Mating behaviour of the water mite Arrenurus manubriator (Acari: Arrenuridae)

Water mites of the genus Arrenurus vary in male sexual dimorphism and in sperm transfer behaviour. Although it is a very large genus (≈800 spp.), mating behaviour has been described for only a few species. Here sperm transfer behaviour is described for the first time in a North American species, Arrenurus manubriator. Behaviour patterns can be divided into pre-pairing (readiness posture and cauda presentation), pre-deposition (high vertical jerking, low vertical shaking, striking/stroking and slow lateral waving), spermatophore deposition, sperm translocation, post-deposition (striking/stroking. slow lateral waving, 'tick-rock', shuttling, violent shaking), and separation. Males deposited 8–21 spermatophores in a mating. Pairs remained together for up to 31/2h. Possible adaptive functions of male courtship behaviour are discussed, including the hypothesis that male intromittant organs evolved in Arrenurus to circumvent female choice.     

楔形维螨和汤旺河维螨雌螨形态补充及若螨描述(蜱螨亚纲:革螨股:维螨科)

本文补充楔形维螨Veigaia cuneata Ma,1996和汤旺河维螨Veigaia tangwanghensis Ma et Yin,1999雌螨形态特征,并描述其若螨.     

Digestion in the soil predatory mite Pergamasus longicornis (Berlese) (Acari: Mesostigmata: Parasitidae)--detectable hydrolases

Nineteen hydrolytic enzymes were detected in individual adult Pergamasus longicornis (Berlese) mites--amylase, hide protease, alkali phosphatase, esterase (C4), esterase lipase (C8), lipase (C14), leucine arylamidase, valine arylamidase, cystine arylamidase, acid phosphatase, phosphoamidase, alpha-galactosidase, beta-galactosidase, beta-glucuronidase, alpha-glucosidase, beta-glucosidase, N-acetyl-beta-glucosaminidase, alpha-mannosidase, and alpha-fucosidase. All but the phosphatases were detected for the first time. Tryptic and chymotryptic activity were consistently not demonstrable. Comparisons are made with saprophagous mites. No clear enzymic specialization for predation was found.     

A new mite superfamily (Acari: Cryptostigmata)

The new superfamily Eutegaeoidea (Acari: Cryptostigmata) is defined and subdivided into three families, viz. Eutegaeidae, Compactozetidae nov., Pterozetidae nov. The Eutegaeidae is considered to possess six genera ( Eutegaeus, Neoeutegaeus, Neseutegaeus, Pareutegaeus, Birotegaeus nov., Atalotegaeus nov.), the Pterozetidae three genera ( Pterozetes, Porrhotegaeus, Dudichella ), and the Compactozetidae four genera ( Compactozetes, Bornebuschia, Hamotegeus, Sadocepheus ). Keys are provided to all taxa down to species and Pareutegaeus similis (Trägardh, 1931) is redescribed from the lectotype.     

Oviposition model of overwintered adult Tetranychus urticae (Acari: Tetranychidae) and mite phenology on the ground cover in apple orchards

The phenology of overwintered Tetranychus urticae was studied on the ground cover in apple orchards in the early season, and an oviposition model of overwintered adults was developed. The movement of overwintered adults from trees to ground cover started from mid-March and continued until mid-April. One life cycle from eggs to new adults (the 1st generation adults) on the ground cover was from late March to early May. The longevity and fecundity of overwintered T. urticae were affected largely by temperature. The longevity ranged from 46.6 days at 10 degrees C to 6.5 days at 35 degrees C. The total fecundity was minimum (0.2 eggs) at 10 degrees C and maximum (45.5 eggs) at 25 degrees C. The relationship between total fecundity and temperature was described well by a nonlinear equation. The cumulative age-specific oviposition rate was described well by the two-parameter Weibull function. The overall adult survival exhibited a reverse logistic curve. Three temperature-dependent components, age-specific cumulative oviposition rate, temperature-dependent total fecundity and age-specific survival rate functions, were incorporated into an oviposition model. The oviposition model simulation described the occurrence pattern of eggs laid by overwintered T. urticae on the ground cover in apple orchards relatively well.     

