Museum Encounter

by Carl Strang

One of my responsibilities is to curate the Forest Preserve District of DuPage County’s natural history collection. Recently I was cataloguing some drawers of insect specimens when I noticed two tree crickets that had been collected in Wheaton a couple of decades ago, but had not been identified. These proved to be a pair of Davis’s tree crickets, a species I have heard singing in several locations but never have seen, as they generally remain high up in the tree canopies.

In dorsal views these appear to be rather generic, as tree crickets go.

In dorsal views these appear to be rather generic, as tree crickets go.

However, under the magnifying glass the basal antenna segments prove them to be Davis’s. Each segment shows a single straight black line. It would be curved or hooked in the narrow-winged tree cricket, or there would be an additional spot if this were one of the meadow-dwelling species.

However, under the magnifying glass the basal antenna segments prove them to be Davis’s. Each segment shows a single straight black line. It would be curved or hooked in the narrow-winged tree cricket, or there would be an additional spot if this were one of the meadow-dwelling species.

This was a reminder of the value of museum collections. Though I seldom collect specimens in my singing insects survey, that is because it seldom is necessary. For the most part, insect songs are distinctive, and if anything are more so than their physical characteristics. Because the insects distinguish themselves by sound, selective pressure on visual features is relatively weak. Sibling species pairs and groups can be found in most major singing insect categories. For example, the Tibicen cicadas closely resemble one another, as do the coneheaded katydids, the ground crickets, the field crickets, many of the meadow katydids, the bush katydids and, as in the present example, many of the tree crickets.

That said, I take voucher specimens in the rare circumstances when songs don’t tell enough of the story, and preserve specimens that I inadvertently damage when handling them to confirm identifications.

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