Artificial diets for larvae of Anarsia lineatella Zeller (Lepidoptera: Gelechiidae)

Maintenance of an insect colony under laboratory conditions is prerequisite for its further study. However, numerous artificial diet formulas, such as dietary replacements or supplements, influence species growth and survivorship and display difficulties in utilization in laboratory settings. In this work, successful rearing in the laboratory is reported for the peach twig borer A. lineatella on artificial diet. The diet contains dry pindo beans (380 g), brewer's yeast (64 g) agar 31 g, 1360 ml distilled water and preservatives. It is a modification of an artificial rearing medium proposed for the development of the Tortricid Cydia pomonella. Larval survivorship, when developed on the above diet, is significantly higher (-90%) when compared to peach fruits (-60%) and to other diets that were initially tested (5-35%). Diet had no effect on larval developmental time when compared to fruits (27.1 +/- 0.4 and 27.2 +/- 0.5 days, respectively, at 25 degrees C and 65 +/- 5% RH). Light presence of 16:8h L:D did not appear to be a critical factor for a successful rearing of A. lineatella larvae in the laboratory. Type of diet had a significant effect on male (d.f. = 4,103, F = 18.562, P < 0.05) and female (d.f. = 4,91, F = 14.990, P < 0.05) pupal weights. Pupal weights, when they developed as larvae on the proposed 'pindo-bean' diet, ranged from 7.7 +/- 0.3-8.2 +/- 0.2 mg. First-instar larvae exhibited lower survivorship during development, regardless of rearing medium. Sex ratio, for individual larval rearing, was in all cases close to 1:1 regardless of tested rearing medium. More than five generations of A. lineatella were reared under constant conditions without observable adverse effects on development.