by Carl Strang
Of the many species of singing insects that have shifted their range boundaries significantly northward in the last half-century, the one that is continuing to move most rapidly is the jumping bush cricket.
In recent years I have been tracing the northernmost locations where I am hearing the distinctive songs of this cricket in northeast Illinois.
The line marking the front of this expansion is diagonal, southwest to northeast, an orientation that seems to point back toward Indiana as the source of this spread. In the central part of the line I found no indication of an advance from 2014 to 2015, but elsewhere there was a shift of about half a mile. If at some point the movement stalls out, I would expect the west end of the line to catch up with the east end and even up latitudinally, unless there is a Lake Michigan climatic influence.