INSECT SCIENCE, Issue 1 2002
ZHENG Bo-yi
Abstract The population of the citrus red mite, Panonychus citri (McGregor), does not increase on pear from spring to mid-summer but thereafter increases abruptly. To elucidate this phenomenon, we compared the performance of the mites on pear leaves with that on citrus leaves, at different time throughout the pear-growing season. No significant difference was detected between the oviposition rate on pear and that on citrus throughout the season. However, the survival rate of ovipositing females that had fed on pear and the hatch rate of eggs laid by those females were significantly lower than those for females that had fed on citrus, until August. However, no significant difference was observed thereafter. The results showed that the decline of the population of citrus red mite before autumn is due to the high mortality of adult females that had fed on pear leaves and the low hatch rate of the eggs produced by those females. [source]

New insertion sequences of Sulfolobus: functional properties and implications for genome evolution in hyperthermophilic archaea

MOLECULAR MICROBIOLOGY, Issue 1 2005
Zachary D. Blount
Summary Analyses of complete genomes indicate that insertion sequences (ISs) are abundant and widespread in hyperthermophilic archaea, but few experimental studies have measured their activities in these hosts. As a way to investigate the impact of ISs on Sulfolobus genomes, we identified seven transpositionally active ISs in a widely distributed Sulfolobus species, and measured their functional properties. Six of the seven were found to be distinct from previously described ISs of Sulfolobus, and one of the six could not be assigned to any known IS family. A type II ,Miniature Inverted-repeat Transposable Element' (MITE) related to one of the ISs was also recovered. Rates of transposition of the different ISs into the pyrEF region of their host strains varied over a 250-fold range. The Sulfolobus ISs also differed with respect to target-site selectivity, although several shared an apparent preference for the pyrEF promoter region. Despite the number of distinct ISs assayed and their molecular diversity, only one demonstrated precise excision from the chromosomal target region. The fact that this IS is the only one lacking inverted repeats and target-site duplication suggests that the observed precise excision may be promoted by the IS itself. Sequence searches revealed previously unidentified partial copies of the newly identified ISs in the Sulfolobus tokodaii and Sulfolobus solfataricus genomes. The structures of these fragmentary copies suggest several distinct molecular mechanisms which, in the absence of precise excision, inactivate ISs and gradually eliminate the defective copies from Sulfolobus genomes. [source]

MUSEUM SPECIMENS AND PHYLOGENIES ELUCIDATE ECOLOGY'S ROLE IN COEVOLUTIONARY ASSOCIATIONS BETWEEN MITES AND THEIR BEE HOSTS

EVOLUTION, Issue 6 2007
Pavel B. Klimov
Coevolutionary associations between hosts and symbionts (or parasites) are often reflected in correlated patterns of divergence as a consequence of limitations on dispersal and establishment on new hosts. Here we show that a phylogenetic correlation is observed between chaetodactylid mites and their hosts, the long-tongued bees; however, this association manifests itself in an atypical fashion. Recently derived mites tend to be associated with basal bee lineages, and vice versa, ruling out a process of cospeciation, and the existence of mites on multiple hosts also suggests ample opportunity for host shifts. An extensive survey of museum collections reveals a pattern of infrequent host shifts at a higher taxonomic level, and yet, frequent shifts at a lower level, which suggests that ecological constraints structure the coevolutionary history of the mites and bees. Certain bee traits, particularly aspects of their nesting behavior, provide a highly predictive framework for the observed pattern of host use, with 82.1% of taxa correctly classified. Thus, the museum survey and phylogenetic analyses provide a unique window into the central role ecology plays in this coevolutionary association. This role is apparent from two different perspectives,as (a) a constraining force evident in the historical processes underlying the significant correlation between the mite and bee phylogenies, as well as (b) by the highly nonrandom composition of bee taxa that serve as hosts to chaetodactylid mites. [source]

Identification of Low Molecular Weight Diapause-Associated Proteins of Two-Spotted Spider Mite, Tetranychus urticae

ENTOMOLOGICAL RESEARCH, Issue 4 2005
JUNG Duck-Oung
ABSTRACT Proteins in whole bodies of two-spotted spider mites, Tetranchus urticae, were compared between non-diapause and diapause conditions using one- and two-dimensional electrophoresis. At one-dimensional analysis diapausing mites synthesized several unique proteins that are higher in their quantity than non-diapausing ones. Overall protein numbers in two-dimensional gel show that diapause mites expressed fewer proteins than non-diapausing ones. However, 25 proteins that have higher quantity in diapause were selected at the range of low molecular weight (5-20 kDa). Among them 13 proteins were only present in diapause mites. Our results thus indicate some proteins uniquely expressed during diapause and may have specifie roles during long overwintering period. [source]

Lebensspuren holzzerstörender Organismen an fossilen Hölzern aus dem Tertiär der Insel Lesbos, Griechenland

