A grasshopper that looks like a leaf

StoryImage( ‘/Images/Story//Auto-img-119264694725758.jpg’, ‘Photo by Norma Hedeen, edited by Dr. Robert A. Hedeen’, ‘A male katydid rests on the window sill.‘);

Editor’s note: Long-time outdoors columnist Dr. Robert A. Hedeen passed away Oct. 4. Prior to his passing, he had compiled a number of columns for publication. Those columns will appear in print until all have been published.

The other evening, I was sitting on my back porch and enjoying being serenaded by a choir of katydids. Their repertoire sounded like, “Katy did; she didn’t; she did.” These bugs obviously get their common name by the sound of the mating call they produce. More and more of the insects joined in the recital of this monotonous verse until I tired of it and retreated back indoors. Only male katydids “sing,” and the notes are supposed to attract a mate to perpetuate the species over the long winter ahead.

Katydids belong to the large insect order named the Orthoptera (meaning straight wing in Latin), which, in older textbooks of entomology and zoology, included the cockroaches, walking sticks, mantids, shorthorned grasshoppers, shieldback, grasshoppers and the longhorn grasshoppers. Katydids belong to the longhorn grasshopper group because of their long, sense organ-bearing antennae, or feelers.

These antennae may be two or three times the length of the body, and the sensory receptors allow the katydid to find its way around in the dark when most of them are active.

You can always tell a male from a female katydid because the male lacks the long, scimitar-like appendage the female has attached to the posterior end of her body. This is the ovipositor with which she deposits eggs along the edges of leaves and twigs and in a variety of other places.

Crickets and katydids create their sometimes irritating sounds by rubbing a scraper-like organ on one front wing against a file-like apparatus on the other front wing. The hearing organ or typannum is on the front legs of both katydids and crickets.

Katydids have no means of chemical or tactical defense against a variety of predators, except having evolved cunning and devious ways to hide. Few other animal groups have devised survival techniques as have the katydids. Some of them resemble leaves so closely that one must look quite sharply to determine if you are looking at a leaf or an insect. This is what is termed mimicry and camouflage in ecological terms.

About 4,000 species of katydids are found worldwide, and this vast number indicates how evolutionary successful they have been. The greatest number of species is found in the rainforests of the Amazon, where more than 2,000 different types have been described. They form an important part of the diet of other animals in this community, including birds, monkeys and bats.

Katydids go through what is termed incomplete metamorphosis (egg, nymph and adult) as opposed to an insect that undergoes complete metamorphosis (egg, larva, pupa and adult). Katydids lay their eggs in a variety of places, including the edges of leaves and twigs, in the soil, and in the stems of plants and the bark of trees. Nymphs are similar to the adults, only are smaller, lack fully-developed wings and are sexually immature. Generally, there are five nymphal stages before the adult stage is reached.

Listen to and enjoy the mating song of the katydid in the early fall, and be prepared for the love song of the cricket as winter approaches.

Dr. Robert Hedeen was a former resident of Maryland’s eastern shore and resided in the Chicago area from 1960 to 1971. He was a retired professor emeritus of biological sciences in the University of Maryland system. He had published more than 30 scientific papers, written numerous magazine articles, and was the author of two books about the natural history of the Chesapeake Bay.

from the Oct. 17-23, 2007, issue

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