Culicoides mortivallis 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 : 113-114

Culicoides mortivallis Wirth and Blanton

( Fig. 41 , 280, 289, 290, 294)

Culicoides mortivallis Wirth and Blanton, 1971: 465 (key; female, male; fig. female antenna, palpus, eye separation, hind tibial comb, wing, spermathecae, legs, male genitalia, parameres; California). Jones and Wirth 1978: 57 (key). Wirth et al. 1985: 36 (numerical characters; fig. female wing).

Diagnosis. ( Tables 14, 15, 17, 18) Yellowish brown; wing without pattern of pale spots (as in Fig. 3 C . stonei); legs straw-colored; two sclerotized ovoid spermathecae and fingerlike vestigial third (as in Fig. 45 C . stonei); posterior portion of female sternite 8 cleft, with blunt submedian posterior projections (as in Fig. 45 C . stonei); ventro-posterior membrane of male sternite 9 spiculate; aedeagus Y-shaped, median process stout, short, blunt, half as long as basal arms; parameres separate, simple, apex curved hooklike. To distinguish from C. owyheensis , ratios to length of flagellomere 9: <1.50 for flagellomeres 7+8, <3.95 for proboscis, <1.90 for palpal segment 3.

Distribution. California (Inyo, Monterey, San Bernardino counties), Utah (Grand County, new state record), Arizona (Greenlee County, new state record). The Arizona specimen was collected with UVLT on 10 October 2019 at 32.96215°N 109.30566°W and 1056 m elevation near the Gila River.

Larval ecology. I reared one female and two presumptive male C. mortivallis along with C. crepuscularis , C. occidentalis , and C. sonorensis from mud collected on 10 September 2020 from nonvegetated sunlit alkaline pools in a stream bed in Grand County at 38.96339°N 109.33585°W and 1315 m elevation. One of the males emerged on 2 October, indicating a development period of at least 22 d at ~25°C.

Adult behavior. Culicoides mortivallis has been collected biting a human at dusk in California ( Wirth and Blanton 1971). In addition, Jones’s sheep host record ( Jones 1961c), description of the Grand County, Utah, pupa variant (1961a: 741), Grand County larval habitat record ( Jones 1961b), and Mesa County, Colorado, record for C. stonei are likely for C. mortivallis . Furthermore, if C. mortivallis and C. owyheensis are synonymous, then reports of C. owyheensis females collected from the ear of a sheep prostrate with bluetongue in Idaho ( Jones and Wirth 1978) are for C. mortivallis . See also Stonei group discussion.

Symbionts. A female with SCo pattern 1, 6–12 collected in Grand County was parasitized by a larval mite (Fig. 294, Table 10); and specimens with SCo patterns 1, 5–12 and 1, (3), 4–12 collected in Grand County were parasitized by what seem to be ciliate protozoans (possibly Tetrahymena sp. [Ciliophora: Oligohymenophorea] [ Mullens and Schmidtmann 1982]) and possibly mermithid nematodes (Fig. 289, Table 11).

Atypical biology. A female with SCo patterns 1, 3–12 and 1, 5–12 and collected in Grand County had three developed spermathecae instead of two with a vestigial third ( Table 12).

Remarks. Using the measurement ratios from Wirth and Jones (1978: 57), 12 of 16 Grand County specimens and an Arizona specimen recognized as either C. owyheensis or C. mortivallis based on SCo pattern were identified as C. mortivallis ( Table 18). See also Stonei group discussion.

Figures

Figures 41–45. Male genitalia of Culicoides, ventral view, gonocoxite (Gc), gonostylus (Gs), paramere (P), aedeagus (A), apicolateral processes of tergite 9 (T9alp), sternite 9 (S9). 41) C. mortivallis. 42) C. werneri (paratype, Pima County, AZ [FSCA]). 43) C. bottimeri. Spermathecae, rudimentary third spermatheca (rsp), sternite 8 (S8), sternite 9 (S9). 44) C. bottimeri. 45) C. stonei.

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]).