Experimental and Applied Acarology最新文献

Cheyletus malaccensis (Oudemans), a generalist predatory mite, is a highly promising biocontrol agent applied for stored products pests management in grain storage systems. To optimize its field deployment, this study evaluated the population dynamics of C. malaccensis and Liposcelis bostrychophila (Badonnel) under varying predator-prey ratios (PPRs: 1:9, 1:5, 1:3, 1:1, 3:1) at 26.0 ± 0.1 °C and 75.0 ± 0.5% relative humidity in simulated grain storage environments. During the 49-day post-release period, the peak population reduction rates of L. bostrychophila at four PPRs (1:5, 1:3, 1:1, 3:1) reached 74.87%, 76.61%, 87.10%, and 95.90% respectively, whereas the 1:9 PPR treatment resulted in progressive pest population growth. Conversely, C. malaccensis population establishment rates increased exponentially with decreasing PPRs, peaking at 1,161.11% (1:9 PPR). These findings demonstrate a density-dependent trade-off: higher PPRs maximize short-term pest suppression, while lower ratios enhance long-term predator persistence. Therefore, we propose a two-phase deployment strategy: (i) preventive low-density releases (PPR < 1:5) prior to pest outbreaks to establish mite populations, and (ii) threshold-triggered supplementary releases based on real-time pest monitoring to achieve economical and long-term control of stored grain pests.

Understanding how vector species such as ticks respond behaviorally to thermal and host-related cues is critical for predicting the effects of climate change on disease transmission. Ticks employ distinct questing strategies-ranging from static sit-and-wait behavior to active host seeking-that influence their exposure to abiotic stressors. We investigated whether Dermacentor andersoni and Dermacentor similis, two sit-and-wait tick species native to Eastern Washington, USA, exhibit behavioral plasticity in response to temperature gradients and host stimuli. We conducted three experiments to assess (1) thermal preferences of D. andersoni under host (dog) scent conditions, (2) thermotactic responses of both species to infrared (IR) radiation in the presence of dog odor, and (3) D. andersoni's approach behavior toward human hosts at various distances, i.e., a host emitting a combination of IR, CO₂, and odors. In thermal gradient assays, D. andersoni showed significantly increased movement toward warmer zones following CO₂ exposure and exhibited wide thermal preferences depending on specific dog odors. However, when exposed to an IR source, we found strong sit-and-wait behaviors by D. andersoni and D. similis regardless of temperature or radiation. The ticks were not attracted to infrared radiation and did not move toward the stationary exposed hand of an observer. Ticks may prioritize optimal locations to encounter potential hosts, over enzymatically optimal temperatures. Rather than evolving to detect hosts at a distance, Haller's organs may have evolved to differentiate warm attachment sites from cooler fur. Our results suggest that Dermacentor questing behavior (remaining on station despite a different preferred temperature) may make them particularly vulnerable to future rises in temperature.

This study aimed to investigate tick-borne agents in ticks (Ixodida: Ixodidae) collected from wild rabbits (Oryctolagus cuniculus) hunted in northern Spain in 2022. A total of 120 ticks were collected from 11 rabbits (mean: 13.7 ticks/rabbit), and identified as 109 Rhipicephalus pusillus and 11 Haemaphysalis hispanica. DNA was extracted from 89 R. pusillus and 5 H. hispanica and tested by a battery of PCR assays targeting tick-borne bacteria (genera Rickettsia, Borrelia, Coxiella, family Ehrlichiaceae) and protozoa (Piroplasmida). All ticks were negative for these agents, except for two specimens (one H. hispanica and one R. pusillus) that yielded amplicons by the Ehrlichiaceae 16 S rRNA assay. These two tick specimens were further tested by PCR assays targeting fragments of the ehrlichial genes groEL and dsb, which were generated only from H. hispanica. The groEL haplotype showed the closest identity (95%) with over 30 Ehrlichia haplotypes, while the dsb haplotype showed closest identity (88%) with 'Candidiatus Ehrlichia pampeana'. Phylogenetic analyses inferred from the groEL, and dsb partial sequences indicated that the ehrlichial agent detected in a H. hispanica male- here designated as Ehrlichia sp. Hhisp1- is a novel agent, distinct from all ehrlichial agents with available sequences in GenBank. Our finding of Ehrlichia sp. Hhisp1 in H. hispanica points out the possibility that the wild rabbit could be a reservoir of this novel ehrlichial agent since there is no transovarial transmission of Ehrlichia spp., and H hispanica is highly specific to wild rabbits and their burrows.

