Behavioural responses of Varroa destructor (Acari: Varroidae) to extracts of larvae, cocoons and brood food of worker and drone honey bees, Apis mellifera (Hymenoptera: Apidae)

Abstract. Varroa destructor is a parasitic mite of the honey bee species Apis cerana Fabr . and A. mellifera L. Mature females reproduce on the immature stages of their hosts, producing more viable female offspring on drone hosts than on worker hosts. Thus, immature drones are more likely to be infested with mites than immature workers. To investigate the hypothesis that differences in host chemistries underlie the biased distribution of mites between worker and drone brood, the arrestment responses of mites to solvent extracts of a number of stimuli normally encountered by a mite during its life cycle were measured. Mites were arrested by cuticular extracts of worker and drone larvae obtained at 0, 24 and 48 h prior to the time when cell capping is completed. Mites were also arrested by extracts of worker and drone, brood food and cocoons, and by a blend of synthetic fatty acid esters previously shown to be active in the host acquisition process. In a wind tunnel bioassay, mites were attracted to odours from living fifth-instar worker and drone larvae, but not to volatiles from cocoons, brood food or a blend of fatty acid esters. The sex of the host was not an important factor affecting the behavioural responses of the mites in any assay. We conclude that host kairomones play a role in the host acquisition process, but we found no evidence to support the hypothesis that mites use these substances to differentiate between worker and drone brood.     

Distribution of deformed wing virus within honey bee (Apis mellifera) brood cells infested with the ectoparasitic mite Varroa destructor

The distribution of deformed wing virus (DWV) in adult female Varroa destructor and in their progeny in relation to the pupal host bee was investigated to evaluate acquisition and transfer of DWV by the mites. The results clearly show that adult female mites regularly act as competent vectors of DWV, however, they do not acquire or transfer virus on all possible occasions. Mother mites may contain DWV while the pupal host remains free from overt infection and both mother mites and mite progeny may not acquire detectable amounts of DWV from an infected host bee. However, a majority of mites feeding on pupae that emerge with deformed wings will contain DWV. The data also demonstrates that both adult and immature mite progeny most likely acquire DWV from DWV-infected host bees and not from their mother mites. Possible explanations for the obtained results are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

The feather mite (Astigmata) fauna of some passerine birds (Passeriformes) in the south of Western Siberia

Feather mites (Astigmata) are specialized parasites living on the plumage and skin of birds. The paper presents data on infestation of some passerines (Passeriformes) by feather mites in the south of Western Siberia (Omsk and Tyumen Provinces). We found 24 species of feather mites belonging to the families Analgidae, Dermoglyphidae, Pteronyssidae, Trouessartiidae, and Proctophyllodidae on 16 bird species. Among them, 19 species are common parasites of the passerine birds examined; five species were detected on atypical hosts. Ten mite species were recorded for the first time on the passerine species examined. Analysis of the distribution of abundant and common mite species on their hosts has demonstrated that the majority of the bird parasites possess a specific distribution pattern in the host plumage with preference for certain feather types. We have also obtained new data on host associations of several mite species.     

Overdispersion of Allothrombium pulvinum larvae (Acari: Trombidiidae) parasitic on Aphis gossypii (Homoptera: Aphididae) in cotton fields

Abstract.

• 1 Dispersion patterns of the protelean parasite, Allothrombium pulvinum Ewing, among individuals of an aphid host, Aphis gossypii Glover, were examined during spring 1991 in several cotton fields in Jiangsu Province, China.
• 2 The variance-to-mean ratios (i.e. dispersion index) of larval mites per host were greater than 1, indicating that the mite parasites were overdispersed among aphid hosts. The variance increased with the mean according to the power law, variance = 1.51 mean¹⁰⁶, which explained 99.7% of the variation in the data.
• 3 The negative binomial distribution adequately describes the patterns of larval mite dispersion among aphid hosts in eight out of ten populations. The degree of clumping (1/k) decreased curvilinearly with parasite density (mites per host).
• 4 Mites were more clumped among adult aphids than among immature ones.
• 5 Ecological and evolutionary consequences of mite overdispersion within host populations are discussed. The role of Allothrombium in pest control is also discussed.

