INFLUENCE OF GROOMING ON PERMANENT ARTHROPOD ASSOCIATES OF BIRDS: CATTLE EGRETS, LICE, AND MITES

Birds have a diverse community of "permanent" arthropods that complete their entire life cycle on the body of the host. Because some of these arthropods are parasites that reduce host fitness, birds control them by grooming, which consists of preening with the beak and scratching with the feet. Although preening is the primary component of grooming, scratching is essential for controlling arthropods on the head and neck, which cannot be preened. Several unrelated groups of birds have evolved comb-like pectinate claws on the middle toenail of each foot. We tested the role of these claws in the control of arthropods by experimentally removing teeth from the claws of captive western cattle egrets (Bubulcus ibis) infested with chewing lice (Insecta: Phthiraptera), feather mites (Acari: Sarcoptiformes), and nasal mites (Acari: Mesostigmata). After a period of 4 mo, we compared the abundance of arthropods on experimental birds to that of control birds with intact teeth. We used video to quantify the grooming rates of the captive birds, which groomed twice as much as wild birds. Experimental and control birds did not differ significantly in grooming time. Both groups virtually eradicated the chewing lice, but not feather mites or nasal mites. We found no support for the hypothesis that pectinate claws increase the efficiency of arthropod control by grooming. Experiments with wild birds are needed to test the hypothesis further under conditions in which birds devote less time to grooming.

Multi-locus sequence analysis unveils a novel genus of filarial nematodes associated with ticks in French Guiana

Filarial nematodes of the Dipetalonema lineage include tick-borne filarioids that infect both domestic and wild vertebrate hosts, but they remain understudied in many cases. In this study, we conducted a molecular characterization of a Dipetalonema-like filarioid (DLF) recently identified in two tick species in French Guiana, South America. While the cox1 mitochondrial gene was the sole marker initially sequenced for describing DLF, its classification and phylogenetic relationship with other members of the Dipetalonema lineage were unclear. Therefore, we better characterized DLF through the sequencing of six additional gene markers and conducted phylogenetic analyses. Based on this multi-locus typing scheme, DLF exhibited significant divergence from known genera and species of filarioids, or other sequences available in public databases, suggesting its potential classification as a novel genus within the Dipetalonema lineage. Phylogenetic analyses further unveiled a close evolutionary relationship between DLF and all other filarioids associated with Acari (ticks and mites) within a robust monophyletic subclade in the Dipetalonema lineage. Overall, these findings confirm the existence of a specialized, Acari-borne group of filarioids and underscore the need for comprehensive investigations into their epidemiology and potential impact on animal health.

Eco-epidemiology of Rickettsia amblyommatis and Rickettsia parkeri in naturally infected ticks (Acari: Ixodida) from South Carolina

BACKGROUND

Spotted fever group Rickettsia (SFGR) is the largest group of Rickettsia species of clinical and veterinary importance emerging worldwide. Historically, SFGR cases were linked to Rickettsia rickettsii, the causal agent of Rocky Mountain spotted fever; however, recently discovered species Rickettsia parkeri and Rickettsia amblyommatis have been shown to cause a wide range of clinical symptoms. The role of R. amblyommatis in SFGR eco-epidemiology and the possible public health implications remain unknown.

METHODS

This study evaluated statewide tick surveillance and land-use classification data to define the eco-epidemiological relationships between R. amblyommatis and R. parkeri among questing and feeding ticks collected across South Carolina between 2021 and 2022. Questing ticks from state parks and feeding ticks from animal shelters were evaluated for R. parkeri and R. amblyommatis using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) on pooled samples. A Bayesian multivariable logistic regression model for pool testing data was used to assess associations between R. parkeri or R. amblyommatis infection and land-use classification variables among questing ticks. The Spearman correlation was used to evaluate the relationship between the two tested pathogens.

RESULTS

The infection prevalence for R. amblyommatis was 24.8% (23.4-26.3%) among questing ticks, and 39.5% (37.4-42.0%) among feeding ticks; conversely, for R. parkeri it was 19.0% (17.6-20.5%) among questing ticks and 22.4% (20.3-24.5%) among feeding ticks. A negative, refractory correlation was found between the species, with ticks significantly more likely to contain one or the other pathogen, but not both simultaneously. The Bayesian analysis revealed that R. amblyommatis infection was positively associated with deciduous, evergreen, and mixed forests, and negatively associated with hay and pasture fields, and emergent herbaceous wetlands. Rickettsia parkeri infection was positively associated with deciduous, mixed, and evergreen forests, herbaceous vegetation, cultivated cropland, woody wetlands, and emergent herbaceous wetlands, and negatively associated with hay and pasture fields.

CONCLUSIONS

This is the first study to evaluate the eco-epidemiological factors driving tick pathogenicity in South Carolina. The negative interactions between SFGR species suggest the possible inhibition between the two pathogens tested, which could have important public health implications. Moreover, land-use classification factors revealed environments associated with tick pathogenicity, highlighting the need for tick vector control in these areas.

Description of the second species of Cingulacarus Elsen (Acari, Mesostigmata, Diplogyniidae), and notes on the genus

Cingulacarus Elsen is a monotypic genus of Trigynaspida based on C. gangeticus Elsen, collected from the scarabaeid beetle Scarabaeus gangeticus (Castelnau) (Col., Scarabaeidae) in the Democratic Republic of the Congo. Herein, a second species of the genus, C. kermanensis sp. nov. is described based on female and male specimens collected in southeastern Iran, in association with Oryctes elegans L. (Col., Scarabaeidae). The diagnosis of the genus Cingulacarus is revised, with a discussion of the impact on current generic keys for the family Diplogyniidae, and a proposal to eliminate the current subfamilial classification within that family.

Intraspecific variation of morphological traits backed up with molecular evidence votes for re-appraisal of hitherto distinguished Balaustium species-a case study of Balaustium murorum (Acariformes: Parasitengona, Erythraeidae)

Molecular examination of representatives of Balaustium from several populations in SW Poland, performed using the sequence data from the mitochondrial cytochrome c oxidase subunit I, confirmed their common specific affiliation and identity with Balaustium murorum. The potential presence of distinct species in the studied material, preliminarily inferred from the discovery of clusters as a result of Principal Component Analysis exploring the metric data sets, was rejected due to the finding of only one haplotype, at intra- and inter-population sampling. An insight into meristic traits in larvae, focused on chaetotaxy of legs, revealed wider variation than hitherto recognized for the species. The variation was higher in laboratory-reared larvae compared to field-collected ones. The overall deviations from the mean character values at intra- and interpopulation levels, higher than hitherto observed for the species, vote for the reappraisal of the criteria adopted for discrimination of members of Balaustium with the application of an integrative approach.

Two new species of the genus Ologamasus (Ologamasidae) from apple orchards in southern Brazil

This paper describes two new species of the genus Ologamasus (Acari: Ologamasidae), namely Ologamasus margaridae n. sp. and Ologamasus tuberculatus n. sp., based on females, males and nymphal stages collected in apple orchards (Malus domestica Borkh.) in southern Brazil. Ologamasus tuberculatus has a distinctive pair of large pores inserted on protuberances on the dorsal shield.

and supplementary descriptions of Fujianacarus wisterianis from China

Two new eriophyid mite species (Acari: Prostigmata: Eriophyoidea) were described from the host plants of the genus Callerya Endl. during a field survey in China: Tetra nitidae sp. nov. vagrant on leaves ofCallerya nitida (Bentham) R. Geesink (Leguminosae),and Calepitrimerus calleryus sp. nov. vagrant on leaves ofCallerya tsui (F. P. Metcalf) Z. Wei & Pedley. Both species caused no apparent symptoms in their host plants. Additionally, this paper provides a supplementary morphological description and illustrations of Fujianacarus wisterianis Song, Xue & Hong, 2008 (Eriophyoidea).

Scientometric Evaluation of the Itch Mite, Sarcoptes scabiei (Acari: Sarcoptidae): The Last Four Decades of Global Academic Output on Scabies

OBJECTIVE

Scabiosis, the infestation of the skin with Sarcoptes scabiei, is a neglected tropical disease, with at least 200 million people being infested with the parasite at any time. It is estimated that scabies is responsible for 0.07% of the total burden of disease worldwide. Objective of this study is to perform a scientometric analysis of S. scabiei literature using the Web of Science Core Collection database for the years 1981-2020.

