Tall goldenrod stems meant loads of fun! Young Sarah and John would scan the stems looking for a ball gall and then scan the discovered gall for the smooth, round exit hole of the insect previously housed within. No exit hole meant the insect remained inside. A rough, chiseled edge on an exit hole (like this one) likely meant that a Downy Woodpecker hammered into the gall for a meal.
In fall, a gall fly larva creates an exit tunnel up to the outermost layer of the gall; and in spring, the adult emerges by pushing through that still intact outer layer. Other insects produce ball galls, but their larvae do not prepare exit tunnels. Because the Downy favors gall flies above the others, they’re known to abandon a gall if a few exploratory pecks do not reveal an exit tunnel. No joke.
Utilizing an exit tunnel to provide an efficient way to reach a favored food by requiring less time and energy? Knowing that the lack of an entrance tunnel indicates smaller, less desirable food? Amazing!
I praise you, Lord, for happy memories of young Sarah and John searching for goldenrod ball galls — and for how happy I feel even now when I find one!
