A method for maintaining successive generations of Monarch butterflies in the laboratory using an artificial larval diet

An artificial diet for the laboratory rearing of larvae of the Monarch butterfly, Danaus plexippus L., has been developed. The composition is as follows: (in grams) Gelcarin, 3; Kretschmer's (toasted) wheat germ, 30; sucrose, 30; Vitafree casein, 30; Torula yeast, 20; Wesson's salt mixture, 5; cholesterol, 1.5; β-sitosterol, 1.5; choline chloride, 1.5; sorbic acid, 1; ascorbic acid, 4; milkweed leaf powder, 15; Alphacel, 5; chlortetracycline, 1; (in ml) 2% formalin, 12; raw linseed oil, 10; vitamin mixture (Riddiford, 1968) 15; 10% KOH, 10; distilled water, 930. . Techniques of preparing the diet and rearing the larvae are described.

Monarch larvae reared on this diet compared favorably with foliage fed control animals. They achieved a pupation weight of 1.24 grams in 13.65 days after hatching with greater than 90% viability.