by Carl Strang
This is the time of year when the singing insect season is nearly done, with only the last song dates to note for the few rugged species still singing. I have been writing my annual research summary, and one data set recently completed was my Fermilab field cricket count. In the warm months I take bike rides through Fermilab, a U.S. Department of Energy research site, on roughly a weekly basis. I count the number of singing crickets I hear. The resulting graph has a double wave shape.
Two species are represented here, the spring field cricket and the fall field cricket. Their songs are identical to the ear. The graph shows that spring field cricket counts increased rapidly from the first appearance on May 18 to a peak in mid-June, then rapidly fell. There never was a time when fewer than 50 crickets were counted in July, probably indicating overlap between the two species, with the last spring field crickets continuing into the last half of that month. Fall field cricket numbers built rapidly to a peak in the first half of September, and exceeded the maximum count for spring field crickets in the same area, before dropping rapidly in early October.