How far North?

by Carl Strang

One of the projects in my singing insects study is tracing the boundaries of species ranges, and following how these are shifting in cases where they are expanding, usually northward. Two of the species I have been pursuing in recent days are the long-spurred meadow katydid and the Nebraska conehead. Several years ago I found a small population of long-spurred meadow katydids at south Blackwell Forest Preserve in DuPage County.

Some of the Blackwell katydids have this unusual black color added to the dorsal surface of the abdomen.

Some of the Blackwell katydids have this unusual black color added to the dorsal surface of the abdomen.

This little population is the northernmost I have found in DuPage County, and a recent search found none farther north. The similar situation in Cook County is a long established population at the Brookfield Zoo. My recent investigation there found one long-spurred meadow katydid a little more than two miles farther north, but none beyond that.

My current Chicago region map for the long-spurred meadow katydid. Black dots indicate counties where I have found the species to date. Red stars indicate the two northernmost known locations, at Blackwell Forest Preserve and along the Des Plaines River.

My current Chicago region map for the long-spurred meadow katydid. Black dots indicate counties where I have found the species to date. Red stars indicate the two northernmost known locations, at Blackwell Forest Preserve and along the Des Plaines River.

This year I found a new north for Nebraska coneheads, at the Carl R. Hansen Woods in northern Cook County.

Nebraska conehead

Nebraska conehead

A drive along rural roads north of that preserve failed to turn up an additional location.

The northern site for this study is indicated by the red star. The open circle in McHenry County represents an old report that I have not been able to confirm in the present day.

The northern site for this study is indicated by the red star. The open circle in McHenry County represents an old report that I have not been able to confirm in the present day.

These are two species for which, so far, there are no indications of expanding ranges in the Chicago region.

 

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