METHODS

All documents indexed between 1981 and 2020 in scabies literature were analyzed by using a search string including keywords of "scabies", "Sarcoptes scabiei" and "S. scabiei" in Web of Science Core Collection database. We excluded all materials including data on the bacterium species named Streptomyces scabies and Streptomyces scabiei.

RESULTS

Overall, 2,933 articles were retrieved on scabies, 66.3% of which were original article. With 663 publications the USA was the most productive country, while The International Journal of Dermatology was the journal with the highest number of publications on scabies. Half of the most productive institutions and seven of the top ten prolific authors were also from Australia. The National Health and Medical Research Council of Australia was the most supportive funding agency. With 4,706 citations, 2020 was the year with most references on scabies. The most cited publication was "The Global Burden of Skin Disease in 2010: An Analysis of the Prevalence and Impact of Skin Conditions" by Hay et al. in the Journal of Investigative Dermatology with a total of 565 citations. The most collaborative country was Australia and the most cooperative institution was the University of Melbourne.

CONCLUSION

The majority of the studies were done in a given country while multicenter studies are very rare. It is recommended that more studies should be conducted on scabiosis in developing countries where the problem of scabies is the biggest.

Description of a new Pavlovskyella species (Acari: Argasidae) from Chile

Soft ticks (Argasidae) of the Pavlovskyella Pospelova-Shtrom subgenus are important vectors of relapsing fever spirochetes, which are agents of disease globally. South American representatives of the Pavlovskyella subgenus include 3 species: Ornithodoros (Pavlovskyella) brasiliensis Aragão, Ornithodoros (Pavlovskyella) furcosus Neumann, and Ornithodoros (Pavlovskyella) rostratus Aragão. Here, we describe a fourth species based on morphological and mitogenomic evidence of ticks collected in burrows of unknown hosts in central Chile. The larva of the new species separates from other South American soft ticks by the following combination of characters: 13 pairs of dorsolateral setae, dorsal plate hexagonal, hypostome blunt with denticles from apex almost to the base. Adults of this new species lack cheeks, possess a dorsoventral groove, and have humps, similar to O. (P.) brasiliensis; however, they lack bulging structures on the flanks of idiosoma. Moreover, females and males differ from O. (P.) rostratus by having 3 humps instead of spurs in tarsi I and from O. (P.) furcosus because of their smaller size and thinner anterior lip of the genital aperture in females. The phylogenetic analysis performed with mitogenomes of the Argasidae family depicts the new Pavlovskyella species from Chile in a monophyletic clade with other South American species in the subgenus, confirming a regional group.

Kill rate as a tool in efficiency evaluation of Neoseiulus californicus (Acari: Phytoseiidae) mass reared on factitious food

The predatory mites of the Phytoseiidae family are crucial biological control agents widely utilized in biological pest management targeting phytophagous mites and insects. Key factors in these control strategies are that phytoseiids must be able to find their main target prey and to maintain high populations and efficacy. To reduce expenses and time-consuming production methods of mass rearing of phytoseiids, pollen and other factitious (i.e., non-natural/nontarget) hosts need to be present as an alternative food for predatory mite populations. The mass-rearing possibilities of these predators on alternative food sources, such as astigmatid mites (i.e., house and stored mites) and pollen, must be evaluated not only by the cost of rearing settings but on the basis of their efficiency maintenance in killing prey. The pest kill rate (km) is the average daily lifetime killing of the pest by the natural enemy under consideration and can represent a useful indicator for phytoseiids efficacy to rank them as BCAs on the basis of their effective killing/predation on target prey. In this study, we evidenced that 2 astigmatid mites, Glycyphagus domesticus (De Geer) and Lepidoglyphus destructor (Schrank), and Quercus ilex L. pollen can be successfully adopted as substitute food sources for mass rearing of the phytoseiid Neoseiulus californicus (MgGregor); then, we determined that these populations of BCAs maintained a consistent km at new/first impact on the main target pest, Tetranychus urticae Koch.

A new species of Zercoseius (Acari: Mesostigmata: Blattisociidae) from Brazil

Zercoseius luizdequeirozi n. sp. is described based on adult females collected from soil/litter samples taken from disturbed areas of the natural vegetation of the Brazilian Atlantic Forest biome. This new species differs from Zercoseius spathuliger (Leonardi, 1899), presently the only species included in this genus, reported so far from Europe, northern Africa and northwestern USA, more obviously by the shape of the dorsal shield setae and by having seta s1.

arizonensis

The genus Neotrichobia Tuttle & Baker is redescribed with a revised diagnosis. The type species Neotrichobia arizonensis Tuttle & Baker, 1968 is redescribed based on larvae, protonymphs, deutonymphs and adults including the paratype male and deutonymph.

Description of the ontogenetic changes in the morphology of Neoseiulus cucumeris (Acari: Phytoseiidae)

This paper reports the results of our studies of the morphological ontogeny of Neoseiulus cucumeris (Oudemans) based primarily on specimens reared in a laboratory at Manaaki Whenua Landcare Research, Auckland, New Zealand. We describe all postembryonic stages and illustrate them in detail: the larva, protonymph, deutonymph (male and female), and adult female and male.

GENETIC VARIATION OF LEPTOTROMBIDIUM (ACARI: TROMBICULIDAE) MITES CARRYING ORIENTIA TSUTSUGAMUSHI, THE BACTERIAL PATHOGEN CAUSING SCRUB TYPHUS

Leptotrombidium (Acari: Trombiculidae) mites are carriers of Orientia tsutsugamushi, the bacterial pathogen causing scrub typhus in humans. Classification of Leptotrombidium is vital because limited mite species carry O. tsutsugamushi. Generally, Leptotrombidium at the larval stage (approximately 0.2 mm in size) are used for morphological identification. However, morphological identification is often challenging because it requires considerable skills and taxonomic expertise. In this study, we found that the full-length sequences of the mitochondrial cytochrome c oxidase subunit 1 gene varied among the significant Leptotrombidium. On the basis of these, we modified the canonical deoxyribonucleic acid (DNA) barcoding method for animals by redesigning the primer set to be suitable for Leptotrombidium. Polymerase chain reaction with the redesigned primer set drastically increased the detection sensitivity, especially against Leptotrombidium scutellare (approximately 17% increase), one of the significant mites carrying O. tsutsugamushi. Phylogenetic analysis showed that the samples morphologically classified as L. scutellare and Leptotrombidium pallidum were further split into 3 and 2 distinct subclusters respectively. The mean genetic distance (p-distance) between L. scutellare and L. pallidum was 0.2147, whereas the mean distances within each species were 0.052 and 0.044, respectively. Within L. scutellare, the mean genetic distances between the 3 subclusters were 0.1626-0.1732, whereas the distances within each subcluster were 0.003-0.017. Within L. pallidum, the mean genetic distance between the 2 subclusters was 0.1029, whereas the distances within each subcluster were 0.010-0.013. The DNA barcoding uncovered a broad genetic diversity of Leptotrombidium, especially of L. scutellare and L. pallidum, the notable species carrying O. tsutsugamushi. We conclude that the DNA barcoding using our primers enables precise and detailed classification of Leptotrombidium and implies the existence of a subgenotype in Leptotrombidium that had not been found by morphological identification.

Hormetic effects of neonicotinoid insecticides on Rhizoglyphus robini (Acari: Acaridae)

The stimulation of biological processes by sublethal doses of insecticides or other stressors is known as hormesis. Here, we have evaluated whether exposure to field-relevant or low concentrations of neonicotinoids induce changes in the reproductive capacity of the bulb mite Rhizoglyphus robini (Acari: Acaridae). Among the tested neonicotinoids imidacloprid, thiamethoxam, and dinotefuran, the highest hormetic effect on the reproduction of R. robini occurred 24 h after the 48 h exposure period to imidacloprid at concentrations of 70 and 140 mg a.i./L. Despite the stimulating effects of imidacloprid on mite reproduction, no significant differences were observed in the offspring (F₁) for biological aspects including egg hatch rate, embryonic period and sex ratio, while an increase was found in the duration of development time from egg to adult. Evaluation of the detoxification enzyme activities of treated adults showed that the highest activity of carboxyl/cholinesterases, cytochrome P450s, and glutathione S-transferases was obtained when exposed to 70, 140 and 70 mg a.i./L imidacloprid, immediately after the exposure period, respectively. Also, an increase in the activity of the antioxidant enzyme catalase was observed compared to that of the control. After imidacloprid pretreatment (140 mg a.i./L), the tolerance of adult mites to diazinon was increased about two-fold. This study shows that exposure to imidacloprid can induce hormetic effects on R. robini and could severely complicate its control due to a higher reproduction, enhanced detoxification enzyme activities, and increased tolerance against other pesticides.

