Phylogenetic investigation of the genus Raoiella (Prostigmata: Tenuipalpidae): diversity, distribution, and world invasions.

The genus Raoiella is best known because of the red palm mite, R. indica, a major pest of palms spreading aggressively throughout the Americas. Not much was known about the biology, geographic origins, or evolutionary history of the genus when R. indica emerged as a major invasive pest. This paper attempts to address some of the basic historical questions regarding the palm mite as well as the genus. Molecular characters from COI and 28S regions were used to produce a phylogenetic hypothesis for the genus in an effort to understand its geographic origin. It also uses COI barcode data to delimit several potentially new species discovered by the authors in Australia. Results show a basal split between R. indica and all other Raoiella species, which indicates Africa or the Middle East as the most probable origin of the genus. Additionally, COI data suggests that at least eight new species are represented among the 20 Australian populations included in this study.

External mouthpart morphology in the Tenuipalpidae (Tetranychoidea): Raoiella a case study.

The use of low-temperature scanning electron microscopy (LTSEM) to study external mouthpart morphology in the Tenuipalpidae, in particular the genus Raoiella, has brought some aspects of the mechanics of feeding in this group into question. In addition, an LTSEM study on the specialized feeding behaviour of Raoiella indica Hirst (Tetranychoidea: Tenuipalpidae) revealed host plant use in this species could be affected by stomatal complex morphology.

Delimiting species boundaries within Dermanyssus Dugès, 1834 (Acari:Dermanyssidae) using a total evidence approach.

The genus Dermanyssus is currently composed of 24 hematophagous mite species and includes the Poultry Red Mite, Dermanyssus gallinae, a serious pest in poultry houses. Morphologically, Dermanyssus species fall into two groups corresponding to Moss'gallinae-group and to hirsutus-group+Microdermanyssus. Species of the gallinae-group exhibit high levels of morphological variability, and are nearly impossible to distinguish. Species of the second group display consistent characters and host associations and are easily distinguishable. Species of the gallinae-group tend to be the major problems in poultry houses and it is unknown whether D. gallinae is the only pest, or if there are numerous cryptic species present in the system. Twenty species of Dermanyssus were tested phylogenetically based on 46 morphological characters. A subset of species, mainly of the gallinae-group, represented each by several populations, was sequenced for two mitochondrial and one nuclear gene regions. This allowed testing their specific status and their interrelationships based and on morphological and molecular characters. The molecular data was analysed separately and in combination with morphological characters. As expected, morphology did a poor job resolving relationships. Molecular data proved more informative. The resulting phylogenetic hypotheses brought some information about interrelationships among species of the gallinae-group showing a split into two main clades. The invasion of human managed environments seems to occur only in taxa within one of the two clades. The host spectrum seems to get enlarged in more derived taxa in the same clade. A delineation of six species within the gallinae-group is provided. Additionally, a key for morphological identification of these species is provided. D. gallinae appears to be the only pest in poultry houses, but is composed of several different and more or less strongly isolated lineages. A new species found from the black swift is described.

Molecular phylogenetic assessment of host range in five Dermanyssus species.

Given that 14 out of the 25 currently described species of Dermanyssus Dugès, 1834, are morphologically very close to each another, misidentifications may occur and are suspected in at least some records. One of these 14 species is the red fowl mite, D. gallinae (De Geer, 1778), a blood parasite of wild birds, but also a pest in the poultry industry. Using molecular phylogenetic tools we aimed to answer two questions concerning host specificity and synanthropicity: (1) is D. gallinae the only species infesting European layer farms?, and (2) can populations of D. gallinae move from wild to domestic birds and vice versa? Mitochondrial cytochrome oxidase I gene sequences were obtained from 73 Dermanyssus populations collected from nests of wild European birds and from poultry farms and these were analyzed using maximum parsimony and Bayesian inference. Mapping of the observed host range on the obtained topology and correlation with behavioural observations revealed that (1) host range is strongly dependent on some ecological parameters (e.g. nest hygiene, exposure to pesticides and predators), that (2) out of five species under test, synanthropic populations were found only in lineages of D. gallinae, and that (3) at least some haplotypes found in wild birds were very close to those found in association with domestic birds.