Experimental and Applied Acarology最新文献

Though the entomopathogenic fungus Beauveria bassiana has shown to be efficacious for managing Dermanyssus gallinae infestations, its delivery as liquid formulation poses concerns related to environmental stability and efficacy. To overcome such concerns, here we proposed a hydrogel matrix based on hydroxyethyl-cellulose (HEC) for delivering B. bassiana to control D. gallinae. Nymph and adult mites were exposed to a hydrogel matrix or filter papers containing B. bassiana (10⁷ conidia/mL), with and without a pre-incubation period of 4 days at 25 °C (treated groups). As control groups, mites were exposed to hydrogel matrix or filter papers with sterile distilled water. Results showed higher mortality of all stages of D. gallinae in treated groups compared to respective control groups. The LT₅₀ and LT₉₀ estimated on D. gallinae were lower in treated groups (LT₅₀ ≤ 9.5 days for adults; and LT₅₀ ≤ 10.7 days for nymphs; LT₉₀ ≤ 14.9 for adults; LT₉₀ ≤ 17.9 days for nymphs) than in control groups (LT_{5 0} ≥14.9 days for adults, LT₅₀ > 19 days for nymphs; LT₉₀ > 20 days for adults and nymphs). Pre-incubation significantly reduced LT₅₀ and LT₉₀ with respect to other treated groups. Overall, our study outlined that the conidial suspension of B. bassiana in hydrogel is efficacious against both nymphs and adults of D. gallinae. The pre-incubation of B. bassiana in the HEC enhanced its efficacy. Thus, delivering B. bassiana through HEC-based hydrogel matrix may represent an effective and sustainable solution for managing D. gallinae infestations in the poultry industry.

Hard ticks are essential biological vectors of pathogens with impacts on humans and animals. This study tried to identify the dominant species of hard ticks, assess their biodiversity, and compare the infestation rates in mountainous to semi-mountainous regions in Fars province, southwestern Iran, during 2021-2022. In total, 4104 domestic animals, such as sheep, goats, cows, camels, and dogs, were examined; 3169 ticks belonging to three genera, Hyalomma, Rhipicephalus, and Dermacentor, were collected. Hyalomma anatolicum was the most dominant species (34.39%), and Dermacentor marginatus was the least frequently found species. Biodiversity analysis by Simpson, Shannon-Wiener, Evenness, and Margalef indices. Generally, species richness, Evenness, and Shanon - Wiener indices were higher in mountainous than semi mountainous area and also results showed a higher diversity and richness in sheep from mountainous regions, especially in Firouzabad. Dogs and camels in Larestan had the lowest diversity and richness. Also, cattle in Marvdasht presented the highest species uniformity. The results reveal that biodiversity and the infestation rate are higher in sheep, thereby increasing the risk of tick-borne diseases. Thus, closer monitoring of livestock, education of farmers, and effective management of ticks are required to reduce the impact of tick infestations and associated diseases within this region.

Species from various animal taxa have been found to use pheromonal communication underwater. Although the use of pheromones in water mites has been previously suggested, experimental evidence for it remains sparse. We examined the behavioral responses of male and female Arrenurus globator to water in which conspecifics of the same and the opposite sex had been kept, in order to test the hypothesis that chemical communication occurs between sexes. Results suggest a putative female-produced sex pheromone that stimulates at least the initial steps of mating behavior in males. Males exhibited arrestant behavior, leg fanning and readiness posture more in female-conditioned water than in male-conditioned or control water. In contrast, females showed no response to either male-conditioned water or female-conditioned water.

Ticks are a medically important group of arthropods, and their control has become a major challenge due to their widespread resistance to synthetic acaricides. Defatted seed meals of plants in the mustard family, commonly generated as byproducts of vegetable oil and biofuel production are known to possess pesticidal properties but their potential to control ticks remain poorly understood. We evaluated the bio-fumigation activity of defatted seed meals of three mustard family species, Brassica juncea (L) Czern. (PG), Lepidium sativum L. (Ls) and Thlaspi arvense L. (DFP), against three medically important hard tick species: Ambylomma americanum (L.) [Aa], Dermacentor variabilis (Say) [Dv] and Ixodes scapularis (Say) [Is]. Volatiles produced by defatted seed meals of the three plant species had strong bio-fumigation activity against ticks, but their effects varied among the three tick species. Toxicity of DFP seed meals was significantly different among the three tick species (no overlap of the 95% CI) with LD₅₀ values of 0.056 g for Aa nymphs, 0.031 g for Dv nymphs, and 0.037 g for Is nymphs. Defatted Ls seed meals were more toxic to Dv (LD₅₀ = 0.022 g) and Is (LD₅₀ = 0.018 g) nymphs compared to Aa nymphs (LD₅₀ = 0.035 g) while defatted PG seed meals were more toxic to Is nymphs (LD₅₀ = 0.009 g) compared to Aa (LD₅₀ = 0.048 g) and Dv (LD₅₀ = 0.032 g) nymphs. This study is the first report to document that defatted Brassicaceae seed meals are a promising plant-based biofumigant for tick control that can be developed as a cheap, practical, and ecofriendly acaricide.

