Experimental and Applied Acarology最新文献

The current understanding of ectoparasitic mites, especially those belonging to Otopheidomenidae, has been constrained by limited data derived primarily from museum specimens. To bridge this knowledge gap, we undertook a study to investigate mite infestations on freshly captured hawkmoths (Lepidoptera: Sphingidae). From August 2016 to July 2018, we collected samples in the Chapada do Araripe area in the municipality of Santana do Cariri (7°12'33''S, 39°43'22''W, 750 m a.s.l.), Ceará, Northeast Brazil. We attracted and captured sphingids using an artificial light source and then gathered mites from them. Among the 3,690 sphingid specimens collected from 37 species of both sexes, 119 individuals from 18 species were found to be mite-infested-a prevalence rate of 3.3%. We identified four mite species: Prasadiseius donahuei (Prasad), Prasadiseius cocytes (Prasad) (Otopheidomenidae), Callidosoma selmae Costa, Klompen, Santos, Favretto & Pepato, and an unidentified Caeculisoma species (Erythraeidae). Our data revealed the importance of seasonality for both host and parasite populations, and we observed no specific preference for infestation sites. This research recorded several first-time observations: a sphingid infested by two species of otopheidomenid mites, C. selmae parasitizing sphingids, and mites recorded from the legs of sphingids. The species Erinnyis ello ello (Linnaeus) was not only the most abundant but also the most frequently parasitized. This host presented the highest parasitism descriptors. Among the 662 mites identified, 506 were P. donahuei, predominantly infesting E. ello ello. We recommend further research to explore the potential for coevolutionary dynamics between mites and their hosts, examining how host defenses and mite adaptations influence each other over time.

The Asian longhorned tick, Haemaphysalis longicornis Neumann (Ixodida: Ixodidae), is widely distributed across temperate East Asia, including Japan, and carries a variety of zoonotic diseases. The species includes bisexual and parthenogenetic lineages. Various aspects of these two lineages, such as their abundance ratio, genetic relationship, and population structure, remain unknown in island environments such as Japan that are isolated from the mainland. Therefore, in this study, 235 individuals were collected across 15 prefectures, and their mtDNA was analyzed to better understand the genetic population structure of this species in Japan. Haplotype analysis of the 631 bp cox1 region revealed the presence of 38 haplotypes, which showed for the first time that a large diversity of haplotypes is present in Japan. In addition, the calculated haplotype diversity was 0.889-equivalent to that reported in the study that examined haplotypes across a larger region in China. This indicates that Japan is a hotspot of genetic diversity of this species. The haplotype network of this species was divided into two major clades, but there were no clear geographical boundaries in the distributions of the haplotypes. However, a qualitative cline was observed in the distribution of sexual lineage, with the parthenogenetic lineage being more prevalent in northeastern Japan and the bisexual lineage being more prevalent in southwestern Japan. Future analysis combining the results of this paper with information from nuclear DNA and large-scale mtDNA analyses would facilitate a more detailed understanding of the population structure and historical distributions of the Asian longhorned tick.

Ixodes ricinus tick is a vector of bacteria of Borreliella genus and Borrelia miyamotoi. Exposure to ticks constitutes occupational risk to soldiers, but the current knowledge on this subject is still limited. Therefore, the aim of this study was to evaluate tick abundance and prevalence of infection with Borreliella spp. and/or B. miyamotoi. Ticks were collected from vegetation on Drawsko, Ustka and Orzysz military training areas. Additionally, ticks infesting soldiers were also obtained. Ticks were examined by nested PCR and sequencing of flaB gene fragment. General Linear Models of One Variable was used for analysis of mean tick abundance and Maximum Likelihood technique based on log-linear analysis of contingency tables was used for analysis of prevalence of pathogens in ticks. Molecular phylogenetic analyses were also performed. 852 I. ricinus were collected from vegetation from three military areas. The overall mean abundance of ticks was almost 4 ticks/100 m². Season of study had a significant effect on density of total ticks, infected nymphs and females and infected nymphs, which were higher in spring-early summer. Total prevalence of pathogens was 25.7% in 711 questing ticks, and 16.0% in 282 I. ricinus collected from soldiers. Six species of Borreliella and Borrelia were identified with predominance of B. afzelii. It should be assumed that there is a risk for soldiers of acquiring infection after tick bite. The awareness of presence of pathogens in ticks should be raised in military.

