Acarology

Inter- and intraspecific variability of morphological and molecular characters in Allothrombium species, with special reference to Allothrombium fuliginosum Abstract Morphology-based identification of Allothrombium spp., in view of the limited knowledge of intraspecific variation, hinders the recognition of species borders and affects the views on the actual distribution of species. Therefore, identification will benefit from reference to molecular methods. The separate species identity of specimens putatively representing Allothrombium fuliginosum and A. pulvinum, both reported as widely distributed in the Palaearctic region and considered as potential biological control agents, was checked using morphological and molecular analyses. The representatives of various Allothrombium spp. collected in the Palaearctic were included in the analysis in order to ascertain the distance between species. The results of the morphological examination, supported by statistical inference, along with the comparison of COI and/or ITS2 sequences, weaken the hypothesis of synoccurrence of both species in the Palaearctic region. Hence, we hypothesize that A. fuliginosum is widely distributed in the Palaearctic, whereas A. pulvinum should be regarded a Nearctic species.

Demodicosis in a captive African straw-coloured fruit bat ( Eidolon helvum ) Abstract Demodicosis is most frequently observed in the domestic dog (Canis familiaris), but it has rarely been reported in bats (Chiroptera). The overpopulation of Demodex spp. that causes dermatological changes is generally associated with a compromised immune system. We describe the gross and histological features of generalized demodicosis in an adult female African straw-coloured fruit bat (Eidolon helvum) drawn from a captive research colony. The histology of the lesions revealed comedones and follicular infundubular cysts harbouring numerous Demodex spp. mites, eliciting a minimal inflammatory response in the adjacent dermis. The histological examination of a full set of tissues did not reveal clear evidence of immunosuppression, although a clinical history of recent abortion and possible stressors due to captivity could be considered risk factors for the demodicosis. Attempts to determine the Demodex species using PCR on DNA extracted from the formalin fixed paraffin embedded tissue failed. This is the first clinical and histological description of demodicosis in Eidolon helvum.

Identifying the tick Amblyomma javanense (Acari: Ixodidae) from Chinese pangolin: generating species barcode, phylogenetic status and its implication in wildlife forensics Abstract Zoonotic diseases transmitted through ticks and other ectoparasites often travel across the globe with illegally traded wildlife parts and products. In this study, we analyzed a confiscated case of pangolin scales and observed a few dead ticks attached. On genetic analysis, the pangolin scales were identified to be originated from Chinese pangolin (Manis pentadactyla), an IUCN listed Critically Endangered species, and ticks were identified as Amblyomma javanense. Here, we provide the first authentic physical record of A. javanense from India as a parasite of Chinese pangolin and also generated its species DNA barcode that may be useful for biologists working on ticks in species validation and constructing phylogenies across the globe.

Integrative taxonomy of Abacarus mites (Eriophyidae) associated with hybrid sugarcane plants, including description of a new species Abstract Phytophagous mites belonging to the Eriophyoidea are extremely diverse and highly host-specific. Their accurate morphological identification is hampered by their reduced size and simplified bodies and by the existence of cryptic species complexes. Previous studies have demonstrated the urgency of applying multisource methods to accurate taxonomic identification of eriophyoid mites, especially species belonging to the genus Abacarus. This genus comprises 65 species, of which 37 are associated with grasses and four with sugarcane Saccharum (Poaceae). Recently, Abacarus specimens very similar to Abacarus sacchari were collected from the sugarcane crop in Brazil; however, their taxonomic placement was uncertain. In this study, we used an integrative approach to determine whether A. aff. sacchari specimens belong to A. sacchari or constitute a cryptic species. Morphological data were combined with molecular phylogeny based on the nucleotide sequences of three markers, one mitochondrial (COI) and two nuclear (D2 region of 28S and ITS). Morphological differences were observed between A. aff. sacchari, A. sacchari and A. doctus. The phylogenetic relationships among these three taxa and the genetic distances separating them revealed an interspecific divergence. The results of the morphological and molecular methods were congruent and supported the existence of a new species: Abacarus neosacchari n. sp. Duarte and Navia, herein described. This species belongs to the Abacarus cryptic species complex associated with sugarcane in the Americas. The results of this study, presenting the occurrence of multiple Abacarus species associated with sugarcane, contribute to the knowledge on plants and mites diversity by adding up one more clue highlighting that plant hybridization can be an important mechanism contributing to the speciation of plant-feeding arthropods.

