Assassins in the Garden

By Caroline Carrico

Within our urban and suburban gardens, lying in wait on stems, leaves and flowers, lurk green and brownish predators with hooked, beaklike projections and sticky front legs. They ambush their prey, impaling them to inject an immobilizing venom that also dissolves their internal tissues. The assassins finish off their victims by sucking out their body contents.

At half an inch long, it can be easy to miss leafhopper assassin bugs (Zelus renardii) and their predation drama in the garden. Zelus renardii are general predators, meaning they will eat any insect they capture – from common garden pests like aphids and caterpillars to beneficial insects such as bees and lady beetles. They are quick movers when disturbed, but they don’t fly well, preferring to stay still and ambush their prey. Leafhopper assassin bugs secrete sticky material from their legs that allows them to adhere to plants and ensnare their food.

Zelus renardii are true bugs that belong to the insect suborder Heteroptera. All true bugs have specialized mouth parts called proboscises that allow them to suck juices from plants, other insects, or animals. The front-half of their wings are hardened while the back-half are membranous, which can make it appear that they only have half a wing. These insects also undergo an incomplete metamorphosis. They hatch from eggs as nymphs, which look like a miniature version of the adult form without the wings. Leaf hopper assassins go through five instar, or immature, stages between molts. They emerge from their final molt with their wings.

So, what should you do if you find these assassins on your plants?

Nothing.

Zelus renardii will only bite humans – albeit painfully – if they are provoked. Don’t try to pick one up. While they will eat beneficial insects, their net impact on insect pests makes them effective garden predators that provide balance to our gardens. Enjoy watching the hunt and know that you’re providing a healthy and sustainable habitat for our invertebrate neighbors.