Since 2002, I have been working on the psyllids of the Pacific region, focusing on Pacific Ocean islands. I have visited eastern and western regions of the Pacific to survey psyllid diversity on different islands, and to determine the host plant associations.

Hawaiian Islands: I have surveyed all the taxonomic groups in the Hawaiian Islands and will be publishing revisions of the psyllid fauna.

Completed is a revision of the psyllids that feed on Metrosideros (Myrtaceae), and in particular the mechanisms of speciation in the Hawaiian Metrosideros-feeding group. Mitochondrial sequence data sets and morphological descriptions for all 36 named species, now included in the genus Pariaconus, are included in the paper (Percy 2017).

One of the most striking features of the Metrosideros-psyllid system in the Hawaiian Islands is the range of gall types produced by this monophyletic lineage of psyllids as it has diversified on Metrosideros polymorpha from one island to the next.

Triozid nymphs of Pariaconus dorsostriatus in the bicoloratus-species group on Metrosideros (Big Island)

stem cup galls of P. crassiorcalix (Kauai)

P. crassiorcalix (Kauai)

stem cup galls of P. caulicalix (Kauai)

leaf galls upper leaf surface P. pele and P. pyramidalis (Big Island)

leaf galls lower leaf surface P. pele and P. pyramidalis (Big Island)

Adult P. crassiorcalix on pubescent bog morphotype of M. polymorpha (Kauai)

Considerable leaf mortality can be imposed by heavy gall load from psyllids. A Metrosideros leaf that has been heavily galled by psyllids (probably all P. hiiaka) and leaf necrosis has occurred while still on the branch