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Abstract. Parasitoid wasps of the subfamily Telenominae (Hymenoptera: Platygastroidea, Platygastridae) develop as immatures within the eggs of other insects (Lepidoptera, Hemiptera, Diptera and Neuroptera). Rearing records indicate that individual species are restricted to attack hosts within only one of these four main groups. We conducted a phylogenetic analysis of the group using sequence data from multiple genes (18S , 28S , COI , EF-1α) to assess the pattern of shifts among host groups and to test the monophyly of and relationships among genera and species-groups. Telenominae sensu Masner -that is, including only the nominate tribe Telenomini -is not monophyletic. Representatives of the Psix group of genera (Psix Kozlov & Lê and Paratelenomus Dodd) form a monophyletic group that is sister to Gryon Haliday (Scelioninae: Gryonini) and are excluded from the subfamily. The remaining telenomines are monophyletic. The genus Phanuromyia Dodd and the crassiclava group of Telenomus Haliday, both recorded as parasitoids of planthopper eggs (Hemiptera: Auchenorrhyncha, Fulgoroidea), form a monophyletic group that is sister to all other telenomines exclusive of the Psix group. Twenty-nine species of the crassiclava and aradi groups of Telenomus are transferred to Phanuromyia as new combinations. Basal elements of the remaining species are all in groups reared from the eggs of true bugs (Heteroptera), primarily the stink bugs (Pentatomoidea) and seed bugs (Lygaeoidea). A shift to parasitism of lepidopteran eggs evolved within a single clade, occurring either one or two times. From this clade a small group of species, the Telenomus tabanivorus group, subsequently shifted to parasitism of egg masses of true flies (Tabanidae and Stratiomyiidae). Aholcus Kieffer and Platytelenomus Dodd both belong to the clade of lepidopteran parasitoids and are considered as junior synonyms of Telenomus (new synonymy for Aholcus). The monophyletic status of the two core genera, Telenomus and Trissolcus could not be resolved using these data. The phylogenetic pattern of host shifts suggests comparisons among taxa that may be fruitful in elucidating mechanisms by which parasitoids locate their hosts, the proximate factors that determine the host range, and the changes in these factors that influence host changes.

Evidence suggesting polyphyly of the traditionally recognised tick genus Aponomma Neumann, 1899 is summarized. Continued recognition of this genus in its current concept leaves a polyphyletic genus Aponomma and a paraphyletic genus Amblyomma Koch, 1844. To improve the correlation between our understanding of phylogenetic relationships in metastriate ticks and their classification, a few changes in classification are proposed. The members of the 'indigenous Australian Aponomma' group (sensu Kaufman, 1972), A. auruginans Schulze, 1936, A. concolor Neumann, 1899, A. glebopalma Keirans, King & Sharrad, 1994, A. hydrosauri (Denny, 1843) and A. undatum (Fabricius, 1775), are transferred to Bothriocroton Keirans, King & Sharrad, 1994, which is raised to full generic rank. The remaining members of Aponomma are transferred to Amblyomma. Uncertainty remains on relationships of Bothriocroton to other metastriate lineages and on the systematic position of the two species formerly included in the 'primitive Aponomma' group, A. elaphense Price, 1959 and A. sphenodonti Dumbleton, 1943.

Mites are frequent ant symbionts, yet the exact nature of their interactions with their hosts is poorly known. Generally, myrmecophilous mites show adaptations for dispersal through phoresis, but species that lack such an adaptation may have evolved unusual specialized relationships with their hosts. The immature stages of Macrodinychus multispinosus develop as ectoparasitoids of pupae of the invasive ant Paratrechina longicornis. Feeding stages show regressed locomotor appendages. These mites complete their development on a single host, sucking all of its body content and therefore killing it. Locally high proportions of parasitized host pupae suggest that M. multispinosus could serve as a biological control agent. This is the ninth species of Macrodinychus reported as ant parasite, and the third known as parasitoid of invasive ants, confirming a unique habit in the evolution of mite feeding strategies and suggesting that the entire genus might be parasitic on ants. Several mites’ characteristics, such as their protective morphology, possible viviparity, lack of a specialized stage for phoretic dispersal, and low host specificity, combined with both the general low aggressiveness of invasive P. longicornis towards other ants and its possible susceptibility to generalist ectoparasites would account for the host shift in native macrodinychid mites.

The superfamily Platygastroidea (Hymenoptera: Proctotrupomorpha) is a diverse group of parasitoid wasps that are parasitoids of nine orders of insects as well as spiders. They appear to show a clear pattern of host group specificity among genera. A robust phylogeny is essential for devising a stable and informative classification and understanding the pattern of the shifts to parasitize new host groups. We conducted phylogenetic analyses of Platygastroidea based on four molecular markers (18S, 28S, COI and wingless) and 119 morphological characters, and a phylogenomic analysis of a subset of taxa based on 4371 single-copy, protein-coding genes. The four-gene analyses, both with and without morphological data, robustly recovered some well-established groups, e.g., Platygastridae (in its traditional sense), Scelionini, Teleasinae and Telenominae, as well as some novel patterns of relationship. The ground-plan host for the superfamily are the eggs of Orthoptera, with multiple shifts to attack new host groups. The phylogenomic analysis of a subset of taxa recovered a clear pattern of relationships for the backbone of the superfamily with maximal bootstrap support. Based on the combination of these two approaches, we present a revised classification for Platygastroidea and recognize the following eight families: Geoscelionidae stat.rev., Janzenellidae fam.nov., Neuroscelionidae fam.nov., Nixoniidae stat.rev., Platygastridae stat.rev., Proterosceliopsidae †, Scelionidae stat.rev. and Sparasionidae stat.rev.

Host specificity of vectors is an important but understudied force shaping parasite evolution and the relationship between hosts and parasites. Low vector specificity may allow a vectored parasite to invade new host species, whereas high specificity of vectors may reduce the host range of the parasite and favor specialization. The 'generalist' and widely distributed avian skin mite Myialges caulotoon Speiser (Acari: Epidermoptidae) is unusual because females require an insect vector to complete their life cycle. Myialges caulotoon was previously reported from 2 lousefly (Diptera: Hippoboscidae) species, Olfersia sordida and Icosta nigra, parasitizing flightless cormorants (Phalacrocorax harrisi) and Galápagos hawks (Buteo galapagoensis), respectively, within the Galápagos Islands. This is a surprising distribution, given that the 2 lousefly species involved are relatively host-specific. Mitochondrial DNA sequences revealed 2 reciprocally monophyletic Myialges clades that sorted out perfectly with respect to their vector species, regardless of whether they were in allopatry or sympatry. One clade was restricted to flies of hawks and the other to flies of cormorants. Females of the 2 Myialges groups were also separated consistently by the shape of the sternal surface sclerotization. Mites of hawk flies were more abundant than those of cormorant flies. Within the Myialges clade associated with hawks, genetic differentiation between 2 island populations mirrored its host's patterns of differentiation.

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