FOSSIL RECORD-MITTEILUNGEN AUS DEM MUSEUM FUER NATURKUNDE, Issue 1 2001
Herbert Süss
Abstract Lebensspuren (Schadbilder) holzzerstörender Organismen an fossilen Holzresten aus dem Untermiozän von Lesbos (Griechenland) werden beschrieben. Von pflanzlichen Holzzerstörern konnten Bakterien, imperfekte Pilze, Weiß- und Braunfäulepilze und in das Holz eingewachsene Wurzeln nachgewiesen werden. Von tierischen Holzzerstörern wurden Termitenfraß, durch Pflanzensauger (Homopteren) verursachtes Wundgewebe, Larvenfraß der Kambium-Minierfliege Palaeophytobia (Agromyzidae, Diptera) und Fraßgänge mit Koprolithen verschiedener Käferarten (Anobiiden?) und Milben (Acari) gefunden. Außerdem werden durch Kristallisationsvorgänge im Holz verursachte kugelförmige Gebilde beschrieben. Traces of wood destroying organisms on fossil wood from the Lower Miocene of Lesbos (Greece) are described. Among nonanimal wood destroyers evidence is presented of bacteria, Fungi imperfecti, whiterot and brownrot fungus and penetrating roots. Animal wood destroyers include termite feeding traces, wound tissues produced by plant suckers (Homoptera), larval feeding traces of the cambium miner Palaeophytobia (Agromyzidae, Diptera) and feeding channels, with coprolites, of several beetle species (Anobiidae?) and Mites (Acari). In addition globe-like structures produced in the wood through crystallization processes are described. [source]

Nectar ,theft' by hummingbird flower mites and its consequences for seed set in Moussonia deppeana

FUNCTIONAL ECOLOGY, Issue 1 2001
Lara C.
Summary 1,Mites (Acari: Mesostigmata: Ascidae) that live and feed in the flowers of about 100 plant species are transported in the nares of hummingbirds (Trochilidae). Mites may compete with hummingbirds for nectar secreted by the host plants, and this could affect the dynamics and reproductive outcomes of the mutualism between plants and their pollinating hummingbirds. 2,Here we combined field observations and experimental manipulations to assess the role of hummingbird flower mites (Tropicoseius sp. nov.) on nectar secretion and reproductive output of protandrous Moussonia deppeana (Schlecht. & Cham.) Hanst. (Gesneriaceae) during their flowering period in a cloud forest remnant. 3,During the 4 days that the flowers of M. deppeana last, flowers were visited exclusively by hummingbirds (Lampornis amethystinus). Bud production per inflorescence peaked in December. There were few open flowers per inflorescence in November, but numbers increased as the flowering season progressed (December and January). 4,The availability of each flower phase differed over the flowering season. Staminate-phase flowers were more abundant over the flowering season than pistillate-phase flowers. These differences were statistically significant over time. 5,Nectar availability was reduced by up to 50% in the presence of hummingbird flower mites. Over the 4 days of observation, significantly more nectar was secreted to flowers from which mites were excluded than to flowers with no mite exclusion. The same effect was observed during flowering, but mites consumed a greater percentage of the total nectar secreted in December. 6,Significantly more nectar was secreted during the staminate phase than in the pistillate phase, independent of time and treatment. 7,A manual pollination experiment suggested that mites act like secondary pollinators in this self-compatible, non-autogamous plant, at least in flowers that were not pollinated manually and had no access to pollinating hummingbirds. 8,Although seed production was not reduced significantly by flower mites, our results suggest that the presence of floral mites can affect pollen transmission, as the amount of nectar available to hummingbirds was reduced drastically. This can directly affect hummingbird foraging patterns and reduce the fitness of the host plants. [source]

On the general dynamic model of oceanic island biogeography

JOURNAL OF BIOGEOGRAPHY, Issue 6 2009
Simone Fattorini
Abstract Aim, To investigate the biological meaning of equations used to apply the general dynamic model (GDM) of oceanic island biogeography proposed by R. J. Whittaker, K. A. Triantis and R. J. Ladle. Location, Analyses are presented for 17 animal groups living on the Aeolian Islands, a volcanic archipelago in the central Mediterranean, near Sicily. Methods, In addition to the mathematical implementation of the GDM proposed by Whittaker, Triantis and Ladle, and termed here logATT2 (, where S is species number or any other diversity metric, t is island age, A is island area, and a, b, c and d are fitted parameters), a new implementation based on the Arrhenius equation of the species,area relationship (SAR) is investigated. The new model (termed powerATT2) is: . For logATT2 and powerATT2 models, equations were developed to calculate (1) the expected number of species at equilibrium (i.e. when the island has reached maturity) per unit area (Seq), and (2) the time required to obtain this value (teq). Whereas the intercept in the Gleason model (S = C + z log A) or the coefficient of the Arrhenius power model (S = CAz) of the SAR can be considered measures of the expected number of species per unit area, this is not the case for the parameter a of the ATT2 models. However, values of Seq can be used for this purpose. The index of ,colonization ability' (CAB), calculated as the ratio , may provide a measure of the mean number of species added per unit area per unit time. Results, Both ATT2 models fitted most of the data well, but the powerATT2 model was in most cases superior. Equilibrial values of species richness (Seq) varied from c. 3 species km,2 (reptiles) to 100 species km,2 (mites). The fitted curves for the powerATT2 model showed large variations in d, from 0.03 to 3. However, most groups had values of d around 0.2,0.4, as commonly observed for the z -values of SARs modelled by a power function. Equilibration times ranged from about 170,000 years to 400,000 years. Mites and springtails had very high values of CAB, thus adding many more species per unit area per unit time than others. Reptiles and phytophagous scarabs showed very low values, being the groups that added fewest species per unit area per unit time. Main conclusions, Values of equilibrial species richness per unit area are influenced by species biology (e.g. body size and ecological specialization). Theoretical and empirical evidence suggests that higher immigration rates should increase the z -values of the Arrhenius model. Thus, in the same archipelago, groups with larger z -values should be characterized by higher dispersal ability. Results obtained here for the parameter d conform to this prediction. [source]

