This nocturnal species nests in soil, most commonly under a covering object.
Major worker similar to Camponotus absquatulator in color and stature but erect setae present along entire head margin; minor workers with at least a few setae along head margins; differs from Camponotus festinatus by its smaller size and, in the major worker, by the lack of standing setae on the side of the pronotum.
United States, Mexico. Camponotus fragilis occurs over most of the Lower California peninsula as far north on the Gulf of California coast at least to Bahía de los Angeles and northwest into southern California via San Diego County. It is also present on most, if not all, the islands of the Gulf of California and in the State of Sonora and north into Arizona (Tempe, Maricopa Co., the easternmost record) in the United States; from Sonora it ranges south along the coast to Nayarit: specimens that I collected on the Tres Marías Islands apparently are referable to C. fragilis. In California C. fragilis appears to be uncommon and is replaced in the lower desert of Imperial and Riverside Counties by Camponotus absquatulator. It is present in chaparral habitat in San Diego County, north to Riverside County and is found at mid-elevation sites along the margins of the lower desert, extending north into the Mojave Desert at least as far as the Old Woman Mountains (1.2 km S Sunflower Springs, 945 m), San Bernardino County. (Snelling 2006)
Distribution based on Regional Taxon Lists
Distribution based on AntMaps
Distribution based on AntWeb specimens
Check data from AntWeb
Creosote Scrub, Coastal Scrub, Chaparral, and Oak Woodland.
The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- fragilis. Camponotus fragilis Pergande, 1893: 26 (s.w.) MEXICO. Combination in C. (Myrmoturba): Forel, 1914a: 267. Subspecies of fumidus: Emery, 1895c: 336. Junior synonym of festinatus: Snelling, R.R. 1968b: 351. Revived from synonymy: Snelling, R.R. 2006: 89.
Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.
Snelling (2006) – Major. (n=12). Measurements: HL 2.25-2.70; HW 1.95-2.58; EL 0.50-0.60; SL 2.00-2.45; ML 3.10-3.45. Indices: CI 87-96; HFI 87-123; OI 21-25; SI 83-98.
Head shape about as in Camponotus festinatus. Mandible moderately shiny and weakly microreticulate between sparse, mostly round punctures; with six teeth, innermost acute or subtruncate to weakly bifid; usually subtended by a small acute tooth on inner margin.
Cephalic sculpture about as in C. festinatus but a little finer; malar area with only scattered round punctures and longest hairs about 0.1 mm long and absent on posterior one-third to one-half.
Pilosity generally similar to C. festinatus; side of pronotum without standing setae above ventral margin. Standing yellowish setae present on indicated surfaces: dorsal face of scape shaft (7-11), ventral margin of profemur (5-9), pronotum (10-16), mesonotum (5-12), propodeum (6-8), petiole (6-8), disc of gastral tergum I (10-12), premarginal row on gastral tergum I (14-16).
Media and minor. (n=12). Measurements: HL 1.20-1.75; HW 0.90-1.25; EL 0.40-0.45; SL 1.40-2.10; ML 1.85-2.60. Indices: CI 63-79; HFI 158-206; OI 27-45; SI 117-129.
Pilosity similar to C. festinatus with standing yellowish setae present on indicated surfaces: dorsal face of scape shaft (1-4), ventral margin of profemur (2-6), pronotum (4-10), mesonotum (2-6), propodeum (2-4), petiole (4-6), disc of gastral tergum I (6-10), premarginal row on gastral tergum I (6-8).
Snelling (2006) - (n=7). Measurements: HL 2.20-2.35; HW 2.00-2.15; EL 0.65-0.70; HFL 2.20-2.45; SL 1.90-2.15; PW 1.80-1.95; ML 3.85-4.20. Indices: CI 89-91; HFI 109-119; OI 28-30; SI 86-93.
Similar to queens of C. festinatus but distinctly smaller (ML 3.85-4.20 vs. 4.51-4.92) and malar area with scattered obscure round to slightly elliptical punctures and longest setae about 0.10 mm long (vs. about 0.20 mm); ICD 0.67-0.71 × HW; EL 0.76-0.93 × OMD; IOD 2.85-3.17 and OOD 3.00-3.25 × OD. Differs from queens of C. absquatulator by presence of erect setae along entire head margin.
Snelling (2006) - Lectotype, by present designation, major worker. Mexico, Baja California Sur: San Fernando (label reads "San Fernando Mex.") (National Museum of Natural History). A paralectotype minor worker in very poor condition in California Academy of Sciences.
- Bolton, B. 1995b. A new general catalogue of the ants of the world. Cambridge, Mass.: Harvard University Press, 504 pp. (page 100, catalogue)
- Emery, C. 1895d. Beiträge zur Kenntniss der nordamerikanischen Ameisenfauna. (Schluss). Zool. Jahrb. Abt. Syst. Geogr. Biol. Tiere 8: 257-360 (page 336, variety of fumidus)
- Forel, A. 1914a. Le genre Camponotus Mayr et les genres voisins. Rev. Suisse Zool. 22: 257-276 (page 267, combination in C. (Myrmoturba))
- Pergande, T. 1893. On a collection of Formicidae from Lower California and Sonora, Mexico. Proc. Calif. Acad. Sci. (2) 4: 26-36 (page 26, soldier, worker described)
- Snelling, R. R. 1968b. Studies on California ants. 4. Two species of Camponotus (Hymenoptera: Formicidae). Proc. Entomol. Soc. Wash. 70: 350-358 (page 351, junior synonym of festinatus)
- Snelling, R. R. 2006. Taxonomy of the Camponotus festinatus complex in the United States of America (Hymenoptera: Formicidae). Myrmecologische Nachrichten. 8:83-97.