Case of mistaken identity: resolving the taxonomy between Trioza eugeniae Froggatt and T. adventicia Tuthill (Psylloidea: Triozidae)

Abstract

The ‘Eugenia psyllid’ or ‘Lilly pilly psyllid’, widely recognized in Australia and in the USA as Trioza eugeniae Froggatt (Hemiptera: Triozidae), is not T. eugeniae, but rather T. adventicia Tuthill. In this study we assessed morphological comparisons of materials from throughout the native and introduced ranges and re-examined original descriptions of both taxa, together with Froggatt's type specimens of T. eugeniae. Furthermore, through DNA barcoding analyses, we confirmed the validity of both T. adventicia and T. eugeniae as separate species. We re-described both species to include additional characters not previously included and designated a lectotype for T. eugeniae. T. eugeniae has smaller fore wings that are slightly more elongate. These lack infuscation around veins R and R1, vein Rs is relatively longer, meeting the costa closer to the wing apex; with certain veins bearing long, fine divergent setae, a character not previously described. It has consistently three inner and one outer metatibial spurs. The male parameres appear narrowly pyriform with a weak dorsolateral lobe and weakly sclerotized apices. T. adventicia has larger fore wings that are slightly more ovate with dark infuscation around veins R and R1; vein Rs is relatively shorter, meeting the costa further from the wing apex, with veins lacking long, fine divergent setae. The usual configuration of two inner and one outer metatibial spurs, previously used to separate the two species, appears inconsistent. The male parameres appear a little more broadly pyriform with slightly more sclerotized apices. T. eugeniae refers to a distinct species which has a restricted distribution only in its native range in southern subcoastal New South Wales, Australia. T. adventicia refers to a separate species, with a natural distribution in eastern subcoastal Australia, but has been introduced widely in southern Australia, to New Zealand and the USA. This study elucidates a long history of misidentification of T. eugeniae in the nursery industry and in almost 30 years of literature on its biological control in the USA. Regardless, the biological control program, unknowingly, targeted the correct species of psyllid, T. adventicia, in its foreign exploration and importation of the appropriate parasitoid as a biocontrol agent in the USA. Despite being firmly entrenched in both the nursery trade and scientific literature, the name T. eugeniae is misapplied. While the acceptance of the valid name, T. adventicia, might be regarded as both problematic and protracted, this is the correct taxonomical attribution.

Description of an Australian endemic species of Trioza (Hemiptera: Triozidae) pest of the endemic tea tree, Melaleuca alternifolia (Myrtaceae)

“…tristaniae are both endemic to Australia, but hosted by Syzygium and Lophostemon confertus (R.Br.) Peter G.Wilson & J.T.Waterh., respectively [ 12 , 28 ]. Furthermore, T .…”

“…adventicia (♂ 2.90–3.10, ♀ 3.24–3.41) and T . eugeniae (♂ 2.72–3.07, ♀ 3.03–3.17) [ 12 ]. The wing apex is also rounder in shape ( Fig 5 ).…”

“…Of these, three are known to be hosted by Myrtaceae: Trioza adventicia Tuthill and T . eugeniae Froggatt [ 12 ], on Syzygium P. Browne ex Gaertn., and T . tristaniae Froggatt, on Lophostemon Schott.…”

Illuminating Insights into the Biodiversity of the Australian Psyllids (Hemiptera: Psylloidea) Collected Using Light Trapping

“…The need for a complete reference database is highlighted in our study, not only to better understand biodiversity, but also for biosecurity-two of the species we collected had their closest matches on GenBank with a major exotic pest, the Asian citrus psyllid Diaphorina citri (Table S1). Furthermore, of the few taxa identified to species level, two species are new records for the state of Queensland: Cryptoneossa triangula and Trioza adventicia [3,43].…”

“…Since the paucity of specimens might complicate morphological identification, DNA barcode data, comprising a short DNA sequence from the 5′ region of the subunit I of the cytochrome oxidase c (COI) gene [ 41 ], could be matched on a publicly available database, such as BOLD [ 42 ], as an alternative means of identification. Furthermore, DNA barcoding has proved extremely valuable when applied to psyllid diversity, allowing biodiversity assessments [ 28 ], species identifications [ 43 ] and the description of new genera [ 17 ].…”