It provides strength to the armor plate of the beetle, keenness to the lancet of the mosquito, endurance to the rasping fiddle and bow of the cricket and the katydid.
~Edwin Way Teale, on the properties of chitin
Late summer and early fall are a time of abundance of many types of invertebrates in our woods. Many are reaching their maximum size and activity levels in preparation for however they spend the winter (most as eggs or pupae).
Last week, I noticed a particularly large katydid on a shrub in the front yard. The songs of katydids reverberate through the treetops here most of the summer, but the onset of cooler weather has quieted them somewhat. They make their sounds by stridulation – rubbing one body part against another. In the case of katydids, they rub the base of the front edge of one forewing against a bumpy ridge at the base of the opposite wing.
Other katydids hear these sounds by means of oval-shaped tympana, or eardrums, located on each front leg.
There are several species of katydids in our area and I have not yet learned how to accurately identify most. I think this one may be one of the Angle-wing species, perhaps the Greater Angle-wing Katydid, Microcentrum rhombifolium, but I can’t swear by it. Looking from above, I can see why this group might be called Angle-wings.
And it is the wings that draw your attention to these beautiful insects once you are lucky enough to find them. The wings help make these katydids excellent leaf mimics, which comes in handy when you spend most of your time feeding on tree leaves.
The closer you look, the more amazing the detail becomes. While looking for caterpillars this time of year, I have been surprised on many occasions to suddenly come face to face with a pair of katydid eyes staring back at me when I grab a tree branch. This disguise can be quite effective, an important trait when you represent a large tasty meal to many other forest-dwellers from birds to mice to predatory insects and spiders. But, blending in isn’t always effective, especially when you take flight, or simply fall from your feeding perch.
This is especially true around houses, where katydids are often attracted to lights at night. And, unfortunately for them and many other night-flying species (and the unwary person exiting a doorway), a variety of spiders also seem to like the windows and doors of woodland houses as sites for their large sticky webs. One night last week, a large katydid was entangled in the web of an orb weaver spider just outside the kitchen door. Too bad for her that KatyDid what she did in this case.