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Dear friends, While preparing for a wetland field trip, I noticed these beautiful yet perplexing structures on a small willow branch. They looked like small, grey-brown pinecones. Why were there pinecones on a willow? I snapped a photo and noted their location. This would be a fun mystery to share with children! With the help of Google Lens, followed by a visit to a webpage by Joe Boggs of The Ohio State University, I learned that these were willow pinecone galls. In the spring, willow pinecone gall midges (Rabdophaga strobiloide) lay eggs near the tips of willow branches. The eggs develop into a larvae, who inch up to the developing buds at the branch tips. There, they secrete chemicals that cause the bud to stop elongating. Layers of overlapping leaves form a protective cone-like structure around each larva. Throughout the summer, the growing larvae feast on sugars made by the willow. After wintering in the gall, they pupate and metamorphose into midges (tiny flies) the following spring. Some scientists consider these flies to be a keystone species because their larvae provide food for myriad birds and host many species of parasitic wasps. Additionally, at least 31 other insect species lay their eggs on and around their galls. I hope to make galls and their creators part of many more field trips. (Note the bee visiting these old galls from last season or before. Photo by Carolyn Combs.)
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