Abundance Of Mites Research Articles

Comparison of Alternative Application Methods for Anti-Varroa Lithium Chloride Treatments.

Simple SummaryThe Varroa mite is one of the most dangerous pests of honey bee colonies, spreading many diseases, and its high infestation rate leads to the death of the colony. Due to its wide-scale distribution and lethal effect, this mite parasite threatens not only the honey industry but also the pollination of many plant species, including several cultivated plants. Therefore, an uncontrolled varroosis could threaten the human food supply as well as trigger biodiversity loss. Control options against Varroa are still inadequate; the mite could develop resistance to synthetic chemicals, whereas the efficiency of organic acid and essential oils-based treatments is very variable. Recently, lithium has been identified as a potential and effective anti-Varroa agent with both systematic and contact modes of action. Present experiments revealed that the efficiency of the lithium treatment depends greatly on the application method. The trickling method of application in repeated treatment and concentration of 500 mM provided very high, >>90%, efficiency. However, further investigations are required before the lithium chloride could be registered as a veterinary medicine in beekeeping practice.Varroosis is one of the most dangerous threats to the bee industry but means of its treatment are still unsatisfactory. Lithium-based anti-Varroa treatments may provide an alternative, as this trace element can be a natural component of honey and is well tolerated by adult bees. However, it can be toxic to larvae and its use in beekeeping practice is not yet well understood. The present study aimed to investigate the efficacy of relevant application methods of acaricides used in beekeeping practice in brood-free conditions for lithium. Vaporisation proved to be an inefficient method of lithium treatment and killed only 9.9 ± 3.3% (mean ± SD) of mites in the hive. Lithium-impregnated paper strips showed moderate efficiency by killing 55.1 ± 26.2% of mites. The most effective way of applying lithium was the trickling method; different trickling treatments decreased the abundance of mites on average by 65 to 99.7%, depending on the applied dosage and the number of treatments. Repeated trickling treatments were more effective than single treatments, and they generally provided >90% efficiency. Experiments also proved that adding sugar to the trickling solution does not influence treatment efficiency. Thus, it is suggested that repeated and sugar-free trickling treatments with moderate lithium dosage could be the most rational methodology. Since lithium is not yet legalised in beekeeping practice, comprehensive studies are also needed to uncover the amount of lithium residue in bee products, depending on the treatment parameters.

Determination of spider mite abundance in soil of field-grown cucumbers and in plants under predatory mite pressure in invasive infestations using HRM real-time PCR assay

The two spotted spider mite, Tetranychus urticae Koch L. (Acari: Tetranychidae), is a plant pest that can lead to severe economic losses in open field cucumber cultivation. Between 2017 and 2019 we studied the abundance of spider mites in the soil to estimate the potential infestation pressure of soil colonizing spider mites. The spider mites were heterogeneously distributed in small concentrations in the soil. Soil colonizing spider mites did not affect spider mite abundance on plants and reversed. We observed that spider mite migration occurred primarily from the edge of the field adjacent to the weed strip. In 2020 and 2021, we investigated the efficacy of the predatory mite Neoseiulus californicus (McGregor) for suppressing spider mite hotspots in the cropland. We compared untreated spider mite hotspots with N. californicus treated hotspots and showed that a single release of predatory mites could result in a high level of control when spider mite infestation density was initially high. With this study, soil can be ruled out as a habitat for spider mites, and attention to spider mite pest control can be directed to plant infestations. The highly sensitive HRM real-time PCR assay was used for the quantification of the spider mites.

