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Natural Aphid Predators: Lacewing Larvae

by Genealle Visagorskis — last modified Nov 14, 2011 03:03 PM

NCAP volunteer Genealle Visagorskis reflects on the symbiotic relationship between gardeners and lacewing larvae.

Lacewing Eating Aphids
Lacewing Larvae Eating Aphid Nymphs: Photo by USDA

One of my favorite methods for combating pests in my own backyard is cultivating an environment that supports and encourages natural predators.  Most people have heard of or used ladybeetles or preying mantises, however one of my favorites  (and just as cool) is the lacewing. The common species is the green lacewing or Chrysoperla rufilabris.

Lacewings belong to the family Chrysopidae and are sometimes referred to as Golden Eyes.  Find an adult and look into its eyes and you can see how they got their name.  One entomologist friend described it like looking into another universe. 

There are around 1600 species of lacewings and they go through complete metamorphosis.  The adult female lays her eggs in groups.  These hatch out into hungry larvae.  The larvae go through 3 stages of development over a couple of weeks, and then spin a spherical cocoon.  After about 5 days the adults emerge.

Lacewing Eggs
Lacewing Eggs: Photo by Challiyan

I love lacewings because they are interesting in almost every stage of development, starting with their eggs.  When I first learned what the egg sacs looked like, I began to see them everywhere.  I had never seen anything like it before.  They are laid on thin threads of mucus, which harden as it contacts air.  There can be a single egg per strand or a group bunched together.  This gives the eggs the appearance of floating and protects them from predatory insects such as ants.  I’ve seen them on the underside of leaves (such as clover) or along the inside of a wooden trellis.

Lacewing Eating Cabbage Worm
Lacewing Larvae Eating a Caterpillar: Photo by USDA

The larvae are called “aphid lions” which seems appropriate for both their brown coloring and voracious appetite.  They can be identified by their prominent pincher-like mouthparts, which resemble a tiny alligator.  Along with aphids they prey on many soft-bodied pests such as mites, thrips, mealybugs, immature whiteflies, and small caterpillars.  It’s said that one hungry lacewing ‘larva lion’ can consume over 300-400 aphids before pupating.

Lacewing Adult
Adult lacewing: Photo by Bruce Marlin

Adult lacewings are mainly nocturnal and can be seen at night, often around front-porch lights.  Though their role in pest reduction is minimal, but they are general pollinators, adding to the overall benefit of this interesting and unique insect.

As an environmentally conscious gardener (and frugal one at that) I derive great pleasure from knowing what insects look like at different stages of development.  It is possible to buy lacewing larvae in a bottle (and they are fun to watch as they crawl around) however better still is to recognize them in your own yard.  I now notice the egg sacs when I’m weeding or pruning and take care not to disturb them. Recently I was watering a heuchera in a container when 3 or 4 adult lacewings crawled out.  I gently finished watering and let them be.  Through insect knowledge and conservation it’s possible (and fun) to practice your own form of predator protection and natural pest control right in your own backyard.