Contrawise to mosquitoes, there is no country-wide long-term surveillance of ticks in Germany, leading to large gaps in coverage for distribution data. Here we report on results from two consecutive tick studies in northern Rhineland-Palatinate, western Germany, conducted in 2022 and 2023. In 2022, a new focus of the ornate sheep tick Dermacentor marginatus was detected at a military training area east of Coblenz ("Schmidtenhöhe") which is partially managed as a nature reserve where old races of cattle and horses are grazing. Two unexpected further foci were discovered north and west of the city in 2024. In 2023, repeated flagging in a small area of a forest southwest of Coblenz ("Stadtwald") revealed four nymphs of the passerine bird tick Ixodes frontalis. However, over 99% of all flagged ticks turned out to belong to the species Ixodes ricinus (Linnaeus, 1758).

The aim of the study was to report the occurrence of Ixodes silvanus outside its distribution range, in the Chaco Serrano vegetation unit of the Chaco Phytogeographic Province, central Argentina. Ticks were collected from vegetation and on birds between November 2021 and December 2023. A possible seasonal activity was observed in the immature stages of I. silvanus, with larvae in autumn-winter and nymphs in spring-summer, consistent with a behavioral diapause. A total of 937 ticks were identified as I. silvanus and confirmed molecularly, 741 host-seeking and 196 parasitizing 49 passerine birds (of 9 species, 6 genera and 5 families). All host-seeking ticks were found in leaf litter in forests dominated by the invasive tree Ligustrum lucidum, suggesting a possible link between environmental changes and the establishment of I. silvanus in this region. The prevalence of I. silvanus on birds was 27.4%, with significant participation of the Turdus genus and new host associations documented. The findings suggest that I. silvanus may be expanding its range, potentially facilitated by environmental modifications, the movement of austral migratory birds (Turdus nigriceps, Synallaxis frontalis and Zonotrichia capensis), and the range expansion of other bird species (Turdus amaurochalinus, Turdus chiguanco and Turdus rufiventris). Therefore, I. silvanus may represent a biological invasion and a potential threat to wild bird populations as a vector of pathogenic microorganisms. Future studies are required to determine the implications this could have.

Symbiotic bacteria play a crucial role in various facets of host biology and physiology. The development and utilization of symbiotic bacteria in insects show promising potential for enhancing their reproduction, temperature tolerance, resistances to pathogens and insecticides. However, limited research has been conducted on symbiotic bacteria in predatory mites. In Phytoseiulus persimilis, we successfully cultivated a strain of Stenotrophomonas maltophilia, which has been noted for its significant contributions to pathogen control, pesticide and toxin resistance, and nutrition provision in some insect species. To explore the effect of S. maltophilia and its potential application on predatory mites, we fed S. maltophilia to P. persimilis and evaluated the transmission dynamics within mite generations. We examined its impacts on predator fitness and resistances to pesticides, pathogens, and starvation. The results showed that the S. maltophilia content in the offspring increased by 12.91 times when gravid mites were fed with the bacterial solution. P. persimilis that consumed prey treated with S. maltophilia showed a 25.20-fold increase in microbial content. Mating with treated males did not affect microbial levels in females. Moreover, S. maltophilia did not cause any discernible effect on the fitness of P. persimilis, including survival, developmental duration, fecundity, and longevity. Notably, it was found to improve P. persimilis survival following exposure to the pathogen Acaricomes phytoseiuli, resulting in a reduction of mortality by 20% compared to the control. This study serves as a foundational step for further utilization of beneficial microbes to improve the efficacy of predatory mite biological control.

The flat mite, Brevipalpus yothersi (Baker, 1949) is widely distributed in the southern United States. This mite is associated with a citrus leprosis virus ((CiLV-C2) Cilevirus colombiaense strain hibiscus) infecting ornamental hibiscus (Hibiscus rosa-sinensis) in Florida and Hawaii. Because hibiscus is a highly traded ornamental plant, CiLV-C2 has the potential to spread. In laboratory experiments, the abundance and distribution of B. yothersi were studied on four varieties of tropical hibiscus. Plants, grown from cuttings, were infested with female mites, and held in environmental chambers (25 °C, 75% RH). After 3 months, the plants were divided into strata representing the top, middle and bottom of the plant. All mites (including eggs) found on the leaves and woody parts (main stems and side branches) were counted, and the surface area of each part calculated. The number and surface area of leaves and woody parts varied between hibiscus varieties; however, the differences between varieties with respect to total number of mites/plant and mites/cm² were not statistically significant. There were twice as many mites on the woody parts than on the leaves. Most mites were found in the bottom stratum of the plants, and they showed an aggregated spatial distribution. The implications of mite distributions for assessing population sizes of B. yothersi were analyzed with the purpose of optimizing sampling without damaging the plant. The efficient sampling protocol developed is an important tool for managing the vector and thereby the disease.