Berry species and crop management approaches affect species diversity and abundance of predatory mites (Acari: Phytoseiidae)

Berries comprise an economically important group of crops. Knowledge about their arthropod pests and biological control agents is important in the development of more efficient integrated pest management programs. Identification of potential biocontrol agents based solely on morphological attributes may be difficult and so molecular techniques should be incorporated. Here we studied the species diversity of predatory mites in the family Phytoseiidae, and how this diversity is affected by the berry species and crop management approaches, specifically pesticide application regimes. We sampled 15 orchards in the State of Michoacán, Mexico. Sites were selected based on berry species and pesticide regimes. Mite identification was achieved by combining morphological attributes and molecular techniques. Phytoseiidae diversity was compared amongst blackberry, raspberry and blueberry. Subsequently we studied the effect of berry species and pesticide regime on the abundance of the most prevalent phytoseiid species. We identified 11 species of phytoseiid mites. The greatest species diversity was found in raspberry, followed by blackberry and then blueberry. The most abundant species were Typhlodromalus peregrinus and Neoseiulus californicus. The abundance of T. peregrinus was significantly affected by pesticide application but not by berry species. In contrast, abundance of N. californicus was significantly affected by berry species but not by pesticide regime.

Artificial Infestation of Sarcoptes scabiei (Acari: Sarcoptidae) in Rabbits Exhibits Progressive Pathological Changes, Apoptosis, and Keratinization in the Skin

Sarcoptes scabiei (S. scabiei) is an ectoparasite that can infest humans and 150 mammalian host species, primarily causing pruritus, crust, and alopecia. However, neither the pathological process of host skin under S. scabiei infection nor the mechanism of S. scabiei infection in regulating apoptosis and keratinization of host skin has been studied yet. In this study, a total of 56 rabbits were artificially infested with S. scabiei, and the skin samples were collected at seven different time points, including 6 h, 12 h, day 1, day 3, 1 week, 4 weeks, and 8 weeks, whereas a group of eight rabbits served as controls. We measured epidermal thickness by H&E staining, observed the skin ultrastructure by electron microscopy, and detected the degree of skin apoptosis by TUNEL staining. The level of transcription of genes related to apoptosis and keratinization was detected by quantitative real-time PCR (qRT-PCR), and the level of Bcl-2 protein expression was further detected using immunohistochemistry. Our results showed that, with increased infestation time, the epidermal layer of the rabbit skin exhibited significant thickening and keratinization, swollen mitochondria in the epidermal cells, and increased skin apoptosis. The level of caspase-1, 3, 8, 10, 14, and Bcl-2 mRNA expression was increased, whereas the level of keratin 1 and 5 was decreased after S. scabiei infestation. In conclusion, S. scabiei infestation causes thickening of the epidermis, which may be related to apoptosis-induced proliferation and skin keratinization.

Alternative food sources for Amblydromella caudiglans (Phytoseiidae) and effects on predation

The addition of supplemental food sources for natural enemies is a growing component of conservation and augmentative biological control. Supplemental foods can be used to retain natural enemies when prey are scarce and to promote survival, fecundity, longevity, and development of natural enemy populations, especially generalist natural enemies. Amblydromella caudiglans (Schuster) (Acari: Phytoseiidae) is one of the most abundant predatory mites found in commercial apple orchards in Washington, USA, and contributes to spider mite control. However, because its widespread presence in commercial apple orchards was only recently discovered, how supplementary food sources affect its performance is unknown. In laboratory studies, we evaluated the performance (fecundity, retention, prey consumption) of the generalist phytoseiid A. caudiglans on commercially available supplemental food sources, including factitious prey (Ephestia eggs and Artemia brine shrimp cysts), and pollens of apple, pear, and cattail. We determined that A. caudiglans will not consume Ephestia eggs and performs best on cattail and pear pollens. Combinations of food sources did not enhance the performance of this predator compared to the best performing single-sources. The presence of alternative food sources did not decrease A. caudiglans predation of twospotted spider mite nymphs, except for Artemia brine shrimp cysts, which had a substantial handling time. These results lay the groundwork for identifying a way to promote and retain this natural enemy in tree fruit cropping systems through the use of food resource applications or floral plantings.

Biology, Systematics, Microbiome, Pathogen Transmission and Control of Chiggers (Acari: Trombiculidae, Leeuwenhoekiidae) with Emphasis on the United States

Chiggers are the larval stage of Trombiculidae and Leeuwenhoekiidae mites of medical and veterinary importance. Some species in the genus Leptotrombidium and Herpetacarus vector Orientia species, the bacteria that causes scrub typhus disease in humans. Scrub typhus is a life-threatening, febrile disease. Chigger bites can also cause dermatitis. There were 248 chigger species reported from the US from almost every state. However, there are large gaps in our knowledge of the life history of other stages of development. North American wide morphological keys are needed for better species identification, and molecular sequence data for identification are minimal and not clearly matched with morphological data. The role of chiggers in disease transmission in the US is especially understudied, and the role of endosymbionts in Orientia infection are suggested in the scientific literature but not confirmed. The most common chiggers in the eastern United States were identified as Eutrombicula alfreddugesi but were likely misidentified and should be replaced with Eutrombicula cinnabaris. Scrub typhus was originally believed to be limited to the Tsutsugamushi Triangle and the chigger genus, Leptotrombidium, but there is increasing evidence this is not the case. The potential of Orientia species establishing in the US is high. In addition, several other recognized pathogens to infect humans, namely Hantavirus, Bartonella, Borrelia, and Rickettsia, were also detected in chiggers. The role that chiggers play in these disease transmissions in the US needs further investigation. It is possible some of the tick-borne diseases and red meat allergies are caused by chiggers.

Acari (Parasitiformes and Acariformes) From Mexico: Analysis of Their Geographical and Host Distribution in Rodentia (Cricetidae)

The study of Acari associated with cricetid rodents in Mexico began at the end of the 1930s. Despite efforts to gathering the information, only listings were built, but none of these studies present an analysis of the available data. A search was made through electronic databases; in addition, some not published records contained at Collection of Laboratorio de Acarología, Facultad de Ciencias, Universidad Nacional Autónoma de México were included in the inventory. Combining the literature records and those deposited in the collection, the total number of species of Acari associated with this family of rodents is 165, distributed in two superorders, four orders, 15 families, and 57 genera. Of the 15 families registered, the richest is Trombiculidae (70 nominal species and 75 taxa), followed by Laelapidae (39 and 42, respectively), Ixodidae (13 nominal and 16 taxa), and Leewenhoekiidae (13 nominal and taxa). From the bibliographic searches, a total of 76 papers were recovered with information on the association between Acari and cricetid rodents in Mexico. The main detected approach in the literature was taxonomic (75 works) and one on detection of pathogens. From the 145 known species of cricetids recorded in Mexico, only 72 (distributed in 18 genera) have been studied and found to host Acari. The use of regionalization of Mexico in provinces allowed us to map the records of Acari associated to cricetids in the most natural approximation of their distribution. We recognize and discuss seven factors that favor the scarcity and asymmetry of acarological studies in Mexico.

hasei (Acari: Argasidae) and blood of the wild mammal hosts in the Orinoquia region, Colombia

Interest in research on soft ticks has increased in recent decades, leading to valuable insight into their role as disease vectors. The use of metagenomics-based analyses have helped to elucidate ecological factors involved in pathogen, vector, and host dynamics. To understand the main bacterial assemblages present in Ornithodoros cf. hasei and its mammalian hosts, 84 ticks and 13 blood samples from bat hosts (Chiroptera) were selected, and the 16S rRNA gene V4 region was sequenced in five pools (each one related to each host-tick pairing). Bacterial taxonomic assignment analyses were performed by comparing operational taxonomic units (OTUs) shared between ticks and their host blood. This analysis showed the presence of Proteobacteria (38.8%), Enterobacteriaceae (25%), Firmicutes (12.3%), and Actinobacteria (10.9%) within blood samples, and Rickettsiaceae (39%), Firmicutes (25%), Actinobacteria (13.1%), and Proteobacteria (9%) within ticks. Species related to potentially pathogenic genera were detected in ticks, such as Borrelia sp., Bartonella tamiae, Ehrlichia sp. and Rickettsia-like endosymbiont, and the presence of these organisms was found in all analyzed bat species (Cynomops planirostris, Molossus pretiosus, Noctilio albiventris), and O. cf. hasei. About 41-48.6% of bacterial OTUs (genera and species) were shared between ticks and the blood of bat hosts. Targeted metagenomic screening techniques allowed the detection of tick-associated pathogens for O. cf. hasei and small mammals for the first time, enabling future research on many of these pathogens.

