Growth and Survival of Culicoides Melleus Larvae (Diptera: Ceratopogonidae) on Four Prey Organisms1

Growth of the predatory larvae of Culicoides melleus on 4 prey organisms was compared by measurement of daily changes in larval body length and dry weight. The prey organisms were Brachionus plicatilis (a haline rotifer), the nematode Panagrellus redivivus (the largest nematode species used), and 2 unnamed nematodes designated species N (intermediate in size) and n (the smallest species). Food organisms were provided in excess throughout larval development and all rearing was done in nutrient agar at 27 °C. Survival of 1st-instar larvae fed P. redivivus was slightly but significantly reduced compared to larvae fed the other 2 nematode species. Growth was rapid and very similar in larvae fed P. redivivus and species N. However, larvae provided with the smallest nematode, species n, showed progressively retarded development after day 9 of the experiment. Nematode n was apparently too small to support optimal larval growth once larvae had reached the 3rd instar. The rotifer B. plicatilis was provided to larvae only after day 8, the larvae having been fed P. redivivus until this time. Larvae so treated continued to develop quite rapidly to pupation, but their growth was somewhat slower than that of larvae fed P. redivivus and species N nematodes. Withholding vitamins and other supplementary trace nutrients from the rearing medium resulted in considerable asynchrony and retardation in development. The importance of the results in defining suitable diets for rearing predatory ceratopogonid larvae is discussed.