A Simple Technique for Purifying Fungal Cultures Contaminated with Bacteria and Mites

JOURNAL OF PHYTOPATHOLOGY, Issue 9 2001
S. S. Ko
A simple technique was developed for purifying fungal cultures contaminated with bacteria and mites. It was based on the observation that the growth of bacteria and movement of mites were confined to the upper surface of the agar. A culture contaminated with bacteria and mites was transferred to a piece of clean paper with the upper surface facing down. Small thin pieces (approximately 3 mm × 3 mm × 0.5 mm) of agar were removed from the exposed surface and transferred to a V-8 agar plate. Colonies that developed from these agar pieces were free from bacteria and mites. [source]

Northern fowl mite orientation in a thermal gradient and evidence for idiothetic course control

PHYSIOLOGICAL ENTOMOLOGY, Issue 3 2005
Jeb P. Owen
Abstract., The northern fowl mite, Ornithonyssus sylviarum, is an ectoparasite of birds and a poultry pest. The ability of northern fowl mites to orientate to a heat source is investigated with individual mites video-recorded in two-dimensional arenas and exposed to spatial or temporal heat gradients. Recorded tracks are digitally analysed for variation in linear velocity, mean direction of movement, and patterns in angular displacement. Mean direction of movement in a spatial gradient is significantly associated with the position of the heat source for 24/29 mites tested (P < 0.05), whereas most control (no heat) mean bearings are randomly distributed (16/25; P > 0.1). Angular displacement that orientates a mite towards the heat source is positively correlated with the preceding deviation from that direction (P < 0.01). Angular displacement away from the heat source is random. The temporal heat gradient is such that no spatial reference to the heat source exists within the plane of the arena. Mites in an ambient (27 °C) to heated (30 °C) transition have angular displacement distributions similar to control mites (ambient to ambient transition). However, mites in a heated to ambient transition execute angular displacements approximately 25° greater than mites in the other treatments (P < 0.03). Mites compare the shift in temperature over time and alter their direction of movement by a programmed (idiothetic) response to a decrease in temperature, rather than through detection of the spatial position of the gradient (allothetic). [source]

Are tree trunks habitats or highways?

AUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 4 2002
A comparison of oribatid mite assemblages from hoop-pine bark, litter
Abstract Oribatid mites (Acari: Oribatida) are among the most diverse and abundant inhabitants of forest soil and litter, but also have species-rich assemblages on bark and in the canopies of trees. It is unclear whether the trunk of a tree acts simply as a ,highway' for movement of mites into and out of the canopy, or whether the trunk has a distinctive acarofauna. We compare oribatid assemblages from the trunk bark of hoop pine (Araucaria cunninghamii) with those from litter collected beneath the same trees. A 1.0 by 0.5 m area of bark was sampled from three trees at each of five sites using a knockdown insecticide. A 1-L sample of leaf litter was collected as close as possible to the base of each sampled tree. Mites were extracted using Tullgren funnels, identified to genus and morphospecies, and counted. Assemblages were almost 100% distinct, with only one oribatid morphospecies (Pseudotocepheus sp.) collected from both litter and bark. Litter had a higher taxon richness than bark in total and per sample, but oribatids made up a greater percentage of the acarofauna in the bark samples. We had expected that the more consistent physical substrate of bark would be reflected in greater similarity of oribatid faunas on trunks than in litter; however, the opposite proved to be the case. We conclude that hoop-pine trunks are habitats rather than highways for oribatid mites. Based on the observed higher turnover among bark faunas, tree trunks may represent habitat islands whose colonisation by particular oribatid species is more stochastic than that of the more continuous ,sea' of litter. [source]

Failure to cospeciate: an unsorted tale of millipedes and mites

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2010
LYNN SWAFFORD
Mites form symbiotic relationships with many animal taxa, including fish, amphibians, reptiles, birds, mammals, mollusks and arthropods. They are often found living on millipedes and it has often been speculated that these two groups of arthropods have, in some cases, undergone coevolution. However, this hypothesis has never been formally tested. Millipedes of the family Xystodesmidae Cook 1895 (Diplopoda: Polydesmida) and their symbiotic mites of the genus Stylochyrus Canestrini & Canestrini 1882 were collected in broadleaf forests of the eastern USA. The DNA from two mitochondrial regions (16S/12S and cox1) was sequenced for all collected millipede and mite specimens. Phylogenetic trees were reconstructed for both millipede and mite taxa using Bayesian inference. Pairwise distance data were used in distance-based coevolutionary analyses and reconstructed phylogenies were used in tree-based coevolutionary analyses. The phylogenetic analyses indicate Stylochyrus and xystodesmid millipede evolutionary history is incongruent. Moreover, the evolutionary relationships among mite individuals and populations have very low support values and indicate little to no geographic structuring. The coevolutionary analyses likewise detected no pattern of coevolution among these millipede and mite lineages. Unlike many arthropod species, Stylochyrus mites appear to be highly vagile. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101, 272,287. [source]

Parasitized Salamanders are Inferior Competitors for Territories and Food Resources