Significant impact of allochthonous nutrient loads on microarthropods in forest soils

Aim of study: To investigate the impact of allochthonous material from piscivorous birds on forest soil microarthropod communities.
 Area of study: Six study zones in the Curonian Spit peninsula (western Lithuania) were designated in Pinus sylvestris stands with nesting sites of the great cormorants, taking into account the relief and the duration of the ornithogenic impact.
 Materials and methods: The total abundance of mites and Collembola and the species richness and diversity of Oribatida and Gamasina mites were assessed and compared.
 Main results: The abundance of Collembola, Tarsonemidae and Acaridae mites positively correlated with ornithogenic activity, while Oribatida and Gamasina mites decreased significantly. The structure of microarthropod communities was similar in most of the studied zones, except for the active nesting zone and the abandoned part of the colony on the dune slope. The greatest species richness of Oribatida and Gamasina was found in the unaffected forest in the dune hollow, whereas the lowest value was found in the active nesting area and in the abandoned part of the colony on the dune slope. Of the environmental parameters studied, soil pH (r = - 0.725) and tree layer (r = 0.827) were those most significantly related to the changes of microarthropod communities.
 Research highlights: We found that cormorant colonies have a strong impact on forest ecosystems and soil properties, leading to significant changes in soil microarthropod communities. Birds thus create a natural disturbance experiment that can help reveal the factors that determine the diversity and composition of natural microarthropod communities.

First data on water mite (Acari, Hydrachnidia) assemblages of Point Rosa Marsh, Harrison Township, Michigan, USA,and their use as environmental bioindicators of aquatic health

Water mites are aquatic arachnids that have been used in Europe and Central America as bioindicators of ecological health in various freshwater ecosystems (including bogs). Water mites can be found in high densities in the Laurentian Great Lakes and adjacent habitats. Although they are abundant, water mites are generally not used in the assessment of aquatic habitats in the Great Lakes and are usually assigned to the “other” category in macroinvertebrate assessments. This is despite evidence of their utility as aquatic bioindicators. In the present study we consider water mites as bioindicators of the environmental health of Point Rosa marsh, a threatened marsh found on the US side of transboundary Lake St. Clair. The abundance of water mites in Point Rosa Marsh increased from 2017 to 2019 as lake water levels increased. Although increasing water levels in Lake St. Clair can be considered a negative event due to loss of irreplaceable coastal habitat by erosion with potential economic impacts, this present study indicates that water mite populations in Point Rosa Marsh increased during the same period (2017 to 2019). As a result of our study we: update the biodiversity of water mites from Lake St. Clair with new records compared to the last report from the lake over 45 years ago, first report on water mite assemblages at Point Rosa marsh at the Lake St. Clair Metropark on Lake St. Clair and the first demonstration of water mites used as bioindicators in the habitats of the Laurentian Great Lakes.

Detangling ecosystem services: Open-field manipulation of soil-dwelling microarthropods provides new opportunities to investigate their effects on nitrogen cycling.

Soil microarthropods have a pivotal role in soil nitrogen cycling in that they affect microbial decomposers. A high abundance of microarthropods may increase the mobility of inorganic nitrogen ions in the soil, mainly in nitrogen‐limited habitats. However, it is difficult to study ecological processes with small‐sized, soil‐dwelling arthropods. The effects of soil microarthropods on nitrogen cycling have mainly been studied in laboratory microcosm experiments. Therefore, we face many practical issues in investigating these effects under field conditions that remain to be resolved.We developed an open‐field mesocosm setup with growing plants. In a two‐part experiment, spring wheat and grass species were grown in chernozem and sandy soils. Leached ammonium and nitrate ions were measured with percolation lysimeters. Half of the mesocosms included natural assemblages, and the other half included less abundant Acari and Collembola assemblages. The application of nitrogen fertilization assured differences in nitrogen sources.We found a large difference in ammonium and nitrate leaching between the two soil types. In chernozem soil, the leached ion concentrations were higher in mesocosms with more abundant mite and springtail assemblages. The expected patterns were less pronounced in sandy soil. Adding nitrogen fertilizer did not modify the effects of soil microarthropods.Open‐field mesocosms are promising for studying the role of soil‐dwelling mesofauna in ecological processes. We solved the problem of keeping mesofauna abundance lower in treated plots than that in control plots. Plants successfully grew in our semi‐closed systems with functioning percolation lysimeters. The use of the equipment in the experiments in this study helped reveal that the role of soil‐dwelling microarthropods in nitrogen cycling depends on the soil type and not on the application of nitrogen fertilizer.

