Family (Alpha): ACRIDIDAE GRYLLACRIDIDAE GRYLLIDAE GRYLLOTALPIDAE RHAPHIDOPHORIDAE ROMALEIDAE TETRIGIDAE TETTIGONIIDAE TRIDACTYLIDAE
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Anaxipha thomasi Walker & Funk, 2014 - Thomas's Trig
Taxonomy
Family: Gryllidae
Subfamily: Trigonidiinae
Tribe: TrigonidiiniSynonym: Anaxipha n. sp. D Comments: One of thirteen species in this genus that occur in North America north of Mexico (SINA, 2017); nine have been recorded in North Carolina. Thomasi belongs to the Exigua Species Group, which also includes exigua, tinnula, tinnulacita , and tinnulenta in North Carolina (Walker and Funk, 2014).Species Status: An unusual song variant exists at a site in Chatham County, differing from the typical prolonged, unbroken trills of this species. Specimens need to be collected to determine if this form represents a separate species.
Identification
Field Guide Descriptions: Online Photographs: SINA, Google Images ,
iNaturalist , GBIF Technical Description, Adults/Nymphs: Walker and Funk (2014)SINA 630a.htm
Comments: A very small, brown Trig. Like other members of the Exigua group, it possess a broad dark stripe on the lateral face of the femur (Walker and Funk, 2014). Structural features -- particularly the number of pegs on the stridulatory file -- must be examined to identify this species; the song is distinctive.Total Length [body plus wings; excludes ovipositor]: 5.5-5.9 mm, males; 6.1-7.1, females (Walker and Funk, 2014)Structural Features: "Stridulatory file with about 150 teeth (range 139-162). Length of ovipositor <2.2 mm" (see Walker and Funk, 2014 for additional structural characteristics). No macropterous individuals have been observed but the sample size is still fairly small.Singing Behavior: The song of Anaxipha thomasi is a trill with a rate of ~21 syllables produced per sec at 77°F (7.8 kHz) (Walker and Funk, 2014), with individual trills typically continuous for long periods of time (see examples on SINA, Macaulay Library, and the Songs of Insects website). However, songs recorded at one site in Chatham County were usually broken into segments with gaps in between, a pattern similar to that of the summer form of Anaxipha vernalis. The pulse rate and dominant frequency are otherwise a good match to that of typical thomasi recorded in other areas, including one site in Iredell County, NC. Among the species of Anaxipha with similarly continuous songs, this rate falls in between A. tinnulacita (13.2 syllables per sec. at 77°F) and A. exigua (43.6 syllables per sec. at 77°F). This rate is also simillar to that of Allonemobius walkeri , but the songs of that species are always produced from the ground rather than from perches up in the vegetation as is always the case with Anaxipha species.Diagnostic Song Parameters: Nymphal Stages and Development: Apparently undescribed but unlikely to be distinguishable, particularly from other members of the Exigua Species Group
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: This species appears to be particularly tied to pine forests (Walker and Funk, 2014). Our records come from mixed stands of hardwoods and pines, including Loblolly and Shortleaf. One record comes from a disjunct stand of White Pines.
Diet: Apparently unrecorded; possibly omnivorous
Observation Methods: Singing males are most easily detected but they may also be captured using sweep netting
Abundance/Frequency: We currently have too few records for this species to estimate either its frequency of occurrence or abundance
Adult Phenology: Walker and Funk (2014) report that this species is univoltine, appearing in late summer and persisting into the fall. Our records are all from August to September, consistent with this phenology.
Status in North Carolina
Natural Heritage Program Status: [W3]
Natural Heritage Program Ranks: GNR SNR [S2S4]
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands
Comments: This recently described species is still too poorly known across its range to estimate either its global or state conservation status. Its occurrence in stands of upland pine forests suggests, however, that it may be fairly secure. However, that remains to be confirmed.
Image Gallery for Anaxipha thomasi - Thomas's Trig
Recorded by: Steve Hall Chatham Co. Comment: 22 syllables per sec.; 82 F at 14:20. Phrases are broken irregularly, with some only 6 sec. in length and others 9 sec. Syllables don\\\'t increase in frequency range or amplitude. Recorded by: Steve Hall, Dee Stuckey, and Savannah Hall Orange Co. Comment: 22 syllables per second @ 7.3kHz and 75F Recorded by: Steve Hall Chatham Co. Comment: 20 syllables per sec @ 6.8kHz and 75F; from a trail running below an old homesite located on top of a ridge. Recorded by: Steve Hall Chatham Co. Comment: Chorus. 20 syllables per sec. @ 7.5 kHz
Recorded by: Steve Hall Chatham Co. Comment: 21 syllables per sec. at 8.4 kHz; mesic ravine where White Pines are common Recorded by: Steve Hall Chatham Co. Comment: 24 syllables per sec @ 7.9kHz and 85F (29C). Recorded near Mountain Laurel thicket on a steep north-facing slope. Intermittent but becoming more continuous. Recorded by: Steve Hall Chatham Co. Comment: 23 syllables per sec @ 8.3 kHz Recorded by: Steve Hall Orange Co. Comment: 24 pulses/sec @ 8.2 kHz. Recorded in a grassy area in a residential neighborhood but with Loblolly and Shortleaf Pines located overhead and White Pines within 50 yards Recorded by: Steve Hall Iredell Co. Comment: 20 syllables per sec @ 7.3 kHz. Trill was continuous for the 17 seconds that were recorded. Heard in stand of second growth hardwoods and pines