     

Redundant species, cryptic host-associated divergence, and secondary shift in Sennertia mites (Acari: Chaetodactylidae) associated with four large carpenter bees (Hymenoptera: Apidae: Xylocopa) in the Japanese island arc

Sennertia mites live as inquilines in the nests of carpenter bees and disperse as deutonymphs on newly emerged adult bees. Because their life cycle is tightly linked to that of the host bees, Sennertia may diverge in response to speciation in the hosts. However, the majority of Sennertia species are associated with several closely related carpenter bees, suggesting that host speciation may not be reflected in mite genetic structure. Here we investigate the extent of host-associated genetic differentiation in two Sennertia mites (S. alfkeni and S. japonica) that share four closely related, strictly allopatric large carpenter bees (Xylocopa). Analysis of the mitochondrial cytochrome oxidase subunit I (COI) gene in Sennertia unexpectedly indicates that the two species represent morphological variants of a single species, and they collectively group into four distinct, allopatric clades that are uniquely associated with a single Xylocopa host. An exception is the mites associated with X. amamensis of the northernmost populations, which have genotypes typical of those associated with neighboring X. appendiculatacircumvolans. Additional analysis using amplified fragment length polymorphism (AFLP) further corroborates the presence of four mite clades but contrary to the COI data, suggests that the mites of the southernmost population of X. appendiculatacircumvolans have genetic profiles typical of those associated with X. amamensis. These results indicate that some mites have undergone secondary host switch after the formation of the four mite lineages and further experienced mitochondrial introgression during period of lineage coexistence. Overall, our results strongly urge reappraisal of deutonymph-based mite taxonomy and illuminate the importance of host-associated divergence during incipient stage of speciation in chaetodactylid mites. Furthermore, the occurrence of host switch and introgression between genetically differentiated mites entails that two host species have co-occurred in the past, thus providing a unique source of evidence for migration and competitive exclusion between the presently allopatric Xylocopa hosts.     

Euseiusfinlandicus (Acari: Phytoseiidae) as a potential biocontrol agent against Tetranychus urticae (Acari: Tetranychidae): life history and feeding habits on three different types of food

Life history and reproductive parameters of the generalist predatory mite Euseius (Amblyseius) finlandicus (Oudemans) were studied in the laboratory at 25 +/- 1 degrees C, with a 16L:8D photoperiod and 60 +/- 15% RH, to investigate its response to different food sources: an eriophyid mite Aceria sp., tulip pollen Tulipa gesnerana L., and two-spotted spider mite Tetranychus urticae Koch. Total developmental time of the immature stages was the shortest on eriophyid mites, followed by pollen, and then spider mites. Fecundity was highest on pollen (43.69 eggs; 1.63 eggs/female/day), then eriophyid mites (39.73 eggs; 1.37 eggs/female/day) and lowest on spider mites (18.16 eggs; 0.80 eggs/female/day). Intrinsic rate of increase (Rm), net reproductive rate (Ro) and finite rate of increase (lambda) followed the same pattern [pollen (0.168, 27.96 and 1.183, respectively), eriophyid mites (0.153, 20.81 and 1.167), spider mites (0.110, 9.44 and 1.119)]. Mean generation time (days) was the shortest on pollen (19.90), followed by eriophyid mites (20.02), and then spider mites (20.59). Average spider mite larvae consumed by E. finlandicus during immature stages were 9.18 for males and 11.85 for females. Adult E. finlandicus females consumed an average of 166.38 spider mite protonymphs during adult stage compared to an average of 66.55 by males. The number of prey protonymphs consumed per day by females was highest in the oviposition period, lower in the pre-oviposition period and the lowest in the post-oviposition period. The eriophyid mite as a prey recorded the shortest developmental time, while pollen as food recorded the highest oviposition rate in E. finlandicus. The potential of this predator as a biocontrol agent against T. urticae is discussed.     

