Marsh Conehead

by Carl Strang

My memory of the great marsh at Indiana Dunes State Park was of an extensive, grass dominated wetland. Perhaps it was once, but today it has succeeded to a shrub swamp.

A tower along one of the trails provides an overlook.

A shrub swamp is a valuable habitat, but for my purposes there are relatively few pockets of the grasses that would harbor the greatest diversity of singing insects.

Here is one such pocket along the north edge.

The drought that has dried the wetlands to a large degree no doubt also contributed to the low numbers of katydids and crickets I found in these grassy patches. One individual of interest, however, was a female conehead.

She instinctively trusted her camouflage, which allowed me to approach and catch her.

Not knowing which characteristics were essential and not wanting to kill her unnecessarily (though I did have the necessary permits), I took a series of photos.

The underside of the cone, its shape and its markings, are an important feature in conehead identification.

In many groups of katydids and crickets, ovipositor shape and size also is helpful in identifying females.

Here is the ovipositor of the female I caught.

Habitat also is helpful, in this case the marsh. Only two species of coneheads with unmarked cones are expected in marshes, the marsh conehead and the robust conehead. In this case the pinched, slightly elongate cone and the ovipositor shorter than the length of the femur point to marsh conehead. The only additional feature I should have checked was the insect’s length, a point to keep in mind for the future.

This finding, which seconds the identification of marsh coneheads that the Missouri students and I found at the nearby National Lakeshore, continues to open my eyes to the limitation of past records. Published accounts don’t show marsh coneheads this far north in Indiana. The same was true for slightly musical coneheads. Consequently I did not have either species on my hypothetical list for the region. Do these discoveries represent range extensions, or simply a mismatch between spotty past surveys of spottily distributed species? It may not be possible to say, but I have to be open to the possibility that my hypothetical list likewise may be incomplete for other groups of singing insects.

1 Comment

  1. September 4, 2012 at 5:55 am

    […] The northern mole cricket was one, but I still have not found them anywhere but Houghton Lake. The marsh conehead was another. We thought we also found slender coneheads at Indiana Dunes National Lakeshore, but […]

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