Photo: Aphids and Acrobat Ants on Black Locust, Judy Gallagher
Judy Gallagher is an NVBA board member and a regular surveyor of local wildlife who also captures photos of what she sees, in particular the less common species.
When I'm out in nature, the one thing I can pretty much count on is seeing ants. This isn't surprising given that a study in 2022 estimated that there are more than 20 quadrillion ants in the world. It's also not surprising that, with that many ants in the world, there are numerous other organisms that have evolved to interact with ants. Organisms that are dependent on ants for at least part of their lifecycle are called myrmecophiles, from the Greek "myrmex" (ant) and "philos" (loving).
Acrobat Ants and Eastern Ant Cricket (the brown blob at the upper right), Judy Gallagher
The Eastern Ant Cricket is an obligate kleptoparasite living in nests of at least 11 different ant species. An obligate kleptoparasite is totally dependent on stealing food from its host, meaning that this cricket could not survive outside of the ants' nests. Unlike most other crickets, it lacks wings and hearing organs, and its eyesight is not well developed. It's about 1/4 inch long, small for a cricket, but perfectly sized to live alongside ants. When an Eastern Ant Cricket enters an ant colony that is new to it, it sneaks up on the ants and rubs its body against the ants to acquire the scent of the ants. This chemically camouflages the ant cricket, fooling the ants into accepting it as a member of the ant colony.
Summer Azure caterpillars being groomed by ants, Judy Gallagher
Caterpillars of Gossamer-winged Butterflies (family Lycaenidae) often are tended by ants. The caterpillars have special organs that secrete a sugary substance that attracts ants. The ants groom the caterpillars to get them to secrete the sugary liquid. The ants then eat the sugary treat and protect the caterpillars from predation. The Summer Azure is not very picky about its ant companion, but some Gossamer-winged Butterflies like the Edwards Hairstreak interact with one ant species, in this case the Allegheny Mound Ant. Allegheny Mound Ants carry Edwards Hairstreak larvae back to the ant nest, and the caterpillars pupate underground. When the butterfly hatches, it has to leave the ant nest quickly, as it is no longer chemically camouflaged.
Treehoppers often are tended by ants, and some tropical Gossamer-winged butterflies lay their eggs near aggregations of ant-tended Treehoppers, as the butterflies know that ants are nearby, and will provide protection for their caterpillars.
Black Locust Treehoppers (adults and nymphs) and Ferruginous Carpenter Ants, Judy Gallagher
As I just mentioned, many treehopper species have a symbiotic relationship with ants. The ants stroke the treehoppers to get them to produce amino acid and carbohydrate-rich excretions which the ants drink, and, in return, the ants protect the treehoppers from predators. Treehoppers are a food source for birds and larger insects and benefit from the protection that ants provide.
Aphids and Acrobat Ants on Black Locust, Judy Gallagher
Many aphid species also have an association with ants. Aphid honeydew (the sugary substance excreted by the aphids) is collected by ants. Ants return to their nests and regurgitate the honeydew for their nestmates. Aphids can produce an amazing amount of honeydew, in some cases more than their body weight in a day, and this can be the primary source of food for some ant species. But sometimes the protection afforded by the ants causes the aphid population to explode, and in that situation the ants sometimes eat some of the aphids.
American Winter Ants at Vetch extrafloral nectaries, Judy Gallagher
Ants also can also provide protection to plants. A number of plant families have structures called extra-floral nectaries. As the name implies, these are structures that provide nectar, but that aren't flowers. A plant that produces nectar from extra-floral nectaries will attract ants, and the ants will help protect the plant from being eaten by other insects. Many plants can control the amount of nectar produced, and will produce more nectar to attract ants when they need to gain more protection from being eaten by herbivores.
Harvester Ant with seed, Judy Gallagher
Ants spread seeds of spring wildflowers such as Bloodroot, Dutchman's Breeches and Trilliums. Typically, the seeds have an elaisome, or fleshy coating that the ants eat. The ants transport the seed to their nest, depositing the seed minus the elaisome there, effectively dispersing the plants' seeds. Plus, ants aerate the soil, also helpful to plants.
Ants are really useful. Aren't you glad there are so many ants?
View more of Judy’s Observations from Meadowood articles here.