Orthoptera of North Carolina
Scientific Name: Common Name:
Family (Alpha):
« »
View Gryllidae Members: NC Records

Gryllus firmus Scudder, 1902 - Sand Field Cricket


Taxonomy
Family: Gryllidae Subfamily: Gryllinae Tribe: GrylliniSynonym: Acheta firma, Gryllus assimilis firmus
Comments: One of eighteen species in this genus that occur in North America north of Mexico (Walker, 2017), six of which have been recorded in North Carolina.
Species Status: Specimens from North Carolina were mentioned by Scudder (1902) in his description of this species, but it is not clear whether they represented the type specimens. Alexander (1957) identified the specimens from Pungo Bluff as lectotypes and OSF recognized North Carolina specimens as syntypes.
Identification
Field Guide Descriptions: Capinera et al. (2004; not illustrated); Himmelman (2009)Online Photographs: SINA; BugGuide, Google ImagesTechnical Description, Adults/Nymphs: Scudder (1902); Alexander (1957)SINA 481a.htm                                                                                  
Comments: This is the largest member of this genus in our area. Adults have shining black heads, thorax, and abdomen; wings are usually contrastingly yellow-brown (Scudder, 1902; Himmelman, 2009).
Total Length [body plus wings; excludes ovipositor]: 27 mm, males; 26 mm, females (Scudder, 1902)
Structural Features: Pronotum is widest towards the anterior and the head of the male is typically wider than the pronotum (Alexander, 1957); the body length is usually over 18 mm, whereas it is usually shorter in all other North Carolina species of Gryllus.
Singing Behavior: Songs consist of the classic Gryllus series of chirps, with each chirp composed of 4-6 pulses and the chirps given at a rate of 1-3 per second at 85 degrees F (Alexander, 1957). The chirp rate is the slowest of the species that occur in North Carolina, including pennsylvanicus, which may or may not overlap with firmus in the eastern Piedmont. The dominant frequency is around 3.6 kHz at 77 degrees F (=24.8 C) (SINA, 2017).

Download Video: "MP4"

Nymphal Stages and Development: Nymphs overwinter (Fulton, 1952)
Distribution in North Carolina
County Map: Clicking on a county returns the records for the species in that county.
Adult Dates:
 High Mountains (HM) ≥ 4,000 ft.
 Low Mountains (LM) < 4,000 ft.
 Piedmont (Pd)
 Coastal Plain (CP)

Click on graph to enlarge
Habitats and Life History
Habitats: Strongly associated with sandy soils. Fulton (1952) described the habitat of his "beach cricket" as sandy, treeless areas along the coast. Alexander (1968) described an inland population associated with sandhills at Spout Springs and Hall and Corey recorded a population at Singletary Lake associated with a xeric Carolina bay rim, dominated by Longleaf Pines and xerophytic oaks.
Diet: Probably omnivorous
Observation Methods: Mostly easily detected by its song, which is given both day and night
Abundance/Frequency: Can be common but with singing males somewhat spread apart
Adult Phenology: A few adults appear to emerge in June but become most numerous in late summer and fall, persisting until the end of November (Fulton, 1952). Fulton also reported hearing a single male singing on May 13th.
See also Habitat Account for Xeric-Mesic Sand Barrens and Glades
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: [GNR S4S5]
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands
Comments: This species is at least somewhat restricted in terms of habitats but the degree to which it requires natural sand ridges is unknown. One population has been reported to be extirpated due to conversion of its habitat to a pine plantation (Alexander, 1968), so it may be at least somewhat vulnerable to habitat loss and fragmentation. More information is needed on its presence in sandy old fields or other agricultural lands before its conservation status in North Carolina can be accurately determined.

Image Gallery for Gryllus firmus - Sand Field Cricket

Recorded by: R. Newman
Carteret Co.
Comment:
Recorded by: Steve Hall and Bo Sullivan
Moore Co.
Comment:
Recorded by: Ken Kneidel
Scotland Co.
Comment:
Recorded by: Ken Kneidel
Scotland Co.
Comment:
Recorded by: Stephen Hall
Moore Co.
Comment:
Recorded by: Stephen Hall
Moore Co.
Comment:
Recorded by: Stephen Hall
Moore Co.
Comment:
Recorded by: Steve Hall
New Hanover Co.
Comment: Calling along the ecotone of a sand ridge and riverine marsh; sunny but a cold front came through this morning and the temperatures were in the low to mid-60s; fairly windy
Recorded by: Steve Hall
Bladen Co.
Comment: Recorded using DSLR video
Recorded by: Newman, Randy
Carteret Co.
Comment: