Experimental and Applied Acarology最新文献

Thermal adaptation plays a crucial role in shaping the development, reproduction and population dynamics of ectothermic organisms. In this study, we compared thermal life history traits among three closely related social spider mites: Stigmaeopsis sabelisi, S. miscanthi high-aggression (HG) form, and their common ancestral group, S. miscanthi mild-aggression (ML) form. We investigated the minimum temperature thresholds for development by measuring the days required for egg hatching under five constant temperature conditions (15 °C, 20 °C, 25 °C, 30 °C, 32 °C) and estimating the thresholds using linear and nonlinear regression models. Additionally, we assessed their reproductive diapause attributes. Our results revealed that the minimum development thresholds were slightly lower in S. sabelisi from colder regions compared to S. miscanthi HG form and S. miscanthi ML form distributed in warmer and subtropical regions. Notably, high-temperature stress negatively affected development only in S. sabelisi, suggesting local adaptation. Reproductive diapause attributes also varied: reproductive diapause was induced under short-day conditions in S. sabelisi, whereas the other two species lacked such diapause. Moreover, phenotypic variation in the number of days required for egg hatching was highest in S. miscanthi ML form, suggesting retained ancestral variability that may have facilitated subsequent divergence. These findings support the hypothesis that populations from colder environments exhibit lower thermal thresholds and more intense diapause than those from warmer environments, and also provide insights into the mechanisms driving local adaptation and speciation in the social spider mites.

Haemaphysalis flava Neumann, 1897 is recognized as a vector for Dabie bandavirus (severe fever with thrombocytopenia syndrome virus, SFTSV), which is the etiological agent of severe fever with thrombocytopenia syndrome (SFTS). The tick vector has proliferated and expanded globally in recent years, likely due to the migration of birds. In this study, we selected the mitochondrial 16S rRNA as the genetic marker to analyze the population genetics of H. flava collected from Nantong, China and other regions separated by geographical barriers, all of which are located along the East Asia-Australasian Flyway (EAAF). Our research revealed significant gene flow among tick populations, which are characterized by low genetic diversity, minimal phylogeographic structure, and the interconnected haplotype network. We identified a total of 38 haplotypes, including 5 shared haplotypes. The high overall average of haplotype diversity, the shared haplotypes with large sample size covering many regions, and the abundant exclusive haplotypes in our study supported that H. flava had the ability to adapt to different environments among the large geographical range along the EAAF. The study did not support the recent expansion of the H. flava population in Nantong. Continuous surveillance of H. flava along the EAAF is essential.

Phytonemus pallidus fragariae Zimmerman (Trombidiformes: Tarsonemidae) is an important pest in strawberry cultivation worldwide, causing considerable economic losses with yield reductions ranging from 22 to 100%. This study investigated the population parameters of P. p. fragariae on three commercially important strawberry cultivars: Albion, Monterey, and San Andreas, using an age-stage, two-sex life table approach. All experimental procedures were conducted under the controlled conditions of 25 ± 2 °C, 65 ± 5% RH, and a 16:8 h (light: dark) photoperiod. The results showed that some developmental times and life table parameters of P. p. fragariae differed among the cultivars. Total pre-adult duration was longest on Albion (8.23 days), followed by Monterey (7.65 days) and San Andreas (7.10 days). Fecundity was highest on Albion (11.85 eggs/female), while no differences were observed in net reproductive rate, intrinsic rate of increase, and finite rate of increase among cultivars. However, the mean generation time was longest on Albion (13.85 days) and shortest on San Andreas (12.10 days). The findings indicate that the Albion cultivar is more suitable for development and reproduction. P. p. fragariae than the Monterey and San Andreas cultivars. This study provides initial insights into the life table parameters of P. p. fragariae on specific strawberry cultivars, enhancing our understanding of pest-host interactions. The data generated helps develop more effective integrated pest management (IPM) strategies targeting this pest in strawberry production systems.

