Gryllus pennsylvanicus

Burmeister, 1838

Fall Field Cricket

Gryllus pennsylvanicus, commonly known as the fall , is a widespread North distinguished by its autumn breeding season and distinctive chirping. are -sized crickets, 15–25 mm in length, with dark black to dark coloration and occasionally a slight reddish tint. The species is notable for its temperature-dependent chirping rate, which has been used as a biological thermometer. Males produce calling songs from burrow entrances to attract females, with older males typically preferred by females. The species has an with one per year, as in soil.

Gryllus pennsylvanicus by (c) Declan McCabe, some rights reserved (CC BY), uploaded by Declan McCabe. Used under a CC-BY license.

Gryllus pennsylvanicus callingsong by Kevinjudge. Used under a CC BY-SA 4.0 license.

Fall Field Cricket (Gryllus pennsylvanicus) - Kitchener, Ontario 2018-06-28 by Ryan Hodnett. Used under a CC BY-SA 4.0 license.

Pronunciation

How to pronounce Gryllus pennsylvanicus: /ˈɡrɪləs ˌpɛn.sɪlˈvænɪkəs/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from the closely related spring (Gryllus veletis) primarily by timing: G. pennsylvanicus breeds in late summer and autumn, while G. veletis breeds in spring. Morphologically, G. pennsylvanicus has longer relative to body size in some , though this trait is variable. The two were historically confused and can only be reliably separated by seasonal activity patterns. Within its range, distinguished from other Gryllus species by its autumn breeding season and associated calling period.

Images

Appearance

reach 15–25 mm in length. Coloration ranges from dark black to dark , with some specimens showing a slight reddish tint. The black are longer than the body span. The are longer than the and combined. The do not extend past the cerci. Males possess a multi-ridged structure called the on one and a hardened on the opposite forewing; rubbing these structures together produces the characteristic chirp.

Habitat

Inhabits fields, forest edges, and grassy disturbed areas. Burrows into soil, creating simple burrows used for shelter and as calling stations by males. Often found around human habitation, particularly in autumn when may enter buildings. Prefers loamy soils in contrast to the sandy soil preference of its Gryllus firmus.

Distribution

Widespread across much of North America from southern Ontario through the eastern and central United States into parts of northern Mexico. Absent from most of the southwestern United States including southern California. Forms extensive hybrid zones with Gryllus firmus in the eastern United States, particularly in Connecticut and Pennsylvania.

Seasonality

active primarily in late summer and autumn (August–November in northern ). Breeding season peaks in autumn, with male calling activity highest during this period. laid in autumn overwinter in soil and hatch the following spring (typically May). One per year (). Adults may enter homes in autumn seeking sites.

Diet

. Consumes seeds, material, and including other . Recorded feeding on smooth crabgrass (Digitaria ischaemum), lamb's quarters (Chenopodium album), English plantain (Plantago lanceolata), switchgrass (Panicum virgatum), common ragweed ( artemisiifolia), and chicory (Cichorium intybus). Serves as significant seed in agricultural and natural .

Life Cycle

with one per year. laid in soil by females using ; approximately 50 eggs per deposition event, with total lifetime exceeding 400 eggs per female. Eggs enter and overwinter, hatching in spring (typically May). develop through eight or more , feeding throughout spring and summer. emerge in late summer, with sexual maturity and breeding activity peaking in autumn. Adults may survive into winter but perish with hard frost; some individuals enter buildings to overwinter.

Behavior

Males call from burrow entrances or ground cracks, producing short chirps at approximately 2–3 per second, each consisting of 3–5 pulses. Calling rate varies with ambient temperature, following Dolbear's Law (approximately: temperature in °F = chirps per 15 seconds + 40). Males maintain spacing of approximately 7.7–10.3 m between calling stations. Males engage in aggressive interactions involving chirping, -snapping, and foreleg grappling; defeated males retreat and may require extended recovery periods. Females select mates based on calling song characteristics, with preference for older males and higher calling effort. Females hear male songs using on the forelegs. When disturbed, males escape into burrows or ground cracks.

Ecological Role

Significant seed affecting composition and agricultural weed seed banks. Serves as for diverse predators including birds, (particularly wasps such as Sphex spp.), and other . Acts as intermediate for parasitic nematodes including Physaloptera maxillaris. Contributes to through consumption of plant material and detritus.

Human Relevance

Occasional household in autumn, entering through door sweeps, foundation gaps, and around utility penetrations; chirping males may disturb sleep. Subject of extensive scientific research on , , and speciation. Used in Chinese -fighting traditions. Chirping rate used as informal biological thermometer. Model organism for studies of male age and reproductive success, immune function signaling, and hybrid zone dynamics.

Similar Taxa

Gryllus veletisSpring — morphologically nearly identical, distinguished by spring breeding season and earlier activity
Gryllus firmusSand — occupies sandy soils versus loamy soils, forms hybrid zone with G. pennsylvanicus in eastern North America; later maturation in parts of hybrid zone
Gryllus ovisopisSister forming well-supported clade with G. pennsylvanicus