Experimental and Applied Acarology最新文献

Because of their low intrinsic mobility, spatial distribution of Ixodes ticks depends strongly on movement of their hosts, but this may be modulated by the tick's decision to detach in relation to environmental cues. This aspect of host-parasite interactions may substantially contribute to micro-geographic heterogeneity in exposure risk to ticks and tick-borne pathogens, but has so far received little attention. We designed a laboratory experiment to investigate whether environmental factors may affect detachment decisions of Ixodes ricinus in two contrasting environments: a dry, bare environment versus a moisturized, enriched environment. We experimentally infested wood mice (Apodemus sylvaticus) with larval ticks and exposed these alternatingly to the two environments in a cross-over design, controlling for temporal variation. Detached larvae were collected whenever hosts were moved from one type of environment to another. Detachment rates were consistently higher in the dry and bare environment. Furthermore, in both environments, the majority of ticks detached in the afternoon and first part of the night. Our results suggest that environmental factors can alter the detachment probability of I. ricinus larvae from A. sylvaticus, either through direct physical or host physiological cues. We postulate that larval detachment favours distribution throughout the forest understorey rather than centred around places of high rodent site fidelity.

Honeybees are critical pollinators for global agriculture but face numerous threats, notably the ubiquitous devastating ectoparasitic mite Varroa destructor. Using acaricides and other chemicals to control mites not only fosters pesticide resistance but also harms honeybees and contaminates their products, thus sparking growing interest in natural alternatives, particularly essential oils (EOs). In this study, the EO extracted from the camphor leaves (Cinnamomum camphora) was used to investigate its effects on V. destructor and the underlying RNA regulatory mechanisms. The results showed that 27 long non-coding RNAs (lncRNAs) and 305 mRNAs were differentially expressed between the camphor EO-treated and control groups. GO enrichment analysis revealed that the biological processes associated with differential lncRNA expression, in EO-exposed or unexposed V. destructor mites, were primarily related to cellular and metabolic processes. Additionally, the lncRNA-targeted mRNAs in V. destructor mites exhibited upregulated ABC transporter expression post EO exposure; mRNAs regulated by the P53 signaling pathway were also upregulated. These results suggest that camphor leaf EO may affect mite biology by triggering immune responses and disrupting the ability of mites to evade or suppress the immune system of the host. This study provides novel insights into how natural EOs control mites in terms of RNA regulatory networks.

The red palm mite, Raoiella indica Hirst (Acari: Tenuipalpidae), is a major pest of coconut, banana and ornamentals in tropical America. Essential oils have proven bioactivity against pest arthropods and are highlighted for its potential in sustainable pest control. In this study, we evaluated the toxicity and sublethal effects of the essential oil extracted from Varronia curassavica Jacq. (Boraginaceae) [syn. Varronia (formerly Cordia) verbenacea DC] on R. indica. The essential oil from V. curassavica (accession VCUR 404) comprised 28 chemical constituents, with ar-turmerone being the predominant component. The oil exhibited high acute toxicity to adult R. indica, with a median lethal concentration (LC₅₀) of 1.9 mg/mL. In addition to toxicity, the oil significantly reduced the mite population growth rate, survival, and egg hatchability. Interestingly, despite its lethal and sublethal effects, adult mites showed a marked preference for oil-treated areas in a laboratory two-choice bioassay, suggesting an attractant-mediated mechanism that may lead to mortality. Overall, our findings highlight the essential oil of V. curassavica as a promising candidate for the development of environmentally sound strategies for the management of R. indica.

