohydrates. While these species primarily consume this sweet exudate, they often supplement their diet with insects to ensure the queen and larvae receive the necessary protein for development. These varied strategies demonstrate that while insect consumption is widespread, the ecological role of ants is diverse and adaptable.