Distribution of Wax Gland Pores on the Body Surface and the Dynamics of Wax Secretion of Wooly Apple Aphid Eriosoma lanigerum (Hemiptera: Aphididae)

ABSTRACT: Eriosoma lanigerum (Hemiptera: Aphididae) is an important invasive pest causing serious damage to apple trees in many countries. The powdery wax covering the integument of this aphid plays an important role in its defense against natural enemies. We examined all instars and adults of E. lanigerum to determine the morphology and distribution of wax gland pores. We found four lines of wax-gland plates, two pleural and two marginal, on all thoracic segments and on the first seven abdominal segments. On the head, there are six pleural and two marginal plates on the first, while the eighth abdominal segment had just two pleural plates. In total, 50 wax gland plates were distributed over the dorsal region of the aphid. Each plate was composed of several wax gland pores arranged in a circle, with from 3 to 12 “petals.” On average, abdominal segments had 8 to 12 pores, thoracic segments had 7 – 10 pores, and the head had 5 – 8 pores. The wax secreted by different instars varied, and the optimal time to ...