The predatory mite, Neoseiulus agrestis (formerly known as Neoseiulus striatus until its revision in 2022), is considered a promising candidate for biological control of small sucking pests, particularly Tetranychid mites. However, in integrated pest management (IPM) programs, understanding the influences of chemical pesticide applications on predatory mites is of great significance. In this study, the toxicity of ten pesticides on adult female N. agrestis was evaluated under laboratory conditions to determine their LC₂₀, LC₅₀, and LC₉₀ concentrations using the slide impregnation method. Among these pesticides, deltamethrin, which exhibited the highest toxicity, was selected for further investigation into its effects on the fitness of the next generation of N. agrestis preying on Tetranychus urticae Koch. The relative toxicity of the ten tested compounds, ranked from highest to lowest was as follows: deltamethrin, bifenthrin, endosulfan, methomyl, omethoate, imidacloprid, emamectin benzoate, carbosulfan, spinosad, and abamectin. Notably, deltamethrin exhibited the highest toxicity against N. agrestis, with a median lethal concentration (LC₅₀) of 0.020 mg/L. Exposure to sublethal and LC₅₀ deltamethrin doses significantly impacted the adult lifespan and reproductive capacity of treated predators. Predators exposed to LC₂₀ concentrations exhibited markedly shorter offspring development time and lower fertility rates. The sublethal deltamethrin dose induced marked alterations in the life table parameters of N. agrestis. These findings suggested that deltamethrin adversely affected both the developmental duration and life table parameters of the next generation of N. agrestis. To better understand predator-insecticide dynamics in the presence of biotic and abiotic stresses in the field, future studies could further evaluate this aspect under field and semi-field conditions.

Ticks are important arthropod vectors of many human and veterinary diseases in temperate regions. Ticks are highly sensitive to desiccation and questing behaviour in search for animal hosts is driven by ambient temperature. This study assessed the association of meteorological factors with the monthly abundance of nymph Ixodes ricinus in three differing botanically classified homogenous study sites over a two-year period in France and then compared predicted abundance with that observed in the third year. We then applied the same approach to Lyme Disease (LD) cases that are notifiable in Connecticut, the USA, over a six-year period and then compared predictions with the observed number for the subsequent four years. There were predictable negative associations between temperature and nymph activity patterns at four months lag time across all vegetation site types and with LD cases at five months lag time. This corresponded to a decrease in Relative Risk of 8-10% for every 1 °C increase. Despite the different tick species in Europe and in northern USA, I. ricinus and Ixodes scapularis respectively, the two species have a similar temperature-dependency. In the context of global warming, we can expect to observe a shift in the temporal pattern of tick activity and risk of Lyme disease. It remains to be assessed as to whether earlier higher activity peaks may lead to shorter tick seasons with the temperature-dependent depletion of the putatively finite annual nymph stock.

Lead (Pb) contamination, a kind of heavy metal pollution, severely impacts organism growth and reproduction. Although vitellogenin (Vg) has been studied in many species, its characteristics in the pest Aleuroglyphus ovatus (Troupeau) (Acari: Acaridae) remain unknown. In this study, the full-length Vg gene of A. ovatus was cloned (6030 bp, encoding 2009 aa), with phylogenetic analysis grouping A. ovatus with Sarcoptes scabiei Linnaeus (Sarcoptiformes: Sarcoptidae) and Euroglyphus maynei Cooremant (Sarcoptiformes: Pyroglyphidae), supporting their phylogenetic relationship. The expression pattern of the AoVg gene under different Pb concentrations (0 mg kg^-1, 12.5 mg kg^-1, 25 mg kg^-1, 50 mg kg^-1, 100 mg kg^-1) was investigated using real-time quantitative PCR (RT-qPCR), and a polyclonal antibody was generated against AoVg. The results showed that lead stress affected the transcription and translation profiles of Vg gene in A. ovatus. Both Western Blot and ELISA kit analysis found that AoVg protein content was slightly boosted under both 25 and 100 mg kg^-1 lead stress and significantly enhanced under 12.5 mg kg^-1 lead stress while that was decreased significantly under 50 mg kg^-1 lead stress. These results would help us to understand the molecular mechanism underlying lead stress in A. ovatus and provide new insight into the theoretical basis for the prevention and control of A. ovatus.

The family Spinturnicidae belongs to the suborder Monogynapsida, superfamily Dermanyssoidea, and exclusively parasitizes the body surface of bats. In the present study, we determined the complete mitochondrial genome of Spinturnix psi, a species of bat mite, and subsequently conducted a comprehensive analysis of its genomic information. The mitochondrial genome of S. psi has a length of 16,299 bp, an AT content of 76.63%, an AT skew of -0.01, and a GC skew of -0.23. Analysis of RSCU revealed a clear usage preference for codons such as AAA, UUU, AAU, UAU, AUU, and UAA. A gene rearrangement involving trnQ was observed. Phylogenetic analysis indicated a close genetic relationship between S. psi and the family Laelapidae. These findings contribute to the molecular data available for Spinturnicidae and provide useful references for species identification. Additionally, these results lay the foundation for future studies on the potential transmission of pathogens carried by bat mites.

