Psyllids are plant sap-feeding insects that harbor prokaryotic endosymbionts in specialized cells within the body cavity. Four-kilobase DNA fragments containing 16S and 23S ribosomal DNA (rDNA) were amplified from the primary (P) endosymbiont of 32 species of psyllids representing three psyllid families and eight subfamilies. In addition, 0.54-kb fragments of the psyllid nuclear gene wingless were also amplified from 26 species. Phylogenetic trees derived from 16S-23S rDNA and from the host wingless gene are very similar, and tests of compatibility of the data sets show no significant conflict between host and endosymbiont phylogenies. This result is consistent with a single infection of a shared psyllid ancestor and subsequent cospeciation of the host and the endosymbiont. In addition, the phylogenies based on DNA sequences generally agreed with psyllid taxonomy based on morphology. The 3' end of the 16S rDNA of the P endosymbionts differs from that of other members of the domain Bacteria in the lack of a sequence complementary to the mRNA ribosome binding site. The rate of sequence change in the 16S-23S rDNA of the psyllid P endosymbiont was considerably higher than that of other bacteria, including other fast-evolving insect endosymbionts. The lineage consisting of the P endosymbionts of psyllids was given the designation Candidatus Carsonella (gen. nov.) with a single species, Candidatus Carsonella ruddii (sp. nov.).

Cospeciation of psyllids and their primary prokaryotic endosymbionts

This paper integrates the scattered information on the life histories of the jumping plant lice or psyllids, examining those aspects of their biology that contribute to successful life cycle completion Variation in life history parameters is reviewed across the world's psyllids and the relative importance of phylogeny and environment, including host‐plant growth strategy, in determining life history strategies is assessed Elements of life cycles considered include: development rate and voltinism, response to high temperature and drought, cold‐hardiness and overwintering strategy, seasonal polymorphism, diapause, metabolism, host‐plant selection and range, phenological and other adaptations to host plants, disease transmission and host amelioration, dispersal, reproduction and mate finding Life history parameters are analyzed for 342 species While a phylogenetic signal can be identified within the data, the main drivers for life history adaptation are environmental temperatures and water availability, 

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Life cycle variation and adaptation in jumping plant lice (Insecta: Hemiptera: Psylloidea): a global synthesis

A revised classification for the world jumping plant-lice (Hemiptera: Psylloidea) is presented comprising all published family and genus-group names. The new classification consists of eight families: Aphalaridae, Carsidaridae, Calophyidae, Homotomidae, Liviidae, Phacopteronidae, Psyllidae and Triozidae. The Aphalaridae, Liviidae and Psyllidae are redefined, 20 family-group names as well as 28 genus-group names are synonymised, and one replacement name is proposed [Sureaca nomen nov., for Acaerus Loginova, 1976]. Forty two new species combinations are proposed resulting from new genus-group synonymies and a replacement name. One subfamily and three genera are considered taxa incertae sedis, and one genus a nomen dubium. Finally eight unavailable names are listed ( one family-group and seven genus-group names).

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A revised classification of the jumping plant-lice (Hemiptera: Psylloidea)

The potato/tomato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Triozidae) has been a major pest of solanaceous crops for decades. This pest can cause damage to crop plants by direct feeding and, as has been recently discovered, by transmitting the bacterial pathogen Candidatus Liberibacter psyllaurous (a.k.a. Ca. L. solanacearum). Many studies have been conducted to determine the relationship of this pest to plant injury and to develop management strategies to alleviate the damage caused by this pest in a wide variety of solanaceous plants. Studies in the past decade have documented substantial genetic variability in this invasive species, enhanced our rapidly-evolving understanding of the interactions between the insect and the pathogen it carries, and improved our appreciation of the invasive potential of the pest. This review seeks to provide a comprehensive update to B. cockerelli life history, relationship to plant diseases, and the current state of management strategies against B. cockerelli.

The potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Triozidae): life history, relationship to plant diseases, and management strategies.

Evolutionary and biological patterns can be obscured by inadequate or ill-defined terminology. An example is the generally very specific relationship between the sap-feeding hemipteran group, psyllids, and their breeding plants, commonly called host-plants. The literature is clogged with references to so called ‘hosts’, which are often merely plants on which psyllids were found accidentally, and no immature development was detected. Recently the term host has also been applied by some authors to any plant on which immature or adults feed. Here we propose a terminology to clarify associated plant definitions, and we suggest restricting the use of the term host-plant to plants on which a psyllid species completes its immature to adult life cycle. For the other plant associations we suggest the terms overwintering or shelter plant (plants on which adult psyllids overwinter and on which they may feed), food plant (plants on which adult psyllids feed, but do not breed and do not spend an extended period of time) and casual plant (plants on which adult psyllids land but do not feed).