ETHOLOGY, Issue 4 2000
Daria S. Maksimowich
Parasites have been shown to impair the behaviour of their hosts, compromising the host's ability to exploit and compete for resources. We conducted two experiments to determine whether infestation with an ectoparasitic mite (Hannemania eltoni) was associated with changes in aggressive and foraging behaviour in the Ozark zigzag salamander, Plethodon angusticlavius. In a first experiment, male salamanders with high parasite loads were less aggressive overall than males with low parasite loads during territorial disputes. In addition, males with high parasite loads were more aggressive toward opponents with high parasite loads (symmetric contests) than toward opponents with low parasite loads (asymmetric contests). In contrast, males with low parasite loads did not adjust their level of aggression according to the parasite load of the opponent. In a second experiment, foraging behaviour of females was tested in response to ,familiar' (Drosophila) prey and ,novel' (termite) prey. Latency to first capture was significantly longer for parasitized than non-parasitized females when tested with ,familiar' prey, but not for ,novel' prey. Our results suggest that parasite-mediated effects may have profound influences on individual fitness in nature. [source]

MUSEUM SPECIMENS AND PHYLOGENIES ELUCIDATE ECOLOGY'S ROLE IN COEVOLUTIONARY ASSOCIATIONS BETWEEN MITES AND THEIR BEE HOSTS

Isolation and characterisation of a 13.8-kDa bacteriolytic enzyme from house dust mite extracts: homology with prokaryotic proteins suggests that the enzyme could be bacterially derived

FEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2002
Leslie T. Mathaba
Abstract Bacteriolytic activity was detected in extracts of whole mite and spent growth medium (SGM) from the clinically important Dermatophagoides pteronyssinus and Dermatophagoides farinae mites and was most abundant in whole mite extract. Gram-positive organisms Micrococcus lysodeikticus, Bacillus megaterium and Listeria monocytogenes were preferentially lysed and the lytic activity was enhanced by thiols, destroyed by mite proteases, inhibited by HgCl2 and high concentrations of NaCl but was resistant to heat and acid treatment. Substrate SDS,PAGE analysis indicated the presence of several lytic enzymes, two of which were isolated from D. pteronyssinus spent growth medium extract by hydroxyapatite chromatography. The N-terminal amino acid sequence of one of them was then used in PCR-based cloning studies. The complete amino acid sequence of this protein was determined and cDNA found to encode a 130-amino acid residue mature protein with a 20-amino acid leader sequence. The deduced protein demonstrated sequence similarity with the C-terminal regions of a group of bacterial proteins belonging to the P60 superfamily. These data suggest that the enzyme is derived from bacteria within the mites rather than from mites per se. [source]

Host,parasite interactions and vectors in the barn swallow in relation to climate change

GLOBAL CHANGE BIOLOGY, Issue 4 2010
A. P. MØLLER
Abstract Recent climate change has affected the phenology of numerous species, and such differential changes may affect host,parasite interactions. Using information on vectors (louseflies, mosquitoes, blackflies) and parasites (tropical fowl mite Ornithonyssus bursa, the lousefly Ornithomyia avicularia, a chewing louse Brueelia sp., two species of feather mites Trouessartia crucifera and Trouessartia appendiculata, and two species of blood parasites Leucozytozoon whitworthi and Haemoproteus prognei) of the barn swallow Hirundo rustica collected during 1971,2008, I analyzed temporal changes in emergence and abundance, relationships with climatic conditions, and changes in the fitness impact of parasites on their hosts. Temperature and rainfall during the summer breeding season of the host increased during the study. The intensity of infestation by mites decreased, but increased for the lousefly during 1982,2008. The prevalence of two species of blood parasites increased during 1988,2008. The timing of first mass emergence of mosquitoes and blackflies advanced. These temporal changes in phenology and abundance of parasites and vectors could be linked to changes in temperature, but less so to changes in precipitation. Parasites had fitness consequences for hosts because intensity of the mite and the chewing louse was significantly associated with delayed breeding of the host, while a greater abundance of feather mites was associated with earlier breeding. Reproductive success of the host decreased with increasing abundance of the chewing louse. The temporal decrease in mite abundance was associated with advanced breeding of the host, while the increase in abundance of the lousefly was associated with earlier breeding. Virulence by the tropical fowl mite decreased with increasing temperature, independent of confounding factors. These findings suggest that climate change affects parasite species differently, hence altering the composition of the parasite community, and that climate change causes changes in the virulence of parasites. Because the changing phenology of different species of parasites had both positive and negative effects on their hosts, and because the abundance of some parasites increased, while that of other decreased, there was no consistent temporal change in host fitness during 1971,2008. [source]

Soil arthropods as indicators of water stress in Antarctic terrestrial habitats?

