What’s this bug ?
Location: Vancouver BC
January 29, 2012 7:21 pm
Hello. At Christmas time I bought a Douglas fir and found a cocoon on it, which I housed in a jar. The cocoon opened today with this not-a-butterfly bug. 4 wings. 2 larger ones and 2 sort of smaller fairy wings on top. About an inch long. I was hoping that you could please help me identify it. I don’t know where the trees were grown. I tried to take some photos but he won’t sit still. He likes honey. The cocoon is in the photo. Thank you a lot !
We are able to identify your insect as a Sawfly. Sawflies are nonstinging relatives of bees and wasps that often have larvae that are mistaken for caterpillars. Your individual most closely resembles the Cimbicid Sawflies (see BugGuide), possibly even the Elm Sawfly, though it looks more to us like a member of the genus Trichiosoma which we also found on BugGuide. The Cimbicid Sawflies are the largest North American Sawflies and they have clubbed antennae like your individual, but the information we have found does not list Douglas Fir as a host plant for the larvae. They feed on deciduous plants including elm, honeysuckle and cherry according to BugGuide. We did do a search for Sawflies that feed on Douglas Fir and we found an Oregon State webpage devoted to members of the genus Neodiprion, called the Douglas Fir Sawflies or Balsam Fir Sawflies, however the images posted to BugGuide do not resemble your individual. It is entirely possible that your Sawfly was feeding on another plant and somehow the cocoon was spun on the Douglas Fir. The Forestry Images Website indicates of the genus Cimbex (and so possibly also other members of the family Cimbicidae) that “The larvae spin tough, papery cocoons in the litter or just below the surface of the soil.” There is also a photo of the cocoon of a Cimbex Sawfly on the Forestry Images website that looks like your cocoon.
We are hoping that one of our readers will eventually be able to assist us in a more definitive identification.
Thank you so much for your help. I will do my best to keep him alive until the weather warms up. Too bad he doesn’t like roses or lettuce or anything else that’s lurking about in my fridge. He is quite an inquisitive little bug and checks out everything I give him.