The Mechanism of Oviposition in Argas (Persicargas) Walkerae (Acari: Argasidae)

The process of oviposition in A. walkerae was observed and found to be a sequence of exactly coordinated, interlocking events independent of the age of ticks. Egg-laying always commenced with numerous dorso-ventral movements of the capitulum. The pedipalps were spread during the last dorso-ventral movement and lowered to the ventral body wall embracing the genital aperture on both sides. Simultaneously, the cuticular sac of Gene's organ emerged and immediately everted maximally. Immediately afterwards the vestibulum vaginae prolapsed from the genital aperture touching the cuticular sac. The vestibulum vaginae handed over an egg to the cuticular sac after a brief contact. Then the vestibulum vaginae invaginated, the pedipalps closed and the cuticular sac was retracted. Finally, the capitulum very frequently moved up and down and the free egg was pushed in front of the ticks. The total time of laying an egg averaged 27min in both 4-week-old and 12-month-old ticks. In 4-week and 12-month-old ticks, egg-laying was preceded by a mean preoviposition period of 6.1 days and 7.5 days, respectively, while the mean oviposition was completed in 14 and 10 days and the average egg totals were 119 and 103.     

Feeding activity of a phthiracarid mite (Arachnida: Acari)

The oribatid mite, Phthiracarus sp., feeds by tearing-out material from the spongy mesophyll of decaying spruce needles with a pair of retractile chelicerae. A pair of dentate rutella localize this tearing activity and limit particles to a manageable size. Mastication is achieved by movements of the chelicerae against each other and the rutella, the process being aided by a pair of palps.     

Fertilization in the two-spotted spider mite (Tetranychus urticae: Acari)

Different aspects of the fertilization of the two-spotted spider mite (Tetranychus urticae Koch) were studied. It appeared that after the mating act of virgin females, haploid eggs were produced first before the appearance of diploid eggs. From this and other facts, it was concluded that fertilization of the oocytes occurs in a very early stage of egg development. The fertilization is assumed to take place in the ovary and not in the oviduct.By using genetic markers, it could be proved that in most cases the first mating is effective. Later matings usually are ineffective. It is suggested that the sperm supply in the first mating determines the success of later matings.

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Zusammenfassung Die Befruchtung der Bohnenspinnmilbe wurde unter verschiedenen Gesichtspunkten untersucht. Nach der Begattung jungfräulicher Weibchen wurden zunächst haploide Eier abgelegt, bevor diploide Eier produziert wurden. Daraus und aus anderen Grüunden wird geschlossen, daß die Befruchtung der Oocyten in einem sehr frühen Stadium der Entwicklung erfolgt. Die Befruchtung findet vermutlicht im Ovar und nicht im Ovidukt statt.Unter Verwendung genetischer Markierung wurde nachgewiesen, daß in den meisten Fällen die erste Begattung ausschlaggebend ist. Spätere Kopulationen bleiben gewöhnlich wirkungslos. Es wird vermutet, daß die Spermafüllung bei der ersten Begattung den Erfolg späterer Begattungen bestimmt.

     

Oviposition behaviour in Paysandisia archon (Lepidoptera: Castniidae)

Paysandisia archon (Burmeister, 1880) (Lepidoptera: Castniidae) is a South American insect developing on palms and recently introduced in Europe where it damages most palm species. Understanding the oviposition behaviour would be decisive for risk assessment and pest management but key points on oviposition behaviour are missing. Using wind tunnel and field experiments, we investigated the oviposition timing, the attraction behaviour of mated females to palms and the different steps of oviposition behaviour. Results showed that oviposition behaviour occurred between 3 pm and 6 pm. In the field, gravid females were significantly more attracted by the palm crown than virgin females. The ovipositing females exhibited distinctive steps before ovipositing. Subsequent to alighting on the crown, pre-oviposition behaviour was characterized by two main behavioural steps: walking and probing the surface with antennae and ovipositor. After the choice of oviposition place, the gravid female remains motionless and the extendible ovipositor is deeply introduced into the upper fibrous part of the crown. About 10 eggs can be lays at the same place. Finally, the female starts to walk again and reinitiates the same behavioural sequences. This paper supports the hypothesis that odours from the crown may play a key role in gravid female attraction. The study assessed that P. archon lays on the palm crown, the part of the palm that should be treated for population monitoring.     

Biological parameters of the predatory mite Cheletomimus bakeri (Acari: Cheyletidae) feeding on Tetranychus cinnabarinus (Acari: Tetranychidae)

Developmental periods of egg, larva and nymphal stages and fecundity as well as predation of Cheletomimus bakeri (Acari: Cheyletidae) feeding on Tetranychus cinnabarinus (Acari: Tetranychidae) were evaluated at different temperatures (15, 20, 25, 30 and 35°C) at 65 ± 10% relative humidity and 16 L: 8D in the laboratory. The development periods of C. bakeri from egg through adult decreased significantly when the temperature was increased from 20°C to 35°C. Egg and total development periods of C. bakeri at 20, 25, 30 and 35°C were 13.86, 7.98, 5.07, 4.08 days and 58.66, 41.51, 21.21, 22.92 days, respectively. The highest numbers of total and daily egg production were found at 20°C and 30°C, respectively. Net reproductive rate (R₀ = 13.29), mean generation time (T = 88.30), gross reproductive rate (GRR = 17.46) and doubling time (DT = 23.66) were the highest at 20°C. The intrinsic rate of increase (r_m = 0.0592) and finite capacity for increase (λ = 1.061) for C. bakeri were the highest at 30°C. Predation of C. bakeri increased throughout the range of prey densities. The highest consumption number of C. bakeri feeding on T. cinnabarinus males per day was 4.63, 4.70 and 4.60 when confined to 40, 80 and 160 individuals, respectively. Our data suggest that C. bakeri does not appear to have much promise for the control of spider mites because of the characteristics of the predator such as slow development period, poor searching capacity and low intrinsic rate of increase.     

