Sunday, October 23, 2011

True Katydid

Common true katydid- Click to enlarge
Early Europeans arriving in Eastern North America were frightened by the mysterious loud sound which pulsated through the forest with no apparent source.  During the summer we hear that again, a loud chorus of katydids high up in the trees. 

This is the time of year when we tend to see lots of katydids around the cabin at Bull Creek.  This particular katydid has distinctive oval wings with veins mimicking a leaf and legs like a leaf stem.  There are brown flat surfaces on top of its head and thorax.  When squeezed lightly it makes a distinctive raucous squawk which you can hear below.  It is a Common True Katydid,  Pterophylla camellifolia.

The males typically alternate chirping (stridulation as described in the last blog) at each other when they are 25 to 50 feet apart.  When they are close together the chirps get longer and more insistent, an aggressive sound.  They shout at each other like a couple of drunks until one leaves.  The females on the other hand are more demure, chirping only when handled.

These katydids spend their life in the tops of the trees where the females deposit their eggs under the bark.  The larvae feed on leaves high in the tree and most remain on the same tree for life.  They are essentially flightless and drop to the ground in an awkward flutter when disturbed.  On the ground they stumble to the nearest vertical surface and start climbing which explains why we find them on the side of our house.

The first frosts cause them to drop to the ground.  They all die off in a freezing winter, to be replaced by the hatching larvae next spring.

You can hear their call at musicofnature.org and more pictures are available at this site.



No comments:

Post a Comment