Northward range expansion of rooting ungulates decreases detritivore and predatory mite abundances in boreal forests.

In the last few decades wild boar populations have expanded northwards, colonizing boreal forests. The soil disturbances caused by wild boar rooting may have an impact on soil organisms that play a key role in organic matter turnover. However, the impact of wild boar colonization on boreal forest ecosystems and soil organisms remains largely unknown. We investigated the effect of natural and simulated rooting on decomposer and predatory soil mites (total, adult and juvenile abundances; and adult–juvenile proportion). Our simulated rooting experiment aimed to disentangle the effects of (i) bioturbation due to soil mixing and (ii) removing organic material (wild boar food resources) on soil mites. Our results showed a decline in the abundance of adult soil mites in response to both natural and artificial rooting, while juvenile abundance and the relative proportion of adults and juveniles were not affected. The expansion of wild boar northwards and into new habitats has negative effects on soil decomposer abundances in boreal forests which may cascade through the soil food web ultimately affecting ecosystem processes. Our study also suggests that a combined use of natural and controlled experimental approaches is the way forward to reveal any subtle interaction between aboveground and belowground organisms and the ecosystem functions they drive.

Positive Interactions between Aceria pallida and Bactericera gobica on Goji Berry Plants.

Simple SummaryThe gall mite Aceria pallida can be phoretic on the psyllid Bactericera gobica to overwinter. Phoresy is often considered as a pattern of phoront–vector mutualism. The phoront A. pallida benefits from phoresy during the overwintering season, but no advantages to the vector B. gobica were found during this period. Therefore, this mutualism may occur during the growing season. Because both species share the same host plant and habitat after detachment, interspecific interactions are very likely to occur. To determine whether such interactions were positive or negative, we studied relationships between A. pallida and B. gobica egg abundances on leaves. Our study suggests positive interactions between two pests during the growing season. Outcomes of positive relationships between gall diameter and mite abundance in the gall provided a way to rapidly estimate mite abundances in the field by measuring gall diameters.The gall mite Aceria pallida and the psyllid Bactericera gobica are serious Goji berry pests. The mite can be phoretic on the psyllid to overwinter, but it is unclear whether the vector can obtain benefits from the phoront during the growing season. After detachment, the mite shares the same habitat with its vector, so there are very likely to be interspecific interactions. To better understand whether the interactions are positive or negative, information on relationships between abundances of A. pallida and B. gobica on leaves is needed. Here, B. gobica abundance was represented by the egg abundance because the inactive nymphs develop on the same sites after hatching. (1) We found a positive linear relationship between the gall diameter and the mite abundance in the gall (one more millimeter on gall diameter for every 30 mites increase), which provided a way to rapidly estimate mite abundances in the field by measuring gall diameters. (2) There was a positive relationship between the abundance of mites and psyllid eggs on leaves. (3) Both species had positive effects on each other’s habitat selections. More importantly, the interactions of the two species prevented leaf abscission induced by B. gobica (leaf lifespan increased by 62.9%), increasing the continuation of the psyllid population. Our study suggests positive interactions between two pests during the growing season. The positive relationship between A. pallida and B. gobica egg abundances highlights the increasing need for novel methods for Goji berry pest management. In practice, A. pallida control can be efficient by eliminating its vector B. gobica. Both pests can be controlled together, which reduces chemical usage.

Diversity and distribution of ectoparasite taxa associated with Micaelamys namaquensis (Rodentia: Muridae), an opportunistic commensal rodent species in South Africa.