The factors influencing the distribution and abundance of ectoparasites in vertebrates have been thoroughly examined in rodents, particularly concerning ticks and fleas. However, there is a paucity of knowledge regarding mites. The aim of this study was to determine if host or landscape traits are responsible for the abundance of dermanyssoid and trombiculoid mites. Rodent captures were carried out in the northwest region of Mexico between 2018 and 2022 in order to collect mites of the superfamilies Dermanyssoidea and Trombiculoidea. We generated generalized linear models to determine if rodent characteristics or the Index of Relative Anthropization (IRA) contribute to the relative abundance of Dermanyssoidea and Trombiculoidea. The best generalized linear model for Dermanyssoidea suggests that mite abundance is influenced by the IRA and the terrestrial rodent abundance. There is a relationship between the abundance of terrestrial rodents and dermanyssoid mites. Data show that as anthropization increases, Dermanyssoidea abundance decreases. The model shows rodent abundance, and the IRA are key factors in Trombiculoidea abundance. Our findings indicate that trombiculoid mites increase alongside rodents but decline as the IRA increases. This is the first study to use an index to investigate the impact of relative anthropization on Dermanyssoidea and Trombiculoidea in Mexico.

Tick hemolymph plays an important role in the transportation of nutrients as well as metabolites. The hemolymph consists of plasma and blood cells, and proteins are the main components of plasma. This study aimed to investigate the protein composition of the hemolymph of Haemaphysalis qinghaiensis and to explore the effects of different hosts on the hemolymph protein composition of ticks, which could provide a reference for the screening of tick-protective antigens. Hemolymph was collected from the engorged females of the H. qinghaiensis ticks from the Bos grunniens (HqB) and Ovis aries (HqO) hosts. We identified 17 host-derived high-confidence proteins and 156 tick-derived high-confidence proteins from HqB. Fifteen host-derived high-confidence proteins and 155 tick-derived high-confidence proteins were identified from HqO. There were significant differences in the composition and abundance of the host-derived protein in the hemolymph from the two sources, with fibrinogen, alpha-1-antiproteinase, α-2-macroglobulin, and an uncharacterized protein present only in HqB, while ubiquitin-60S ribosomal protein L 40 was found only at HqO. Besides, the abundance of these proteins also varied significantly. The 163 tick-derived proteins identified are classified as enzymes, inhibitors, transporters, immunity-related proteins, cytoskeletal proteins, heat shock proteins, nuclear proteins, other proteins, uncharacterized proteins, and secreted proteins. The KGD sequence of A1 in the uncharacterized protein suggested that the unidentified protein may be associated with anti-coagulants, but further research was needed to confirm the function of these uncovered proteins. HqB and HqO shared a total of 148 tick-derived proteins, with eight proteins present only in HqB and seven only in HqO. The abundance of 65 shared proteins was significantly higher in HqO. In conclusion, the hemolymph proteins of H. qinghaiensis tick were composed of host-derived and tick-derived proteins. Different blood meals had a large effect on the composition and abundance of both host-derived and tick-derived proteins.

The Lewis spider mite (LSM), Eotetranychus lewisi, is an important pest of poinsettias (Euphorbia pulcherrima) and agricultural crops worldwide. In Europe it is a quarantine-regulated pest with established outdoor populations in Portugal. We investigated the pest status and host plants of the LSM in Madeira and the Algarve, collecting and inspecting plants and crops. The LSM was mainly found on naturalized poinsettias and castor-bean. Additionally, live mites were collected in very low numbers from plants of vine, cherimoya, mango, papaya, cherry plum, wild tobacco, and bladder vine, in direct contact or close to LSM-infested poinsettias, strongly suggesting these plants would not be breeding hosts. LSM abundance was low and no damage was observed. Mites were absent from strawberry, bramble and citrus, important hosts worldwide. Field surveys were complemented with a citizen-science experiment in outdoor conditions to test whether proximity to mite-infested poinsettias affected subsequent detections on poinsettia, strawberry, or grapevine. After two months of exposure to potentially dispersing LSM individuals and a further two months under controlled conditions to allow the mite to develop, LSM was detected on the three-recipient species but at low infestation rates, with a higher number of infested leaves and abundance on poinsettias, and absence of damages to crops. Overall, we conclude that the primary reservoirs for LSM populations in southwestern Europe are poinsettia and castor-bean plants, and our results suggest that the LSM is not causing damages to crops and may not be as harmful as expected, which can have implications to the current quarantine-regulation of this mite in Europe.