Impact of starvation on paternal reproductive investment in Neoseiulus californicus

Neoseiulus californicus is an important biological control agent of small arthropod pests, widely used in preventive releases at low prey densities. Therefore, it is important to study reproductive investment of this species, both females and males, under environmental pressure of limited prey availability. Laboratory experiments were performed to investigate N. californicus male reproductive investment after short-time fasting or long-term starvation. When fasted for 36 h, males are still able to complete a single mating with no significant change in reproductive parameters of its mate. But the total mating duration became 24% longer, especially timing for the male to fill the first spermatheca of its mate increased by 35%. If daily food availability was less than 20% of demand, males were still able to mate until the end of life, but their fertility reduced after ca. the seventh mating. Mating of some males at the end of their lives are invalid, with their mates failing to oviposit. Overall, we summarized that reproductive investment demand for a single mating was low in N. californicus males, but its priority in energy allocation was high. When starved, males tried to guarantee their mating capability, but their fertility decreased gradually.

New records of soft ticks (Acari: Argasidae) in the Caatinga biome of Brazil, with a phylogenetic analysis of argasids using the nuclear Histone 3 (H3) gene

In Brazil, 19 species of the genus Ornithodoros (Acari: Argasidae) have been reported. The medical and veterinary importance of Ornithodoros ticks has increased substantially in recent decades, with the discovery of various relapsing fever Borrelia infecting Ornithodoros ticks. Herein, argasid ticks were collected during 2019-2020 from caves, abandoned nests and homes in various regions of Ceará State, Brazilian semiarid-Caatinga biome. In total, 289 ticks were collected and identified into five species: Ornithodoros cavernicolous (176 specimens), Ornithodoros fonsecai (81), Ornithodoros mimon (12), Ornithodoros rietcorreai (4), and a fifth species provisionally retained as Ornithodoros sp. Ubajara. Tick identifications were corroborated by a phylogenetic analysis inferred using the 16S rRNA gene. To extend the molecular characterization, DNA samples were tested by an additional PCR assay targeting the nuclear Histone 3 (H3) gene. Because there were no H3 sequences of argasids in GenBank, we extended this PCR assay for additional Ornithodoros species, available in our laboratory. In total, 15 partial sequences of the H3 gene were generated for 10 Ornithodoros species, showing 0% intraspecific polymorphism, and 1.5-11.6% interspecific polymorphism. Phylogenetic analyses inferred segregated Ornithodoros sp. Ubajara as a potential novel species. Our results also highlight the potential of the H3 gene for deeper phylogenetic analyses of argasids. The present study provides new data for argasid ticks of the genus Ornithodoros in the Caatinga biome. Because some of these tick species are human-biting ticks, active surveillance for the incidence of human infection due to Ornithodoros-borne agents is imperative in the Caatinga biome.

Insights into gene manipulation techniques for Acari functional genomics

Functional genomics is an essential tool for elucidating the structure and function of genes in any living organism. Here, we review the use of different gene manipulation techniques in functional genomics of Acari (mites and ticks). Some of these Acari species inflict severe economic losses to managed crops and health problems to humans, wild and domestic animals, but many also provide important ecosystem services worldwide. Currently, RNA interference (RNAi) is the leading gene expression manipulation tool followed by gene editing via the bacterial type II Clustered Regularly Interspaced Short Palindromic Repeats and associated protein 9 system (CRISPR-Cas9). Whilst RNAi, via siRNA, does not always lead to expected outcomes, the exploitations of the CRISPR systems in Acari are still in their infancy and are limited only to CRISP/Cas9 to date. In this review, we discuss the advantages and disadvantages of RNAi and CRISPR-Cas9 and the technical challenges associated with their exploitations. We also compare the biochemical machinery of RNAi and CRISPR-Cas9 technologies. We highlight some potential solutions for experimental optimization of each mechanism in gene function studies. The potential benefits of adopting various CRISPR-Cas9 systems for expanding on functional genomics experiments in Acari are also discussed.

First Report of the Bat Tick Carios kelleyi (Acari: Ixodida: Argasidae) From Vermont, United States

The soft tick Carios kelleyi (Cooley and Kohls, 1941) is an ectoparasite of bats that can harbor bacteria known to cause disease in humans, such as Rickettsia spp., Bartonella spp., and relapsing fever Borrelia spp. Human-tick encounters may occur when bats occupy attics or similar dwellings with access points to human-inhabited areas. During May 2021, a partially engorged adult female C. kelleyi was collected from a Vermont home with an attic that was being used as a roost by big brown bats, Eptesicus fuscus (Chiroptera: Vespertilionidae). The source of the blood in the tick was the domestic dog, Canis lupus familiaris. Subsequently, eight C. kelleyi larvae were collected from a rescued E. fuscus adult. This is the first report of a soft tick species from Vermont and it is unknown how long C. kelleyi has been present in this state. Reports of C. kelleyi are on the rise across the northeastern United States but the implications for the health of humans, domestic animals, and bats in northern New England remain unclear. Bat management plans should consider the importance of bat exclusion in preventing tick encounters with members of the household and should include a tick monitoring component if bats are evicted.

Parasitism, seasonality, and diversity of trombiculid mites (Trombidiformes: Parasitengona, Trombiculidae) infesting bats (Chiroptera) in Poland

The study aims to ascertain the diversity of trombiculid species associated with Chiroptera in Poland, and for the first time in the case of research on Central European Trombiculidae, we use both DNA and morphology in an integrative taxonomic approach to determine species identities of trombiculids. The research was carried out from 2015 to 2019. In total, 2725 larvae were collected from 300 specimens of bats belonging to 11 species. Deutonymphs were obtained through laboratory rearing of larvae; few larvae and deutonymphs were collected also from bats' daily roosts. The presence of trombiculid larvae on hosts was observed between July and April of the following year, with the highest numbers recorded in autumn, during bat swarming. Male bats were infested more often than females (16.4 vs. 6.6%). The highest infestation rate was recorded for Barbastella barbastellus, Myotis nattereri and Plecotus auritus, and the highest prevalence of chiggers (> 30%) for Myotis bechsteinii and P. auritus. The larvae found on bats occupied the areas with free access to the host's skin: auricles, tragus, and snout. Morphological identification of specimens to the species level was hindered by the mosaic distribution of diagnostic traits. Morphological analyses indicated the presence of Leptotrombidium russicum and Leptotrombidium spp. in the examined material, whereas molecular analyses additionally suggested three other potential species assigned to the same genus based on the assessed scope of intrageneric variation (ASAP method). We argue that the identification of the parasitic larvae (chiggers) using morphological characters does not address the question of actual species boundaries, which, in turn, affects the inferences about host specificity and host range.