South Africa boasts a rich diversity of small mammals of which several are commensal and harbour parasites of zoonotic importance. However, limited information is available on the parasite diversity and distribution associated with rodents in South Africa. This is particularly relevant for Micaelamys namaquensis (Namaqua rock mouse), a regionally widespread and locally abundant species that is often commensal. To address the paucity of data, the aims of the study were to record the ectoparasite diversity associated with M. namaquensis and develop distribution maps of lice and mites associated with M. namaquensis and other rodents in South Africa. Micaelamys namaquensis individuals (n = 216) were obtained from 12 localities representing multiple biomes during 2017–2018. A total of 5591 ectoparasites representing 5 taxonomic groups – fleas, lice, mesostigmatid mites, chiggers and ticks was recorded. These consisted of at least 57 taxa of which ticks were the most speciose (20 taxa). Novel contributions include new host and locality data for several ectoparasite taxa and undescribed chigger species. Known vector species were recorded which included fleas (Ctenocephalides felis, Dinopsyllus ellobius and Xenopsylla brasiliensis) and ticks (Haemaphysalis elliptica, Rhipicephalus appendiculatus and Rhipicephalus simus). Locality records indicate within-taxon geographic differences between the 2 louse species and the 2 most abundant mite species. It is clear that M. namaquensis hosts a rich diversity of ectoparasite taxa and, as such, is an important rodent species to monitor in habitats where it occurs in close proximity to humans and domestic animals.

Effects of nitrogen addition on soil faunal abundance: A global meta‐analysis

AbstractAimSoil fauna has a wide range of ecosystem functions. Anthropogenic atmospheric nitrogen (N) deposition affects the structure and function of soil fauna by changing the microenvironment and resources. Given that soil faunal responses can vary considerably among taxonomic groups, N deposition rate, and ecosystems, however, there is little consensus. We aimed to evaluate the effects of N deposition on different soil faunal taxa across different terrestrial ecosystems.LocationGlobal.Time period1970–2021.Major taxa studiedSoil fauna.MethodsWe conducted a meta‐analysis that yielded 264 observations from 43 publications. We evaluated the responses to N addition of soil faunal abundance for three different taxa (nematodes, mites, collembolans) in three ecosystem types (cropland, forest, and grassland).ResultsOur results showed an overall negative effect of N addition on soil fauna. However, the effect varied among soil faunal taxa. Specifically, N addition had no significant effects on the abundance of collembolans and mites in any ecosystem. On the other hand, N addition significantly reduced the abundance of all nematode trophic groups except bacterivores. The overall reduction of soil fauna is likely driven by the nematode response. The negative effects of N addition on nematode abundance were contingent on the N addition rate, N addition form, and ecosystem type. N addition decreased nematode abundance at N addition rates of more than 100 kg/ha/year. Inorganic N addition negatively affected nematode abundance. Finally, N addition had a greater adverse effect on nematodes in cropland and grassland compared to forest ecosystems.Main conclusionsOur results demonstrate the overall negative effects of N addition on nematode abundance. Excessive N addition should be avoided in cropland and grassland management. Further, we suggest the application of organic fertilizer instead of inorganic fertilizer to minimize the N‐induced negative effects on soil nematodes.

Ecological factors driving the feather mite associations in tropical avian hosts

Birds host a diversity of ectosymbionts including feather‐dwelling arthropods such as feather mites and lice that they have co‐evolved and speciated with. Among these ectosymbionts, feather mites have evolved more mutualistic to commensal associations with birds than other groups. However, our understanding of the biological and ecological drivers that shape the associations between avian hosts and feather mites in tropical communities is poor. Thus, to help fill this knowledge gap we investigated the factors that govern feather mite abundances at host community, host species and individual levels in bird communities from different elevations on the tropical island of New Guinea. We examined the effects of abiotic factors, such as temperature and precipitation, the influence of host species, feeding guilds, bill morphology, body region, body conditions and infections with haemosporidian blood parasites on feather mite abundance. We found that feather mites were very prevalent among New Guinean birds and that mite abundance was not significantly different between elevations. Bird species with curved bills experienced significantly lower number of mites compared to species with straight bills. Feather mite abundance was significantly higher on flight feathers than on the rest of the body and mite abundance was not strongly associated with the body condition of individuals in most host species, except for a significant negative relationships in three species. Moreover, we did not find an association between feather mite abundance and blood parasite infections, potentially indicating a non‐synergistic association of these two symbionts. Overall, our study demonstrates that tropical avian‐feather mite associations are driven by different biotic and abiotic factors at host community, species and individual levels, highlighting the importance of examining these associations at both broad and fine scales to thoroughly understand the evolution of these symbioses.

