Mystery Object

The mystery object is a

GALLmade by a

GOLDENROD GALL FLY.

Goldenrod is a common flowering weed. It has sweet-smelling, yellow flowers that bloom through the summer and fall. It is often found in open fields and along roads. Although many people blame goldenrod for their allergies, it is actually caused by ragweed, which blooms at the same time of year.

The goldenrod gall fly is a parasite that lives its entire life around the goldenrod plant. A parasite is an organism that grows, feeds, and is sheltered by another organism, without providing any benefit to its host.

Adult gall flies do not fly well. They spend most of their time walking up and down the goldenrod stems. After mating, the female gall fly injects eggs into the goldenrod stem. Adults do not eat and only live about 2 weeks.

After about 10 days, the larva hatches from the egg and begins eating inside the stem. The larva’s saliva has a chemical that causes the plant to grow abnormally, creating a ball-shaped “gall.” The larva lives inside of the gall for a full year before becoming an adult.

When fall approaches, the larva digs an escape tunnel that it won’t use until spring. It stays inside the gall during the winter. In spring, the larva becomes a pupa (resting stage) before it becomes an adult. The adult leaves the gall to find a mate.

Goldenrod gall flies have several predators. Downy Woodpeckers, Carolina Chickadees, beetles, and wasps search out the galls, knowing there is a meal inside.