Radmila Petanović

Plant–eriophyoid mite interactions: cellular biochemistry and metabolic responses induced in mite-injured plants. Part I

This review is a comprehensive study of recent advances related to cytological, biochemical and physiological changes induced in plants in response to eriophyoid mite attack. It has been shown that responses of host plants to eriophyoids are variable. Most of the variability is due to individual eriophyoid mite–plant interactions. Usually, the direction and intensity of changes in eriophyoid-infested plant organs depend on mite genotype, density, or the feeding period, and are strongly differentiated relative to host plant species, cultivar, age and location. Although the mechanisms of changes elicited by eriophyoid mites within plants are not fully understood, in many cases the qualitative and quantitative biochemical status of mite-infested plants are known to affect the performance of consecutive herbivorous arthropods. In future, elucidation of the pathways from eriophyoid mite damage to plant gene activation will be necessary to clarify plant responses and to explain variation in plant tissue damage at the feeding and adjacent sites.

Plant–eriophyoid mite interactions: specific and unspecific morphological alterations. Part II

The paper presents recent advances related to both specific and unspecific morphological alterations of plant organs caused by eriophyoid mites. Based on old and new case studies, the diversity of plant malformations, such as galls, non-distortive feeding effects and complex symptoms induced by eriophyoids and/or pathogens vectored by them, is analysed and summarised.

Collection and detection of eriophyoid mites

Methods for collecting and detecting eriophyoid mites are crucial components in research, taxonomical and biological studies, and control programs for these organisms. Their small size, their specific host-plant interactions and their hidden life-style make them difficult to find in routine inspections. This review examines successful and unsuccessful approaches for collecting eriophyoid mites, and makes recommendations for their detection, supporting studies in taxonomy, ecology, biology, molecular systematics and population genetics.

Anatomical injury induced by the eriophyid mite Aceria anthocoptes on the leaves of Cirsium arvense

Anatomical injury of the leaves of the invasive species, Cirsium arvense (L.) Scop., caused by the eriophyid mite Aceria anthocoptes (Nal.), which is the only eriophyid mite that has been recorded on C. arvense worldwide, is described. The injury induced by the mite feeding on the leaves of C. arvense results in visible russeting and bronzing of the leaves. Other conspicuous deformations are folding and distortion of the leaf blade and curling of leaf edge, as well as gradual drying of leaves. The anatomical injury of the mature leaves of field-collected plants was limited to the epidermis of the lower leaf surface. However, on young leaves of experimentally infested plants, rust mite injuries extend to epidermal cells on both leaf surfaces and to those of deeper mesophyll layers. On these leaves, lesions on the lower leaf surface even affected the phloem of the vascular bundles. Leaf damage induced by A. anthocoptes is discussed with regard to the mite’s potential as a biological control agent of C. arvense.

Oziella sibirica (Acari: Eriophyoidea: Phytoptidae), a new eriophyoid mite species described using confocal microscopy, COI barcoding and 3D surface reconstruction

Oziella sibirica sp. nov., collected from sedges (Cyperaceae: Carex macroura) in Siberia, Russia, is herein described based on the external morphology of all active instars using primarily conventional phase contrast microscopy, and on the female internal genitalia and prodorsal shield design using confocal laser scanning microscopy (CLSM) imaging and a 3D modelling technique. A partial mitochondrial COI gene sequence of O. sibirica sp. nov. is also provided, through GenBank, and this represents the first published record of any gene sequence data for the family Phytoptidae. We present remarks on the phylogenetic significance of the position of setae 3a in immature instars of eriophyoids and on the ontogenic variability of the empodium morphology of O. sibirica sp. nov. Using this species as a model, we propose a method for describing the internal genitalia of eriophyoids based on CLSM. We advocate the use of CLSM imaging as a new, relatively simple technique for observing and describing the internal genitalia of eriophyoids, as these largely unexplored genitalic structures may provide phylogenetically meaningful information for improving the classification of this poorly understood group of mites. In addition, CLSM may complement conventional light microscopy techniques in facilitating the interpretation of external structures such as body ornamentation or chaetotaxy.

Morphological variation in different populations of Aceria anthocoptes (Acari: Eriophyoidea) associated with the Canada thistle, Cirsium arvense, in Serbia

The russet mite, Aceria anthocoptes (Nal.), is the only eriophyid that has been recorded on Canada thistle, Cirsium arvense (L.) Scop. It has been noted in several European countries and recently in the USA. With its apparent host specificity and because of the damage it causes to its host plant, A. anthocoptes is being studied as a potential candidate for classical biological control. The aim of the present study was to examine quantitative morphological traits in four populations of A. anthocoptes living on two infraspecific host plant taxa (C. arvense var. arvense and C. arvense var. vestitum) in two geographically separate areas of Serbia in order to test the hypothesis of absence of the possible host plant impact on mite morphology. MANOVA analysis revealed significant differences between populations from different localities in Serbia. Populations of A. anthocoptes inhabiting two thistle varieties in the vicinity of Belgrade differed significantly from mites inhabiting the same two host varieties in the vicinity of the town of Ivanjica. Canonical discriminant analysis showed that the trait which best discriminates the populations of A. anthocoptes is the number of dorsal annuli. It was not possible to ascribe morphological differences to the impact of the host plant.

