A key is provided for the recognition of previously described Encarsia species which are known to attack the tobacco whitefly, Bemisia tabaci (Gennadius). 28 nominal species are included, of which type material has been examined for 22. Eight new synonymies are proposed: Encarsia aleyrodis (Mercet) and E. partenopea Masi are both synonymized with E. inaron (Walker); E. bemisiae (Ishii) is synonymized with E. transvena (Timberlake); £. citri (Ishii) is synonymized with E. strenua (Silvestri), E. angelica Howard and E. deserti Rivnay & Gerling are both synonymized with E. luteola Howard; E. perspicuipennis (Girault) is synonymized with E. auaintancei (Howard); £. tabacivora Viggiani is synonymized with E. pergandiella Howard. E. hispida De Santis is removed from synonymy with E. meritoria Gahan. A lectotype is designated for E. porteri (Mercet). The known distributions and alternative hosts of Encarsia species attacking B. tabaci are provided as well as references to biology and notes on their use in biological control.

The family Tenuipalpidae is worldwide in distribution and includes several economically important pest species. Species of the genus Brevipalpus have been identified as vectors of rhabdoviruses that cause diseases such as citrus leprosis, coffee ring spot virus, passion fruit green spot virus and others that reduce the production and the life span of the plants. An updated list of the Tenuipalpidae (Acari: Prostigmata), a key to the genera of the world and data on zoogeographical distribution of the species are presented. The catalogue provides information on 891 known species (including 3 species incertae sedis) belonging to 34 genera. The valid name of each species, the author, date and page of the corresponding original description, type locality and host, species designation(s), references to species redescription(s) and other complementary information are presented. The genera Rarosiella Rimando 1996 and Neoraoiella Mohanasundaram 1996 are synonymized with Raoiella Hirst 1924. The genus Meyeraepalpus Smiley, Frost & Gerson 1996 is synonymized with the genus Aegyptobia Sayed 1950. Three new genera, Magdalenapalpus, Chaudhripalpus and Urigersonus are erected. Indices of the plant host species and families associated with each species, the number and regional distribution of species in each genus, and a list of relevant publications of species from each zoogeographical region are included.

BackgroundHumans and insect herbivores are competing for the same food crops and have been for thousands of years. Despite considerable advances in crop pest management, losses due to insects remain considerable. The global homogenisation of agriculture has supported the range expansion of numerous insect pests and has been driven in part by human-assisted dispersal supported through rapid global trade and low-cost air passenger transport. One of these pests, is the whitefly, Bemisia tabaci, a cryptic species complex that contains some of the world’s most damaging pests of agriculture. The complex shows considerable genetic diversity and strong phylogeographic relationships. One consequence of the considerable impact that members of the B. tabaci complex have on agriculture, is the view that human activity, particularly in relation to agricultural practices, such as use of insecticides, has driven the diversification found within the species complex. This has been particularly so in the case of two members of the complex, Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED), which have become globally distributed invasive species. An alternative hypothesis is that diversification is due to paleogeographic and paleoclimatological changes.ResultsThe idea that human activity is driving speciation within the B. tabaci complex has never been tested, but the increased interest in fossil whiteflies and the growth in molecular data have enabled us to apply a relaxed molecular clock and so estimate divergence dates for the major lineages within the B. tabaci species complex. The divergence estimates do not support the view that human activity has been a major driver of diversification.ConclusionsOur analysis suggests that the major lineages within the complex arose approximately 60–30 mya and the highly invasive MED and MEAM1 split from the rest of the species complex around 12 mya well before the evolution of Homo sapiens and agriculture. Furthermore, the divergence dates coincide with a period of global diversification that occurred broadly across the plant and animal kingdoms and was most likely associated with major climatic and tectonic events.

Since Panayiotis Gennadius first identified the whitefly, Aleyrodes tabaci in 1889, there have been numerous revisions of the taxonomy of what has since become one of the world's most damaging insect pests. Most of the taxonomic revisions have been based on synonymising different species under the name Bemisia tabaci. It is now considered that there is sufficient biological, behavioural and molecular genetic data to support its being a cryptic species complex composed of at least 34 morphologically indistinguishable species. The first step in revising the taxonomy of this complex involves matching the A. tabaci collected in 1889 to one of the members of the species complex using molecular genetic data. To do this we extracted and then amplified a 496 bp fragment from the 3′ end of the mitochondrial DNA cytochrome oxidase one (mtCOI) gene belonging to a single whitefly taken from Gennadius' original 1889 collection. The sequence identity of this 123 year-old specimen enabled unambiguous assignment to a single haplotype known from 13 Mediterranean locations across Greece and Tunisia. This enabled us to unambiguously assign the Gennadius A. tabaci to the member of the B. tabaci cryptic species complex known as Mediterranean or as it is commonly, but erroneously referred to, as the ‘Q-biotype’. Mediterranean is therefore the real B. tabaci. This study demonstrates the importance of matching museum syntypes with known species to assist in the delimitation of cryptic species based on the organism's biology and molecular genetic data. This study is the first step towards the reclassification of B. tabaci which is central to an improved understanding how best to manage this globally important agricultural and horticultural insect pest complex.

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