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In recent years, an increase in baseline arthropod surveys and closer scrutiny of specimens from current and past collections have resulted in a rise of adventive psyllid species discoveries in the Hawaiian Islands. In some cases, the new records reported here may have been known for some time but not officially published in the literature. In other cases, specimens remained unidentified for several years. We provide an updated checklist of the 23 adventive psyllid species in the Hawaiian Islands, including six new state records, and at least one new island record. The majority of recent psyllid establishment records, including those newly reported here, are in the subfamily Spondyliaspidinae (Aphalaridae). These records are overwhelmingly Australasian in origin, with host plant associations in the family Myrtaceae, predominantly Eucalyptus . One of these new Australasian-origin records, Australopsylla exotica Matsunaga & Percy, sp. nov ., is described here as a new species from adults and immatures. A molecular systematic overview of the phylogenetic placement of native and adventive taxa includes an analysis of the position of A. exotica within Australopsylla .

The Psylloidea, >4000 named species known today, are plant-feeding, sap-sucking insects sleeved under the Sternorrhyncha. Most species of Psylloidea are confined to the tropics. They occur as gall-inducing, free-living, and lerp-forming taxa. Lifecycles and generations of gall-inducing Psylloidea vary in temperate and tropical worlds. The Triozidae, Aphalaridae, and Calophyidae include several taxa that induce galls of diverse morphologies, from simple pits and leaf-margin rolls to complex pouches and of two-tier structures. The feeding mechanism and nutritional physiology of the gall-inducing taxa of the Psylloidea differ from those of the free-living and lerp-forming species. A majority of the gall-inducing Psylloidea are associated with the dicotyledons and a small number with the monocotyledons. The gall-inducing Psylloidea are specific to certain plants. Their host specificity is regulated by specific lipids and sterols. The gall-inducing Psylloidea show conservative behavior in terms of geographical distribution. Although the life histories of several gall-inducing Psylloidea are known today, aspects explaining their association with host plants are little known. Details of nutritional physiology of gall-inducing Psylloidea are less known presently compared with that of the free-living species. A better understanding of the association and level of relationship between gall-inducing Psylloidea and their host plants is necessary.

Bacteria associated with sap-feeding insect herbivores include not only symbionts that may increase their hosts' fitness but also harmful plant pathogens. Calophya spp. gall-inducing psyllids (Hemiptera: Calophyidae) are being investigated for their potential as biological control agents of the noxious weed, Brazilian peppertree (Schinus terebinthifolia), in Florida. Although there are no examples of plant pathogen transmission by members of the family Calophyidae, several insects in the superfamily Psylloidea are known to transmit pathogenic bacteria in the genera Candidatus Liberibacter and Candidatus Phytoplasma. To determine whether Calophya spp. harbor potentially harmful plant pathogenic bacteria, we sequenced small subunit (SSU) ribosomal RNA (rRNA) gene amplicons generated from individuals from four Calophya spp. populations: All microbial SSU gene sequences fell into the bacterial domain, with 98-99% belonging to the Proteobacteria. The Calophya microbiomes contained a relatively simple community, with 49-79 operational taxonomic units (OTUs; 97%) detected, and only 5-8 OTUs with greater than 1% abundance. Candidatus Carsonella showed the highest relative abundance, with OTUs from this candidate genus representing between 51-65% of all recovered sequences. The next most abundant clade observed was an unclassified Enterobacteriacae group closely related to bacteria from the genera Buchnera and Blochmannia that ranged from 20-31% in relative abundance. Wolbachia populations were the third most abundant group and represented 7-27% of the diversity in microbial OTUs. No SSU rRNA gene sequences from putative pathogenic bacteria from the genera Ca. Liberibacter or Ca. Phytoplasma were detected in the microbiomes of the four Calophya populations. The probability that infected psyllids were present in our colonies, but were not sampled, was extremley low (1.39 x 10(-10)). As far as we are aware, our study is the first to characterize the microbiome of a candidate biological control agent, and coupled with previous work demonstrating a high degree of host specificity and absence of plant viruses, suggests that releasing Calophya spp. in United States poses minimal risk to non-target plants.

The expression of plant secondary metabolism is strongly controlled by plant both in time and space. Although the variation of secondary metabolites, such as soluble and structural phenolics (e.g., lignins), has been largely observed in gall-inducing insects, and compared to their non-galled host organs, only a few datasets recording such variation are available. Accordingly, the relative importance of spatiotemporal variability in phenolic contents, and the influence of gall developmental stages on the original composition of host organs are poorly discussed. To address this knowledge gap, we histochemically determined the sites of polyphenol and lignin accumulation, and the polyphenol contents in three developmental stages of two calophyid galls and their correspondent host organs. Current results indicate that the compartmentalization of phenolics and lignins on Schinus polygama (Cav.) Cabrera follows a similar pattern in the two-calophyid galls, accumulating in the outer (the external tissue layers) and in the inner tissue compartments (the cell layers in contact with the gall chamber). The non-accumulation in the median compartment (median parenchyma layers of gall wall with vascular bundles, where gall inducer feeds) is important for the inducer, because its mouth apparatus enter in contact with the cells of this compartment. Also, the concentration of phenolics has opposite dynamics, decreasing in leaf galls and increasing in stem galls, in temporal scale, i.e., from maturation toward senescence. The concentration of phenolics in non-galled host organs, and in both galls indicated the extended phenotype of Calophya rubra (Blanchard) and C. mammifex Burckhardt & Basset (Hemiptera: Sternorrhyncha: Psylloidea: Calophyidae) over the same host plant metabolic potentiality.

