common name: sand field cricket
scientific name: Gryllus firmus Scudder (Insecta: Orthoptera: Gryllidae)
The sand field cricket, Gryllus firmus Scudder, is the common chirping field cricket of lawns, pastures, and roadsides throughout Florida.
Sand field crickets occur throughout the southeastern United States. To the north and west the species is replaced by the fall field cricket (Gryllus pennsylvanicus). In areas of contact the two hybridize to a minor extent.
Figure 1. U.S. distribution of the common chirping field cricket, Gryllus firmus Scudder.
The sand field cricket and the southeastern or Texas field cricket often occur together and may be difficult to distinguish except by song. The easiest morphological means of telling the two apart is the color pattern on the forewings. For males, the number and spacing of the teeth in the stridulatory file is definitive.
Figure 2. Short-winged, adult male sand field cricket, Gryllus firmus (Scudder). Photograph by Paul M. Choate, University of Florida.
Figure 3. Short-winged, adult female sand field cricket, Gryllus firmus (Scudder). Photograph by Paul M. Choate, University of Florida.
Sand field crickets have the most variable life cycle known for field crickets. During much of the year females lay some eggs that hatch within a few weeks at room temperatures and other eggs that take a month or two to hatch under the same conditions. Furthermore, if potentially quick-hatching eggs are exposed to cool temperatures, some lose that potential. Nymphal development is also variable with some developing quickly and some much more slowly, even when exposed to the same conditions. The effect of all this is that a female's progeny may mature over a 10-month period, with slow developers maturing at the same time as some of the progeny of their faster-developing sibs. In spite of the variability, there are peaks of adults in late spring (mostly from over-wintering eggs) and in fall (mostly from fast-developing progeny of spring adults).
This species is characteristic of lawns, pastures, and roadsides, especially those that are well drained and sandy.
The calling song (689 Kb wav file) is a series of slow-pulsed chirps, with a chirp rate of about two per second. Most chirps have four pulses, with the initial one being much weaker than the rest (graphs).
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