Host assessment and feeding behaviour of adult female <i>Glycaspis brimblecombei</i> on preferred and non‐preferred eucalypts

Insect herbivores assess plants by integrating responses elicited a variety of external and internal cues signals mediated physical chemical traits. We investigated host assessment behaviours adult females the Eucalyptus-feeding psyllid, Glycaspis brimblecombei Moore (Hemiptera: Aphalaridae), on 10 species subspecies (comprising preferred non-preferred hosts) using video recordings, electrical penetration graph (EPG) technology, histological examination tissues surrounding secondary veins. Our recordings indicated that shortest first searching time (mean 7.5 s) occurred hosts. Females placed novel (non-preferred) hosts jumped off leaves in <10 s. found acceptance surprisingly rapidly after stylet penetration, e.g., between 7 11 s eucalypts, suggesting strong role for gustatory cues. studies provided no evidence barriers to phloem access. produced eight EPG waveforms, as observed other psyllids aphids, but durations PG (xylem activity) PE2 (phloem ingestion), particular, were unlike those recorded any hemipteran. On hosts, ingestion represented 21.5% duration 4 h 18 min) individual feeding bouts, whereas there was almost from phloem. Xylem 20.1% 1 presumably imbibe water. Thus, contrary widespread belief, female G. did not feed exclusively even also regularly ingested xylem. This is surprising considering nymphs construct lerps consisting approximately 16% sugars, suggests adults shorter periods than offspring. Rapid could mean positive stimuli induced sugars are opposed negative experienced non-vascular tissues. The most likely source such water-soluble polyphenolic compounds cell vacuoles.