Distribution of chigger mites (Acari: Trombiculidae) over hosts, parasitopes, collection localities, and seasons in northern Iran

We studied the distribution of chigger mite species over mammal hosts, attachment sites on the host body, habitats, and seasons in Iran. The study was based on 2155 specimens of 36 chigger species collected from 10 species of Muridae, Cricetidae, and Soricidae across six provinces of northern Iran. A high level of mixed infestation by chiggers was recorded-76% of hosts parasitized by chiggers were infested by more than one (2-8) species. Statistically significant differences in the preference for anterior and posterior parts of the host body were found. Three species-Neotrombicula lubrica, N. delijani, and Cheladonta firdousii-preferred the posterior part of the host body; 12 species were characterized by the occurrence in the anterior part and differed from one another by the frequency of presence in the posterior part. One species, Hirsutiella alpina, was found only in the anterior part of the host body (inside the ears of rodents). The most diverse chigger fauna was on the fringe of Golestan National Park (species richness = 21, Shannon-Wiener index = 2.823). The chigger fauna of the high-mountain localities on the Alborz Range was the least diverse (species richness = 16, Shannon-Wiener index = 2.439). The seasonal aspect of activity was evident for Neotrombicula elegans, which exposed the autumn-winter period of the occurrence on hosts, and N. vernalis, with the winter-spring peak of abundance.

Adding a Natural Enemy to Respond to Pest Immigration and Delayed Natural Enemy Releases in Augmentative Biological Control

Whether increased natural enemy density or adding a second natural enemy species will provide superior pest suppression in greenhouse augmentative biological control is unknown for many commercially available natural enemy species. In this study, we use sweetpotato whiteflies, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), on poinsettias, Euphorbia pulcherrima Willd. ex Klotzsch (Malpighiales: Euphorbiaceae), to determine whether adding Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae) to Eretmocerus eremicus Rose and Zolnerowich (Hymenoptera: Aphelinidae) is better for B. tabaci suppression compared with either natural enemy alone, both with and without challenges with whitefly immigration or delayed natural enemy releases. The number of whiteflies on caged poinsettias treated with different natural enemy release rates (single or double rate), natural enemy species (one or two species), natural enemy delayed release (weeks 4 and 8), and whitefly immigration treatments (introduced at week 4 or week 8) was censused biweekly for 16 wk. Both species used in combination provided similar or better suppression of whiteflies compared with either natural enemy alone. Both species combined also provided superior suppression of whiteflies when challenged with whitefly immigration or delays in natural enemy releases compared with E. eremicus alone. Whitefly immigration or delays in E. eremicus releases did not increase whitefly populations, suggesting that suppression of whiteflies by E. eremicus alone is relatively robust. This study found no evidence for negative interactions between E. eremicus and A. swirskii for suppressing B. tabaci.

Screening and genotyping of Orientia tsutsugamushi from field-collected on-host chiggers (Acari: Prostigmata) recovered from a positive scrub typhus locality in Kelantan, Malaysia

Orientia tsutsugamushi is the causative agent of scrub typhus vectored by larval stages of trombiculid mites (chiggers) that occur in most tropical regions of Southeast Asia. A total of 242 chiggers extracted from eight small mammals captured from a positive scrub typhus locality in Kelantan, Malaysia, were screened for the presence of O. tsutsugamushi. The chiggers were grouped in 16 pools for extraction of DNA prior to screening of O. tsutsugamushi based on the nucleotide sequence of 56-kDa type specific antigen (TSA) gene using nested polymerase chain reaction. Two species of on-host chiggers were identified, the one, Leptotrombidium deliense, much more dominant (94.8%) than the other, Ascoshoengastia sp. (5.2%). The pathogen was detected in two pools (12.5%) of L. deliense recovered from Rattus rattus and Tupaia sp. The 56-kDa TSA gene sequence analysis revealed the O. tsutsugamushi harboured in those chiggers were Karp prototype strain with high similarity (99.3%). Findings of this study strongly supported the existence of scrub typhus infections in certain parts of Malaysia which agrees with previous local reports. Moreover, this study highlighted the pressing need of a large-scale close observation of O. tsutsugamushi DNA sequences from chiggers that can probably be collected from other positive scrub typhus localities to precisely provide the distribution and prevalence of this zoonotic pathogen.

Feeding design in free-living mesostigmatid chelicerae (Acari: Anactinotrichida)

A model based upon mechanics is used in a re-analysis of historical acarine morphological work augmented by an extra seven zoophagous mesostigmatid species. This review shows that predatory mesostigmatids do have cheliceral designs with clear rational purposes. Almost invariably within an overall body size class, the switch in predatory style from a worm-like prey feeding ('crushing/mashing' kill) functional group to a micro-arthropod feeding ('active prey cutting/slicing/slashing' kill) functional group is matched by: an increased cheliceral reach, a bigger chelal gape, a larger morphologically estimated chelal crunch force, and a drop in the adductive lever arm velocity ratio of the chela. Small size matters. Several uropodines (Eviphis ostrinus, the omnivore Trachytes aegrota, Urodiaspis tecta and, Uropoda orbicularis) have more elongate chelicerae (greater reach) than their chelal gape would suggest, even allowing for allometry across mesostigmatids. They may be: plesiosaur-like high-speed strikers of prey, scavenging carrion feeders (like long-necked vultures), probing/burrowing crevice feeders of cryptic nematodes, or small morsel/fragmentary food feeders. Some uropodoids have chelicerae and chelae which probably work like a construction-site mechanical excavator-digger with its small bucket. Possible hoeing/bulldozing, spore-cracking and tiny sabre-tooth cat-like striking actions are discussed for others. Subtle changes lead small mesostigmatids to be predator-scavengers (mesocarnivores) or to be predator-fungivores (hypocarnivores). Some uropodines (e.g., the worm-like prey feeder Alliphis siculus and, Uropoda orbicularis) show chelae similar in design to astigmatids and cryptostigmatids indicating possible facultative saprophagy. Scale matters-obligate predatory designs (hypercarnivory) start for mesostigmatids with chelal gape > 150 μm and cheliceral reach > 350 μm (i.e., about 500-650 μm in body size). Commonality of trophic design in these larger species with solifugids is indicated. Veigaia species with low chelal velocity ratio and other morphological strengthening specialisms, appear specially adapted in a concerted way for predating active soft and fast moving springtails (Collembola). Veigaia cerva shows a markedly bigger chelal gape than its cheliceral reach would proportionately infer suggesting it is a crocodile-like sit-and-wait or ambush predator par excellence. A small chelal gape, low cheliceral reach, moderate velocity ratio variant of the worm-like feeding habit design is supported for phytoseiid pollenophagy. Evidence for a resource partitioning model in the evolution of gnathosomal development is found. A comparison to crustacean claws and vertebrate mandibles is made. Alliphis siculus and Rhodacarus strenzkei are surprisingly powerful mega-cephalics for their small size. Parasitids show a canid-like trophic design. The chelicera of the nematophagous Alliphis halleri shows felid-like features. Glyphtholaspis confusa has hyaena-like cheliceral dentition. The latter species has a markedly smaller chelal gape than its cheliceral reach would suggest proportionately, which together with a high chelal velocity ratio and a high estimated chelal crunch force matches a power specialism of feeding on immobile tough fly eggs/pupae by crushing (durophagy). A consideration of gnathosomal orientation is made. Predatory specialisms appear to often match genera especially in larger mesostigmatids, which may scale quite differently. Comparison to holothyrids and opilioacarids indicates that the cheliceral chelae of the former are cutting-style and those of the latter are crushing-style. A simple validated easy-to-use '2:1 on' predictive algorithm of feeding habit type is included based on a strength-speed tradeoff in chelal velocity ratio for ecologists to test in the field.

Host plant and humidity effects on phytoseiid mite, Gynaeseius liturivorus (Acari: Phytoseiidae) egg hatchability

Gynaeseius liturivorus (Ehara) (Acari: Phytoseiidae) is a promising biological control agent for tiny arthropod pests, including Thrips tabaci Lindeman (Thysanoptera: Thripidae) known as a major pest of Welsh onion. In fields during summer, G. liturivorus is observed on soybean, but not on Welsh onion, even when numerous T. tabaci are present. To elucidate G. liturivorus's occurrence on soybean and Welsh onion in relation to relative humidity (RH), we examined its egg hatching on their seedlings under low RH conditions. Then we estimated the moisture transpiration from both plants. Egg hatching occurred only on soybean plants exhibiting greater moisture transpiration. Aiming at utilizing G. liturivorus as a biological control agent for Welsh onion production in summer, evaluation of its relative tolerance and compensation potential for drought injury is necessary. Therefore, we used five phytoseiid species including G. liturivorus and Neoseiulus californicus to estimate the RH and vapor pressure deficit (VPD) at which 50% of eggs hatch (RH₅₀ and VPD₅₀). Furthermore, we examined G. liturivorus and N. californicus egg hatching under different RH oscillation conditions. Results show G. liturivorus as the most drought-sensitive among the five species tested, but G. liturivorus is able to compensate for lethal low-RH effects on egg hatching in part by periodic exposure to high RH conditions, as observed for N. californicus.