Spider mites (Acari: Tetranychidae) overwinter as eggs or adult females, but some do so as multiple life stages on evergreen hosts. However, proximate factors influencing such overwintering stages remain poorly understood. This study investigated photoperiodic responses and life-stage compositions during winter in a population of Schizotetranychus shii, a specialist of Japanese chinquapin (Fagaceae). The proportion of non-ovipositing females at 20 °C followed a sigmoid curve with increasing photoperiod. The critical day length was estimated as a photoperiod of 11.8 h light and 12.2 h dark (11.8L), which was similar to the natural photoperiod from late September to early October. Although females grown under 10L and 11L conditions never oviposited within 7 days, 90-96% of them started oviposition within 30 days without chilling, indicating shallow reproductive diapause. In the field, all life stages occurred throughout winter, but their proportions varied considerably. The proportion of eggs declined from early October (62%) to early December (12%), as predicted by the critical day length, but steeply increased toward late February (96%), in which only adult females and eggs remained. These findings suggest that short-day conditions in the field do not maintain adult diapause as predicted by the above experiment. In summary, a short photoperiod in October or November arrests oviposition in emerging females, but they commence oviposition during the short-day season when immature stages are still growing. As a result, individuals at all life stages coexist until all immature stages mature in February.

In this study, molecular analysis was used to show the possibility of transovarial and transstadial transmission of Borrelia valaisiana in Ixodes ricinus ticks in the natural biotopes of North-Western Russia. Female ticks collected in nature were fed on rabbits; larvae obtained from these females were fed on white mice. Eggs, female ticks after the egg deposition, larvae and nymphs of ticks after overwintering were studied for Borrelia burgdorferi s.l. within the natural inserts. The identification of Borrelia burgdorferi in ticks was carried out using the PCR method with real-time hybridization-fluorescence detection. The genotyping was performed by sequencing fragments of the intergenic region rrf-rrl. Spirochetes of only one genospecies B. valaisiana, previously not detected in North-Western Russia, were identified in ticks I. ricinus. The isolates of B. burgdorferi were obtained by inoculation of the gut contents of ticks into a prepared nutrient medium BSK-H with 6% rabbit serum (Sigma, USA). The positive reaction for B. valaisiana was observed in six out of 13 I. ricinus females (46.2%), which were successfully fed and laid eggs. Of the six infected female ticks, four (66.7%) (30.8% of the total four out of 13) were able to transmit B. valaisiana to eggs and then to larvae. 50.0% of the infected female ticks (23.1% of the total number) could transmit B. valaisiana to nymphs. In addition, the overwintered larvae and nymphs did not retain B. valaisiana. The subsequent transmission can occur as a result of feeding the overwintered larvae and nymphs on the infected overwintered hosts.

The incidence of tick-borne diseases in the United States has more than doubled since the early 2000s. Research on ticks is a priority to mitigate the spread of tick-borne diseases. Thus, it is important to understand how to efficiently collect large numbers of ticks for studies of genetics, behavior, physiology, vector competence, tick repellants, and acaricides. In this study, we compared the efficiency of two methods-dragging and CO₂-baited trapping-for collecting lone star ticks (Amblyomma americanum) across two distinct regions of its expanding range. We performed simultaneous dragging and trapping collections at six sites, three in Oklahoma and three in New York and New Jersey, USA. Our results demonstrate that dragging was more efficient than trapping for collecting lone star tick nymphs. However, dragging and trapping were similar in efficiency for collecting adult males and females. There were no regional differences in trapping or dragging efficiency. Additionally, we discuss material and labor costs of each method to inform researchers who need to rapidly collect as many ticks as possible with the most efficient and cost-effective method.