Orthoptera of North Carolina
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View Gryllidae Members: NC Records

Cycloptilum bidens Hebard, 1931 - Two-Toothed Scaly Cricket


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Taxonomy
Family: Gryllidae Subfamily: Mogoplistinae Tribe: Mogoplistini
Comments: One of sixteen species in this genus that occur in North America north of Mexico (Love and Walker, 1979), four of which have been recorded in North Carolina. Cycloptilum bidens belongs to the Bidens Complex of the Squamosum Species Group of Love and Walker (1979).
Species Status: According to Love and Walker (1979), Cycloptilum bidens represents a complex of species. Some like velox and tardum were described by Love and Walker as full species but several more undescribed species appear to exist. That includes the form that has been recorded in North Carolina, all records for which Walker lists as C. near bidens (i.e., an unidentified species close to bidens) in the GrylTett database (Walker, 2016). Fulton (1951) also described two forms of bidens based on differences in both song and habitat. One of them has a call rate of 4 chirps per second, which appears to correspond to the song described for true bidens by Love and Walker. However, Fulton described the habitat for that species as beach dunes, which corresponds more closely with the habitat for C. pigrum. Fulton's other form has a chirp rate of 2 per second, which matches pigrum more closely, but he gives the habitat as low undergrowth in woodlands, especially pine lands, a close match to the habitats described by Love and Walker for true bidens and C. tardum. More studies need to be conducted to resolve the taxonomy of this group. In the meantime, we treat all inland records for this group as bidens, at least where not otherwise identified as tardum.
Identification
Field Guide Descriptions: Online Photographs: SINA, BugGuide, OSF, Google Images,  iNaturalist, GBIFTechnical Description, Adults/Nymphs: Hebard (1931); Love and Walker (1979)SINA 453a.htm                                                                                  
Comments: A very small, mottled brown Scaly Cricket. The general color is light reddish brown but the scales are blackish or dark gray, producing a mottled appearance overall, especially in unworn individuals (Hebard, 1931). While members of the Bidens Species Group are easily distinguished from C. trigonipalpum and slossoni based on structural features (see below) and by a distinctive brown blotch located on the outer edge of the wins in the males, members of this group are themselves probably indistinguishable based on coloration or markings. Instead, they are best identified by the songs of the male, although there are at least some structural differences that distinguish females of bidens from the other species in this complex (Love and Walker, 1979).
Total Length [body plus wings; excludes ovipositor]: 4.5 mm, males; 6.4 mm, females (Love and Walker, 1979)
Structural Features: This species is smaller and wider-bodied -- especially at the middle of the body, near the end of the pronotum -- than either trigonipalpum or slossoni; the wings of the males extend by nearly a third of their length beyond the end of the pronotum, whereas in the other two species the wings are completely covered by the pronotum. Males of the Bidens Species Group may be only distinguishable based on their songs (see below) but females of bidens lack an apical spike on the subgenital plate that is present in at least tardum and velox but has not been determined for females of pigrum (Love and Walker, 1979).
Singing Behavior: Songs of the Squamosum Species Group, including the Bidens Complex, characteristically consist of chirps composed of two pulses, with each chirp spaced far enough apart to count individually (Love and Walker, 1979). The main differences separating the species in this group are the number of chirps given per second: at 77 F (25 C), bidens produces about 3.5 chirps per second, which is faster than pigrum and tardum but slower than velox (see Figures 32 and 50 in Love and Walker) The dominant frequency is just above 6 kHz at 77 F for all of these species.
Nymphal Stages and Development: Undescribed
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: Love and Walker (1979) describe the habitat of bidens in Florida as well-drained, frequently burned areas of sandy soil, usually supporting stands of Longleaf Pine and/or xerophytic oaks; in North Carolina, this matches the Pine-Scrub Oak Sandhills natural community type of Schafale and Weakley (1990). Records from the Piedmont, however, suggest a wider range of habitats may be used, although all of our records from that region are historic and they could represent other species in this complex.
Diet: Undescribed but this species is possibly omnivorous
Observation Methods: Members of this species group live either on the ground or in dense ground cover and are hard to observe directly. Singing males are the easiest to detect and to identify. Spectrograms or waveforms should be used to determine the rate of chirping.
Abundance/Frequency: Too little information exists to estimate the frequency of occurrence or abundance of this species in North Carolina
Adult Phenology: Exact dates are missing for most of our historic records for this species but we have one record from July and another from August
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 is possibly a specialist on Longleaf Pine sandhills habitats, but we have too few documented records for this species -- especially given the uncertainty of all records for this species outside of Florida -- to be sure about anything with regard to its biology. More surveys need to be conducted to determine the taxonomic identity, distribution, abundance, and habitat affinities of this species before its conservation status can be determined.