The phytoseiid mite, Neoseiulus longispinosus (Evans) is considered as one of the effective biological control agents against the tetranychid mites in the Indian subcontinent. This predator can be effectively utilized to manage the two-spotted spider mite, Tetranychus urticae Koch under protected conditions. Carnation holds a significantly important position as cut flower crop in India as well as throughout the world. In this study, the biology and population growth parameters of predatory mite were studied against three different stages of T. urticae on three different cultivars of carnation viz., Kleos, Bizet and Baltico. The predator was able to complete its life cycle on all the offered stages of the prey and on all the three cultivars. The results indicated that the biology was not much affected by the different cultivars. However, the cultivar Bizet was found to be slightly better for the development of the predatory mite as the maximum fecundity (62.26 eggs/female) was recorded on this cultivar. Although numerically higher fecundity was observed on Bizet, no statistically significant superiority was found. Among the different stages of prey fed to the predator i.e., egg, protonymph and deutonymph, the predator showed better biology and population growth parameters on egg stage compared to both protonymphal and deutonymphal stages of T. urticae.

This study evaluated the significance of ten different pollen types-maize, Spanish broom, cattail, marshmallow, malva, sunflower, khejri, pomegranate, ice flower, and bee pollen-in influencing the development, reproduction, and population growth of E. scutalis. The aim was to enhance our understanding of the pollen spectrum acceptable to this predatory mite. Our results indicated that E. scutalis could not complete its immature development on maize, malva, marshmallow, and Spanish broom pollen. Bee and sunflower pollen resulted in the longest developmental times, while khejri, pomegranate, and cattail led to the shortest. The females fed ice flower and pomegranate pollen had the longest lifespans. The adult pre-oviposition period (APOP) was longest with bee and sunflower pollen and shortest with khejri and pomegranate pollen. The total pre-oviposition period (TPOP) was also longest on bee and sunflower pollen, with khejri resulting in the shortest TPOP. Females fed on pomegranate had the longest oviposition days, whereas those on sunflower had the shortest. The highest and lowest fecundity were on pomegranate and sunflower pollen, respectively. Ice flower, khejri, and pomegranate supported the highest gross and net reproductive rates, while bee and sunflower pollen yielded the lowest. Khejri and pomegranate resulted in the fastest growth rates and the highest intrinsic and finite rates of increase. Consequently, maize, malva, marshmallow, and Spanish broom were unsuitable to the growth and reproduction of E. scutalis; bee and sunflower pollen were the least suitable options; ice flower and cattail provided intermediate benefits; and khejri and pomegranate pollen were the most suitable.

The tomato russet mite, Aculops lycopersici (Tryon), is a key pest of commercially grown tomatoes worldwide. Due to its minute size, its detection is often not timely for effective control. In this study, the approach of limiting A. lycopersici population growth by repeated application of barriers on tomato stems is tested. In potted plant trials, barriers of oils, oil formulations, insect glue, diatomaceous earth [DE] and adhesive tape [NT] impeded upward movement of A. lycopersici on tomato stems for several weeks as compared to the control. Iolinid mites have shown promising results for A. lycopersici control. Therefore, the selectivity of barriers regarding predatory mites was also tested, using A. swirskii as a model organism. Barriers with [NT] showed the best selectivity ([NT] > oil formulation >[DE], p < 0.05 for each day count of mites above barriers). However, application of [NT] seems challenging in a broader scale. Under greenhouse conditions with practical crop stands, regularly applied barriers reduced the percentage of symptomatic leaves for two weeks (oil formulation and [DE], variety Roterno, 2023 and oil formulation, variety Baylee, 2024, p < 0.05; in 2024 no significant reduction was found on Roterno and [DE] was not tested). The comparison of different varieties showed less effect of barriers in the variety Roterno with more upward facing leaves, indicating that leave angle affects overcoming of barriers by A. lycopersici. The fact that under greenhouse conditions this control effect did not cover the whole season reduces the practical applicability of the method. Under similar conditions, an earlier study reached longer lasting control using insect glue as a barrier substance. Possible reasons for the discrepancy between studies include differences in tomato varieties, barrier positions and pest densities.