Aspen Twig-Gall Fly Eggs

"Galls are abnormal growths that may be found on nearly every part of quaking aspen trees, from the roots to the leaves. Reactions between the plant's hormones and chemical signals from certain insects are responsible for most tree galls, which can take on many different forms. Many galls on quaking aspen trees are caused by the poplar twiggall fly. The tiny flies overwinter in the galls as maggots, and leave the galls behind once they are finished with them. Although they are disfiguring, most galls are ultimately harmless."

I've have seen the galls before but never knew the origin so I had to find out. I sometimes wonder if my curiosity will ever wane...

"The important thing is not to stop questioning. Curiosity has its own reason for existing." -Albert Einstein