Ecological indices and factors influencing communities of ectoparasitic laelapid mites (Acari, Mesostigmata, Laelapidae) of small mammals in Lithuania.

Family Laelapidae is an ecologically diverse group that includes free-living species and parasites of vertebrates and invertebrates. At least seven genera in this family are associated with small mammals. In this study, ectoparasitic laelapid mites of rodents and shrews were investigated in Lithuania. In total, 2,274 small mammal specimens of 12 species were trapped and 6,089 laelapid mites were collected. The updated list of ectoparasitic mites in Lithuania included 21 mite species. Seven mite species were identified as highly specific for a host species or genus, one species was moderately specific, and four mite species were assigned to generalist parasites. All host species had one or two superdominant mite species. The prevalence and mean intensity varied significantly depending on host species and habitat. We analyzed the influence of the host (species, sex, age) and environmental factors (landscape morphology type, habitat, anthropogenic effect) on the abundance of the mite community and most numerous mite species, as well as the impact of the host community (Shannon's diversity index, species richness, host abundance) on mean abundance of the mite community. Only particular host species (Apodemus flavicollis, Microtus agrestis, and Microtus arvalis) and habitats (pastures, mixed forests) influenced the abundance of mites.

Effect of host and environment related factors on the distribution of the ectoparasites of the montane grass mouse Akodon montensis (Cricetidae, Sigmodontinae) in the Atlantic Forest ecoregion in northeastern Argentina

Akodon montensis is dominant in the Urugua-í Provincial Park in northeastern Argentina. We analyse the effect of variables related to the hosts and the environment on the parasitic burden (PB), and specific richness and mean abundance of Laelapidae mites (Mesostigmata) (SL, MAL). PB, SL and MAL were used with the logarithm transformed data in the analysis. One-way ANOVA was used to test differences between rodents of different sex in an exploratory analysis, and the Levene test was then used to confirm the homogeneity of variances. Using the same technique, differences in these parameters were tested between the states of sexual maturity. To test the effect of trapped site and its interaction with the sex of the rodent on MAL and SL, a two-way ANOVA was performed. The PAST software was used. The results support that the sex of the host would be the main factor that modulates PB and MAL, but not SL. The size and weight of the hosts (as a proxy for age), the reproductive stage and site of capture of the rodents, would not affect any of the variables analysed. The results obtained contribute to the comprehension of the epidemiological role of laelapids.

Mesostigmata diversity by manure type: a reference study and new datasets from southwestern Iran

Manure-inhabiting Mesostigmata mites are important biological control agents of pest flies. However, the biodiversity of this mite community is mainly known from Europe and America, and especially from cattle manure. This study examined the diversity and abundance of Mesostigmata mites associated with various types of manure in an (intensive) agricultural region of the Middle East, i.e., the city Ahvaz and its suburbs, in southwest Iran. Mite samples were extracted from manure of cattle, buffalo, sheep, horse, poultry and quail in 30 livestock and poultry farms. In total, 40 species belonging to 24 genera and 16 families were identified. The most diverse families were Laelapidae with eight species, Macrochelidae with seven and Parasitidae with six. Macrocheles muscaedomesticae and Uroobovella marginata were the most widespread species, recorded in 28 and 27 out of 30 collection sites, respectively. Two species, M. sumbaensis and U. marginata, were found in all studied manures. Simpson’s diversity index recorded the highest diversity in buffalo and sheep manure. Real and theoretical species richness (rarefaction curves) were congruent in number of individuals. The presence of seven species of Macrochelidae in the manure confirms that these are important predators of the house fly for the region of Ahvaz and its suburbs. Members of the Parasitidae were highly prevalent, with one species known as a specialized predator of house fly eggs. This work aims to encourage further studies on the diversity of Mesostigmata in these agricultural settings, and further continue assessing the feasibility of these mites as effective biocontrol agents of filth flies in different types of manure and from different corners of the world.

