Dec 31 2010
The gall of it all
The winter daycamp class reminded me today that amidst the cold winds, bare trees and quiet winter forest, there are insects living warm and snug inside their very unlikely twiggy homes. I’m talking about galls, deformed plant tissue brought on by an invasion of another organism. More often than not, these organisms are insects that act in a parasitic manner.
When I heard that the daycampers were heading out in the park to look for examples of insects overwintering, I mentioned the thimbleberry plants along the bike trail. Well, they came back with more than one type of gall and some of them actually had the larvae inside!
Simply put, these insects lay eggs in the stem in the spring when the plant is growing quickly; the egg hatches and the larva bore into the stem and starts eating the plant; the larval activity and chemicals injected into the plant stimulates the plant to produce more tissue forming a “tumor”; in the fall the larva creates an exit tunnel stopping before breaking the outer layer; the larva goes back to the center of the gall to over winter; in the spring it pupates and in late spring to early summer it emerges as an adult.
Check out these examples of galls that we found today!
Twig gall on thimbleberry
Wild rose galls
Over wintering larvae!
Happy Gall Hunting & Happy New Year too!
