This insect that looks like popcorn is actually a voracious predator
Aug. 4—At first glance, you might mistake it for a small piece of popcorn crawling over a leaf or flower petal in your garden. But this pest is green lacewing larvae, a well-armed voracious predator that has perfected the art of natural camouflage.
And it's carrying the corpses of its kill.
If you are plagued by aphids, this is the bug for you — everything about the green lacewing has evolved to search out and destroy those tiny garden pests. One lacewing larva can devour 100 aphids in a week. And by many accounts, they are fierce and relentless hunters.
"They are really interesting and neat little things," according to Jim Dill, pest management specialist with University of Maine Cooperative Extension. "They can do quite a number on an aphid population."
An infestation of aphids feeding on plants in flower or vegetable gardens can damage crops. The aphids suck the sap out of the plant stems and that can weaken the plant's growth and cause leaves to turn yellow and drop off.
According to Dill, green lacewing larvae are born with ravenous appetites. So much so, the adult female lacewing lays her eggs in a way that protects other lacewing eggs. Each egg is laid on top of a slender stalk constructed by the female. These stalks are around an eighth of an inch tall and there could be one, or as many as 30 on a single leaf.
"When the larva hatches, it crawls down that stalk looking for food," Dill said. "They hatch hungry, so if there are any eggs on the leaf they would think, 'look, there's something for me to eat,' and they would nibble on their brothers or sisters."
The females often lay their eggs where there are aphids so that the larvae have a ready source of food when they hatch. Yellow-gray in color with brown markings and tufts of hair, the larvae are born with long jaws with pincer-like mandibles and look overall like tiny alligators.
Also known as aphid lions, the larva uses its mandibles to grab its prey and then inject it with a paralyzing venom before sucking all the liquid out of it. Once it's done feeding, the green lacewing larva will often toss the dried out aphid husk up and onto its back. From start to finish this whole process takes less than 90 seconds.
After a while, the pest can have so many dried out aphid corpses piled on and stuck to its body it resembles a moving piece of fluff or popcorn.
"All of a sudden you see this little pile of whatever crawling around among the aphids," Dill said. "It's a wolf in sheep's clothing that could fool the aphids and be protection from other predators."
The larvae are no threat to humans, Dill said. You can actually buy green lacewings commercially in any of its life stages to use as natural pest controls.
The adult green lacewing feeds on plant nectar. They don't bite, but Dill said they do possess a notable chemical defense. The adult has glands that can emit a substance that contains the compound skatole — the same thing that makes mammal feces stink.
"If you were to capture one they will give off a terrible smell," Dill said. "The best way I can describe it is, it smells like bad breath."