Acalitus simplex is an erinose eriophyoid mite that feeds exclusively on plants in the genus Ruellia, which are frequently sold as ornamentals for landscape plantings. This study presents a comprehensive examination of A. simplex collected from Anguilla, Brazil, Dominican Republic, Florida, and Hawaii through sequencing of the mitochondrial cytochrome oxidase I gene (COI), coupled with morphological examination by several microscopy techniques. The collected A. simplex specimens were similar in morphology across geographic locations and populations clustered together in a phylogenetic analysis based on COI sequences. In addition to Ruellia simplex, new host plant associations are reported in Florida, including R. blechum, R. squarrosa and R. caroliniensis. We defined the different erineum stages, determined the number of days after infestation on an uninfested plant required for erinea development, and estimated population densities in each erineum stage. Four erineum stages were observed on R. simplex - hyaline (stage 1), white (stage 2), purple (stage 3) and beige (stage 4). At 25 ± 2 ^oC, 12:12/L: D and 50 ± 10% RH, the purple stage did not develop and the duration of the hyaline, white and beige erinea was 12.4 ± 0.7 (mean ± SE), 44.4 ± 1.3, and 20.5 ± 0.9 days, respectively. Population densities varied significantly across the erineum stages, with most individuals in the white and purple stages and fewer in the hyaline and beige stages. This study improves our understanding of interactions between A. simplex and R. simplex, aiding the development of IPM strategies to mitigate this mite.

Agricultural practices affect non-target soil fauna either directly or indirectly, e.g. by altering the soil physical structure or by application of chemicals. The effects of tillage, insecticide and herbicide applications on the dominant taxon of soil microarthropods-oribatid mites was studied in two fields over three years (2020, 2021, 2022) at three seasons (spring, summer and autumn). In total 87 species were identified. Herbicide and insecticide application had negative effects on oribatid mite species numbers and abundance; however, tillage mitigated the negative effects of herbicide and insecticide applications, possibly since tillage increases the rate of pesticide degradation and thereby reduces the direct exposure to soil fauna to those chemicals. Insecticides and tillage reduced the number of parthenogenetic individuals, possibly by a decrease of available resources (dead organic matter). Oribatid species richness and density steadily declined from 2020 to 2022 likely due to increased average annual temperature and decreased precipitation associated with global warming. The species richness and density declined from spring to summer and increased again in autumn. The annual decline of the oribatid species richness was expressed by the loss of oribatids with a thin cuticle (Mixonomata, Enarthronota, Oppioidea) and those, who are sensitive towards disturbance (Liacaridae, Ceratozetidae). Dry grassland specific species (Passalozetes africanus, P. perforatus, Scutovertex sculptus) were constantly present in all samples. The study points to the effects of agricultural practices on non-target soil fauna and also on the changes in soil animal communities from meadow to dry steppe species due to global warming.

This study assessed the efficacy of a plant-based premix of feed additives (PFA) composed of essential oils and vitamins on a farm with 1560 laying hens (ISA Brown line), naturally infested with poultry red mite (PRM), Dermanyssus gallinae. The trial lasted 44 days. The AVIVET traps were used to determine PRM mass, number of eggs, larvae, blood-engorged and unfed nymphs, and adults on day - 12, - 5, and 0 before, and on days 2, 5, 8, 11, 15, 23, and 30, after, hens started to consume PFA. Friedman's ANOVA was utilised to identify differences between means, and the post hoc Wilcoxon matched Pairs Test was then employed to ascertain the impact of the tested PFA on the D. gallinae population. From the eighth day until the end of the trial period, a statistically lower mass of mites (P < 0.05), the number of nymphs (P < 0.05) and the number of blood-engorged mites (P < 0.05) were observed compared to day 0. In comparison to day 0, a statistically significantly lower number of eggs (P < 0.01) was observed on day 5 (P < 0.05), day 11 (P < 0.01), larvae on day 23 (P < 0.05) and day 30 (P < 0.01), as well as unfed mites on days 15, 23, and 30 (P < 0.01, P < 0.01 and P < 0.001, respectively). Egg production (%, hen-day) in 52-54 weeks of age (control period) was 88.7, while in 55-58 weeks of age (trial period) was 89.5. The results indicate that the tested PFA can control PRM without adversely affecting egg production.

Rhipicephalus larvae (n = 3) were collected from the ricefield rats, Rattus argentiventer, during a pest control program in Paya Laka, Peninsular Malaysia. Morphological examination indicated that these larvae closely resembled Rhipicephalus pilans, based on features such as the acutely pointed end of palpal segment III and a basis capitulum posterior margin that is wider than the scutal anterior margin. However, molecular analyses of the 12 S rRNA, 16 S rRNA, and COI genes showed that they are closely similar to those of Rhipicephalus haemaphysaloides. This discordance between morphological and genetic data suggests that there may be multiple species currently classified under the name R. haemaphysaloides.

