Culicoides mohave Wirth, 1952

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 : 101-102

Culicoides mohave Wirth

( Fig. 79 , 131, 132, 207–210)

Culicoides mohave Wirth, 1952a: 187 (key; female; male genitalia; fig. female palpus, wing, male genitalia; California).

Culicoides (Oecacta) mohave: Khalaf 1954: 37 (assignment to subgenus Oecacta ). Fox 1955: 247 (key and diagnoses of subgenera; species key; taxonomy). Wirth and Moraes 1979: 288 (female, male; fig. female antenna, wing, palpus, eye separation, spermathecae, male genitalia, parameres, leg). Wirth et al. 1985: 38 (numerical characters; fig. female wing). Wirth et al. 1988: 58 (numerical characters; fig. female wing). Borkent and Spinelli 2000: 40 (in Neotropical catalog).

Diagnosis. ( Tables 14, 15) Brown; wing pattern faint on distal half; r 2 dark; distal pale spot in r 3 distinct, sometimes irregular, centered at ~0.6 the distance from apex of costa to apex of M 1, not extending into distal 0.2 of cell; one pale spot in distal half of anal cell; two ovoid subequal spermathecae, with necks ~2× longer than wide; sclerotized ring on spermathecal duct; male tergite 9 apicolateral processes small: their length ~0.1 the distance between them; ventral apodeme of gonocoxite with two widely divergent processes, footlike; aedeagal arms simple V-shaped, median process tapering triangular to a truncated tip having two black apicolateral spines; paramere with bulbous submedian lobe and subapical fringe of spines.

Distribution. California, Arizona, Baja California, Baja California Sur.

Larval ecology. A habitat adjacent to a small stream near the Salton Sea in Southern California characterized by scattered iodinebush ( Allenrolfea occidentalis ) and desert holly ( Atriplex hymenelytra ) and sandy alkali or saline soil with 10–13% moisture produced C. mohave and larval L. knowltoni and Dasyhelea festiva ( Foulk 1966) .

Adult behavior. Mullens and Dada (1992a) reported collecting unfed females from bighorn sheep ( Ovis canadensis nelsoni ) and Japanese quail ( Coturnix japonica ). Breidenbaugh and Mullens (1999b) reported collecting females with CO 2 -baited traps, and also observed laboratory-reared larvae would not feed on the nematodes provided.

Mullens and Dada (1992b) reported C. mohave to be most abundant in the summer at lower elevations in Southern California. Brenner et al. (1984b) observed C. mohave had evening and morning crepuscular hostseeking peaks. In addition, they used a capture-mark-release-recapture method to determine a mean 1.2 km flight distance over the first 12 h and a cumulative 1.9 km flight distance over 30 h after release.

Vector potential. Rosenstock et al. (2003) detected epizootic hemorrhagic disease virus (EHDV) in C. mohave in Arizona, suggesting it may be a vector of that virus.

Remarks. Culicoides mohave has been confused with C. inyoensis where their populations overlap in the Mojave Desert. See C. (Diphaomyia) inyoensis remarks.

Subgenus unplaced, Palmerae group

The species of this group rely heavily on male characters for differentiation. Even when slide-mounted, some females can be only tentatively identified.

Diagnoses for the Palmerae group are presented by Atchley (1967) and Wirth and Rowley (1971). In addition, apical spines on fore and hind tarsomeres would also be a diagnostic character for the group ( Table 14) if they were also on the Palmerae group species not examined in the present study.

The sclerotized ring on the spermathecal duct in the members of the Palmerae group has been inconsistently reported: Wirth (1952a) reported it present in C. utahensis ; Bullock (1952) reported it present in C. palmerae ; Atchley (1967) reported it present in C. palmerae and C. utahensis ; Jorgensen (1969) reported it present in 3 of 27 C. palmerae ; however, Wirth and Rowley (1971: 161) state, “In hawsi , the sclerotized ring…persists, a generalized feature found in no other species of this group”. Hence, this character is apparently variable in the Palmerae group and may not be reliable in some other groups as well (see subgenus Silvaticulicoides discussion).

Some males of the Palmerae group (one of one C. calexicanus and four of ten C. palmerae in the present study) have minute divergent spines on the apices of the parameres ( Fig. 90 ). This characteristic is less pronounced but similar to that of subgenus Silvaticulicoides and has been reported by Jorgensen (1969) for C. palmerae as “apex with a few microscopic hairs”. Together with the apical spines on hind tarsomeres of the Palmerae group and C. (Silvaticulicoides) usingeri , the prominent apicolateral processes, the simple gonocoxal apodemes, the strongly convex lateral contours of the gonostyli, the simple aedeagus of both groups except for C. palmerae and Culicoides davisi Wirth and Rowley , the otherwise simple parameres, the usual absence of a sclerotized ring on the spermathecal duct of both groups except for Culicoides hawsi Wirth and Rowley , and the similarity of wing patterns of subgenus Silvaticulicoides species variously with the Palmerae group species C. hawsi , Culicoides leechi Wirth , Culicoides oregonensis Wirth and Rowley , and Culicoides wirthi Foote and Pratt suggest a close relationship of the Palmerae group to the subgenus Silvaticulicoides .

Figures

Figures 79–80. Male genitalia of Culicoides, ventral view, basal arms of aedeagus (Aa), submedian lobe on paramere (Pml), ventral apodeme of gonocoxite (Gcva), distal spines of paramere (Pds). 79) C. mohave, apex of aedeagus circled (San Bernardino County, CA [FSCA]). 80) C. kettlei (Riverside County, CA [BM]).

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.