Scarab beetles in the sub-family Melolonthinae have two common, common names: May beetles and Junebugs (more later). There are over 600 species in North America, and all have frilly, fanning antennae, claws on their forelegs, and a large plate near the mouthparts… with no teeth. 

I found one May beetle (I’ll use that name because it’s May and they are beetles, not bugs) near the river in a mixed forest area of Mount Pisgah. I was happily surprised to find two more a few days later. I’d assumed that because a lot of these beetles are night-flying, the first one I saw was disoriented, out late from the night before. However, these are in the Dichelonyx genus, and they’re diurnal. 

May beetles live relatively long lives. The females dig–presumably with those built-in shovels on their front legs–fairly deep tunnels to lay their eggs. Dichelonyx grubs live a year underground eating roots before they emerge, newly winged, and live another year above ground as plant-eaters. Some other May beetles live two or even three years as larvae. 

The antennae, as most insect antennae, help the beetles sense the pheromones of other beetles. The three added prongs can fold up into a club-like shape, or fan out in a W for better detection. It’s like they have six long-handled noses!

A note on less common, common names: Europeans call beetles in this genus cockchafers (meaning large plant eaters), and have given them an array of whimsical nicknames like bummler, dumbledore, kittywitch and snartlegog. The U.S. has some playful but less Harry-Potter-like nicknames for various May beetles, including Little Bear and Monkey Beetle.

Lastly, this is slightly off topic, but I want to point out how accessible it is to add to our understanding of insects. For the past two summers, an 11-year-old boy in Japan studied the rhinoceros beetles (a type of scarab beetle) in his yard. His work on these usually night-time beetles was recently published in Ecology Today. There’s a link below. 

Stay curious!

Karen Richards

Sources:

A 1972 PhD thesis on the Dichelonyx genus: https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/z029p939x?locale=en. Accessed 5/20/21. 

Eleven-year old Ryo Shibata’s scarab beetle paper: https://esajournals.onlinelibrary.wiley.com/doi/epdf/10.1002/ecy.3366. Accessed 5/20/21.