Culicoides atchleyi Wirth and Blanton

Phillips, Robert A., 2022, Culicoides Latreille and Leptoconops Skuse biting midges of the southwestern United States with emphasis on the Canyonlands of southeastern Utah (Diptera: Ceratopogonidae), Insecta Mundi 2022 (907), pp. 1-214 : 111-112

Culicoides atchleyi Wirth and Blanton

( Fig. 4 )

Culicoides atchleyi Wirth and Blanton, 1969a: 559 (female, male; fig. female antenna, palpus, wing, eye separation, spermathecae, male genitalia, parameres; Alaska). Wirth et al. 1985: 36 (numerical characters; fig. female wing; placement in Chaetophthalmus group). Borkent and Dominiak 2020: 22 (rename Chaetophthalmus group as Saundersi group).

Diagnosis. ( Tables 14, 15) Brown; wing without pattern of pale spots, veins thicker and darker than normal, nearly obliterating cell r 2; eyes with prominent interommatidial pubescence; mandibular teeth vestigial; two sclerotized ovoid spermathecae, vestigial third fingerlike; ventro-posterior membrane of male sternite 9 bare; aedeagus Y-shaped, median process simple, moderately slender, blunt, aedeagal ratio ~0.45; parameres separate, apex simple, straight, not extending beyond tip of aedeagus.

Distribution. Alaska, New Brunswick, Nova Scotia, Idaho (Bonneville County, new state record), New Mexico. A widely distributed, but apparently rare species. The week 27 collection record (x) in the seasonal distribution (Table 5) is by a light trap in a pinyon-juniper-Douglas fir forest area, 6 July 1953 at ~ 2280 m elevation in Taos County, New Mexico. This record, and my collection of one female with UVLT on 14 July 2019 at 43.52974°N 111.18504°W and 2002 m elevation in the Snake River Range of Idaho, indicate it may be present in similar montane habitats in Utah and other western states during July. The other Xs in Table 5 are from Alaska records.

Adult behavior. The absence of mandibular teeth on the female indicates it does not blood-feed.

Larval ecology. Culicoides atchleyi ’s larval habitat is unknown. However, experiments have shown that interommatidial pubescence helps protect insect eyes by reducing impact and deposition of airborne particles onto ommatidia ( Amador et al. 2015). Similarly, C. atchleyi ’s eye hairs may help prevent soil particles from lodging between or damaging ommatidia, suggesting a relatively dry or deep soil larval habitat such as that of L. carteri —the only other southwestern species of biting midge with abundant inter-ommatidial pubescence for which the larval habitat is known.

Remarks. The female collected in Idaho more closely matches the Wirth and Blanton (1969a) description of C. atchleyi rather than that of C. saundersi in having a 2.3 palpal ratio, 0.67 proboscis ratio, 0.9 ommatidium diameter eye separation, 4 tibial comb spines, the same position of SCo on flagellomeres 12 and 13 as in their figure 2a, and smaller (0.52 mm) rounder spermathecae with narrower necks. However, its 1.04 antennal ratio is like that of C. saundersi ; and having seven teeth on one mandible, but none on the other or on the laciniae is ambiguous—other examples of the variability of diagnostic characters.

Figures

Figures 3–8. Female wings with cells (lower case) and veins (upper case) labeled. 3) Culicoides stonei. 4) C. atchleyi (Bonneville County, ID). 5) Leptoconops torrens. Female abdomen, ventral view. 6) L. torrens. 7) C. stonei. 8) L. californiensis, dorsal habitus (in alcohol, Yuma County, AZ [Carl Olson, with permission]).