Two Artificial (Oligidic) Media for the Douglas-fir Beetle, Dendroctonus pseudotsugae Hopkins (Coleoptera: Scolytidae)

Abstract

Two artificial (oligidic) media have been developed for the rearing of Dendroctonus pseudotsugae under xenic conditions. One medium composed of macerated, frozen inner bark of Douglas fir, brewers yeast, antimicrobial agents sorbic acid and sodium benzoate, and water, permitted 75.17%, ± 3.04 S.E., of newly hatched larvae to develop to the adult stage. A second medium, composed of powdered, lyophilized inner bark of Douglas fir, brewers yeast, sorbic acid, sodium benzoate, glucose, cellulose, water, and agar, permitted 41.72%, ± 3.14 S.E., of newly hatched larvae to develop to the adult stage. The rate of development on each medium to the fourth-instar, pupal, and adult stages was somewhat shorter than that in published developmental data for this species. Immature beetles appear to be tolerant of considerable variation in pH and physical consistency and palatability of food material but are relatively sensitive to moisture levels. The adults obtained from each of the two media appeared to be normal, and the females were capable of laying viable eggs.