Differences in the quality and quantity of honeydew from first instar soldier and ordinary morph nymphs of the bamboo aphid, Pseudoregma koshunensis (Takahashi) (Homoptera : Aphididae)

Abstract

Although the body size of 1st-instar soldier nymphs was larger than that of ordinary morphs of the bamboo aphid, Pseudoregma koshunensis (Takahashi), the diameters of the honeydew droplets excreted by these two morphs did not differ significantly. Soldiers excreted honeydew droplets significantly less frequently than ordinary 1st-instar nymphs. Total sugar and sugar per droplet excreted by soldiers were significantly less than those excreted by ordinary 1st-instar nymphs. However, the amino acid content of each honeydew droplet was slightly greater for soldiers than for ordinary 1st-instar nymphs. In the soldier's honeydew, asparagine was the most abundant amino acid, and constituted as much as 62 mol% of the total amino acid content, while in the honeydew of ordinary 1st-instar nymphs, both asparagine (32 mol%) and serine (20 mol%) were abundant. These results suggest a difference in nutritional requirements between the two morphs.