Effects of temperature on the adults and progeny of the predaceous mite Lasioseius japonicus (Acari: Blattisociidae) fed on the cereal mite Tyrophagus putrescentiae (Acari: Acaridae)

The predatory mite Lasioseius japonicus Ehara is a newly recorded species in China that has been shown to have great potential as a biological control agent. The species is a soil-dwelling mite that is known to prey on various pests including economically important mites, fungus gnats and other terricolous arthropods. Considering that temperature is one of the most important factors affecting the population dynamics of arthropods, the development, survival and reproduction of L. japonicus were evaluated under indoor conditions at seven temperatures: 19, 22, 25, 28, 31, 34 and 37 °C, at 75% relative humidity and L0:D24 h photoperiod. The mites were fed on the cereal mite Tyrophagus putrescentiae (Schrank) and the data were analyzed using the two-sex life table. The results demonstrated that L. japonicus could complete their development and reproduce at temperatures between 19 and 34 °C, but were unsuccessful at 37 °C. Increasing temperature shortened the development time of the pre-adult stage and the average generation time (T). The life table parameters indicated that at temperatures from 22 to 31 °C the development rate and reproduction of L. japonicus were highest: at 22, 25, 28 and 31 °C the net reproduction rate (R₀) was 55.5, 61.6, 61.2 and 59.0, respectively, and the average fecundity rate (F) was 81.7, 88.0, 102.0 and 86.8, respectively. The maximum values of intrinsic population growth rate (r) (0.341) and finite rate of increase (λ) (1.407) occurred at 31 °C.

     

Prey detection by the water mite Unionicola crassipes (Acari: Unionicolidae)

SUMMARY. 1. The importance of different senses in prey detection by the common water mite Unionicola carssipes was investigated.
2. Mechanoreception is likely to be the most important mode of detection; mites preferentially attacked vibrating over non-vibrating glass probes. The net-stance, a characteristic posture in which the mite raises its first two sets of legs from the substrate and orients toward vibrations in the water column, is assumed by U. crassipes when hunting.
3. Chemoreception may have a role in area-restricted search: mites exposed to prey-conditioned water were more sedentary than those exposed to unconditioned water. For a sit-and-wait predator like U. crassipes , remaining still in an area that contains prey will result in a greater predator/prey encounter rate. It is possible that contact chemoreception is used to determine the palatability of an already captured prey item, but mites did not attempt to capture prey they had touched unless the prey moved.
4. Vision is not necessary for prey capture; however, mites captured more prey in the light than in the dark. It is not clear whether this is because vision plays a part in prey detection or because prey behave differently in the two situations.     

Energy budget of the grain mite,Acarus siro (Acari: Acaridae)

Immature individuals ofAcarus siro L. ingest a total of 0.1408 J of food energy, 58.5% of which is consumed by the deutonymph, 27.1% by the protonymph and only 14.1% by the larva. The total ingestion is much greater (2.8169 J±0.0981se). Much energy, 0.7031 J±0.0231se, is used for egg production, which is concentrated in the first 20 days of adult life. Assimilation efficiency during this period varies from 63 to 71%. Most energy ingested between the 20th and 40th days of adult life is used in biomass production, and biomass increases significantly up to th 30th day. Afterwards, old individuals expend a large amount of assimilated energy on respiration due to the increased cost of maintenance.Present address: Biology Dept., LB 8042, Georgia Southern University, Statesboro, GA 30460, U.S.A.     

