Pileated Woodpecker Feeding Holes
There is no mistaking what bird is responsible for the large holes that a pileated woodpecker makes in an attempt to gain access to the carpenter ants living within a tree. No other bird in North America is capable of excavating holes of this size. Pileated woodpeckers tend to work vertically, and you often find one hole drilled above another. A look inside these holes reveals the galleries that the ants create in order to travel to all parts of their nest located within the dead center of the tree. (Carpenter ants, while omnivorous, do not consume or digest wood; they merely tunnel through it.) A tree’s inner core provides structural support, but is not essential for the tree’s survival. This eastern hemlock’s cambium layer, just inside the bark, is very much alive and the tree may continue to live long after its center becomes hollow.
Ant Mandibles
Ants go through complete metamorphosis, passing through four stages (egg, larva, pupa, adult). Like honeybees, there are queens, female workers and male drones in an ant colony. The female worker ants have a series of “jobs” that they perform in a certain order. A young worker spends the first few days of its life caring for the queen and young. After that she maintains the nest and eventually forages for food. Like most insects, ants lack grasping forelegs and compensate for this by using their mandibles as “hands.” When the nest is disturbed, workers rush to rescue the eggs, larvae (depicted in photograph) and pupae by clasping them in their mandibles and transporting them to safety. They also use their mandibles to carry food, construct nests, and for defense.
Bloodroot Seeds and Myrmecochory
Bloodroot seeds, as well as the seeds of as many as 5% of flowering plants, have a fatty white appendage called an elaiosome attached to them which ants are very fond of. This adaptation benefits both the ants as well as the plant. The ants collect the seeds and take them down into their tunnels where they feed the elaiosomes to their larvae. The actual seeds are discarded underground, often in with ant compost, where their chances of germinating are enhanced. The dispersal of seeds by ants is referred to as myrmecochory. As the photographs indicate, ants don’t always wait until the seeds have dropped out of the seed pod to collect them.Ant Farmers
Certain species of ants have what is called a mutualistic relationship with aphids – a win-win situation for both the ants and the aphids. The ants protect the aphids from predators. In return, the aphids secrete droplets of “honeydew” from their abdomen when stroked by the ants’ antennae, which the ants devour. The act of stroking the aphids is referred to as “milking” them; hence, the ants are referred to as “farmers.”
Ants Farming Aphids
Some species of ants “farm” aphids. Ants and aphids have a mutualistic relationship, in which each benefits from the presence of the other. The aphids feed off of the sap of plants, which is low in nutrients. They must therefore consume a lot of sap in order to get adequate nutrition. As a result, the aphids excrete large quantities of waste, called honeydew, which is high in sugar content. This is where the ants come in – they love honeydew, and have actually learned to “milk” aphids by stroking them with their antennae, which stimulates the aphids to release honeydew. In return for this delicacy, the ants protect the aphids from predators. Chemicals on the ants’ feet tranquilize and subdue the aphids, and even inhibit their wing development, keeping them close by as a ready source of food. Ants have also been observed tearing the wings from aphids before they can become airborne.
Naturally Curious with Mary Holland 
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