Phylogeography of the parasitic mite Laelaps agilis in Western Palearctic shows lineages lacking host specificity but possessing different demographic histories

BackgroundLaelaps agilis C.L. Koch, 1836 is one the most abundant and widespread parasitic mite species in the Western Palearctic. It is a permanent ectoparasite associated with the Apodemus genus, which transmits Hepatozoon species via the host’s blood. Phylogenetic relationships, genealogy and host specificity of the mite are uncertain in the Western Palearctic. Here, we investigated the population genetic structure of 132 individual mites across Europe from their Apodemus and Clethrionomys hosts. Phylogenetic relationships and genetic variation of the populations were analyzed using cytochrome c oxidase subunit I (COI) gene sequences.ResultsWe recovered three main mtDNA lineages within L. agilis in the Western Palearctic, which differentiated between 1.02 and 1.79 million years ago during the Pleistocene period: (i) Lineage A, including structured populations from Western Europe and the Czech Republic, (ii) Lineage B, which included only a few individuals from Greece and the Czech Republic; and (iii) Lineage C, which comprised admixed populations from Western and Eastern Europe. Contrary to their population genetic differentiation, the lineages did not show signs of specificity to different hosts. Finally, we confirmed that the sympatric congener L. clethrionomydis is represented by a separated monophyletic lineage.ConclusionDifferences in the depth of population structure between L. agilis Lineages A and C, corroborated by the neutrality tests and demographic history analyses, suggested a stable population size in the structured Lineage A and a rapid range expansion for the geographically admixed Lineage C. We hypothesized that the two lineages were associated with hosts experiencing different glaciation histories. The lack of host specificity in L. agilis lineages was in contrast to the co-occurring highly host-specific lineages of Polyplax serrata lice, sharing Apodemus hosts. The incongruence was attributed to the differences in mobility between the parasites, allowing mites to switch hosts more often.

Temperature and precipitation affect seasonal changes in mite communities (Acari: Mesostigmata) in decomposing litter of broadleaved and coniferous temperate tree species

Key messageWe identified the effect of microclimatic conditions on soil mite communities (Mesostigmata) during the decomposition of broadleaved and coniferous litter. The abundance, species richness, and diversity of mite communities decreased from spring to autumn regardless of litter quality and was related to changes in temperature and precipitation.ContextLitter decomposition is one of the fundamental soil-supporting processes in terrestrial ecosystems. However, there is still a lack of knowledge on some general patterns of the relationships between litter quality (tree species), microclimate, and structure of soil mite assemblages.AimsThe study aimed to analyze the impact of climatic conditions (temperature and precipitation) on mesostigmatid mite communities in the litter of 11 tree species through the vegetation season.MethodsThe experiment tested litter decomposition of 11 different tree species (693 litterbags), for seven consecutive months (April-October) under homogenous Scots pine (Pinus sylvestris L.) canopy monocultures in common garden conditions. Soil mites were extracted in Tullgren funnels.ResultsMesostigmatid mite abundance was positively correlated with the temperature of the sampling month and negatively with the temperature of the previous month. Species richness depended on the sampling month temperature. Changes in litter mass loss in late autumn (after litterfall) and overwinter were important for colonization of litterbags by soil mesostigmatid mites in the following spring.ConclusionsChanges in climatic conditions, i.e., temperature and precipitation between the sampling months (during the following vegetation period), may cause significant changes in mesostigmatid mite abundance and thus may impact ecosystem functions. The winter period is important for mesostigmatid mite abundance in the following vegetation period.

