Finally, the weather has been more favorable for our six legged friends! On my most recent visit to Mount Pisgah, I saw bees, butterflies, flies, lacewings, a snakefly, beetles, an earwig, a caddis fly, and several true bugs, including this interesting shield bug: Aelia americana.
Pentatomidae family bugs are named for the five (penta) segments (tomos) on their antennae. Members of the group are also called shield bugs or stink bugs. That last title is because they can emit a smelly chemical when they’re threatened. The “shield” part of their common name has to do with their shape, and the triangular “scutellum” — there’s your vocabulary word for the day — or plate, on the back.
This bug is more plump than most in the family, and it feeds on grasses. The long grasses in Mount Pisgah’s meadows must be heavenly for them right now.
On their way to adulthood, these bugs go through five stages after they hatch from their tin-can-shaped eggs. Each stage is slightly larger than the one before and may have different color patterns. Only as adults do they earn their wings and have the ability to fly.
Because most bugs spend the winter as adults, and we’ve not had much warm weather yet, I assume this Aelia americana was nestled in the soil at the base of the grasses over the winter, and is emerging now to eat and look for a partner. I know its identity to the species because there’s only one species of the genus in North America.
There’s not much research on these bugs, but I found one paper on another member of the Aelia genus in Europe. In 1971 in Czechoslovakia, researchers found that in order to lay eggs, female Aelia rely on increasing amounts of sunlight. When they decreased the hours of light per day, the insects reverted to a state of diapause.
P.S. BugGuide.net had not yet recorded an Aelia americana in Oregon, so I was able to provide the first photo of one for their records. Insect watching is a treasure hunt!
Stay curious!
See more of Karen’s work here.
Sources:
Stink bugs of Oregon, which does not include this species, but is a fantastic reference: https://www.oregon.gov/oda/shared/Documents/Publications/IPPM/StinkBugGuide.pdf. Accessed 5/9/23.
Nice photos of a developing Aelia americana: https://bugguide.net/node/view/1256963. Accessed 5/9/23.
Diapause photoperiod study: https://www.jstor.org/stable/4214634. Accessed 5/9/23.