Proteomic analysis of saliva from partially and fully engorged adult female Rhipicephalus microplus (Acari: Ixodidae) Abstract Rhipicephalus microplus salivary gland secretes a number of complex bioactive proteins during feeding. These components are important in feeding and affect anti-coagulation, anti-inflammation and also have anti-microbial effects. In this study, tick saliva was collected from partially engorged female (PEF) and fully engorged female (FEF) ticks. Liquid chromatography tandem–mass spectrometry (LC–MS/MS) and isobaric tags for relative and absolute quantification (iTRAQ) were used to identify and quantify R. microplus salivary proteins. A total of 322 unique peptides were detected and 151 proteins were characterized in both PEF and FEF. Of these, 41 proteins are considered as high-confidence proteins. Fifteen high-confidence proteins were upregulated and six high-confidence proteins were downregulated (p < 0.05; PEF:FEF ratio ≥ 1.2 or PEF:FEF ratio ≤ 0.83); 17 high-confidence proteins are slightly changed (PEF:FEF ratio > 0.83 and < 1.2). These high-confidence proteins are involved in several physiological roles, including egg development, transportation of proteins, immunity and anti-microorganism, anti-coagulant, and adhesion. In comparison with PEF, the number of upregulated proteins exceeded the number of proteins downregulated. Salivary protein may be induced by the blood-meal and these proteins contribute to successful feeding.

Coexistence of genetically different Varroa destructor in Apis mellifera colonies Abstract The aim of this study was to investigate the genetic diversity of Varroa destructor parasitizing Apis mellifera colonies and to test for possible host–parasite association at the mitochondrial DNA (mtDNA) level. Six A. melliferahaplotypes (including a novel C2aa) and five haplotypes of V. destructor were detected in 29 analyzed colonies from eight sampling sites in Serbia. We revealed the presence of the K and S1 haplotypes as well as KS1 and KP1 heteroplasmic mite individuals in all localities, while the P1 haplotype was only found in four sampling sites. Significant differences in V. destructor genetic diversity were found at both apiary and colony levels, with mite haplotypes coexisting in almost all tested colonies. In addition, a significant correlation between the number of analyzed mites per colony and the number of identified V. destructor haplotypes was observed. However, no significant host–parasite relationship was found, suggesting that mites bearing different haplotypes as well as those heteroplasmic individuals are well adapted to the host, A. mellifera, independently of the identified haplotype present in each colony. Our results will contribute to future population and biogeographic studies concerning V. destructor infesting A. mellifera, as well as to better understanding their host–parasite relationship.

Optimizing cold storage of the ectoparasitic mite Pyemotes zhonghuajia (Acari: Pyemotidae), an efficient biological control agent of stem borers Abstract Pyemotes zhonghuajia Yu, Zhang and He is a newly discovered native ectoparasitic mite that efficiently controls stem borers in China. To provide a steady and sufficient supply, extend adult lifespan and synchronize field augmentative releases of P. zhonghuajia, we determined the optimal cold storage temperature and duration by storing 1-day-old mated females at 8, 10 and 12 °C for 10–90 days with a 10-day interval in the laboratory. We then recorded mite survival during storage and monitored the post-storage reproductive performance of mites at a control temperature of 25 °C. We found that all mites survived at 10 and 12 °C for different durations, but mortality occurred when mites were stored at 8 °C for ≥ 30 days with more than 70% of mites dead when the storage duration prolonged up to 50 days. The proportion of reproductive females was higher at 10 °C but decreased with the prolonged storage duration at all test temperatures. Storage temperature had no significant effect on the pre-reproductive period and offspring sex ratio, whereas prolonged storage induced longer pre-reproductive period and lower proportion of female offspring. The reproductive period increased with increasing storage temperature and with prolonged storage up to 50 and 60 days; however, the longer reproductive period did not directly translate into greater reproductive output. We found that compared with the control, mites stored at 10 °C for up to 30 days did not significantly reduce their survival, proportion of reproductive success and number and sex ratio of offspring, suggesting that 10 °C and ≤ 30 days were the optimal cold storage temperature and duration, respectively, for post-mass production storage before the field augmentative release of P. zhonghuajia.