Asexual reproduction can be advantageous in the short term but is generally considered an evolutionary dead end due to the lack of genetic diversity and the accumulation of deleterious mutations. The thelytokous predatory mite Amblyseius herbicolus (Chant) (Acari: Mesostigmata) shows potential for biological pest control, but its reproductive mechanism remains poorly understood. This study examined whether A. herbicolus females have retained mating ability by exposing them to morphologically similar heterospecific males from three sexually reproducing phytoseiid species: Amblydromalus limonicus (Garman & McGregor), Amblyseius lentiginosus Denmark & Schicha, and Neoseiulus cucumeris (Oudemans). No mating or insemination occurred between A. herbicolus females and heterospecific males within 24 h. In contrast, nearly all males successfully inseminated conspecific females in a follow-up observation. Mating behaviours varied across species, with A. lentiginosus showing the longest pre-mating duration and lowest insemination rate, indicating higher mate selectivity. Most Ad. limonicus males inseminated a single spermatophore, while A. lentiginosus and N. cucumeris deposited two spermatophores, suggesting differences in sperm allocation and competition. No correlation was found between male body size, mating duration, and endospermatophore volume, possibly due to the small sample size. This study does not establish whether A. herbicolus reproduces strictly through thelytoky, nor does it exclude the possibility of sexually reproducing populations elsewhere. Further research, including interspecific mating trials with the more morphologically similar Amblyseius largoensis and an investigation into the role of endosymbionts such as Wolbachia, is needed to reveal the mechanisms underlying asexuality in A. herbicolus.

Superfamily Eriophyoidea is a group of highly miniaturized and host-specific phytophagous acariform mites closely related to the soil-dwelling nematalycid mites. Limited number of reliable morphological characters, multiple homoplasies, and numerous cryptic species impede systematics of this group. Most recent multigene phylogenies of Eriophyoidea suffer from incomplete sampling, inclusion of erroneous sequences, and unreliable alignments resulting in biologically inconsistent results. In this study, we obtained five new mitogenomes of eriophyoids and reanalyzed the mitogenomic dataset by Zhang et al. (2024) in order to test their conclusion on the polyphyly of the subfamily Cecidophyinae. We found out that it was based on the wrong identification of the phyllocoptine sequence OQ615736 as a cecidophyine taxon. Our analysis showed that a group of seven mitogenomic sequences assigned to cecidophyine genera Cecidophyes, Cecidophyopsis, Coptophylla, Cosetacus, and Glyptacus form a monophyletic group, which was itself divided into two clades corresponding to previously recognized tribes Colomerini and Cecidophyini. However, no mitochondrial gene clusters unique to Cecidophyinae were found. Gene order variability in Cecidophyinae is low and concerns only positions of the control region and tRNA genes trnC and trnI. Analysis of nucleotide diversity showed that three mitochondrial protein coding genes (COX1, COX3 and CYTB) are promising molecular markers for future eriophyoid studies, whereas genes ATP8, NAD4L, NAD5, NAD6 are hypervariable and should be used with caution or even excluded (ATP8) from multigene phylogenetic analyses. Finally, we identified numerous sequences of Eriophyoidea in GenBank with incorrect taxonomic affinities, underscoring the urgent need for a comprehensive revision of all eriophyoid mite sequences deposited in public databases.

Mass rearing of the predatory mite Euseius scutalis (Athias-Henriot) using natural prey is costly and labor-intensive, limiting its application in biological pest control. Artificial diets may serve as alternative food sources; however, some studies should be previously conducted, to evaluate the possible biological consequences of their adoption. In this study, we compared the suitability of eight artificial diets, including a basic artificial diet (A) consisting of a combination of 10% honey, 10% sucrose, 5% tryptone, 5% yeast extract, 10% egg yolk, and 60% distilled water (w/w), along with seven other diets, each consisting of 80% of diet A enriched with date palm pollen (B), Typha pollen (C), Ephestia kuehniella eggs (D), Helicoverpa armigera hemolymph (E), a mixture of date palm pollen and E. kuehniella eggs (F), Tetranychus turkestani adults (G), and hen's liver (H). The data showed that E. scutalis was able to complete its development on all tested diets. Oviposition of the predator was observed on all diets, except for diets E and H. Females reared on diets B and F had the shortest adult pre-oviposition period (APOP), while those on diet B had the shortest total pre-oviposition period (TPOP). Furthermore, the number of oviposition days and fecundity were highest on diets B, D and F. Diets B and F resulted in significantly higher intrinsic (r) and finite (λ) rates of increase than the other diets, with values statistically similar to those obtained on D. The lowest values of r and λ were recorded on diet G. Based on our results, date palm pollen, E. kuehniella eggs or their mixture added to the basic diet A are more beneficial than other options for use in artificial diets for the mass rearing of E. scutalis.