Phylogenetic taxonomy of the marine mite genus Rhombognathides (Acari: Halacaridae: Rhombognathinae)

This study examined the impacts of the alien waterweed, water hyacinth, on the abundance and diversity of aquatic macroinvertebrates in the littoral areas of northern Lake Victoria in Uganda. The weed had undergone explosive growth on the lake causing serious disruption to people, the economy and the ecosystem. This study was confined to impact of the weed in the littoral zone, not to the large floating mats of vegetation which float across the lake and clog large areas of shoreline.The littoral area studied comprised of fringing mats of Eichhornia crassipes (Mart) Solms (water hyacinth) to the lakeward of Cyperus papyrus; water hyacinth mats undergoing colonisation by Vossia cuspidata (Roxb.) Griff.; and a typical Cyperus papyrus L shore with no outer floating mat of water hyacinth. Numerical abundance (Nos. m^–2) and diversity (No. of taxa) of macroinvertebrates recovered from pure Eichhornia crassipes and the Eichhornia-Vossia succession increased from the fringe of the Cyperus papyrus towards the open water. In the typical Cyperus papyrus fringe, in the absence of water hyacinth, abundance was highest at the papyrus/open water interface and dropped off sharply towards open water. The Shannon–Weaver diversity index (H) of macroinvertebrates decreased progressively from pure Eichhornia crassipes stands, to Vossia/Eichhornia beds and Cyperus papyrus stands (H=0.56, 0.54 and 0.34, respectively) but were not significantly different. Dissolved oxygen decreased from open water into vegetation where it approached anoxia. Water hyacinth appeared to enhance the abundance and diversity of aquatic macroinvertebrates at the interface with the open water. The impoverished abundance and diversity of the macroinvertebrates deeper into the vegetation mats suggested negative environmental impacts of the water hyacinth when the fringe is too wide. Further research is recommended to establish the optimum width of the fringe of stationery water hyacinth that promotes maximum abundance and diversity of aquatic macroinvertebrates and, possibly, of other aquatic life. Since this study in 1997, there has been a dramatic decrease in Eichhornia infestations and by June 2000 it appeared largely to exist only as fringing vegetation in bays and inlets.     

Biological studies of the Australian predatory mite Typhlodromalus lailae (Schicha) (Acari: Phytoseiidae)

Abstract The biology of the Australian phytoseiid mite Typhlodromalus lailae is described from material collected in Western Australia and New South Wales in 1994. At 25°C, when fed on cumbungi ( Typha sp.) pollen, the life cycle is completed in approximately 6 days, with an intrinsic rate of natural increase ( r _m ), of 0.38. Female−male pairs produced a mean total of 44.6 eggs within 22 days of oviposition, with 39% of these females living in excess of 29 days. Females that were deprived of males after first mating stopped laying eggs after 4−9 days, but if another male was added they resumed egg laying and produced close to a full complement of eggs (mean 42 eggs). At 25°C, fecundity on a diet of cumbungi pollen or thrips larvae (first-instar Frankliniella schutzei Trybom) was high, averaging 3.71 and 3.33 eggs per day, respectively, over a 3-day period. The sex ratio was approximately 1.5 females to 1 male. Consumption rate of thrips was also high, with an average of approximately seven first-instar or two second-instar F. schultzei larvae eaten per day. The species was also observed to feed on broad mite, Polyphagotarsonemus latus (Banks), and tomato russet mite, Aculops lycopersici (Massee). No diapause was observed under conditions of 25°C 8 h light and 10°C 16 h dark. Eggs were sensitive to low humidity, with 50% failing to hatch below 71.1% relative humidity. This species is of interest as a candidate biological control agent for thrips, broad mite and tomato russet mite in protected crops.     

Spatial-typological organization of the soil Gamasina mite (Acari,Mesostigmata) community of Northeastern Altai. Communication II

The second communication continues the analysis of altitudinal changes and the spatial-typological structure of the Gamasina mite community of the Northeastern Altai based on the data of August 2006 and 2007.     

Javanese species of the mite genus Macrocheles (Arachnida: Acari: Gamasina: Macrochelidae)

Twelve mite species of the genus Macrocheles (Acari: Macrochelidae) were collected from the body surface of dung beetles in Java, Indonesia. Of these, three species, i.e., Macrocheles jabarensis, M. jonggolensis, and M. sukabumiensis, were described as new to science. Female of M. dispar was redescribed. Two species, i.e., M. baliensis and M. sukaramiensis, were recorded from Java for the first time. The occurrence of five species previously recorded from Java, i.e., M. hallidayi, M. kraepelini, M. limue, M. oigru, and M. merdarius, were reconfirmed. Taxonomic status of M. sp. aff. glaber was not settled in the present study, because we could not obtain the male and immatures which are indispensable for exact identification. In total 15 species of the genus Macrocheles, including 3 species already recorded but not collected in this research (M. crispa, M. krantzi, and M. subbadius), are known from Java up to date.     

Spatial-typological organization of the soil Gamasina mite (Acari,Mesostigmata) community of the Northeastern Altai. Communication I

The results of this work are presented in two communications. In this first communication, altitudinal changes and the spatial-typological structure of the Mesostigmata mite community in the Northeastern Altai are studied on the basis of the results of investigations carried out in June 2006 and 2007.