Do Bush Crickets Eat Aphids?

In Great Britain, they’re bush crickets. In the United States, they’re katydids. In your garden, however, these members of the Tettigoniidae insect family are responsible for the serenade, or stridulation, that may keep you awake on a summer’s night. During courtship, male katydids "sing" to prospective mates through a special front-wing appendage. The complex wings also disguise the bugs as they feed on a varied menu that occasionally includes aphids.

When it comes to camouflage, bush crickets, or katydids, give chameleons a run for their money. Although coloration varies among katydid species, it always matches whatever plants they call home. Many species perfect their environmental mimicry with leaf-shaped bodies and leaf-veined wings. Some have markings indistinguishable from fungal spots or insect damage. Others boast bark lichen’s green-and-brown coloring, or double for twigs or sticks. Blending into the background serves two purposes: It conceals the insects from predators and lets them bushwhack their prey. They're dressed to survive and to kill.

An aphid infestation is equivalent to death by 1,000 cuts for prized garden plants. An aphid never works alone; each tiny, long-legged insect feeds in ever-expanding colonies. Born pregnant, female aphids give birth to live young as they consume a plant's tender, succulent growth. In mild-winter climates, they may reproduce all year. Where winters are cold, some aphid species adapt by laying eggs on perennial plants in fall, giving their spring-hatching young an immediate food supply. Aphids pierce and suck the sap from leaf and stem tissue with their hypodermic needlelike mouths. Large populations stunt and yellow new growth, and they cover plants in gooey waste called honeydew.

Unlike aphids, katydids chew with their mouth parts. Most katydid species prefer to bite and chew stationary meals, such as foliage, seeds and dead insects. They tackle aphids because those insects are nearly immobile once they've have attached to a plant. The exceptions are the 45 species of strictly predatory katdids native to France, the Middle East and eastern and southern Africa. Those carnivores have muscular, spiny legs for pouncing on and impaling their prey and razorlike jaws for shredding it. Only one predatory katydid species, the matriarchal katydid, has been seen in the United States. In 1970, the first matriarchal katydid, 2 1/2 inches long and native to Europe, was collected as a specimen in Michigan.

As adept as katydids are in the art of disguise, often they succumb to predators. Spiders, praying mantises, beetles, toads, snakes, bats and birds feast on katydid adults and nymphs. Parasitic wasps deposit their eggs in katydid eggs, where the wasp larvae devour the katydid larvae. Great black and golden digger wasps paralyze katydids before transporting them to underground chambers to feed their young. Repeated insecticide applications won't stop katydids from munching on plants, but katydid predators usually keep the insect's population under control.