This is the first article in a series I will be doing on beneficial bugs. Although there are a few well-known beneficial insects, there are so many more of which you may be unaware (and may even be trying to kill.)
First up: the green lacewings.
Green lacewings are amazingly beneficial insects in both their larval and their adult stages, as they eat many pest insects and one individual can consume an huge number in their lifetime. There are ~85 species in the United States and more abroad.
Females lay their eggs in small groups and at the end of very long, thin stalks attached to the underside of leaves. They do this because the larvae are prone to cannibalism, but they are less likely to reach siblings when laid in the manner.
Once lacewing larvae hatch they are voracious predators. They prefer soft-bodied prey like aphids, mites, thrips, mealybugs, and the eggs and larvae of other insects. Once they find their prey they will stab their hollow mouthparts (maxillae) into its body and inject a digestive secretion that rapidly dissolves the prey’s organs. Then they eat their prey by sucking their liquefied internal organs through their mouthparts like a smoothie through a straw.
There are some larvae known as debris-carrying lacewing larvae, which attach the empty integuments (after having their organs turned into smoothies) of their prey along with random debris to their backs as a means of camouflaging themselves from predators.
Lacewing larvae spin their cocoons for pupation and will pupate for one to three weeks on average, before emerging as adults. At the end of the summer season the last larvae will overwinter as prepupa and then proceed with pupation in the spring.
Adult lacewings are nocturnal, so they are less-commonly encountered. They are attracted to light, so you may find them outside your house if you leave lights on at night. The adults feed primarily on nectar, pollen, and honeydew but they do supplement this diet with aphids, mites, other small insects, and other arthropods.
You can attract these amazing helpers to your garden by planting companion plants that provide nectar and pollen for adults. They prefer cilantro, dill, sunflowers, buckwheat, oregano, cosmos, coreopsis, asters, sweet alyssum, verbena, daisies and many more. If you have good pollinator habitat, you will be taking steps to attract green lacewings, as they like many of the same native species that we would recommend for a pollinator garden.
So, if you see these dainty green insects flying at night, crawling around on your tomatoes, or if you see a small lump of debris that appears to be crawling across a leaf all by itself, you will know what it is!
Read more articles in the Spring 2024 CSWCD Newsletter.