Laboratory Observations on the Biology and Life Cycle of the Australian Biting Midge Culicoides Subimmaculatus (Diptera: Ceratopogonidae)

Culicoides subimviaculatus was reared in agar from egg to adult at 25°C. The egg stage lasted 5½ days, the 4 larval instars 9, 4, 6 and 18 days, respectively, and the pupal stage 3½ days. Survival from egg to adult was 47%. Rearing in sand resulted in higher survival rates than rearing in agar, but larvae in sand could not be observed directly for instar determination. Effect of temperature on rate of development of immature stages was determined. Pupae had a higher zero-development temperature than did eggs and larvae, and this was related to field populations that overwinter in the 4th instar. Adult female C. subimviaculatus matured the 1st egg batch autogenously even if not mated. At 22 to 27 °C, the 1st ovarian cycle lasted 2½ days and the 2nd cycle 5 days. Gonotrophic harmony did not occur under laboratory conditions. Mean fecundity of fieldcaught females in their 1st cycle was higher in spring (67 eggs) than in autumn (53 eggs), but when expressed as fecundity of similar-sized females (wing length 890 μm), autumn females matured more eggs (73) than spring females (58). Fecundity was much lower in subsequent anautogenous cycles (ca. 10 eggs per batch).