Ground Predator Activity-Density and Predation Rates Are Weakly Supported by Dry-Stack Cow Manure and Wheat Cover Crops in No-Till Maize

Because it keeps land in production, conservation programs that focus on in-field habitat manipulations may help farmers better support predators than by building predator habitat around fields. We investigated two in-field habitat manipulations that benefit producers and soil quality: fertilizing with dry-stack cow manure and planting a wheat cover crop. We hypothesized that, compared with inorganic fertilizer and fallow plots, both treatments augment habitat and residue and support more small arthropods that can serve as alternative prey for larger predators. As a result, we expected manure and the cover crop to increase ground-active predators. In turn, these predators could provide biological control of pests. Each year in a 3-yr field experiment, we applied manure and in 2 yr planted a wheat cover crop. We found that both planting a cover crop and applying dry-stack manure increased the plant cover in May. In the last year, this translated to greater soil mite (Acari) density. At the end of the experiment, however, neither manure nor the wheat cover crop had increased residue on the soil surface. As a result, our treatments had inconsistent effects on predator activity-density, especially for carabids and spiders. We observed strong edge effects from neighboring grass alleys on carabid activity-density. Regardless of treatment, we observed high predation of sentinel prey. We conclude that even without cover crops or organic fertilizer, the stability of no-till maize and increased weeds in fallow treatments generate sufficient habitat complexity and alternative prey to support robust predator communities.

Bat parasites (Acari, Anoplura, Cestoda, Diptera, Hemiptera, Nematoda, Siphonaptera, Trematoda) in France (1762-2018): a literature review and contribution to a checklist

This paper is a bibliographical survey of records of bat parasites in France (including Corsica) between 1762 and 2018. In total, 237 scientific publications were analysed. They show that bats are infected with a large diversity of endoparasites and ectoparasites. A total of 113 parasite taxa were identified from 27 host species; in addition, six bats were not identified to the species-level. The helminth fauna of bats comprises three species of Cestoda, 15 of Trematoda, and 13 of Nematoda. Acari parasites include 53 species (in addition to 22 invalid species). Finally, insect parasites comprise 13 species of Diptera (bat flies), 12 of Siphonaptera (fleas), 3 of Hemiptera (bugs), and 1 Anoplura species. Bat taxa reported with parasites were Barbastella barbastellus, Eptesicus serotinus, Hypsugo savii, Miniopterus schreibersii, Myotis bechsteinii, M. blythii, M. capaccinii, M. dasycneme, M. daubentonii, M. emarginatus, M. myotis, M. mystacinus, M. nattereri, M. punicus, Nyctalus lasiopterus, N. leisleri, N. noctula, Pipistrellus kuhlii, P. nathusii, P. pipistrellus, Plecotus auritus, P. austriacus, Rhinolophus euryale, R. ferrumequinum, R. hipposideros, R. mehelyi, Tadarida teniotis, Eptesicus sp., Myotis sp., Pipistrellus sp., Plecotus sp., Rhinolophus sp. and the species complex Pipistrellus pipistrellus/kuhlii/nathusii. As regards E. nilssonii, Vespertilio murinus (Particoloured Bat), M. alcathoe, M. escalerai, P. macrobullaris and P. pygmaeus, no records were found. These published field data originated from 72 of the 96 departments in metropolitan France. The most commonly cited were Ardèche, Ariège, Bouches-du-Rhône, Haute-Savoie, Maine-et-Loire, Moselle, Meurthe-et-Moselle, Pyrénées-Orientales, Sarthe, Haute-Corse and Corse-du-Sud.

Arthropods Associated with Mammals. Their Importance as Part of the Richness in a Biosphere Reserve in Mexico

The Chamela Biological Station (ChBS) is located in the Pacific Coast of Mexico in the State of Jalisco. This represents one of the core areas of the Chamela-Cuixmala Biosphere Reserve, characterized by one of the most threatened ecosystems, the tropical dry forest. Although accumulated knowledge of biological diversity, only few studies have been focused on ectoparasites or ectodytes associated with mammals, only 23 arthropod taxa had been recorded. In order to increase knowledge about arthropods associated with Mexican mammals, the objective of this work was to record the richness of arthropods (mites, ticks, lice, and fleas) associated with small and medium-sized mammals in the ChBS. A total of 81 hosts belonging to four orders, six families and nine species were captured. From these hosts, 4,946 arthropods were recovered: 4,007 mites, 673 ticks, 230 lice, and 36 fleas. Among medium-sized mammals, Nasua narica (L.) and Didelphis virginiana Kerr showed the highest levels of richness, with six arthropod taxa; among rodents, Heteromys pictus (Thomas) had the highest number of associated species (five). Within the 22 arthropod taxa registered in the present work, 12 represent new records for the reserve, and 3 represent new records for Mexico. With this study, the arthropod fauna associated with mammals in the ChBS has been raised to 38 taxa. In terms of biological conservation, knowledge of the species that inhabit natural reserves must be a priority, since this represents the baseline for species protected, not only in Mexico but around the world.

Evaluating the Efficacy of Oxalic Acid Vaporization and Brood Interruption in Controlling the Honey Bee Pest Varroa destructor (Acari: Varroidae)

A successful Integrated Pest Management approach to Varroa destructor Anderson and Trueman control in managed colonies of western honey bees Apis mellifera Linnaeus (Hymenoptera: Apidae) must be an improvement over conventional control methods and include cost-effective treatments that can be readily employed by beekeepers. Herein, we tested the efficacy of oxalic acid (OA) vaporization and brood interruption as Varroa controls. Sixty experimental colonies were randomly assigned to one of six treatment groups with 10 colonies per group. The six treatments were: 1) OA applied once, 2) OA applied three times, 3) brood interruption, 4) OA applied once + brood interruption, 5) OA applied three times + brood interruption, and 6) no OA or brood interruption. The OA was applied via vaporization, with each application being 1 g OA applied through the hive entrance (label rate), on the bottom board. Brood interruption was accomplished by caging a colony's queen in a queen cage for a period of 24 d. An additional 10 colonies were treated with amitraz (Apivar - positive control). Varroa levels were estimated before, during, and after treatment applications using sticky boards left in colonies for 3 d. Our data suggest that queen caging to achieve brood interruption during the fall season can negatively impact colony strength and survival. We observed high colony mortality in some treatments, despite diligent colony management to alleviate the side effects of the treatments. Colonies treated with amitraz were healthier and had better survival than those treated with OA vaporization. In conclusion, OA and/or brood interruption did not provide sufficient Varroa control.

Productivity of Neoseiulus bicaudus (Acari: Phytoseiidae) Reared on Natural Prey, Alternative Prey, and Artificial Diet

The predatory mite, Neoseiulus bicaudus (Wainstein), is a potential biological control agent against spider mites and thrips. The objective of this experiment was to compare the effects of three diets on the life table of N. bicaudus. The three diets were 1) Tetranychus turkestani (Ugarov & Nikolskii) (Acari: Tetranychidae), the natural prey of N. bicaudus; 2) Tyrophagus putrescentiae (Schrank) (Acari: Acaridae), an alternative prey; and 3) artificial diet primarily consisting of decapsulated shrimp cysts, egg yolk, and honey. The computer simulation was used to project the population growth of N. bicaudus fed on different diets. The preadult developmental time (3.83 d) of N. bicaudus was shortest, and the intrinsic rate of increase (r = 0.2782 d-1) and the net reproductive rate (R0 = 18.98 offspring) were highest when reared on the alternative prey Ty. putrescentiae. The total development time (7.37 d) was longest, and the population parameters were the lowest (r = -0.0081 d-1, R0 = 0.85 offspring) when N. bicaudus was reared on artificial diet. The population projection showed that the population of N. bicaudus reared on Ty. putrescentiae could increase fast. Our results showed that the Ty. putrescentiae was the most suitable prey for mass rearing of N. bicaudus. The artificial diet could not support the N. bicaudus population and needs to be improved.