Resistance incidence and presence of resistance mutations in populations of Tetranychus urticae from vegetable crops in Turkey Abstract Tetranychus urticae Koch is one of the most common and harmful pests in vegetable production areas. Similar to other countries, control of T. urticae is mainly based on acaricides in Turkey. However, T. urticae rapidly develops resistance and failures in chemical control have occurred frequently. The toxicity of various acaricides was investigated in ten T. urticae populations collected from vegetable crops in Turkey. In addition, populations were screened for the presence of currently known target-site resistance mutations. It was shown that resistance to bifenthrin was the most widespread, but also half of the populations were resistant to abamectin and hexythiazox. Resistance mutations in the voltage-gated sodium channel (VGSC) and chitin synthase 1 were found in various populations. Moreover, for the first time, F1538I and L1024V VGSC mutations were reported for Turkish populations. Mutations that confer resistance to abamectin, bifenazate and METI-I acaricides such as pyridaben were not detected. These results will contribute to the design of an effective resistance management program in Turkey.

A relapsing fever Borrelia and spotted fever Rickettsia in ticks from an Andean valley, central Chile Abstract In humans, emerging infectious diseases are mostly zoonoses with ticks playing an important role as vectors. Tick-borne relapsing fever Borrelia and spotted fever Rickettsia occur in endemic foci along tropical and subtropical regions of the globe. However, both are widely neglected etiologic agents. In this study, we performed molecular analyses in order to assess the presence of Borrelia and Rickettsia DNA in ticks infesting small-mammals within a National Reserve located in the Andes Mountains, central Chile. While hard ticks were negative for the presence of both agents, sequences of four rickettsial (gltA, htrA, ompA, ompB) and two borrelial (16S rRNA and flaB) genes were obtained from larvae of an Ornithodoros sp. morphologically related with Ornithodoros atacamensis. Phylogenetic analyses indicated that the detected Borrelia and Rickettsia spp. belong to the relapsing fever and spotted fever groups, respectively. Moreover, the agents formed monophyletic clades with Rickettsia amblyommatis and "Candidatus Borrelia johnsonii." As positive ticks parasitize rodents within a highly visited National Reserve where outdoor activities are of common practice, the risk for human parasitism should not be discarded.

Expression dynamics of key ecdysteroid and juvenile hormone biosynthesis genes imply a coordinated regulation pattern in the molting process of a spider mite, Tetranychus urticae Abstract In insects, the ecdysteroid 20-hydroxyecdysone coordinates with juvenile hormone (JH) to regulate the process of molting, development and metamorphosis; however, this interaction is still unclear in the mites. In this study, we investigated the gene related to ecdysteroid and JH biosynthesis pathways, including four ecdysteroid and 11 JH biosynthesis genes. We examined their expression patterns during molting of different developmental stages of the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), an important agricultural pest that feeds on more than 1100 plant species. The expression of ecdysteroid biosynthesis Halloween genes exhibited a positive zigzag-like pattern, with a peak after 8 h of molting and a drop 8 h after entering each quiescent stage. In contrast, JH biosynthesis genes expression displayed a negative zigzag-like pattern, with a peak at 8 h after entering each quiescent stage and a drop after 8 h of each molting. These opposite patterns imply that ecdysteroid and JH expression is coordinated during the developmental transition. Our data provide an initial perspective on the co-expression of ecdysteroid and JH biosynthesis genes to regulate this important developmental process in the two-spotted spider mite.

Alexandros Sfakianakis
Anapafseos 5 . Agios Nikolaos
Crete.Greece.72100
2841026182

6948891480

alsfakia@gmail.com