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Psyllid host-plants (hemiptera: psylloidea): resolving a semantic problem

The phylogenetic significance of morphological characters used to diagnose Bactericera, Rhinopsylla, Paratrioza, Allotrioza, Klimaszewskiella, Eubactericera, Phylloplecta and Sinitrioza is examined. There is no evidence that the genera or subgenera, in any of their present or past definitions, constitute natural units. The six former together, however, form a monophyletic group, defined by a combination of adult, larval and egg characters. Phylloplecta and Sinitrioza, which share similar adult characters with Bactericera, differ in the larval and egg morphology. The following new synonymies are established: Bactericera (=Rhinopsylla pro parte, = Paratrioza, = Allotrioza, = Klimaszewskiella, = Eubactericera pro parte) and Phylloplecta (= Sinitrioza). A list of the 121 species included in Bacerticera is provided and 75 new combinations are introduced (60 in Bactericera, 4 in Phylloplecta, 9 in Trioza and 1 in Kuwayama). Bactericera equisetifolii sp. n. and B. vellae sp. n. are described from Israel and Spai...

A taxonomic reassessment of the triozid genus Bactericera (Hemiptera: Psylloidea).

The jumping plant-lice of Iran (Homoptera, Psylloidea).

Based on a cladistic analysis, the subfamily Rhinocolinae is redefined to comprise 13 genera and 39 species, of which two genera and eight species remain unnamed. Four new genera and 14 new species are described; one subfamily and one genus are synonymized, and two species are recombined; one lectotype is designated. The subfamily is divided into two groups, one with a Gondwanan distribution comprising four genera in Australia, New Zealand, South America and Africa, and another with Laurasian distribution in the Palaeotropics, the Western Palaerctic and North America comprising nine genera. Twenty-one species develop on host plants in the Rutales, three on Asteraceae, three on Cistaceae and one on Zygophyllaceae. The genus Pistacia (Anacardiaceae) in particular hosts six species whose biology is discussed.

Systematics and biology of the Rhinocolinae (Homoptera: Psylloidea)

The species of an ill-defined assemblage centred around Aphalara exilis are revised. Two species, viz. A. siamensis and A. taiwanensis, are described as new and three species are synonymised (A. soosi with A. exilis, A. kunashirensis with A. itadori, and A. augusta with A. fasciata). A neotype is designated for Tettigonia exilis, a lectotype is designated for Aphalara rumicis Mally, and Aphalara ulicis is removed from synonymy with Aphalara calthae. The species are diagnosed, illustrated and keyed. The revision of types of A. polygoni, the type species of Aphalara, showed that it had been misinterpreted and that it corresponds to A. rumicicola Klimaszewski which is synonymised with it. A. polygoni auct. nec Foerster is described as A. freji sp. n. A list is given of the 37 currently recognised valid species of Aphalara with their distributions and host plants, and of 4 nomina dubia. A cladistic analysis using PAUP yielded 5 most parsimonious trees suggesting that Aphalara contains six monophyletic species groups (the itadori (2 spp.), siamensis (1 sp.), exilis (7 spp.), rumicis (2 spp.), maculipennis (4 spp.) and calthae (21 spp.) groups). Biogeographical aspects are analysed in terms of area relationships (BPA), ancestral areas (methods of Bremer and Ronquist) and dispersal (cladistic subordinateness). Four species groups are restricted to the palaearctic, one to the nearctic and only one occurs in both. It is concluded that vicariance events may have occurred in the palaearctic but that the presence in the nearctic is probably due to dispersal. The east palaearctic is likely to have been part of the ancestral area of Aphalara. Three of the species groups are monophagous on Polygonum, two on Rumex and one is polyphagous on Polygonaceae (Polygonum, Rumex), Brassicaceae, Caryophyllaceae, Primulaceae and Ranunculaceae. Polygonum is the likely ancestral host association of Aphalara; Rumex has been colonised independently at least three times.

Systematics and biology of the Aphalara exilis (Weber & Mohr) species assemblage (Hemiptera: Psyllidae)

The psylloid fauna of Afghanistan is reviewed comprising, 32 identifi ed species, 15 of which are recorded from the country for the fi rst time, including Agonoscena klapperichi sp. nov. (Psyllidae: Rhinocolinae), which is formally described and illustrated. Additional illustrations are provided for Craspedolepta manica Baeva, 1978, Cacopsylla cf. nasuta (Horváth, 1904) and Trioza urticae Linnaeus, 1758. Another 5 species are represented by insuffi cient material and cannot be currently identifi ed. The bulk of the examined material comes from four expeditions by J. Klapperich, O. Jakeš, M. Daniel and E. S. Sugonyaev in the 1950’s and 1960’s. The psylloid fauna of Afghanistan remains poorly known and additional species can be expected. The biogeographical relationships and economic importance of the Afghan psylloid fauna are briefl y discussed. In addition, a new record of Psyllopsis securicola Loginova, 1963 from Iraq is provided.

Pavel Lauterer

Papers

A taxonomic reassessment of the triozid genus Bactericera (Hemiptera: Psylloidea).

The jumping plant-lice of Iran (Homoptera, Psylloidea).

Systematics and biology of the Rhinocolinae (Homoptera: Psylloidea)

Systematics and biology of the Aphalara exilis (Weber & Mohr) species assemblage (Hemiptera: Psyllidae)

Jumping plant-lice (Hemiptera: Psylloidea) of Afghanistan.