In order to make room for a few new perennials, I removed some sod from the lawn and expanded a garden bed. As I was taking up the sod, I noticed that there were a lot of small beetles flying around where I was working. They seemed to be coming from the area where I had removed the sod. I took a photo of one of these dudes, the better to identify them and learned that they are rose chafers (Macrodactylus subspinosus). Their classification looks like this:
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Class Insecta (Insects)
Order Coleoptera (Beetles)
Family Scarabaeidae (Scarab Beetles)
Subfamily Melolonthinae (May Beetles and June Bugs)
Genus Macrodactylus
Species subspinosus (Rose Chafer)
So they are a type of scarab beetle that are related to June bugs. The adults emerge in early summer. They are herbivores, and feed on a wide variety of flowers and leaves, so it’s not clear why they are named Rose Chafers. They live for up to 6 weeks, mating on food sources. Eggs are laid deep in soil, up to 6 inches, and hatch in one to three weeks. Larvae then feed on roots and overwinter deep in the soil. In early spring, the larvae pupate in the soil, just under the surface, and emerge as adults to begin the cycle again.
It was soon possible to see the rose chafers mating on their food source! Pictured below are rose chafers on a coneflower (echinacea purpurea alba). I think that I must have removed the sod just as the adult rose chafers were about to emerge and helped them on their way.
Willow House Chronicles 
I was wondering as I read your fine post if they do much damage and are they indigenous.? — barbara
Hi Barbara! These rose chafers are native, although there is another different insect in Europe that is also called a rose chafer. In sufficient numbers, Macrodactylus subspinosus can skeletonize leaves and damage flowers, but I haven’t found them to be a problem here. I have a ‘live and let live’ garden philosophy, so wouldn’t do anything about them anyway, but then, I don’t depend on my garden to make a living.
These guys, along with the Colorado potato beetle, are the bane of my gardens! They have killed off at least one shrub, and the other day I found they are back for another season, infesting all the little shurbs I planted last year. I sprayed, went out again a couple hours later to see it made no difference, so I sprayed again. Then I started picking them off and drowning them in a jar of soapy water. They are eating all the leaves on my hawthorns and are devouring the flowers on my ninebarks. They will next move on to the apple trees and grape vines and skeletonize their leaves.
The books all say “not usually a problem, unless infestations are severe.” They are severe in my yard. The plants literally writhe from all the bodies. And why? Because they like sandy soil – and that’s what we have here in the Adirondacks!
Grrrrr!
Awesome photo.
Ellen, that must be terrible. I have sandy soil too, which no doubt is why I have rose chafers, but nothing like the infestation you describe. Good Luck with your garden.
Hi Stamperdad. Thanks, nice to hear from you!
[…] at Willow House Chronicles, Barefootheart recently discovered a population of Rose Chafers, Macrodactylus subspinosus, which were released from the soil as she was taking up sod to expand her garden. Most likely they […]
[…] I was digging up the sod and getting to know the rose chafers, I also found white grubs. Lots of them, just under the roots of the sod. I don’t like to be […]
chafers are a problem here in Brighton Ontario and yes soil is sandy. How do I get rid of them and do they have any natural enemies?
How do I get rid of them they are everywhere
I never worry about them. They aren’t around for long. In a few weeks they will all be gone.