Dispersal of the broad mite, Polyphagotarsonemus latus (Acari: Tarsonemidae) on Bemisia argentifolii (Homoptera: Aleyrodidae)

The broad mite Polyphagotarsonemus latus (Banks) and silverleaf whitefly Bemisia argentifolii Bellows & Perring (=B strain of Bemisia tabaci (Gennadius)) have many common host plants. It was found that broad mites can attach themselves to B. argentifolii adults and use them as a carrier for their dispersal. In a cage experiment, we observed that more than 80% of B. argentifolii adults had more than one broad mite attached within 4 h after B. argentifolii landed on broad mite-infested plants. Overall, 97.5% of the broad mites examined were attached to the legs, mostly on the tibiae and tarsi of B. argentifolii adults, and 99.5% of the broad mites attached to B. argentifolii were adult females. The successful dispersal of broad mite via B. argentifolii was also demonstrated with a cage experiment.     

中国云南小兽体表革螨的群落相似性

运用系统聚类分析方法对中国云南省境内17种主要小型哺乳动物(小兽)体表革螨群落相似性进行研究,每一种小兽体表的所有外寄生革螨被定义为一个相应的革螨群落。运用SPSS11.5软件完成17种革螨群落的相似性比较。研究结果表明:小兽体表革螨群落结构复杂,物种多样性高;隶属同一个属的小兽体表的革螨群落相似程度高,在系统聚类分析中聚为一类;大多数革螨群落相似性大小与相应小兽宿主在动物分类上的近缘性高低呈现高度一致,但也有一些革螨群落是例外的。这说明小兽体表革螨群落不仅受小兽宿主分类地位的影响,可能还受宿主生境的影响     

云南省锡金小鼠体表革螨感染分析

为了解云南省锡金小鼠(Mus pahari)体表革螨的感染情况及分布规律,本研究基于1990至2015年云南省39个县(市)的调查数据,统计分析锡金小鼠体表革螨的基本感染情况和感染差异.使用聚块指数测定革螨空间分布型,用Jaccard指数计算革螨物种相似性.从捕获的720只锡金小鼠体表共采集到革螨14 098只,鉴定为...     

Effects of western honey bee (Hymenoptera: Apidae) colony, cell type, and larval sex on host acquisition by female Varroa destructor (Acari: Varroidae).

Female mites of the genus Varroa reproduce on the immature stages of Apis cerana F. and A. mellifera L. Mites are found more often in drone brood than worker brood, and while evolutionary explanations for this bias are well supported, the proximate mechanisms are not known. In one experiment, we verified that the proportion of hosts with one or more mites (MPV, mite prevalence value) was significantly greater for drones (0.763 +/- 0.043) (lsmean +/- SE) than for workers (0.253 +/- 0.043) in populations of mites and bees in the United States. Similar results were found for the average number of mites per host. In a second experiment, using a cross-fostering technique in which worker and drone larvae were reared in both worker and drone cells, we found that cell type, larval sex, colony and all interactions affected the level of mites on a host. Mite prevalence values were greatest in drone larvae reared in drone cells (0.907 +/- 0.025), followed by drone larvae reared in worker cells (0.751 +/- 0.025), worker larvae reared in worker cells (0.499 +/- 0.025), and worker larvae reared in drone cells (0.383 +/- 0.025). Similar results were found for the average number of mites per host. Our data show that mite levels are affected by environmental factors (cell type), by factors intrinsic to the host (sex), and by interactions between these factors. In addition, colony-to-colony variation is important to the expression of intrinsic and environmental factors.     

Control of the straw itch mite (Acari: Pyemotidae) with sulfur in an insect rearing facility.

The ectoparasitic mite Pyemotes tritici (Lagrèze-Fossat & Montané) (Acari: Pyemotidae) caused paralysis and reduced longevity in eucalyptus longhorned borer, Phoracantha semipunctata F., under laboratory rearing conditions. Application of dusting sulfur to logs that contained pupating borers greatly reduced densities of mites on emerging adult beetles and increased beetle survivorship. Uniform application to all logs in a glasshouse effectively eradicated the mite infestation. A bioassay showed that sulfur may physically impede the dispersal of immature mites by adhering to the cuticle, but sulfur vapor did not act as a toxin.     

