Lawns Are Dumb: Exomala orientalis (Oriental Beetle)

After work today I went out in the yard to see what bugs I might find. Here’s one which my Kaufman field guide (an actual book, with pictures and text and stuff) along with Google search leads me to identify as an “oriental beetle,” also known as the “Asiatic beetle.” This is different from a Japanese beetle. According to, the oriental beetle is an invasive species in the scarab beetle family that first appeared in the United States in the 1920s. Larvae live in the soil and eat the roots of grass and ornamentals, and can become pests on golf courses and such. (We always have lots of grubs living in our yard dirt so it’s interesting to see what they grow into.) The adults emerge in late June and July, so this is probably one that recently hatched. They are sometimes found on flowers — like this cosmos daisy.


(Just a phone photo, my camera batteries were dead.)

Did a little bit of research and according to the work of Henry Facundo, who got his PhD in Cornell’s International Integrated Pest Management program in 1997, when they’re ready to do the deed the females bury their faces in the dirt and the males first hold her to mate, then, as she digs into the soil (presumably to lay her eggs) the male not only continues holding onto her but also proceeds to grab and hold into any other males that come by to see her, sometimes for hours at a time. Also, “the mating sequence was highly stereotypic (stereotypy index, SI = 0.92),” which I only add because wow, there’s such a thing as a “sterotypy index??” Wonder how I might score.

“Based on these behavioral findings, synthetic pheromone traps were used to predict grub densities in a golf course in 1995 and 1996 at Bethpage State Park, Farmingdale, NY. There was a significant positive relationship between trap catches during the peak of the mating season and the grub densities ….” (Henry Tagalog Facundo, “The reproductive ecology of the oriental beetle, Exomala orientalis (Waterhouse) (Coleoptera:Scarabaeidae),” Ph. D. thesis, Cornell University, Aug., 1997)

As you can see, the pest management idea here is that if you attract and trap lots of male beetles during mating season with pheromones, you can reduce the number of grubs created. Facundo’s PhD advisor at Cornell was the famous entomologist Wendell Roelots, who in the 1960s pioneered research in insect chemical communication, “achieving major breakthroughs in the chemical identification, characterization, and biosynthesis of insect pheromones and the ways in which insects perceive and respond to pheromones. This work has important implications for basic and applied biological sciences and the worldwide importance of his work is reflected in numerous awards and honors.” (From his bio on Cornell’s website.) In 1989 he and a colleague published a letter to the editor of the New York Times describing the importance of pheromones to biological pest control and the need to reduce the “regulatory burden” created by classifying pheromones as pesticides.

Me, I don’t have much use for golf courses, at least the chemical- and water-intensive way they are now maintained, other than that they probably prevent the building of suburban houses, parking lots, etc., and that they get people outside walking around. (I’m sure there’s at least one nature essay out there by a golfer.) Also you can sled on them in the winter.

Still, wanting to have perfect lawn grass in a golf course or at your own house not only seems like a big waste of time but also evidence of totally wacky life priorities. In my opinion. Not to mention the enormous quantities of pesticides, herbicides, fertilizer, and fossil-fuel-powered maintenance equipment involved in keeping the grass in this unnatural state. My brother Ray told me about a neighbor who left threatening notes in his mailbox because Ray was the only one on their suburban street who didn’t hire someone with a truck to come out and poison their dandelions every year. (They had about a zillion of them. In blooming season you could pick out their lawn, covered in yellow dots, from blocks away, which helped because in that neighborhood every house looked exactly the same and I always drove past it when I came to visit.) He didn’t mow them all that often either. Fun for the kids though. You can’t make dandelion crowns or test your friends to see if they like butter or blow the puffball seed heads without them.

Lawns. I went down on the train to watch the ginormous climate change march in NYC last summer and took a lot of pictures of the signs people were carrying. (The march went on for hours so I took a LOT of photos.) This was one of my favorites (it’s a 2-sided sign).

First side.
Second side.

Go ahead, Exomala orientales grubs. Eat all the grass. Then when it’s gone we can plant a ton of interesting ground cover plants and the human kids can play on that.