Phenotypic variability in five Aceria spp. (Acari: Prostigmata: Eriophyoidea) inhabiting Cirsium species (Asteraceae) in Serbia

From about 250 Cirsium spp., only two Aceria spp. (Acari: Eriophyoidea) have been described, Aceria anthocoptes (Nal.) and Aceria cirsii Pet. B. & Shi. Host specificity, which generally characterizes eriophyoid mites, potentially leads to speciation, so we may expect more than two Aceria spp. and/or other infraspecific taxa. Furthermore, studies on host-related variability in the morphology of Aceria mites are generally lacking. The purpose of this study was to investigate quantitative morphological traits of five Aceria populations inhabiting five Cirsium spp. in Serbia. MANOVA analysis revealed significant differences in 23 commonly used morphological traits as well as four additional traits related to the prodorsal shield design. In addition, the most important qualitative traits using scanning electron microphotographs were studied in order to clarify phenotypic differences among five Aceria spp. Discriminant analysis identified eight traits that significantly differentiate five populations. UPGMA cluster analysis of the squared Mahalanobis distances indicates that A. cirsii was morphologically the most divergent, while A. anthocoptes populations from Cirsium arvense and Aceria sp. from Cirsium heterophyllum were isolated from the branch clustering Aceria spp. populations from Cirsium eriophorum and Cirsium creticum. Analysis of qualitative traits using SEM confirmed results obtained from the analysis of morphometric features.

A New Species of Leipothrix (Acari: Prostigmata: Eriophyidae) on Dipsacus spp. in Europe and Reassignment of Two Epitrimerus spp. (Acari: Prostigmata: Eriophyidae) to the Genus Leipothrix

Abstract A new species of eriophyid mite, Leipothrix dipsacivagus n. sp. (Acari: Prostigmata: Eriophyidae), collected from Dipsacus laciniatus L. (Dipsacaceae) and Dipsacus fullonum L. in Serbia, Bulgaria, and France, is described and illustrated. Differential diagnosis is provided in comparison with Leipothrix knautiae (Liro) n. comb., and Leipothrix succisae (Roivainen) n. comb., two species that also are proposed here for reassignment from the genus Epitrimerus Nalepa to the genus Leipothrix Keifer, within the family Eriophyidae. L. dipsacivagus n. sp. is being investigated as a candidate for biological control of invasive Dipsacus spp. in the United States.

Geometric morphometric study of geographic and host-related variability in Aceria spp. (Acari: Eriophyoidea) inhabiting Cirsium spp. (Asteraceae)

The russet mite, Aceria anthocoptes (Nalepa), is the only eriophyoid that has been recorded on Cirsium arvense (L.) Scop. It has been noted in several European countries and recently in the USA. In this study we explored the geographic and host-related variability of Aceria spp. inhabiting different Cirsium spp. We applied landmark-based geometric morphometric methods to study morphological variability of three body regions (ventral, coxigenital and prodorsal) of 13 Aceria spp. populations inhabiting five Cirsium spp. in Serbia (Europe) and four Cirsium spp. in Colorado (North America). Analyses of size and shape variation revealed statistically significant differences between Aceria spp. living on European native and North American native Cirsium spp., as well as between A. anthocoptes s.s. inhabiting European C. arvense and North American C. arvense. The coxigenital region was the most informative when considering inter-population shape differences. European Aceria spp. dwelling on Cirsium spp., including A. anthocoptes s.s. from C. arvense, are characterized by higher inter-population size and shape variability than their North American counterparts. This finding supports a Eurasian origin of A. anthocoptes, presumed to consist of a complex of cryptic taxa probably coevolved with host plants in the native environment. Morphological similarity among Aceria spp. inhabiting North American native Cirsium spp. may indicate that speciation of A. anthocoptes started relatively soon after the host shift to plants different from C. arvense in the invaded region.

Phenetic and phylogenetic relationships among Aceria spp. (Acari: Eriophyoidea) inhabiting species within the family Brassicaceae in Serbia

We examined morphological and genetic differences among Aceria spp. inhabiting six Brassicaceae species in Serbia. Five of them have been already mentioned in the literature as original or alternate hosts of Aceria spp. (Berteroa incana (L.) DC., Capsella bursa-pastoris (L.) Medik., Cardamine hirsuta L., Lepidium draba L. and Sisymbrium orientale L.), whereas Aurinia petraea (Ard.) Schur was registered here for the first time as a host for Aceria sp. Results of morphometric analyses indicated clear differentiation of Aceria spp. from B. incana, L. draba, A. petraea and S. orientale, whereas the other two entities were less diverse and clustered together. Molecular analyses indicated that the average mean divergence over all sequence pairs was 18.3% (11.8–25.9%) and disclosed that the observed mtCOI distances between the six host-associated Aceria entities are large enough to represent differences between species. The Aceria sp. hosted by B. incana was morphologically and genetically most distinctive, whereas discrepancy between phenetic and phylogenetic relationships was found in the position of Aceria sp. hosted by L. draba when compared with those inhabiting C. hirsuta, S. orientale and C. bursa-pastoris.