Can Community Structure Causally Determine Dynamics of Constituent Species? A Test Using a Host-Parasite Community

Structures of communities have been widely studied with the assumption that they not only are a useful bookkeeping tool but also can causally influence dynamics of the populations from which they emerge. However, convincing tests of this assumption have remained elusive because generally the only way to alter a community property is by manipulating its constituent populations, thereby preventing independent measurements of effects on those populations. There is a growing body of evidence that methods like convergent cross-mapping (CCM) can be used to make inferences about causal interactions using state space reconstructions of coupled time series, a method that relies on only observational data. Here we show that CCM can be used to test the causal effects of community properties using a well-studied Slovakian rodent-ectoparasite community. CCM identified causal drivers across the organizational scales of this community, including evidence that host dynamics were influenced by the degree to which the community at large was connected and clustered. Our findings add to the growing literature on the importance of community structures in disease dynamics and argue for a broader use of causal inference in the analysis of community dynamics.

Biological Features of Neoseiulus californicus (Acari: Phytoseiidae) Feeding on Schizotetranychus oryzae (Acari: Tetranychidae) Kept on Rice Leaves

Schizotetranychus oryzae Rossi de Simons attains pest level in rice crops. This study aimed to evaluate the biological features of Neoseiulus californicus (McGregor) feeding on S. oryzae on leaves of flooded rice. We also evaluated N. californicus behavior in response to S. oryzae and conspecific cues. Thirty-two eggs were individually placed in arenas on rice leaves and fed on S. oryzae for the biological test. Three cultivars were used to test the behavior of N. californicus in response to S. oryzae and conspecific cues. The intrinsic rate of increase (rm) of the predator feeding on S. oryzae was 0.21 female/female/day. Schizotetranychus oryzae was considered a suitable prey for N. californicus under laboratory conditions. The results obtained in behavioral tests showed that N. californicus preferred laying eggs on leaves uninfested by S. oryzae and it did not show oviposition preference in arenas with conspecific predator cues. This predator was found in all rice cultivation areas in the state of Rio Grande do Sul, Brazil. Neoseiulus californicus proved to be a control agent for S. oryzae.

Beekeeping Operations

The parasitic mite Varroa destructor (Acari: Varroidae) is a major cause of overwintering honey bee (Apis mellifera) colony losses in the United States, suggesting that beekeepers must control Varroa populations to maintain viable colonies. Beekeepers have access to several chemical varroacides and nonchemical practices to control Varroa populations. However, no studies have examined large-scale patterns in Varroa control methods in the United States. Here we used responses from 4 yr of annual surveys of beekeepers representing all regions and operation sizes across the United States to investigate use of Varroa control methods and winter colony losses associated with use of different methods. We focused on seven varroacide products (amitraz, coumaphos, fluvalinate, hop oil, oxalic acid, formic acid, and thymol) and six nonchemical practices (drone brood removal, small-cell comb, screened bottom boards, powdered sugar, mite-resistant bees, and splitting colonies) suggested to aid in Varroa control. We found that nearly all large-scale beekeepers used at least one varroacide, whereas small-scale beekeepers were more likely to use only nonchemical practices or not use any Varroa control. Use of varroacides was consistently associated with the lowest winter losses, with amitraz being associated with lower losses than any other varroacide product. Among nonchemical practices, splitting colonies was associated with the lowest winter losses, although losses associated with sole use of nonchemical practices were high overall. Our results suggest potential control methods that are effective or preferred by beekeepers and should therefore inform experiments that directly test the efficacy of different control methods. This will allow beekeepers to incorporate Varroa control methods into management plans that improve the overwintering success of their colonies.

Novel RNAi delivery systems in the control of medical and veterinary pests

RNA interference (RNAi) is a transformative technology with great potential to control, study or even protect insects and acarines through the knockdown of target gene expression. RNAi offers unprecedented levels of control, but fundamental to its successful deployment is the need to deliver 'trigger' RNA in an appropriate fashion giving due consideration to potential barriers of RNAi efficiency, safety, and the intended purpose of the knockdown. This short review focusses on recent innovations in RNAi delivery that are designed for, or could be adapted for use with, insect and acarine pests of medical or veterinary importance.

Testing the Enemy Release Hypothesis on tall-statured grasses in South Africa, using Arundo donax, Phragmites australis, and Phragmites mauritianus as models

The Enemy Release Hypothesis (ERH) predicts that introduced plant species can escape herbivory and therefore have a competitive advantage over native plants, which are exposed to both generalist and specialist natural enemies. In this study, the ERH was explored using the invasive alien species, Arundo donax and two native tall-statured grasses, the cosmopolitan Phragmites australis and African endemic Phragmites mauritianus in South Africa. It was predicted that A. donax would have reduced species richness of herbivores compared with the native Phragmites spp., that it would be devoid of specialist herbivores and would thus be experiencing enemy escape in the adventive range. The herbivore assemblages were determined from both field surveys and a literature review. The assumptions of the ERH were for the most part not met; 13 herbivores were found on A. donax compared with 17 on P. australis and 20 on P. mauritianus. Arundo donax had two specialist herbivores from its native range, and shared native herbivores with Phragmites spp. Although A. donax had reduced species richness and diversity compared with that found in the native distribution, it has partially re-acquired a herbivore assemblage which is similar to that found on analogous native species. This suggests that enemy release may not fully explain the invasive success of A. donax in South Africa.

Prevalence and Load of Demodex folliculorum and Demodex brevis (Acari: Demodicidae) in Patients With Chronic Blepharitis in the Province of Erzincan, Turkey

Chronic blepharitis is an ocular disease frequently encountered by ophthalmologists. Demodex mites can play a role in the pathogenesis of blepharitis along with bacterial agents, especially in treatment-resistant cases or recurrent cases after treatment. This study was performed to determine the prevalence and load of Demodex folliculorum (Simon) and Demodex brevis Akbulutova in chronic blepharitis patients and to assess the relationship between the prevalence and load of Demodex species and ocular symptoms. The study included 365 patients diagnosed with chronic blepharitis in clinical examination, and 175 controls without any chronic or ocular disease. In the study, two eyelashes were sampled from the lower and upper lids of the right and left eyes (a total of eight samples) of the participants. Eyelash samples were examined under a light microscope, and Demodex species were identified and counted. Demodex were detected in 79.2% (95% CI: 75-83%) of patients and 31.4% (95% CI: 24-38%) of controls in this study. D. folliculorum alone (mean: 4.96; min: 1; max: 17; P < 0.001) was detected in 72.3% of patients, in 0.7% D. brevis alone (mean: 1.00, P > 0.05), and in 27% both D. folliculorum and D. brevis (mean: 21.65; min: 2; max: 79; P < 0.001). In Demodex positive controls, only D. folliculorum (mean: 2.38; min: 1; max: 6) was detected while there was no D. brevis. Nevertheless, mean ocular symptom scores were significantly higher in Demodex positive patients than in Demodex negative patients (P < 0.001). Itching, foreign body sensation, and redness were the most common complaints in Demodex positive patients. As a result, Demodex mites were high in numbers in patients with chronic blepharitis in Erzincan. There was a positive correlation between Demodex mites and chronic blepharitis and ocular symptoms. It may be helpful to consider these findings in clinical assessment of blepharitis patients.

Argasidae and Nuttallielidae（Acari ∶ Ixodida)]

In ixodology, the world records of the nominated species of the ticks reached close to thousand. Towards the end of 2015, altogether 200 valid species names of Argasidae accommodated in 5 genera have been consensed by most of the world ixodologists, namely Argas 61 species, Ornithodoros 118 species, Antricola 17 species, Nothoaspida 2 species, and Otobius 2 species. The monotypic status of the genus Nuttalliella of Nuttalliellidae remained unchange. China is a country of poor in soft tick fauna, only 14 species were recorded so far. In order to facilitate the exchange of the scientific view-point among the colleagues about both ticks and tick-borne diseases in this country, a latest list of world argasid and nuttalliellid valid names was introduced. Meanwhile a Chinese scientific term for each valid species and named genus in conformity with the principle of simplicity and pithy, as well as systematization was proposed. A series of abbreviations for the nominated genera and subgenera of Argasidae was also suggested.

