Culicoides utahensis Fox, 1950

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 : 105-106

Culicoides utahensis Fox

( Fig. 93 , 147, 221, 251)

Culicoides utahensis Fox, 1946: 246 (male; fig. male genitalia; Utah: Cache County). Knowlton and Fronk 1950: 114 (Utah: Sanpete County, from jackrabbit ear). Wirth 1952a: 189 (key; female; male genitalia; fig. female wing, palpus, male genitalia). Bullock 1952: 14 (female; male genitalia; Utah: Salt Lake County). Rees and Bullock 1954 (Utah: Salt Lake County).

Culicoides (Oecacta) utahensis: Khalaf 1954: 38 (assignment to subgenus Oecacta ). Fox 1955: 258 (key and diagnoses of subgenera; species key; taxonomy). Atchley 1967: 1010 (key; numerical characters; female; male genitalia; fig. female palpus, male genitalia, parameres). Wirth and Rowley 1971: 166 (numerical characters; key; female, male; fig. female antenna, eye separation, palpus, spermathecae, male antenna, palpus, genitalia, parameres; Utah: Beaver, Iron, Kane, Millard, Salt Lake counties). Wirth et al. 1985: 26 (numerical characters; fig. female wing). Breidenbaugh and Mullens 1999a: 862 (egg; fig.).

Diagnosis. ( Tables 14, 15) Wing pattern extensive; r 2 dark; distal pale spots large, often diffuse in r 3, m 1, m 2; scutellum about same brown as scutum; fore and hind tarsomeres with apical spines (not evident on the one male collected); spermathecae subequal, with sclerotized necks shorter than wide; male antenna and palpus feminized, flagellomeres 9–10 lengthened similar to 11–13, lacking dense whorls of sensilla chaeticae on 1–10, palpal ratio ~2, with large sensory pit; ventral apodeme of gonocoxite simple; gonostylus about evenly curved, not abruptly bent, entire lateral contour convex; aedeagus V-shaped, median process tapering to broad tip ~0.4 as wide as basal arm spread; parameres separate, apices abruptly bent ventro-laterally with simple sharp tip.

Distribution. Washington, Idaho, Montana, south through Oregon, to California, Nevada, Utah (Beaver, Cache, Grand, Iron, Kane, Millard, Salt Lake, Sanpete counties), New Mexico.

Adult behavior. Known hosts are jackrabbit, black-tailed jackrabbit ( Knowlton and Fronk 1950; Wirth 1952a; Wirth and Rowley 1971), ground squirrel ( Spermophilus Cuvier sp. , Sciuridae ) ( Wirth 1952a), rabbit, sheep, deer ( Wirth and Rowley 1971), and black-tailed deer ( Odocoileus hemionus ) ( Hopken et al. 2017).

Culicoides utahensis has been found mating within the ears of jackrabbits, sheep, and deer in California ( Wirth 1977) and from jackrabbit ears in Idaho, Nevada, and Utah ( Wirth and Rowley 1971). The feminization of the antennae and palpi of the males was originally thought to be an abnormality; however, it is now known to be normal for this species and correlates with the ability to find and mate with females on their hosts ( Wirth and Rowley 1971).

Breidenbaugh and Mullens (1999a) found C. utahensis eggs failed to hatch in the laboratory even though the embryos seemed to develop normally and survive, suggesting they overwinter in diapause and need cold conditioning or interaction with photoperiod to continue development. Bullock (1952) collected adults during June in Salt Lake County, which has a much colder winter climate. Bradley Mullens (personal communication) observed that wild-caught adults were unusually willing to feed through chick skin membranes on bovine blood in the laboratory, and much mating occurred in the feeding apparatus or aspirator tubes. This likely reflects a considerable degree of stenogamy, as are the reports of mating within the ears of its hosts; thus, if the apparent egg diapause could be investigated and managed and the larvae reared on laboratory substrates, this species might be easily colonized.

Remarks. Culicoides leechi , a closely related species of the Palmerae group, also has males normally with feminized antennae and palpi; however, collections of C. leechi mating-pairs have been only at light ( Wirth 1977).

Figures

Figures 88–93. Male genitalia of Culicoides, ventral view. 88) C. luglani, submedian processes of parameres circled. 89) C. crepuscularis, ventral apodeme of gonocoxite circled. 90) C. calexicanus, apices of parameres circled, apex of aedeagus delineated. 91) C. hawsi (paratype, Modoc County, CA [FSCA]). 92) C. palmerae, sharp lateral shoulders on median process of aedeagus indicated (A). 93) C. utahensis.