Brazilian peppertree, Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae), is a highly successful invasive species in the continental United States, Hawaiian archipelago, several Caribbean Islands, Australia, Bermuda, and a number of other countries worldwide. It also is one of only a few invasive intraspecific hybrids that has been well characterized genetically. The natural enemy complex of Brazilian peppertree includes two thrips and two psyllids that appear to be highly adapted to specific haplotypes or their hybrids. Successful biological control of Brazilian peppertree will require careful matching of the appropriate natural enemies with their host plant genotypes. The Brazilian peppertree model reviewed here could provide a useful framework for studying biological control agents on other invasive weed species that have exhibited intraspecific hybridization.

Out of the nearly 250 species of plant-feeding arthropods that utilize Mangifera indica, about 25 gall midge species (Diptera Cecidomyiidae) (mostly species of Procontarinia Kieffer & Cecconi 1906) and one psylloid species (Apsylla cistellata (Buckton 1893), Hemiptera Calophyidae) are the known gall-inducing taxa. Almost all of these gall midges induce galls on leaves, whereas the psylloid induces galls on axillary vegetative buds. The M. indica-associated species of Procontarinia do not show any striking level of shifts either between organs within M. indica or between other Indian anacardiaceous taxa such as Anacardium, Buchanania, Lannea, Holigama, Pistacia, and Semecarpus, which, in fact, host several other species of Cecidomyiidae and Calophyidae. Given that galls induced by a suspected gall-midge species on the fossil leaves of an ancestral taxon of Mangifera indica from the Upper Palaeocene sediments of north-eastern India exist, the lack of radiation from leaves either to other organs of M. indica or to other anacardiaceous extant taxa suggests that neither the feeding behaviour nor the larval salivary physiology of species of Procontarinia has changed over time. The reason for such a conservative behaviour could be either the lack of resistance-breaking genes in the M. indica-associated Procontarinia complex or the abundance of populations of M. indica. A provisional reconstruction of the relationships among the extant M. indica-infesting gall-inducing Cecidomyiidae reveals that an extremely modest level of radiation in the leaf-gall-inducing species has occurred from those species that induce structurally simple galls to those that induce structurally complex galls. Because M. indica is an evergreen, polyaxial species, with new leaf flushes available almost throughout the year, and thus offering a continuous nutritional supply, the radiation and diversification of gall midges could have been restricted. In addition, the diverse, geographically localized varieties of M. indica with different types of secondary chemicals (e.g., xanthones and flavanols) may have also imposed a selection pressure on the radiation of gall midges; for instance, mangiferin, the principal secondary chemical present in M. indica, possibly acts as an attractant to the Cecidomyiidae and Apsylla cistellata and has, consequently, restricted their diversification. We speculate that the gall midges may have progressed conservatively specializing along the host-plant lines, because of the need for precise timing and for minimizing competitive interactions with other parasitic, predatory, and inquilinous arthropods, from the time of original host colonization. Available data on the gall-inducing species of the Procontarinia complex on the leaves of M. indica indicates that both the location and structure of galls generally agree with the patterns evident in other groups of gall-inducing insects, which induce galls of similar morphology, suggesting pathways of Procontarinia phy-logeny. Galls of different morphologies occur concurrently, mostly on the leaves of M. indica, and such an occurrence needs to be explored to establish the origin of multiple species of Procontarinia. In the context of M. indica-associated gall midges, only Procontarinia mangiferae lives both on stems and leaves of M. indica, indicating a critical step in Procontarinia speciation, through reproductive isolation involving phenologi-cal separation. Different species of Procontarinia occur on the same host tree and on the same leaf, but how different populations of gall-midge taxa partition their resources effectively and reduce inter-specific competition remain as questions. Effective utilization of the host plant and consequent speciation in the Procontarinia complex have resulted from the condition that continuously blossoming individual trees of M. indica are available throughout extensive landscapes. But apart from these speculative propositions, a need for empirical studies on the phylogeny and interactions between Procontarinia (and related genera) and M. indica exists. In Calophyidae, Apsylla Crawford 1912 did not speciate on M. indica; this may also be true for the three species of Calophya Loew 1879 associated with M. indica. Due to insufficient information this proposition remains unverified.