Factors associated with prevalence and intensity of the northern fowl mite (Ornithonyssus sylviarum) in commercial poultry farms of Argentina.

The haematophagous mite Ornithonyssus sylviarum may cause important economic losses in commercial poultry farms whilst also potentially affecting the health of farm workers. The dynamics of this ectoparasite has been linked to several factors, including wild birds, fomites, farm workers, management of hen houses, and host traits. Along two consecutive years, we carried out systematic sampling at three laying hen farms located in Santa Fe province, Argentina, with the aim of identifying factors that may influence O. sylviarum prevalence and intensity. We found that the density of feathers around the hen vent area and the presence of Menoponidae lice were negatively associated with mite abundance. We also found that the density of hens in the cages was negatively associated with mite prevalence, suggesting a possible dilution effect, whereas prior reports found a positive association with hen density. In addition, summer was the season with minimum mite prevalences and intensities, contrary to previous studies in northern farms where warm weather appeared to prompt an increase in mite populations. Another factor associated with mite intensity was age, but this effect varied depending on the season, which hints that the association between hen's age and mites is complex. Basic epidemiological knowledge on O. sylviarum in poultry farms from South America may aid in a more efficient and integrative approach to its control.

Influence of laying hen-systems and ecologic variables on mites of medical and veterinary importance

The search for improvements in the poultry production chain and for increased egg productivity have grown significantly. However, intensive production with or by using of confinement systems negatively affect the welfare of animals and is favoring the appearance of harmful ectoparasites in production. Due to differences in the existing management systems, (e.g. Californian and cage-free systems) and given the importance of the poultry industry in the international market, the aim of the present study was: (1) to compare mite community between SIG (Intensive system – cage: Californian) and SIF (Intensive system – free: cage free); (2) egg-laying systems to analyze how the abundances of the ectoparasites Dermanyssus gallinae, Megninia ginlgymura, and Ornithonyssus sylviarum are affected by these egg-laying models; (3) to evaluate the association between the functional diversity found in traps, organic matter, and feathers in both systems; and finally, (4) to analyze how abiotic factors (e.g. humidity, temperature at sampling) affect mite community composition inside each model. A total of 860,571 mites were sampled, belonging to 59 taxa from six functional groups. Mite composition in the SIF system was different from the SIG system, while their variations in dispersion homogeneity were quite similar to each other. Although taxonomic composition is different between them, they are quite similar when clustered according to functional diversity. The variables 'humidity' and 'temperature' were not determining factors for the appearance of species. The species that most contributed for distinguishing the models were: M. ginlgymura, Dermatophagoides farinae, D. gallinae, Tyrophagus putrescentiae, O. sylviarum, Blattisocius keegani, Glycyphagus sp., Acotyledon sp., and Cheyletus malaccensis, respectively. Dermanyssus gallinae was strongly associated with the Californian model. Two taxa were highly correlated with cloaca, neck, dorsum, and inner wings; variations in relative air humidity also affected M. ginlgymura and O. sylviarum populations. Organic matter had a high abundance of predatory mites with potential for controlling mites of sanitary importance in the poultry chain.

Differential effects of environmental climatic variables on parasite abundances in blue tit nests during a decade.