GLOBAL CHANGE BIOLOGY, Issue 12 2003
Peter Convey
Abstract Abiotic features of Antarctic terrestrial habitats, particularly low temperatures and limited availability of liquid water, strongly influence the ecophysiology and life histories of resident biota. However, while temperature regimes of a range of land microhabitats are reasonably well characterized, much less is known of patterns of soil water stress, as current technology does not allow measurement at the required scale. An alternative approach is to use the water status of individual organisms as a proxy for habitat water status and to sample over several years from a population to identify seasonal or long-term patterns. This broad generalization for terrestrial invertebrates was tested on arthropods in the maritime Antarctic. We present analyses of a long-term data set of body water content generated by monthly sampling for 8,11 years of seven species of soil arthropods (four species of Acari, two Collembola and one Diptera) on maritime Antarctic Signy Island, South Orkney Islands. In all species, there was considerable within- and between-sample variability. Despite this, clear seasonal patterns were present in five species, particularly the two collembolans and a prostigmatid mite. Analyses of monthly water content trends across the entire study period identified several statistically significant trends of either increase or decrease in body water content, which we interpret in the context of regional climate change. The data further support the separation of the species into two groups as follows: firstly, the soft-bodied Collembola and Prostigmata, with limited cuticular sclerotization, which are sensitive to changes in soil moisture and are potentially rapid sensors of microhabitat water status, secondly, more heavily sclerotized forms such as Cryptostigmata (=Oribatida) and Mesostigmata mites, which are much less sensitive and responsive to short-term fluctuations in soil water availability. The significance of these findings is discussed and it is concluded that annual cycles of water content were driven by temperature, mediated via radiation and precipitation, and constituted reliable indicators of habitat moisture regimes. However, detailed ecophysiological studies are required on particular species before such information can be used to predict over long timescales. [source]

Molecular characterization of two novel esterase genes from carmine spider mite, Tetranychus cinnabarinus (Acarina: Tetranychidae)

INSECT SCIENCE, Issue 2 2010
Wei Sun
Abstract, Two novel esterase complementary DNAs were identified and cloned from the insecticide-susceptible strain of Tetranychus cinnabarinus (Boisduval) (Acarina: Tetranychidae), which were designated as TCE1 and TCE2, respectively. The cDNA of TCE1 gene contained an open reading frame (ORF) of 1701 bp encoding 567 amino acids, and a predicted molecular weight of 62.75 kDa, the cDNA of TCE2 contained an ORF of 1680 bp encoding 560 amino acids, and a predicted molecular weight of 63.14 kDa. TCE1 and TCE2 were submitted to GenBank, accession number EU130461 and EU130462. The well-conserved sequence motif, GXSXG, used as a signature pattern in the esterase family are present in both TCE1 and TCE2 (GQSAG in TCE1, whereas GESAG in TCE2), indicating that these two genes are predicted to be esterases. Comparison of the deduced amino acid sequence with the published mite esterase sequence coming from Boophilus microplus showed that TCE1 shares 33.98% identity and TCE2 shares 33.46% identity. TCE1 and TCE2 share 46.4% identity. Quantitative real-time polymerase chain reaction revealed that expression level of the TCE2 gene was relatively higher than that of the TCE1 in all instars examined except the protonymph, and the expression level of these two esterase genes in adults of T. cinnabarinus was significantly higher than that in any other instars, respectively. T. cinnabarinus is an important agricultural mite pest and esterases are important in the metabolisms of insects and mites; the genomic information obtained in this study will contribute to esterase molecular biological study on mite pest species. [source]

SEASONAL PERFORMANCE AFFECTING POPULATION DYNAMICS OF CITRUS RED MITE, FANONYCHUS CITRI (MCGREGOR) (ACARI: TETRANYCHIDAE), ON PEAR

Spanning the gap: experimental determination of paratenic host specificity of horsehair worms (Nematomorpha: Gordiida)

INVERTEBRATE BIOLOGY, Issue 1 2003
Ben Hanelt
Abstract. Details of the life cycle of freshwater nematomorphs (gordiids) remain unclear. Free-living aquatic larval gordiids must make a critical transition from an epibenthic aquatic environment to terrestrial hosts. In order to identify potential hosts capable of bridging this ecological gap, the specificity of paratenic hosts of three common species of North American gordiids was investigated. All three species were characterized by an identical infection pattern: low host specificity. Gordiids were able to encyst within annelids, mollusks, crustaceans, insects and a vertebrate. Three species of putative host (a turbellarian, a water mite, and a mosquito larva) were not infected with any of the gordiid species. Internal defense reactions (IDR) and feeding behaviors are implicated as preventing infection in these species. Several of the other host species produced either an IDR or an immune reaction to the cysts, although reactions to the cysts were highly variable between species. In most species, IDR did not cause noticeable harm to the encysted larvae. It is proposed that although many species are easily infected with gordiid cysts, most do not act as natural paratenic hosts. For some of these host groups, especially snails, a role as reservoir host is suggested. Of all hosts included in this study, aquatic insects were identified as the hosts likely responsible for spanning the ecological gap and acting as true hosts for gordiids. [source]

Host reproduction and a sexually transmitted disease: causes and consequences of Coccipolipus hippodamiae distribution on coccinellid beetles

JOURNAL OF ANIMAL ECOLOGY, Issue 1 2004
K. Mary Webberley
Summary 1We know that sexually transmitted parasites and pathogens have extremely deleterious effects in human and domesticated animal populations, but know little of sexually transmitted diseases (STDs) in natural populations. 2One previously reported natural system is the sexually transmitted mite, Coccipolipus hippodamiae, on the eastern European coccinellid, Adalia bipunctata. Our aims were to determine how widespread this parasite is in terms of incidence and prevalence across host species, to identify the causes of the prevalence pattern and whether the parasite reduces fertility in all host species. 3Coccipolipus hippodamiae was present on four of 19 European species examined. The wide distribution and high prevalence of C. hippodamiae on A. bipunctata indicates that this is the major host. The mite was also present at substantial prevalence on Adalia decempunctata and at lower prevalence on Synharmonia (=Oenopia) conglobata and Calvia quatuordecimguttata. 4Laboratory studies on mite development time and transmission efficiency revealed that although physiological factors may affect incidence, they do not explain prevalence variation between hosts, but characteristics of host life history and reproductive behaviour are important in this context. Adalia bipunctata is more promiscuous than the less commonly infected A. decempunctata and S. conglobata. Diapause is needed before breeding will occur in C. quatuordecimguttata, leading to a lack of the consistent sexual activity between generations, which is needed for STD maintenance. Calvia quatuordecimguttata is probably periodically reinfected through hybrid matings with other host species. 5Coccipolipus hippodamiae infection has similar strong deleterious effects on female reproduction in A. decempunctata and S. conglobata as have previously been demonstrated in A. bipunctata. 6The results indicate that STDs may play a profound role in the ecology of promiscuous insect populations with overlapping generations. Here they may reach significant prevalence whilst exhibiting extreme virulence. [source]

