Yolk deposition in the Douglas-fir bark beetle, Dendroctonus pseudotsugae (Hopk.): the significance of physiological state of oocytes

Abstract

In vitro yolk deposition was studied in ovaries dissected out of Dendroctonus pseudotsugae at various times after attack on host logs, and incubated in medium containing a mixture of labeled haemolymph and ovarial proteins. These proteins were not deposited in the oocytes taken from beetles which had been on host logs for less than 48 h. Such proteins were deposited as yolk in the basal and penultimate oocytes from beetles which had been on host logs for more than 48 h; younger oocytes from the same ovaries did not exhibit yolk deposition. Presence of juvenile hormone in the incubating medium did not induce yolk deposition in oocytes not already engaged in vitellogenesis.