Ferocious in Their Youth: Beneficial Insects in the Larval Stage

If you are seeing scary looking little insects in your garden, chances are high that you're seeing the younger larval stage of insects that are strong indicators of a healthy environment. Beloved beneficial insects like lady beetles and lacewings have a much more dangerous-looking early physical form (like the lacewing larva pictured above being mischievous next to a Monarch butterfly egg). They look exactly like the predators they are. 

Both types of insect feed on aphids in the larval stage, earning lacewing larvae the nickname Aphid Lions. Aphids feed on the sap of plants and can weaken them if they become too numerous. There is a whole ecosystem surrounding aphids in the garden. Along with being the primary prey for lady beetle and lacewing larvae, ants often farm them for their excretions, akin to human dairy farmers with cows. The ants protect their herd of aphids, often driving off lady beetles that attempt to eat them. 

As adults, lacewings are often quite pretty (see above). Like lady beetles, they tend to lay eggs near populations of aphids, giving their young ready access to their food source when they hatch.

Lady beetle nymphs are also very different from their adult forms, with a spiky look and orange that screams "I'm toxic and I taste terrible!" to potential predators. Over the course of their lifetime, lady beetles can eat over 5,000 aphids! And they are particularly ravenous during their larval stage.

In our garden, we have seen a number of different lady beetle species, but are very happy to welcome those like the two-spotted lady beetle (see below) that had been rare until recent times in New York City. By bringing native plants into your garden, they will attract aphids that have generally co-evolved with the plants (except introduced aphid species like the Oleander aphid), but they in turn attract lady beetles and others that feed on them.

Another predator of aphids is Syrphid fly larvae. These larvae are impressively large. I watched ants that had been farming an aphid colony on a Joe Pye plant appear dismayed as the Syrphid fly larvae hoovered up their herd (see below), but didn't actually attack them like they tend to do with lady beetles. Within a day or two, all of the aphids on the plant were gone.

Now that it's summer and planting season is mostly behind us, it's a great time to be out in the garden observing the many beneficial insects in their various forms.

-Andrew