Poor host plant quality causes omnivore to consume predator eggs

JOURNAL OF ANIMAL ECOLOGY, Issue 3 2003
Arne Janssen
Summary 1Omnivorous arthropods are known to change their diet when host plant quality is low. Consequently, it has been suggested that decreased plant quality has a twofold negative effect on herbivore populations: (1) a decrease in growth rate of herbivores; (2) omnivores include more herbivores in their diet. We hypothesized that decreased host plant quality may also cause omnivores to feed on predators, including their own enemies. 2We tested this hypothesis, using the omnivorous western flower thrips. This species is known to feed on many plant species, but also on the eggs of another herbivore, the two-spotted spider mite. Previous research has shown that a decrease in plant quality leads to increased feeding on spider mite eggs by western flower thrips. Western flower thrips also kill the eggs of various predatory mites, including those of the specialist predator of spider mites and those of a predatory mite that attacks western flower thrips itself. 3In this paper we investigate whether thrips larvae kill predator eggs to feed on them and whether this predation depends on host plant quality. 4Larval survival as well as developmental rate increased when plant tissue of low quality (sweet pepper) was supplemented with eggs of two predatory mite species or when it was supplemented with pollen, a high-quality food type. 5Supplementing high quality leaf tissue (cucumber) with predator eggs did not lead to increased survival and developmental rate. Thrips larvae fed significantly less on predatory mite eggs when pollen was available. 6Thus, thrips larvae indeed feed on predator eggs, including those of their predator, and they feed more on predator eggs when host plants are of low quality. [source]

Disruption of an exotic mutualism can improve management of an invasive plant: varroa mite, honeybees and biological control of Scotch broom Cytisus scoparius in New Zealand

JOURNAL OF APPLIED ECOLOGY, Issue 2 2010
Quentin Paynter
Summary 1.,A seed-feeding biocontrol agent Bruchidius villosus was released in New Zealand (NZ) to control the invasive European shrub, broom Cytisus scoparius, in 1988 but it was subsequently considered unable to destroy sufficient seed to suppress broom populations. We hypothesized that an invasive mite Varroa destructor, which has caused honeybee decline in NZ, may cause pollinator limitation, so that the additional impact of B. villosus might now reach thresholds for population suppression. 2.,We performed manipulative pollination treatments and broad-scale surveys of pollination, seed rain and seed destruction by B. villosus to investigate how pollinator limitation and biocontrol interact throughout the NZ range of broom. 3.,The effect of reduced pollination in combination with seed-destruction was explored using a population model parameterized for NZ populations. 4.,Broom seed rain ranged from 59 to 21 416 seeds m,2 from 2004 to 2008, and was closely correlated with visitation frequency of honeybees and bumblebees. Infestation of broom seeds by B. villosus is expected to eventually reach 73% (the average rate observed at the localities adjacent to early release sites). 5.,The model demonstrated that 73% seed destruction, combined with an absence of honeybee pollination, could cause broom extinction at many sites and, where broom persists, reduce the intensity of treatment required to control broom by conventional means. 6.,Nevertheless, seed rain was predicted to be sufficient to maintain broom invasions over many sites in NZ, even in the presence of the varroa mite and B. villosus, largely due to the continued presence of commercial beehives that are treated for varroa mite infestation. 7.,Synthesis and applications. Reduced pollination through absence of honeybees can reduce broom seed set to levels at which biocontrol can be more effective. To capitalize on the impact of the varroa mite on feral honeybees, improved management of commercial beehives (for example, withdrawal of licences for beekeepers to locate hives on Department of Conservation land) could be used as part of a successful integrated broom management programme at many sites in NZ. [source]

Alternative pollinator taxa are equally efficient but not as effective as the honeybee in a mass flowering crop