During blood feeding, ticks face significant oxidative stress due to hemoglobin breakdown. In this context, GSTs are proposed to act as critical antioxidants, possibly by detoxifying lipid peroxides. The transcriptome of H. doenitzi was screened for GST genes, followed by the recombinant expression and functional analysis of these genes. Specifically, HdGSTm1 was cloned by PCR, and the recombinant protein rHdGSTm1 was expressed and purified. The properties of rHdGSTm1 were analyzed, gene transcription was assessed, and RNA interference was employed to evaluate its functional impact. As results, the open reading frame of HdGSTm1 is 693 base pairs (bp) in length and number of coding amino acids is 230 and it belongs to Mu-class GSTs. And the activity of GST for GSH was measured (V_max =1.39 ± 0.07 µmol/(min·mg), K_m=1.254 ± 0.12 µM). It has the highest enzyme activity at pH 7.0, 30 ℃. Antioxidant assay showed that rHdGSTm1 had concentration-dependent antioxidant capacity. The relative expression of HdGSTm1 was higher in adult ticks and the highest in Malpighian tubules. RNAi results demonstrated that HdGSTm1 had a significant effect on bloodsucking (t-test, t₍₃₄₎ = 4.296, p = 0.0001). In summary, this study isolated and characterized a Mu-class GST gene from H. doenitzi. The recombinant protein exhibits free radical scavenging activity. Evaluation of its antioxidant capacity facilitates analysis of the active oxidative stress response mechanism during blood feeding in adult Malpighian tubules, and provides a basis for elucidating the molecular mechanism. Notably, it impacts blood feeding behavior. HdGSTm1, even at low expression levels, can significantly reduce the blood-feeding duration in H. doenitzi.

Predatory mites, particularly those of the Phytoseiidae family, play a key role in sustainable pest management by reducing pest populations and minimizing reliance on chemical pesticides. Amblyseius largoensis (Muma) (Acari: Phytoseiidae) is a generalist predator, with great potential for controlling noxious agricultural pests. However, large-scale rearing of A. largoensis remains a challenge due to the lack of an efficient mass-production system. This study aimed to select a factitious prey species from the order Astigmata that could support the mass-rearing of A. largoensis. Four Astigmata species (Carpoglyphus lactis L., Thyreophagus crasentiseta Barbosa, OConnor & Moraes, Tyrophagus putrescentiae Schrank, and Glycycometus aff. molitor Volgin & Akimov) were evaluated for their ability to sustain the predator's survival, development, and reproduction. Tetranychus urticae Koch, a well-established natural prey, was used as a control. Bioassays assessed the growth rates of A. largoensis when fed exclusively on each prey species. The results showed that C. lactis supported survival and reproduction rates comparable to T. urticae, with an intrinsic growth rate favorable for mass-rearing. The other prey proved unsuitable for A. largoensis mass-rearing. Additionally, C. lactis offers practical advantages as it is easy to rearing, thrives on simple and inexpensive food sources, and allows for continuous predator production. This study highlights the potential of C. lactis as a viable factitious prey for the large-scale production of A. largoensis, contributing to the diversification of biological control strategies. Future research should focus on optimizing rearing protocols and field evaluation to validate the effectiveness of A. largoensis as a biocontrol agent in tropical and subtropical regions.

Tetranychus urticae Koch, commonly known as the two-spotted spider mite, is a serious threat to many crop species. This species can rapidly develop resistance to acaricides, rendering chemical control of the mite extremely difficult. In the present study, a homozygous mite population of T. urticae was established, and the potential involvement of transgenerational phenotypic plasticity in the development of resistance to the acaricide abamectin was investigated. The mite methylome was analyzed for the first time to evaluate the possible role of this epigenetic mark in the observed response to abamectin. The results showed a significant maladaptive transgenerational phenotypic response. Mites, previously exposed to abamectin treatments for seven consecutive generations, showed lower acaricide resistance compared to mites that were never treated with abamectin. This phenotype persisted for two consecutive generations after the termination of abamectin exposure. Methylome analysis of treated and untreated mite groups revealed that this species possessed an extremely low level of cytosine methylation, if any, suggesting that this epigenetic mark is unlikely to be involved in the transgenerational response. Overall, the results show that transgenerational phenotypic plasticity can significantly modify the phenotype of T. urticae. However, under the conditions tested, transgenerational phenotypic plasticity is not directly involved in the development of abamectin resistance. Further work is needed to better understand how transgenerational phenotypes are involved in the response of T. urticae to acaricides.

