Culicoides (Silvicola) lahontan 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 : 92-93

Culicoides (Silvicola) lahontan Wirth and Blanton

( Fig. 68 , 121 , 180, 241, 242)

Culicoides (Culicoides) lahontan Wirth and Blanton, 1969b: 223 (key; numerical characters; female, male; fig. female antenna, palpus, wing, spermathecae, eye separation, male genitalia, parameres; California). Wirth et al. 1985: 10 (numerical characters; fig. female wing). Breidenbaugh and Mullens 1999a: 845 (egg, larva, pupa; fig. egg, larval head, mouthparts, thorax, pupal respiratory trumpet, operculum, caudal segment, chaetotaxy).

Culicoides (Silvicola) lahontan: Mirzaeva and Isaev 1990: 156 in English translation (as part of Cockerellii group, assignment to new subgenus Silvicola ).

Culicoides luteovenus Root and Hoffman , misidentified: Root and Hoffman 1937: 156 (in part; female, male; fig. female wing, male genitalia; Federal District, Mexico). Knowlton and Fronk 1950: 114 (Utah: Uintah County). Wirth 1952a: 175 (key; female; male genitalia; fig. female wing, mesonotum, palpus). Bullock 1952: 10 (key). Fox 1955: 245 (in part; key and diagnoses of subgenera; species key; taxonomy). Spinelli and Huerta 2015: 818 (mistaken as to presence of C. luteovenus in United States; compared with Culicoides rulfoi Spinelli and Huerta ).

Diagnosis. ( Tables 14, 15) Wing pattern extensive, with distal stripes and pale spots; pale spot over at least distal half of r 2; cua 1 without central dark spot; eyes contiguous for 1–2 ommatidium diameters; superior transverse suture nearly always present; palpal segment 3 with distinct wide shallow sensory pit on female, small distinct on male, scattered sensilla lacking; scutum with trace of faint pattern; scutellum often with 6–8 setae on female, 4–6 on male; tibiae without pale bands; fore and hind tarsomeres without apical spines; spermathecae subequal; male tergite 9 with tiny apicolateral processes not projecting beyond median lobe; ventral apodeme of gonocoxite shorter than dorsal apodeme, strongly tapered, pointed, 1–2× as long as basal width; gonocoxite with short fine black setae on mesal surface; aedeagus somewhat Y-shaped, median process abruptly narrowing on distal half to slender fingerlike tip, aedeagal ratio ~0.4; parameres separate, apices slender, posteriorly directed, with fringe of tiny hairs at tip.

Distribution. Alberta ( Lysyk and Galloway 2014), Montana, south through Oregon, to California, Utah (Grand, Salt Lake, Uintah, Washington counties). See remarks.

Larval ecology and life cycle. Breidenbaugh and Mullens (1999a) collected C. lahontan adults with emergence traps from soil margins of an ephemeral creek at 300–350 m elevation in San Bernardino County, California. They also conducted laboratory studies and found that wild-caught females laid an average of 89 eggs, of which 55% hatched in ~7 d at 21–25 °C. The larvae fed on the bacterial-feeding nematode Panagrellus redivivus , pupated ~60 d after hatch, and eclosed ~4 d later.

Adult behavior. Mullens and Dada (1992a) reported bighorn sheep ( Ovis canadensis nelsoni ) as a host. They also reported (1992b) moderate parity rates of 13% to 25% for females collected using CO 2 -with-light-baited traps, suggesting a moderate vector potential. Their finding (1992b) of a single activity peak of May–June in the Santa Rosa Mountains of Southern California sharply contrasts with the double peaks of March–April (week 14) and October (week 43) I found in Grand County, Utah (Table 5).

Symbionts. Mullens et al. (1997b) experimented with the potential biocontrol parasitic nematode, Heleidomermis magnapapula in the laboratory and found it readily entered, infected, developed, but did not emerge from C. lahontan larvae, which continued to develop to adults with no sign of the nematode.

Atypical biology. A C. lahontan collected in Grand County and another collected by Xinmi Zhang in Riverside County, California, have three fully developed spermathecae instead of two with a vestigial third ( Table 12).

Remarks. Knowlton and Fronk (1950), Wirth (1952a), Bullock (1952), and Wirth and Blanton (1959) reported the (now only Neotropical) C. luteovenus from Utah. However, upon examining the redescriptions of C. luteovenus in Wirth (1952a: 175) and Wirth and Blanton (1959: 297), the wing photographs in Wirth et al. (1985) and Wirth et al. (1988), and the key characters in Bullock (1952: 10–11), it seems Wirth in part, Bullock, and probably Knowlton and Fronk are referring to C. lahontan instead. The broad shallow sensory pit on palpal segment 3, mesonotal pattern, and narrow median process of the aedeagus are distinctive. Wirth and Blanton (1969b) state C. freeborni was often mistaken for C. luteovenus but do not offer C. lahontan as mistaken for C. luteovenus , which seems more likely.

Figures

Figures 66–72. Male genitalia of Culicoides subgenus Silvicola, ventral view. 66) C. cockerellii (Bonneville County, ID). 67) C. freeborni (San Diego County, CA [BM]). 68) C. lahontan. 69) C. neofagineus (paratype, Mendocino County, CA [FSCA]). 70) C. neomontanus, basal and apical tips of aedeagus triangulated. 71) C. saltonensis (Imperial County, CA [FSCA]). 72) C. sierrensis (paratype, Modoc County, CA [FSCA]).

Figures 117–125. Male wings of Culicoides subgenera Avaritia and Silvicola. 117) C. boydi (in grayscale) (Riverside County, CA [BM]). 118) C. obsoletus (MD [FSCA]). 119) C. cockerellii (Bonneville County, ID). 120) C. freeborni (San Diego County, CA [BM]). 121) C. lahontan. 122) C. neofagineus (in grayscale) (paratype, Mendocino County, CA [FSCA]). 123) C. neomontanus. 124) C. saltonensis (Imperial County, CA [FSCA]). 125) C. sierrensis (paratype, Modoc County, CA [FSCA]).