JOURNAL OF APPLIED ECOLOGY, Issue 5 2009
Romina Rader
Summary 1. ,The honeybee Apis mellifera is currently in decline worldwide because of the combined impacts of Colony Collapse Disorder and the Varroa destructor mite. In order to gain a balanced perspective of the importance of both wild and managed pollination services, it is essential to compare these services directly, a priori, within a cropping landscape. This process will determine the capacity of other flower visitors to act as honeybee replacements. 2. ,In a highly modified New Zealand agricultural landscape, we compared the pollination services provided by managed honeybees to unmanaged pollinator taxa (including flies) within a Brassica rapa var. chinensis mass flowering crop. 3. ,We evaluate overall pollinator effectiveness by separating the pollination service into two components: efficiency (i.e. per visit pollen deposition) and visit rate (i.e. pollinator abundance per available flower and the number of flower visits per minute). 4. ,We observed 31 species attending flowers of B. rapa. In addition to A. mellifera, seven insect species visited flowers frequently. These were three other bees (Lasioglossum sordidum, Bombus terrestris and Leioproctus sp.) and four flies (Dilophus nigrostigma, Melanostoma fasciatum, Melangyna novae-zelandiae and Eristalis tenax). 5. ,Two bee species, Bombus terrestris and Leioproctus sp. and one fly, Eristalis tenax were as efficient as the honeybee and as effective (in terms of rate of flower visitation). A higher honeybee abundance, however, resulted in it being the more effective pollinator overall. 6. ,Synthesis and applications. Alternative land management practices that increase the population sizes of unmanaged pollinator taxa to levels resulting in visitation frequencies as high as A. mellifera, have the potential to replace services provided by the honeybee. This will require a thorough investigation of each taxon's intrinsic biology and a change in land management practices to ensure year round refuge, feeding, nesting and other resource requirements of pollinator taxa are met. [source]

Functional response of Neoseiulus californicus (Acari: Phytoseiidae) to Tetranychus urticae (Acari: Tetranychidae) on strawberry leaves

JOURNAL OF APPLIED ENTOMOLOGY, Issue 2 2010
J. J. Ahn
Abstract Neoseiulus californicus (McGregor) is a predatory mite employed for biological control of the agricultural pest Tetranychus urticae (Koch). We explored whether environmental differences, in this case the trichome densities of abaxial leaf surfaces of strawberry cultivars (,Maehyang' and ,Sulhyang' varieties) affect the functional response of adult female N. californicus preying on immature stages (egg, larva and nymph) of T. urticae. We also evaluated the functional response of N. californicus to eggs of T. urticae at different temperatures (15, 20, 25, 30 and 35°C). We conducted a logistic regression of the proportion of prey consumed as a function of initial prey density to identify functional response types, and used nonlinear least-squares regression and the random predator equation to estimate attack rates and handling times. The functional response of adult female N. californicus to T. urticae was not influenced by non-glandular trichomes on abaxial leaves but was affected by temperature. Overall, adult female N. californicus exhibited a type 2 functional response to T. urticae. The handling time of N. californicus was highest (1.9970 h) against T. urticae nymphs. The attack rate did not change much at 15,30°C, but was significantly higher at 35°C. The handling time decreased significantly with increasing temperature at 15,35°C. At 35°C, the attack rate was highest (0.2087) and the handling time was lowest (0.9511 h). [source]

Effect of vegetation management on autumn dispersal of Tetranychus urticae (Acari: Tetranychidae) from tomato

JOURNAL OF APPLIED ENTOMOLOGY, Issue 9-10 2009
E. D. Meck
Abstract Autumn dispersal of twospotted spider mite (Tetranychus urticae Koch) from tomato to overwintering host plants was studied in field experiments during 2004,2006. Three vegetation management strategies (herbicide, cultivation and no vegetation control) were established around mite-infested, senescing tomato plants. Tetranychus urticae dispersal was monitored using trap plants of common chickweed (Stellaria media) at 2, 6 and 12 m from the tomatoes within each vegetation management plot. Chickweed plants were sampled in the autumn and spring from 2004 to 2006. Sticky traps were placed next to trap plants in the autumn of 2005 to monitor aerial dispersal of mites. Mite populations infesting chickweed were low, and autumn dispersal of mites from tomatoes to the chickweed plots was considered to be short range. The vegetation management strategies had no effect on mite densities found in the chickweed, but the capture of mites on sticky traps indicated that aerial dispersal was also a means of dispersal to overwintering hosts. [source]

Nest-to-nest dispersal of Chaetodactylus krombeini (Acari, Chaetodactylidae) associated with Osmia cornifrons (Hym., Megachilidae)

JOURNAL OF APPLIED ENTOMOLOGY, Issue 3 2009
Y.-L. Park
Abstract A cleptoparasitic mite, the Krombein's hairy-footed mite, Chaetodactylus krombeini Baker (Acari, Chaetodactylidae) became a key pest that affects the maintenance and propagation of Osmia spp. (Hym., Megachilidae), thus disrupting orchard pollination in the United States. Although hypopi, the dispersal stages of C. krombeini, are known to disperse from nest to nest by hitchhiking on Osmia cornifrons adults, we observed that they might disperse in other ways too in commercial orchards. This study was conducted to elucidate the nest-to-nest dispersal mechanisms of C. krombeini hypopi. We tested three potential dispersal mechanisms of C. krombeini other than phoresy by O. cornifrons: (1) dispersal by walking from nest to entrances of nearby nests, (2) dispersal by walking from nest to nest through emergence holes made by parasitic wasps on nests, and (3) dispersal by being unloaded and uptaken to and from flowers by O. cornifrons. Results of this study showed that C. krombeini hypopi could disperse from a nest to nearby nests by walking through nest entrances and holes made by parasitic wasps of O. cornifrons. Although 0.06% of C. krombeini hypopi on blueberry flowers were picked up by O. cornifrons, they were not able to be unloaded to flowers from O. cornifrons and no hypopi could inhabit or survive on blueberry flowers. This indicated no or very low chance of C. krombeini hypopi dispersal via blueberry flowers. Based on our findings of C. krombeini dispersal ecology, development of C. krombeini control strategies are discussed in this article. [source]

Effect of some characters on the population growth of mite Varroa jacobsoni in Apis mellifera L colonies and results of a bi-directional selection