Spatial distributions of the red palm mite, Raoiella indica (Acari: Tenuipalpidae) on coconut and their implications for development of efficient sampling plans

The red palm mite (Raoiella indica), an invasive pest of coconut, entered the Western hemisphere in 2004, then rapidly spread through the Caribbean and into Florida, USA. Developing effective sampling methods may aid in the timely detection of the pest in a new area. Studies were conducted to provide and compare intra tree spatial distribution of red palm mite populations on coconut in two different geographical areas, Trinidad and Puerto Rico, recently invaded by the mite. The middle stratum of a palm hosted significantly more mites than fronds from the upper or lower canopy and fronds from the lower stratum, on average, had significantly fewer mites than the two other strata. The mite populations did not vary within a frond. Mite densities on the top section of the pinna had significantly lower mite densities than the two other sections, which were not significantly different from each other. In order to improve future sampling plans for the red palm mite, the data was used to estimate the variance components associated with the various levels of the hierarchical sampling design. Additionally, presence-absence data were used to investigate the probability of no mites being present in a pinna section randomly chosen from a frond inhabited by mites at a certain density. Our results show that the most precise density estimate at the plantation level is to sample one pinna section per tree from as many trees as possible.     

The associations of phoretic mites (Acarina: Chelicerata) with sand-hoppers (Amphipoda: Crustacea) on the South Wales coast

Mites of the genera Halolaelaps and Phaulodinychus (Gamasida), together with Histiostoma (Acaridida) (Acarina: Chelicerata), occur amongst tidal debris strandlines on the sandy shores of the South Wales coast. Phoretic deuteronymphs of all three mites are dispersed between strandlines via talitrid amphipods (Talitridae: Amphipoda: Crustacea) which provide two principal advantages over the insect hosts used by most other phoretic Acarina. First, amphipods migrate between strandlines throughout the year allowing continual phoretic mite dispersal, and second, even juvenile Talitridae are sufficiently large to transport several mites. The highly aggregated populations of all three mites are distributed independently of amphipod age, sex and species, suggesting that host selection is primarily influenced by other factors. The most likely factors are those related to host behaviour and, in particular, monthly/diurnal quiescence when the mites encounter, and are boarded by, the desiccation-sensitive phoretic mites. The discrete site selection exhibited by each mite species is at least partly influenced by attachment mechanisms.     

Modelling Fungal (Neozygites cf. Floridana) Epizootics in Local Populations of Cassava Green Mites (Mononychellus Tanajoa)

The fungus, Neozygitis cf. floridana is parasitic on the cassava green mite, Mononychellus tanajoa (Bondar) (Acari: Tetranychidae) in South America and may be considered for classical biological control of cassava green mites in Africa, where cassava is an important subsistence crop, cassava green mites are an imported pest and specific natural enemies are lacking. Spider mites generally have a viscous structure of local populations, a trait that would normally hamper the spread of a fungus that is transmitted by the contact of susceptible hosts with the halo of capilliconidia surrounding an infectious host. However, if infected mites search and settle to produce capilliconidia on sites where they are surrounded by susceptible mites before becoming infectious, then the conditions for maximal transmission in a viscous host population are met. Because the ratio between spider mites and the leaf area they occupy is constant, parasite-induced host searching behaviour leads to a constant per capita transmission rate. Hence, the transmission rate only depends on the number of infectious hosts. These assumptions on parasite-induced host search and constant host density lead to a simple, analytically tractable model that can be used to estimate the maximal capacity of the fungus to decimate local populations of the cassava green mite. By estimating the parameters of this model (host density, per capita transmission rate and duration of infected and infectious state) it was shown that the fungal pathogen can reduce the population growth of M. tanajoa, but cannot drive local mite populations to extinction. Only when the initial ratio of infectious to susceptible mites exceeds unity or the effective growth rate of the mite population is sufficiently reduced by other factors than the fungus (e.g. lower food quality of the host plant, dislodgement and death by rain and wind and predation), will the fungal pathogen be capable of decimating the cassava green mite population. Under realistic field conditions, where all of these growth-reducing factors are likely to operate, there may well be room for effective control by the parasitic fungus. This revised version was published online in November 2006 with corrections to the Cover Date.     