Entomopathogenic fungi (EPF) is one of the most promising alternatives to regulate tick populations. However, these fungi may lose acaricidal effectiveness over time, due to the storage period and/or successive cultivation on artificial media. It is known that using arthropod pests as a substrate for EPF could potentially alter their acaricidal behavior over time, however, studies using ticks for this purpose are scarce. Hence, the aims of this research were: (1) to isolate strains of Metarhizium anisopliae from paddocks of cattle farms, (2) to evaluate the effect of engorged adult ticks of Rhipicephalus microplus as a substrate on the tickicide behavior of Metarhizium anisopliae strains, and (3) to determine the lethal time of each M. anisopliae strain to kill 50% (LT50) and 99% (LT99) of engorged ticks. First, the natural acaricidal effect of 10 strains of M. anisopliae sensu lato isolated from soils of cattle farms on R. microplus was evaluated. Second, the influence of substrate (R. microplus, Galleria mellonella and Sabouraud dextrose agar [SDA]) on the acaricidal activity and virulence index (lethal time) of each strain during four generations was evaluated. Strains MaV69, MaV60 and MaV67 showed more than 90% mortality at day 20 post-treatment. The use of engorged adult ticks as substrate increased the virulence of five M. anisopliae s.l. strains. Larvae of G. mellonella and SDA as substrate did not modify the acaricidal behavior of the 10 strains evaluated. Seven of ten EPF decreased their LT50 and three decreased their LT99 as an index of their virulence enhancement.

The Varroa destructor (hereafter referred to as Varroa) is a major pest of honeybees that is generally controlled using pyrethroid-based acaricides. However, resistance to these insecticides has become a growing problem, driven by the acquisition of knockdown resistance (kdr) mutations in the mite's voltage-gated sodium channel (vgsc) gene. Resistance mutations in the vgsc gene, such as the L925V mutation, can confer resistance to pyrethroids like flumethrin and tau-fluvalinate. Monitoring genotypic resistance through molecular mutation screening is crucial for tracking and mitigating resistance spread. In this study, the frequency of resistance mutations in the vgsc was examined using a Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) approach in Varroa populations sampled throughout the Mediterranean, Aegean, and Black Sea regions of Türkiye. Considering all the samples analyzed, the results demonstrated a mean resistance allele frequency of 83.29%, indicating a relatively high frequency of resistant alleles. We observed 94.58%, 85.71%, and 69.58% resistant allele frequencies in populations sampled from the Mediterranean, Aegean, and Black Sea regions, respectively, in our study. The results of our investigation demonstrated substantial regional variations in the frequencies of resistant alleles among Varroa populations throughout Türkiye, with notably elevated resistance levels observed in the Mediterranean and Aegean regions. Due to the significant resistance mutation frequency differences between both provinces and regions, long-term monitoring of resistance alleles and the planning of regional control strategies are required for effective control of this pest.

Tick salivary proteins are crucial for efficient and successful tick feeding. Most of them are still uncharacterized, especially those involved in the formation of tick cement. Tick salivary protein PA107 is a putative cement protein, which is transcribed in salivary glands during the initial phase of tick feeding. It is a tick-unique protein, with homologs described in several tick genera. In this study, a detailed in silico analysis of its primary and tertiary structure was performed, along with the immunogenicity assessment for the PA107 protein from Ixodes ricinus species. The screening of the primary structure placed it to the glycine-rich protein family, revealing in parallel an overlapping 15mer at the C-terminus and borderline homology to non-tick proteins with antimicrobial activity. The analysis of tertiary structure revealed a high degree of intrinsic disorder for monomeric PA107, in contrast to highly ordered structures for different oligomeric states that might correlate with the putative role in the tick cement formation process. Regarding in silico PA107 immunogenicity inference, obtained results were inconclusive, which aligns with the in vitro findings showing definitely the lack of humoral response induction in experimentally infested rats and persons bitten by the I. ricinus ticks. The results represent new pieces of a huge puzzle depicting a complex tick-host relationship, but also identify PA107 as a possible compound of novel formulations to be used in biomedicine as bioadhesives, and as a target for new anti-tick strategies, by interfering with the cement cone formation and stability, i.e. tick attachment and feeding.