JOURNAL OF APPLIED ENTOMOLOGY, Issue 2-3 2002
M. Lodesani
Two lines of honey bees (Apis mellifera ligustica) were selectively propagated by instrumental insemination using the population growth of the Varroa mite as a criteria. Different infestation rates are at least partially genetic since selection produced significant bi-directional differences between lines over a period of three subsequent generations. There was no correlation between several behavioural and physiological characteristics which are potentially associated with Varroa resistance (hygienic behaviour, physical damage to mites, infertility of the intruding mites) and the development of the Varroa population after artificial infestation. There was a positive significant correlation between the total mites in the colonies and the amount of reared brood. Colony infestation was also positively correlated with the amount of honey harvested. [source]

Local,regional boundary shifts in oribatid mite (Acari: Oribatida) communities: species,area relationships in arboreal habitat islands of a coastal temperate rain forest, Vancouver Island, Canada

JOURNAL OF BIOGEOGRAPHY, Issue 9 2007
Zoë Lindo
Abstract Aim, This study investigates the species,area relationship (SAR) for oribatid mite communities of isolated suspended soil habitats, and compares the shape and slope of the SAR with a nested data set collected over three spatial scales (core, patch and tree level). We investigate whether scale dependence is exhibited in the nested sampling design, use multivariate regression models to elucidate factors affecting richness and abundance patterns, and ask whether the community composition of oribatid mites changes in suspended soil patches of different sizes. Location, Walbran Valley, Vancouver Island, Canada. Methods, A total of 216 core samples were collected from 72 small, medium and large isolated suspended soil habitats in six western redcedar trees in June 2005. The relationship between oribatid species richness and habitat volume was modelled for suspended soil habitat isolates (type 3) and a nested sampling design (type 1) over multiple spatial scales. Nonlinear estimation parameterized linear, power and Weibull function regression models for both SAR designs, and these were assessed for best fit using R2 and Akaike's information criteria (,AIC) values. Factors affecting oribatid mite species richness and standardized abundance (number per g dry weight) were analysed by anova and linear regression models. Results, Sixty-seven species of oribatid mites were identified from 9064 adult specimens. Surface area and moisture content of suspended soils contributed to the variation in species richness, while overall oribatid mite abundance was explained by moisture and depth. A power-law function best described the isolate SAR (S = 3.97 × A0.12, R2 = 0.247, F1,70 = 22.450, P < 0.001), although linear and Weibull functions were also valid models. Oribatid mite species richness in nested samples closely fitted a power-law model (S = 1.96 × A0.39, R2 = 0.854, F1,18 = 2693.6, P < 0.001). The nested SAR constructed over spatial scales of core, patch and tree levels proved to be scale-independent. Main conclusions, Unique microhabitats provided by well developed suspended soil accumulations are a habitat template responsible for the diversity of canopy oribatid mites. Species,area relationships of isolate vs. nested species richness data differed in the rate of accumulation of species with increased area. We suggest that colonization history, stability of suspended soil environments, and structural habitat complexity at local and regional scales are major determinants of arboreal oribatid mite species richness. [source]

Cryptic diversification in ancient asexuals: evidence from the bdelloid rotifer Philodina flaviceps

JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 2 2008
D. FONTANETO
Abstract Bdelloid rotifers, darwinulid ostracods and some oribatid mites have been called ,ancient asexuals' as they speciated and survived over long-term evolutionary timescale without sexual recombination. Data on their genetic diversification are contrasting: within-species diversification is present mostly at a continental scale in a parthenogenetic oribatid mite, whereas almost no genetic diversification at all seems to occur within darwinulid ostracod species. Strangely enough, no clear data for bdelloid rotifers are available so far. In this paper, we analyse partial COI mtDNA sequences to show that a bdelloid rotifer, Philodina flaviceps, so far considered a single traditional morphological species, has actually been able to diversify into at least nine distinct evolutionary entities, with genetic distances between lineages comparable with those between different traditional species within the same genus. We discovered that local coexistence of such different independent lineages is very common: up to four lineages were found in a same stream, and up to three in a single moss sample of 5 cm2. In contrast to the large-scale geographic pattern that has recently been reported in the oribatid mite, the spatial distribution of the bdelloid lineages provided evidence of micro-phylogeographic patterns. If the mtDNA diversity indicates that the lineages are independent and represent sympatric cryptic species within P. flaviceps, then the actual bdelloid diversity can be expected to be much greater than that recognized today. [source]

Inbreeding depression by recessive deleterious genes affecting female fecundity of a haplo-diploid mite

JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 4 2000
Saito
The effect of inbreeding on haplo-diploid organisms has been regarded as very low, because deleterious recessive genes on hemizygous (haploid) males were immediately purged generation by generation. However, we determined such recessive genes to decrease female fecundity in a population of Schizotetranychus miscanthi Saito which is known in the Acari as a subsocial species with haplo-diploidy. In mother,son inbreeding experiments, there was no depression in egg hatchability nor in the larval survival of progeny over four generations. There was, on the other hand, significant inbreeding depression in the fecundity with increasing f -value. Crosses between two lineages, one having deleterious effects on the fecundity and the other having no such effects, established during the inbreeding, revealed heterosis, and backcrosses showed that the depression was caused by deleterious recessive(s). These results strongly suggest the existence of some deleterious genes governing only the traits of adult females in wild populations of haplo-diploid organisms. [source]