Feather mites (Acari: Astigmata) and body condition of their avian hosts: a large correlative study

Feather mites are arthropods that live on or in the feathers of birds, and are among the commonest avian ectosymbionts. However, the nature of the ecological interaction between feather mites and birds remains unclear, some studies reporting negative effects of feather mites on their hosts and others reporting positive or no effects. Here we use a large dataset comprising 20 189 measurements taken from 83 species of birds collected during 22 yr in 151 localities from seven countries in Europe and North Africa to explore the correlation between feather mite abundance and body condition of their hosts. We predicted that, if wing‐dwelling feather mites are parasites, a negative correlation with host body condition should be found, while a mutualistic interaction should yield positive correlation. Although negative relationships between feather mite abundance and host body condition were found in a few species of birds, the sign of the correlation was positive in most bird species (69%). The overall effect size was only slightly positive (r =0.066). The effect of feather mite abundance explained <10% of variance in body condition in most species (87%). Results suggest that feather mites are not parasites of birds, but rather that they hold a commensalistic relationship where feather mites may benefit from feeding on uropygial gland secretions of their hosts and birds do not seem to obtain a great benefit from the presence of feather mites.     

Stimuli inducing detachment of larvalArrenurus danbyensis (Hydrachnidia: Arrenuridae) from adultCoquillettidia perturbans (Diptera: Culicidae)

In this study, potential cues for detachment of parasitic larvalArrenurus danbyensis Mullen mites fromCoquillettidia perturbans (Walker) mosquitoes were investigated. Contact with water did not induce a dramatic rate of dissociation. Crushing the host's abdomen was not as effective as crushing the head or thorax; although general body trauma has an effect, it is not sufficient to explain these results. Crushing the host's head following application of a ligature slowed the rate of mite detachment. We infer that haemolymph-borne cues, possibly hormones, are released by crushing the head or thorax of the host and induce rapid mite detachment. External application of Ringers solution or body fluids from mosquitoes significantly increased rate of mite detachment. It is possible that two separate mechanisms stimulate detachment of mites: external haemolymph reception signifying damage to the host and internal reception of haemolymph-borne cues associated with oviposition behavior.     

Population dynamics ofHemisarcoptes coccophagus Meyer (Astigmata: Hemisarcoptidae) attacking three species of armored scale insects (Homoptera: Diaspididae)

The parasitic miteHemisarcoptes coccophagus Meyer (Astigmata: Hemisarcoptidae) feeds on armored scale insects (Homoptera: Diaspididae). Three host scales were studied: chaff scale (Parlatoria pergandii Comstock andP. cinerea Hadden) infesting citrus (grapefruit and orange) orchards, latania scale [Hemiberlesia lataniae (Signoret)] and olcander scale (Aspidiotus nerii Bouche) occurring on acacia (Acacia cyanophylla) branches and leaves. The overall dynamics of mite populations were similar on the different scale species, although the level of attack on each sampled diaspidid host was different. Rates of young mite stages were highly variable on all three hosts throughout the sampling period while adult rates were stable, constituting around 20% of all mites. No oviposition by mites occurred in mid-winter on any scale species, on any plants or parts, at all sampling sites. Of the three diaspidids, highest mite prevalence (parasitization rate) occurred on latania scale. Mite prevalence on oleander scale infesting mature leaves was higher than on young leaves.H. coccophagus apparently first attacks latania scale on branches, it then disperses to the same host inhabiting mature leaves, from there to co-occurring oleander scale and finally to oleander scale infesting young leaves. Mite prevalence on chaff scale was influenced by host plants and climatic regions: in the Negev it was higher than in the coastal plain, with scales on grapefruit being more heavily attacked at the former site but not on coastal plain. Our data suggest thatH. coccophagus prefers ovipositing scale females. The decreasing order of preference for other scale stages was: young females immature males, 2nd-instar nymphs females.     