Euseius citrifolius Denmark & Muma is a type IV generalist predatory mite with a dietary preference for pollen. In this study, we tested the hypothesis that different prey, even if phylogenetically related and reared on the same host, can influence the predator's fitness by affecting its development and reproduction. We evaluated the biological performance of E. citrifolius when fed on Ricinus communis pollen and prey-based diets. Prey-based diets consisted of Oligonychus punicae and Tetranychus urticae reared on grapevines, as well as pollen. The following parameters of E. citrifolius were evaluated: developmental time of immature stages, longevity, reproduction, cumulative percentage of adults, mean oviposition rate, life-table parameters, and fertility. Oligonychus punicae and T. urticae diets resulted in a longer development time from egg to adult, increased longevity, higher oviposition rate, higher cumulative percentage of adults, and higher daily oviposition than the pollen diet. Although the pollen diet was less efficient at reproduction, it promoted higher viability. The net reproduction rate, intrinsic rate of increase, and mean generation time were higher in prey-based diets (O. punicae and T. urticae) than in the pollen diet. Overall, both prey diets supported the biological performance of E. citrifolius. These findings provide valuable insights for future research on the mass production of E. citrifolius and its potential for controlling O. punicae and T. urticae in grapevines.

Geometric morphometrics has contributed significantly to understanding ecological and evolutionary patterns by analyzing shape variation in biological structures, including species identification, population differentiation, and phenotypic plasticity of different organisms. In the context of bat ectoparasites, particularly wing mites, geometric morphometrics could present a novel approach for tracking the migratory patterns of bat hosts over time. To evaluate the morphological variation of Spinturnix psi (Kolenati, 1856) mites sampled from its typical host, Miniopterus schreibersii (Kuhl, 1817), in the three caves in eastern Serbia (Bogovinska, Sokolovica, and Sesalačka caves), we applied geometric morphometrics methods. We selected the sternal shield as the character to be analyzed and positioned 10 landmarks to describe its shape in females and 20 landmarks in males respectively. The analysis revealed statistically significant shape differences in the males, where a clear differentiation of specimens from Bogovinska cave compared to specimens from the other two localities was found, while in the females no differences were observed. Nevertheless, pairwise comparisons showed a weak but significant signal indicating differences between females from Bogovinska and Sesalačka caves. These subtle morphological variation in mites could help clarify the links between different host roosting sites, and a better understanding of the migration patterns of bats.

Proprioseiopsis asetus (Chant) (Acari: Phytoseiidae) is a newly developed and commercialized predatory mite that can prey on various phytophagous mites and small insects. To evaluate its potential as a biocontrol agent against pest thrips (Thysanoptera: Thripidae), we constructed age-stage, two-sex life tables and investigated the biological characteristics of P. asetus fed on two economically important thrip species, Megalurothrips usitatus and Thrips flavus (Thysanoptera: Thripidae), both of which cause significant crop damage. Our results show that P. asetus successfully develops and reproduces when fed on both thrips species, indicating its biocontrol potential against these pests. However, P. asetus reared on T. flavus exhibits shorter preadult duration, mean generation time (T), and population doubling time (DT), along with obviously reduced longevity, compared to P. asetus reared on M. usitatus. Despite the shorter lifespan, P. asetus fed on T. flavus shows significantly higher fecundity (F = 36.35 eggs/female), intrinsic rate of increase (r = 0.1816 d^-1) and finite rate of increase (λ = 1.1991 d^-1) than on M. usitatus (F = 30.75 eggs/female, r = 0.1375 d^-1 and λ = 1.1474 d^-1). Notably, no significant differences were observed in net reproductive rate (R₀), adult preoviposition period (APOP), total oviposition period (TPOP), or oviposition duration between the two prey species. These findings indicate that P. asetus is a promising biological control agent for both thrip species, with T. flavus being a more suitable prey to support its rapid development, high fecundity and faster population growth, despite the trade-off in adult longevity. Based on these results, we propose tailored biocontrol strategies: frequent releases of P. asetus for T. flavus management to compensate for its shorter lifespan, and early release for M. usitatus to establish a population before the pest reaches damaging levels, aiming for more efficient and sustainable pest management in crop production systems.