Ants (Hymenoptera: Formicidae) of
Cold Canyon
Philip S. Ward
Entomology Department
University of California
Davis, CA 95616
This list is based on Phil Ward's observations over an 18-year period at Stebbins Cold Canyon Reserve, 19km NNW Vacaville, Solano County, California (38°30'N, 122°06'W). It includes ant collections made throughout the Cold Canyon watershed, not just those within the Reserve boundaries. All of the 39 ant species observed in Cold Canyon are native species, and they are typical of "lower Sonoran" (oak woodland and chaparral) habitats. Ant species not yet recorded from Cold Canyon, but found nearby in the Vaca Mountains or along Putah Creek, include Lasius alienus, Formica aerata, Formica subpolita, Camponotus sp. nr. vicinus, Polyergus breviceps, Cardiocondyla ectopia (introduced species) and Linepithema humile (introduced species). Voucher specimens of all species listed are deposited in the Bohart Museum of Entomology (UCDC) and a partial set in the Museum of Comparative Zoology, Harvard University (MCZC).
Cold Canyon was arbitrarily divided into six separate
sampling sites. The table below describes these sites, as well as the number of
species found in each site.
| Site | Site Description | Width | Number of spp. | Number of spp. only in this site |
| Site A | Mouth of canyon, between Hwy. 128 and Putah Creek | ~120m | 22 | 1 |
| Site B | Canyon proper, Hwy. 128 to old homestead | ~120m | 31 | 3 |
| Site C | Ridge west of Cold Canyon proper (Blue Ridge) | ~420m | 20 | 0 |
| Site D | Ridge east of Cold Canyon proper (Pleasants Ridge) | ~360m | 19 | 1 |
| Site E | Upper canyon, south of the old homestead | ~300m | 23 | 0 |
| Site F | Upper watershed ridge (extreme south end) | ~600m | 25 | 1 |
The 39 ant species are categorized by site, by nesting habit (A=arboreal, G=ground), and by feeding habit (O=omnivore/scavenger, P=predator, S=seed-harvester), in the table below.
| Subfamily, species | Site(s) | Nesting Habits | Feeding Habits |
| Dolichoderinae | |||
| Dorymyrmex bicolor | B | G | O |
| Dorymyrmex insanus | A, B, C | G | O |
| Liometopum luctuosum | A, B, D | A | O |
| Liometopum occidentale | A, B, D, E | A | O |
| Tapinoma sessile | A, B, C, F | G | O |
| Ecitoninae | |||
| Neivamyrmexnigrescens | B, C, D, E, F | G | P |
| Formicinae | |||
| Brachymyrmex depilis | B, D | G | O |
| Camponotus essigi | A, B, C, D, E, F | A | O |
| Camponotus hyatti | C, E, F | G | O |
| Camponotus quercicola | B, E | A | O |
| Camponotus semitestaceus | A, B, C, D, E, F | G | O |
| Camponotus yogi | B, D, F | A/G | O |
| Formica moki | A, B, C, D, E, F | G | O |
| Prenolepis imparis | A, B, C, D, E, F | G | O |
| Myrmicinae | |||
| Crematogastercoarctata | B, C, D, E, F | G | O |
| Crematogasterhespera | A | A | O |
| Crematogastermarioni | E, F | A | O |
| Cyphomyrmex wheeleri | B, D | G | O |
| Leptothorax andrei | A, B, C, D, E, F | G | O |
| Leptothorax sp. cf. andrei | F | G | ? |
| Leptothorax gallae | A, C, E, F | A | O |
| Leptothorax nevadensis | B, C, D, E, F | G | O |
| Leptothorax nitens | C, E, F | G | O |
| Messor andrei | B, C, D, E, F | G | S (O) |
| Monomorium ergatogyna | A, F | G | O |
| Myrmecina americana | A, B, C, D | G | P |
| Pheidole californica | A, B, F | G | S (O) |
| Pogonomyrmex subdentatus | B | G | S (O) |
| Solenopsis molesta (s.l.) | A, B, C, D, E, F | G | O |
| Solenopsis tennesseensis | B | G | O |
| Solenopsis xyloni | A, B, C, D, E, F | G | S (O) |
| Stenamma californicum | A, B | G | O |
| Stenamma diecki | A, B, C, D, E, F | G | O |
| Stenamma punctatoventre | A, B, E, F | G | O |
| Ponerinae | |||
| Amblyopone pallipes | B, E, F | G | P |
| Hypoponera sp. cf. inexorata | A, B, C, E, F | G | P |
| Hypoponera opacior | A, B, E | G | P |
| Proceratium californicum | D | G | P |
| Pseudomyrmecinae | |||
| Pseudomyrmex apache | A, B, C, E, F | A | O |