MIL-OSI USA: Gall watching is the new bird watching

Source: US Geological Survey

In a new article out recently in American Entomologist, USGS scientists and collaborators describe how you can get into the exciting hobby of “gall watching.” 

It all starts with an observation: maybe you see a weird, miscolored wart on stems of the oak tree in your backyard, or a fuzzy lump on the leaves of a maple tree on the sidewalk. You can draw, photograph, paint, or simply take notice of the gall. 

Photos: oak trees parasitized by a variety of gall wasps.

The next step is identifying the type of gall, maybe from a website like gallformers.com or through an app like iNaturalist. This might narrow your gall observation down to a few species of gall-forming wasps that lay their eggs in oak tree leaves.

How do you find out which species is it is? Knowing something about the biology of a gall can help. For example, galls formed by wasps typically contain wasp eggs or larva. You can determine what type of wasp laid those eggs by taking a leaf or stem containing galls, adding it to a jar or plastic tub, and bringing it home to see exactly what hatches. And don’t worry – these aren’t wasps that will sting or hurt you. 

Photos: Red cone galls on an oak tree, and a wasp emerging from a red cone gall in someone’s home. All photos from iNaturalist.

Ready to take on this new endeavor or want to learn more? 

MIL OSI USA News