Katydids

Katydids are cousins to crickets, grasshoppers, and mole crickets, and you might not want them in your garden or landscape.

There are over 250 different species of katydid in North America (over 2,000 species worldwide). The name ‘katydid’ refers to the sound made by males when they are trying to attract receptive females.

Katydid identification
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Katydids can be difficult to see. It’s not that they are small, because they aren’t. Mature katydids can range from 1/2” to nearly 5” in length! The difficulty lies in their resemblance to leaves and the fact that they are mostly nocturnal. During the day, they hide out in trees and shrubs, blending with the foliage. They tend to have a bright green, blade-like body, with large hind legs. They look a lot like flattened grasshoppers, but with extra long antennae (or ‘horns’). Very often, the only notice you will get that katydids are present is the damage they cause and a male’s strident chirp.

Katydid mimicking a leaf (Vishalsh521) CC BY 3.0

Katydid lifecycle

Katydids (Tettigoniidae) start out as oval-shaped eggs that are laid in rows, at the end of summer, in the soil and in host plant stem holes. These eggs often hatch out looking like tiny adult katydids with big heads and small wings. Nymphs of some species of katydid mimic spiders or leaf-footed bugs in their early stages of development to avoid being eaten. As they feed and grow, they shed their outer exoskeleton and go through several instars before reaching adult size. As summer nears its end, males start singing to attract females. Females use the volume and fluency of a male’s chirp to judge his fitness level. In order to ensure a healthy pregnancy for the female, male katydids provide their (temporary) mates with a ‘nuptial gift’ of sperm and highly nutritious food.

Some katydids adapt to exposure to red foliage by turning pink! (Richard Whitby) CC BY-SA 2.0

Katydid damage

Katydids bite and chew many different plant parts, including leaves, stems, seeds, bark, buds, flowers, roots… okay, pretty much every part of a plant is vulnerable to katydid feeding. The damage often looks like it was caused by caterpillars or grubs. Citrus, peaches, pears, blueberries, apricots, plums, and pomegranates are just a few katydid menu items.

Leaf damage by katydids (Scot Nelson) Public Domain

Katydid control
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These pests are super fast, and difficult to catch. I use a butterfly net to catch them, and then I feed them to my chickens, who are very happy to help reduce my garden’s pest populations. Commercial growers often use spinosad to control katydids. I have read that katydids can inflict a painful bite or pinch, but I never give them the opportunity. Apparently, in Uganda, people eat katydids.

Katydids as thermometers
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If you hear a katydid, you can estimate the ambient temperature using Dolbear’s law. According to Amos Dolbear’s 1897 calculations, you can count the number of cricket chirps that occur over a 15 second period and then add 40 to that number for a reasonable estimate of temperature. If you are using katydids for this experiment, it is suggested that you add 37, instead of 40.

If you hear katydids in the garden, go get your butterfly net and start hunting! These suckers can reproduce exponentially!