Models on climate change have predicted an increase of temperature over the earth's surface with potential drastic effects on living organisms. We analyzed the relationships between climatic conditions (temperature, rainfall, and wind speed) and the abundance of blood‐sucking flying insects (biting midges and blackflies) and nest‐dwelling ectoparasites (mites, fleas, and blowflies) collected from blue tit nests during bird breeding seasons for a period of 10 years. Average temperature, rainfall, and wind speed showed significant differences among years. Temperature and wind speed increased during the period of study while rainfall decreased. Biting midge, blackfly, and blowfly abundances increased across years but not flea and mite abundances. Hatching date decreased and brood size increased across years. Independently of year variation, parasites were related to climatic variables. For example, biting midge, blowfly, mite, and flea abundances were positive and significantly related to average temperature. We also found a positive and significant relationship between abundances of Haemoproteus infections and biting midge abundances during the first year of life of birds out of nests. However, abundance and prevalence of Lankesterella infections in yearlings were positive and significantly related to mite abundances during the year of birth of birds. Leucocytozoon and Lankesterella infections were also significantly related to climatic variables and Haemoproteus and Lankesterella infections increased across years. In addition, body condition of adult females and males were negatively related to flea larvae and blowfly abundance respectively. Nestling body condition was also negatively related to biting midge abundance. Changes in climatic conditions across years could therefore affect several parasites of birds but also to birds themselves.

Airborne pollen can affect the abundance of predatory mites in vineyards: implications for conservation biological control strategies.

BACKGROUNDThe importance of pollen as alternative food for generalist phytoseiid mites occurring in vineyards has been investigated in northeastern Italy. We compared pollen and phytoseiid abundance in four vineyards and in plots located at different distance from flowering hop plants. Pollen (Carpinus betulus and Typha spp.) was sprayed onto the foliage to evaluate the potential impact of this food source on predatory mite abundance. Finally, grass management was investigated to analyze the effect of a reduced mowing frequency on predatory mite population densities.RESULTSArboreal pollen was found mostly during the spring and the grapevine blossoming period. Nonarboreal pollen dominated throughout the growing seasons. In vineyards, the abundance of Amblyseius andersoni, Kampimodromus aberrans, Phytoseius finitimus, Typhlodromus pyri eggs and motile forms increased after a phase of large pollen availability. Hop pollen promoted K. aberrans population increases in vineyards. Pollen applications increased predatory mite egg and motile form densities and similar effects were obtained by reducing mowing frequency in vineyards.CONCLUSIONPollen availability positively affects the biology of four phytoseiid species, promoting stable predatory mite populations in vineyards. However, natural pollen availability and predatory mite abundance often decrease in summer, and pollen supply can mitigate this trend. A higher pollen availability could be guaranteed by inserting hedges comprising species having scalar bloom, reducing mowing of inter‐row groundcover and spraying pollen. The presence of flowering plants surrounding vineyards and in their inter‐rows should be considered as a relevant factor to enhance the success of biocontrol tactics against phytophagous mites in viticulture.

Do non-native plants affect terrestrial arthropods in the sub-Antarctic Kerguelen Islands?

Biological invasions are a major threat to the terrestrial ecosystems of the sub-Antarctic islands. While non-native plants generally have negative impacts on native arthropods, few studies have investigated how both native and non-native arthropods and plants interact in the sub-Antarctic islands. This was the aim of our study, which was conducted on three islands of the Kerguelen archipelago. The design was based on the spatial proximity of areas dominated by non-native or native plant species. Trait-based indices were calculated to characterize the functional structure of plant communities, considering plant stature and leaf traits. Native and non-native vegetation had contrasting functional composition but their functional diversity was similar. The effects of the type of vegetation, native or non-native, and plant functional diversity on arthropods were tested. Native macro-arthropod richness and abundance were similar or higher in non-native vegetation, and benefited from greater plant functional diversity. Abundances of macro-herbivores, macro-decomposers and macro-predators were also similar or higher in non-native vegetation. Conversely, the abundances of micro-arthropods, Symphypleona springtails and Oribatida mites, were higher in native vegetation but we also found that plant functional diversity had a negative effect on Symphypleona. Our results suggest that non-native plants can affect micro-arthropods directly or indirectly, likely through their effects on abiotic factors. By affecting macro-arthropod abundances across different trophic groups and by depleting micro-arthropods, non-native plants can alter trophic interactions, functional balances and the functioning of whole ecosystem.