Parasite-host associations and life cycles of spring-living water mites (Hydrachnidia, Acari) from Luxembourg

Larval water mites are parasites of various insect species. The main aim of the present study was to analyse the host range of spring dwelling water mites. The investigation focuses on seven spring sites in Luxembourg. Some 24 water mite species were recorded either from the benthos or as parasites attached to flying insects captured in emergence traps. For 20 mite species 35 host species from four Nematocera (Diptera) families were recorded. About 80% of the host species and over 90% of the host individuals were Chironomidae, the others were Limoniidae, Dixidae and Simuliidae. For all water mite species recorded we present the observed host spectrum and/or potential hosts as well as the intensity of parasitism and the phenology of the mites. For 10 mite species the hosts were previously unknown. For another ten species the known host spectrum can be confirmed and extended. The host spectrum ranged from one host species (e.g. for Sperchon insignis) to at least 10 host species (for Sperchon thienemanni, Ljania bipapillata), but the effective host range could not be definitively estimated due to the lack of corresponding data. The hypothesised host preference of the water mites, of which most are strictly confined to spring habitats, for similarly spring-preferring hosts could not be proven. The mean intensity of parasitism was highest for Thyas palustris (10.8 larvae/host) and lowest for Sperchon insignis and Hygrobates norvegicus (1.2 larvae per host for each). The hydryphantid mite Thyas palustris occurred at maximal intensity (41 larvae per host) and the two abdominal parasites Ljania bipapillata and Arrenurus fontinalis showed higher mean intensities than the thoracic parasites did. Larval water mites parasitising chironomids did not exhibit a preference for host sex. The phenology of the larval mite species was varied, some species were only present in samples early in the year and others exclusively in the summer. Another species showed two peaks of occurrence, springtime/early summer and late summer/autumn. In conclusion, the water mite larvae in the studied springs showed differences in host spectra and phenology but there are no clear evidences in both for host partitioning. Maybe, the relative low species diversity of water mites in individual springs and the low inter-specific competition for suitable hosts in combination with the high host abundances and species richness makes springs such favourable habitats for the mites.     

Effect of host plants on diapause induction in immature and adult <Emphasis Type="Italic">Tetranychus kanzawai</Emphasis> (Acari: Tetranychidae)

I determined the difference in sensitivity of immature and adult mites to host plants with regard to diapause induction. I used immature and adult polyphagous spider mites, Tetranychus kanzawai Kishida (Acari: Tetranychidae), and two host plants, Orixa japonica Thunb. (Rutaceae) and Phaseolus vulgaris L. (Fabaceae). The diapause incidence was investigated in two adult mite-host and two immature mite-host combinations of treatments. The incidence of diapause induction was much higher in mites developing on O. japonica than those on P. vulgaris, whichever host plants they fed on in adulthood. The host plants affected adult mites to a much lesser extent than the immature mites, though the mites feeding on O. japonica showed a consistently higher diapause incidence. These results suggest that host plants affect diapause induction to a greater extent in immature mites than in adult mites.     

The Role of Cuticular Compounds in the Resistance of Honey Bees (Apis Mellifera) to Tracheal Mites (Acarapis Woodi)

This study examined the migration of tracheal mites (Acarapis woodi) into honey bees (Apis mellifera) from different colonies and the relative attraction of mites to hexane extracts from the external body surfaces of young bees. Relative resistance of bees from different colonies initially was assessed with a field bioassay that involved tagging newly emerged bees, pooling them in heavily mite-infested colonies, retrieving them 7 days later, and examining them for tracheal mite prevalence and abundance. For those colonies identified as most resistant and least resistant, cuticular chemicals were extracted in hexane from frozen, newly emerged worker bees. These extracts were presented to individual tracheal mites in pairwise fashion in a laboratory bioassay. The results demonstrated that mites prefer extracts of bees from some colonies more than others, however, no consistent differences were demonstrated. Our inability to predict mite responses to extracts based on our initial assessment of relative resistance indicates that other mechanisms of resistance influence mite success in colonizing new host bees.