The sight of ants crawling across a blooming garden is common, often leading to the assumption that these insects are directly consuming the plant. The interaction between ants and flowers is far more complex than simple herbivory, involving a delicate balance of resource exchange and protection. Their frequent presence is generally not driven by a desire to eat the plant’s structure itself, but rather by a search for specific, highly concentrated food sources.
Do Ants Consume Floral Structures?
For the vast majority of species, ants do not consume the physical structures of a flower, such as the petals, sepals, or buds. Most ants lack the specialized mandibles and digestive enzymes necessary to break down tough plant components like cellulose and lignin. The structural material that gives a flower its shape and rigidity is largely indigestible for these insects.
While they generally avoid eating the plant tissue, some ants may inadvertently cause damage with their powerful mandibles. They can chew on tender shoots or flower parts while foraging or clearing a path, but this is physical injury rather than consumption.
A notable exception is the group of fungus-gardening ants, such as the leaf-cutters, which harvest large quantities of plant material, including flowers. They do not eat the cuttings directly; instead, they use the vegetation as a substrate to cultivate a specific fungus within their nests, which they then consume for nourishment.
The Real Reason Ants Are Attracted to Flowers
The primary attraction that draws ants onto flowers is the presence of sweet, liquid resources. Floral nectar, a sugary secretion produced by the plant, is a highly desirable energy source for these active insects. Ants will often seek out this nectar, sometimes acting as “nectar robbers” by accessing the sugary liquid without contacting the reproductive parts of the flower, thus gaining a meal without aiding in pollination.
A significant reason for ant presence is their mutualistic relationship with sap-sucking pests like aphids and scale insects. These pests feed on the plant’s phloem and excrete a sugar-rich waste product called honeydew. Ants actively “farm” these insects, protecting them from predators in exchange for this sweet substance, which they consume readily. This activity concentrates ant traffic on stems, buds, and flowers where the pests congregate. Some ant species will also collect pollen as a protein-rich food source for their larvae.
Ecological Consequences of Ant Presence
The presence of ants on flowers has a mixed impact on the plant’s overall health and reproductive success. Ants that protect honeydew-producing pests can lead to severe infestations of aphids or mealybugs, which weaken the plant by sucking out its vital fluids. Their patrolling behavior can also interfere with more effective pollinators, such as bees and butterflies, potentially disrupting the plant’s reproductive cycle and lowering seed production.
Conversely, ants can provide a beneficial service by acting as guards, attacking and deterring larger, destructive herbivores. While generally considered poor pollinators due to their small size and frequent self-grooming, some species of ants do facilitate pollination, particularly for plants with low-growing, inconspicuous flowers. A distinct benefit to flowering plants is myrmecochory, or seed dispersal by ants. Certain plants produce seeds with a fatty attachment called an elaiosome, which ants collect and carry back to their nests, dispersing the seed to a new, often nutrient-rich location.