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

Allonemobius fultoni Howard & Furth, 1986 - Fulton's Ground Cricket


Taxonomy
Family: Gryllidae Subfamily: Nemobiinae Tribe: Pteronemobiini
Comments: One of ten species in this genus, all of which occur in North America north of Mexico (Cigliano et al., 2017). Eight species have been recorded in North Carolina.
Identification
Field Guide Descriptions: Online Photographs: BugGuide, Google ImagesTechnical Description, Adults/Nymphs: Howard and Furth (1986)SINA 542a.htm                                                                                  
Comments: According to Howard and Furth (1986), Allonemobius fultoni is essentially identical in terms of markings to both A. allardi and walkeri. The head is darker than in socius/fasciatus but the stripes at the back of the head are more obscure and the posterior edge has a black bar. The pronotum is mottled irregularly with light and dark brown, with a mid-dorsal yellowish stripe, and bordered on the upper lateral face by a yelllowish band. The tegmen of the male is brown, with the basal third darker. The legs are lighter brown. In the one photo we believe represents this species, this pattern generally holds although the yellow medial stripe on the pronotum is very narrow and the yellow lateral bands are somewhat obscure. There is also a conspicuous pale lateral border on the tegmen that is not mentioned by Howard and Furth.
Total Length [body plus wings; excludes ovipositor]: 8.7-10.5 mm, males; 10.0-11.9, females (Howard and Furth, 1986)
Structural Features: Males have 140-157 stridulatory teeth, which is well below the range of both allardi and walkeri (Howard and Furth, 1986). According to Howard and Furth (1986), fultoni is smaller than walkeri in all measurements, with a table giving detailed comparisons between the two species presented in their monograph.
Singing Behavior: Songs consist of trills, with a pulse rate of 22 pulses per second and a dominant frequency of between 6.6 and 7.0 kHz at 75 degrees F (= 24 C). Trills are similar to those of A. walkeri, but the length of the trill is usually much shorter, about 5.3 seconds, compared to those of walkeri, which last from 12-32 seconds; the interval between trills is also longer and the pauses occur at more regular intervals in fultoni (Howard and Furth, 1986). Howard and Furth also describe what appears to be an unusual feature of the trills of fultoni: "the trill began at a frequency of ca. 6,640 Hz but, about halfway through, abruptly shifted to a frequency of ca. 7,040 Hz. The lower frequency did not disappear subsequently, but its intensity was considerably reduced." We have observed something similar in our recordings. Each syllable has a short initial upward slur followed by a downward tail. As the trill progresses, the initial part rises in pitch and the downward tails corresponding elongate. This produces a series of pulses that widens along the frequency axis as the series progress, accompanied by an increase in amplitude. We have also noted this pattern in recordings in the Macaulay Library. We have not seen that pattern in the songs that we are identifying as A. walkeri, which are much more uniform, but the intensification in amplitude within a given trill is also characteristic of Neonemobius cubensis, which has similar habitat preferences. The trills of that species, however, are higher in pitch, have a higher within trill pulse rate, and last much longer than in fultoni.
Recording playback at normal speed.

Download Video: "MP4"

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: Fulton's Ground Crickets are associated with wet grassy areas, including open marshes or under deep shade (Howard and Furth, 1986). In the Coastal Plain, we have recorded this species under shrub cover adjoining freshwater marshes, depression ponds, and sandhill seeps. We have also found it along the edge of an artificial impoundment in the Sandhills region. In the Piedmont, we have found a population in a wet semi-natural grassland maintained for decades by mowing.
Diet: Probably omnivorous
Observation Methods: Mostly easily detected and identified by its song
Abundance/Frequency:
Adult Phenology: Adults are present in the fall, with the eggs overwintering (Howard and Furth, 1986)
Status in North Carolina
Natural Heritage Program Status: [W3]
Natural Heritage Program Ranks: [GNR] [SU]
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands
Comments: This species was considered rare by Howard and Furth (1986), who had collected it only at two sites in New Jersey and one in North Carolina; Walker (2017) shows only three additional sites, in Georgia and Florida. Not enough is yet known about its distribution, abundance, and habitat preferences, however, to accurately assess its conservation status.

Image Gallery for Allonemobius fultoni - Fulton's Ground Cricket

Recorded by: Steve Hall, Dee Stuckey, Savannah Hall
Durham Co.
Comment: A large number were heard singing in an old field. Temperature was about 73 F and the pulse rate was 22-23 pps. The distinct pattern of increasing amplitude and frequency is more typical of fultoni than walkeri, as is the shortness of the pulse trains and the long gaps in between.
Recorded by: Steve Hall and Bo Sullivan
Scotland Co.
Comment: Several heard singing in grassy vegetation along the shoreline of an impoundment
Recorded by: Stephen Hall
Carteret Co.
Comment: Found under grasses growing in wet margin of a depression pond. Both fultoni and socius were recorded singing in the vicinity. This individual appears to have less contrasting stripes on the back of the head than is typical of socius. The pronotum also appears to be narrower towards the front, rather than the more uniform or barrel-shape typical of socius (at least in micropterous individuals)
Recorded by: Stephen Hall
Carteret Co.
Comment: In grassy border of a wet, pocosin-filled depression. The temperature at 14:36 was 77 F (= 25 C). The pulse rate was 28 pulses per second, with each trill lasting around 3.5 seconds.
Recorded by: Steve Hall and Bo Sullivan
Carteret Co.
Comment: Two trills, with the one to the right combining songs of two different individuals. Trills last between 3.5 to about 5 seconds, with regular pauses between trills; trills rise in both amplitude and pitch, starting as a series of clicks and ending with more musical downslurs. Recorded at the edge of a marsh; calling from on the ground beneath wax myrtles.
Recorded by: Steve Hall and Bo Sullivan
Carteret Co.
Comment: Terminal second of a trill. The dominant frequency was about 7.8 kHz; the pulse rate is 28 pulses per seconds.

MP3 Gallery for Allonemobius fultoni - Fulton's Ground Cricket

1 Recorded by: Steve Hall, Dee Stuckey, Savannah Hall
Durham Co.
2020-11-15
A number of individuals were heard singing in an oldfield that has been maintained for decades solely by mowing. Recorded in late afternoon but with the temperature = 73 F (23 C)
2 Recorded by: Steve Hall and Bo Sullivan
Scotland Co.
2020-10-13
Several heard singing in grassy vegetation along the shoreline of an impoundment