Note: These pictures were taken a few days before wildfires made it unsafe to visit Mt. Pisgah.
Green lacewings are one of the rare insects that are doubly blessed. They’re beloved as predators of aphids and other pests, and they’re nice to look at. Lucky for us, they’re fairly common in Oregon. They also have some fascinating and unique traits.
For starters, females lay eggs on the end of a hair-like stalk. The stalk helps protect them from predators, including, some sources say, each other. More on that in a minute, because as I was looking back through my photos to find a lacewing egg I’d seen in my yard, I found the picture above from Mount Pisgah. While trying to capture what I think is a grass veneer moth, I accidentally photographed a lacewing egg! It’s not in great focus, but that’s what they look like.
Anyway, the larvae that emerge from those eggs look like little six-legged pincer-mouthed alligators, and they are such voracious predators that they have their own name: aphid lions. Two research-based sources say the larvae can eat 200 aphids in a week. I’ve also seen 100, 400 and 600, and one ultra-suspicious source says they consume up to 1,000 pests per day. Suffice it to say, they’re big eaters, and they munch more than just aphids, so they’re often farmed and sold as a biological pest control. The larvae of some lacewing species also have a strange camouflage adaptation: They cover their backs with debris, including the emptied bodies of their prey.
After a few weeks of relentless gorging, it’s time for a nap, and the larvae spin a pillowy, round cocoon in which to metamorphose. After about a week, adults emerge with golden eyes and filigree wings. The lacewing’s scientific order, Neuroptera, means “net wing.”
Adults prefer to be out in the mornings or evenings or, in the case of the individual in the pictures above, in the dapple-shaded area of the Upper Plateau loop. Lacewings have kind of a built-in drum at the base of their wings to “tremulate,” or make sound to attract a mate. Both sexes do this, as a duet. There are many species of green lacewing, in fact, that are impossible to tell apart, except for their different mating songs. Entomologists call these “cryptic” species.
Most lacewings spend the winters as pupae in the Pacific Northwest, but some overwinter as adults. They don’t move very quickly, and are flimsy fliers, so if you spot one, you’ll probably see more than just a flash.
Stay curious!
Karen Richards
Sources:
For amazing pictures of eggs and emerging larvae click here. Accessed 9/16/20.
For another picture (from Oregon!) of lacewing larva with litter on its back, see Joshua Coleman’s 2016 Smithsonian Magazine photo here. Accessed 9/16/20.
“Obligatory Duetting Behaviour in the Chrysoperla Carnea-group of Cryptic Species,” Henry, Brooks, et al, accessed 9/16/20.