Potential of Five Brazilian Populations of Phytoseiidae (Acari) for the Biological Control of Bemisia tabaci (Insecta: Hemiptera)

Biotype B of the whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), causes considerable losses to growers worldwide. Phytoseiid mites have been successfully used for the control of this pest in several countries. The Brazilian phytoseiid fauna is very diverse and potentially useful for this purpose. The aim of this study was to evaluate five Brazilian populations of phytoseiids as candidates for the control of the whitefly, a serious pest of different crops worldwide. Evaluated species were Amblydromalus limonicus (Garman & McGregor), Amblyseius herbicolus (Chant), Amblyseius largoensis (Muma), Amblyseius tamatavensis (Blommers), and Neoseiulus tunus (De Leon), which are found naturally in Brazil and elsewhere. The work was conducted at 28±1°C, 75±10% relative humidity, and a photoperiod of 12:12 (L:D) h. All evaluated phytoseiids preyed on eggs of B. tabaci, with the highest levels of predation recorded for Am. herbicolus and N. tunus, and highest level of oviposition recorded for Am. tamatavensis. The results show the Brazilian populations of those three species to be promising as control agents of B. tabaci. Aleuroglyphus ovatus (Troupeau) (Acari: Acaridae) was found to be a suitable prey for the mass production of those predators. Complementary studies are considered justified, given the positive results of this study.

Activity of flonicamid on the sweet potato whitely Bemisia tabaci (Homoptera: Aleyrodidae) and its natural enemies

BACKGROUND

Flonicamid is a novel systemic insecticide that acts as a feeding blocker with potential use against whiteflies within IPM control tactics. Flonicamid efficacy against Bemisia tabaci Mediterranean populations from Crete was examined, as well as side effects on selected beneficials used extensively in current IPM schemes.

RESULTS

Low variability in adulticide activity was detected (<tenfold), while there was no resistance compared with a reference susceptible population. Flonicamid exhibited low to no insecticidal activity on eggs, emerging crawlers and second-instar nymphs at the maximum registered label rate (RLRmax ). In long-term cage experiments, flonicamid at the RLRmax (125 mg L(-1)) caused 95% mortality to whiteflies 10 days after treatment and delayed population growth by one generation (32 days). Flonicamid significantly delayed nymphal development by increasing the development time (DT50 ) of treated insects by 7.2 days. Flonicamid did not affect the survival of Eretmocerus eremicus adults, while lethal effects of an intermediate level were observed on Nesidiocoris tenuis adults and nymphs, Amblyseius swirskii adults and preimaginal stages of E. eremicus. Flonicamid reduced the feeding activity (consumption of B. tabaci eggs) of N. tenuis and A. swirskii by 28 and 37% respectively. Moreover, the fecundity of A. swirskii was reduced by 36% after exposure to flonicamid.

CONCLUSIONS

Flonicamid is an effective tool for the management of B. tabaci populations from Crete, and initial studies indicate that it could be combined with B. tabaci natural enemies.

The use of essential oils in veterinary ectoparasite control: a review

There is a growing body of evidence indicating the potential value of essential oils as control agents against a range of arthropod ectoparasites, particularly lice, mites and ticks. Toxicity has been demonstrated following immersion and physical contact with treated surfaces, as well as after exposure to the vapour of these oils; the last of these factors implies that there is a neurotoxic, rather than simply a mechanical, pathway in their mode of action. However, the volatile nature of essential oils suggests that their residual activity is likely to be short-lived. A possible advantage of essential oils over conventional ectoparasite treatments may refer to their reported ovicidal efficacy, although it is unclear whether this results from neurotoxicity or mechanical suffocation. There are many difficulties in comparing the findings of existing studies of essential oil toxicity. One major issue is the wide variation among batches in the relative concentrations of oil constituents. A second issue concerns the fact that many experimental designs make it difficult to confirm that the effect seen is attributable to the oil; in many cases inappropriate controls mean that the effects of the excipient on mortality cannot be distinguished. Hence, it is important that an excipient-only control is always included in these bioassays. Furthermore, in direct contact assays, when attempting to identify the toxicity pathway of the essential oil tested, it is important to include a hydrophobic control. Without this, it is impossible to distinguish simple mechanical effects from neurological or other cellular toxicity. The use of essential oils in the control of veterinary ectoparasites is an area which holds considerable potential for the future and research into their use is still at an early stage. More extensive field trials, the standardization of components, the standardization of extraction, the standardization of good experimental design, mammalian toxicology profiling and excipient development, as well as further investigation into the residual activities and shelf-lives of these oils are all required to allow the full realization of their potential.

Potential of the predatory mite Phytoseius finitimus (Acari: Phytoseiidae) to feed and reproduce on greenhouse pests

Phytoseiid mites of the genus Phytoseius are natural enemies of tetranychid and eriophyid herbivorous mites mostly found on hairy plants where they feed on prey, as well as on pollen. Nevertheless, the nutritional ecology and the role of these predators in biological pest control are only rarely addressed. In the present study, we evaluated the potential of Phytoseius finitimus to feed and reproduce on three major greenhouse pests, the two-spotted spider mite, the greenhouse whitefly and the western flower thrips. Additionally, we estimated the effect of cattail pollen when provided to the predator alone or in mixed diets with prey. Contrary to thrips larvae, both spider mite larvae and whitefly crawlers sustained the development of P. finitimus. In addition, females consumed more spider mite eggs and larvae, as well as whitefly crawlers than thrips larvae, but laid eggs when feeding on all prey. When provided alone, cattail pollen sustained the development and reproduction of the predator. The addition of pollen in mixed diets with prey reduced prey consumption, though it increased the predator's egg production. We discuss the implications of our findings for biological pest control.

Synthetic pesticides in agro-ecosystems: are they as detrimental to nontarget invertebrate fauna as we suspect?

Broad-spectrum pesticides used to protect field crops and pastures from invertebrate pests are frequently reported to reduce populations of nontarget fauna, but there is often little relevant field data. Nonetheless, this notion is used to promote the adoption of more selective pesticides with less impact on nontarget invertebrates, including beneficial insects. Selective pesticides are not widely available for broad-acre grain crops and pastures in southern Australia; however, several options available in other industries could be compatible with these agricultural systems. In this study, the impact of broad-spectrum pesticides and several selective pesticides on nontarget invertebrate fauna was assessed in five field trials in wheat and canola fields. Despite extensive sampling over short and medium timeframes, few treatment effects on nontarget groups were detected. In cases where broad-spectrum pesticides were detrimental, patterns were often inconsistent among nontarget groups and between field trials. In contrast, the pest species, Halotydeus destructor Tucker and Penthaleus spp., were effectively controlled by the broad-spectrum treatments and less effectively by the selective pesticides. The inconsistent and relatively small impact of broad-spectrum pesticides on some nontarget invertebrates demonstrates that caution is required when extrapolating from laboratory-based assessments routinely used to assess the impacts of pesticides to field conditions in agriculture.

Sequential sampling plan for Tenuipalpus heveae Baker (Acari: Tenuipalpidae) on rubber tree

The objective of the present study was to develop a sequential sampling plan for the decision-making process to control Tenuipalpus heveae Baker (Acari: Tenuipalpidae), an important pest of the rubber tree crop. The experimental area was represented by 1,000 plants of the RRIM 600 clone divided in 100 plots with 10 plants each. Leaves were collected and the number of mites determined under laboratory conditions. The sequential sampling plan was developed in accordance with the Sequential Test Likelihood Ratio. The value 0.10 was pre-established for α and β representing type I and type II errors, respectively. The level of control adopted was six mites per 12 cm(2). The operating characteristic curve and the curve of maximum expected sample were determined. Two lines were generated: the upper one, when the condition for chemical control is recommended (S1 = 23.3080 + 2.1972); and the lower, when chemical control is not recommended (S0 = -23.3080 + 2.1972). Sample size for the decision-making process to control T. heveae requires 6 to 18 plants.