Tetranychus Urticae Research Articles

The impact of conspecific presence on diet-induced developmental responses in a predatory mite

Diet and social experience during development can have profound influences on the fitness of individuals and subsequently affect population dynamics. Understanding the factors driving population size is fundamental to ecological studies and pest management. In this study, we investigated the interplay between diet-induced plasticity, cannibalism, social interactions, and life history traits in Phytoseiulus persimilis Athias-Henriot, a natural predator of the two-spotted spider mite, Tetranychus urticae Koch. This research explored how varying prey densities and the presence of a non-feeding conspecific during P. persimilis’ immature development impacts survival, cannibalism, prey consumption, developmental time, and size at maturity. Results show that survival rates are influenced by prey availability, with an increase in cannibalism observed under low prey density conditions. The presence of non-feeding conspecifics had a significant impact on P. persimilis, leading to increased prey consumption, accelerated immature development, and reduced size at maturity. These findings provide insights into the complex dynamics of predator-prey interactions and offer valuable implications for pest management strategies involving P. persimilis. The influence of diet and social interaction on additional life history traits, such as lifespan and fecundity, should be examined in future studies.

Contrasting roles of cytochrome P450s in amitraz and chlorfenapyr resistance in the crop pest Tetranychus urticae

The molecular mechanisms of amitraz and chlorfenapyr resistance remain only poorly understood for major agricultural pests and vectors of human diseases. This study focusses on a multi-resistant field strain of the crop pest Tetranychus urticae, which could be readily selected in the laboratory to high levels of amitraz and chlorfenapyr resistance. Toxicity experiments using tralopyril, the active toxophore of chlorfenapyr, suggested decreased activation as a likely mechanism underlying resistance. Starting from the same parental strain, transcriptome profiling revealed that a cluster of detoxifying genes was upregulated after amitraz selection, but unexpectedly downregulated after chlorfenapyr selection. Further functional validation associated the upregulation of CYP392A16 with amitraz metabolism and the downregulation of CYP392D8 with reduced activation of chlorfenapyr to tralopyril. Genetic mapping (QTL analysis by BSA) was conducted in an attempt to unravel the genetic mechanisms of expression variation and resistance. This revealed that chlorfenapyr resistance was associated with a single QTL, while 3 QTLs were uncovered for amitraz resistance. Together with the observed contrasting gene expression patterns, we argue that transcriptional regulators most likely underly the distinct expression profiles associated with resistance, but these await further functional validation.

The effect of spermine on Tetranychus urticae-Cucumis sativus interaction

BackgroundTwo spotted spider mite, Tetranychus urticae (Acari: Tetranychidae) is one of the most important plant pests in the world. Due to increased resistance of mites to acaricides, it is necessary to use other methods such as inducing resistance in plants by natural compounds for pests' management. Polyamins such as spermine are effective in increasing plant resistance to biotic and abiotic stressors. In this research, the effect of spermine treatments in cucumber plants on life table parameters of T. urticae was investigated. Also, top-down effect of spermine and T. urticae on cucumber biochemical parameters was measured. In the experiments, 1, 2 and 3 mM spermine concentrations were used.ResultsAmongst the spermine treatments, those mites that fed on cucumbers which received 1 mM spermine showed the shortest protonymphal period and higher ovipositon period, fecundity, gross and net reproductive rates and life expectancy compare to control. Treatment with 2 mM spermine lead to the longest teleochrysalis period and shortest range of age-stage-specific fecundity period. In addition, 2 mM spermine lowered intrinsic and finite rate of population increase in T. urticae. The longest larval period of T. urticae was observed in 3 mM spermine. Feeding of T. urticae from cucumber plants increased hydrogen peroxide (H2O2), malondialdehyde (MDA) content, electrolyte leakage (EL) level and ascorbate peroxidase (APX) activity but inhibited catalase (CAT) activity in this plant. Infested cucumber plants treated with 2 mM spermine showed lower H2O2 and MDA content and highest activity of APX and CAT on day 1 and 3 compare to the others. The 3 mM spermine increased H2O2 content in infested plants during the whole experiment as well as non-infested plants in day 5 and 9 only. This treatment induced the highest MDA content and lowest catalase activity on day1, 3 and 5 of experiment in infested plants.ConclusionThis study showed that 2 mM spermine was the only effective concentration that reduce cucumber sensitivity to T. urticae. The trend of changes in biochemical parameters, especially H2O2, in 3 mM spermine was abnormal, and this concentration could be considered toxic.

Mite biodiversity on vegetables in plastic-houses and the efficacy of an essential oil mixture on Tetranychus urticae and Phytoseiulus persimilis

ABSTRACTWe surveyed the mite fauna on three vegetable crops (cucumber, eggplant, and pepper) in plastic-houses throughout the autumn of 2020 by taking weekly leaf samples. These samples revealed several plant-feeding and predatory mites belonging to 13 species in ten genera and five families, as well as some insect pests. Tetranychus urticae Koch (Tetranychidae) was a significant pest in all three crops and Integrated Pest Management (IPM) control was used for its control. A bioassay was performed to evaluate the effect of a mixture of essential oils (clove, lavender, eucalyptus, and sweet orange) on T. urticae and its associated predator, Phytoseiulus persimilis Athias-Henriot (Phytoseiidae). The lethal concentration of this essential oil mixture determined by laboratory bioassay, was used on eggplant and cucumber crops in plastic-houses. The active ingredients of the tested oil mixture were determined using GC-MS analysis of the mixed essential oil. The total constituents of the mixed essential oil were identified as 43 compounds, primarily d-limonene, but also monoterpenes, sesquiterpens, diterpens, sestetraterpens, triterpens, and tetraterpens.

Increasing resistance of Tetranychus urticae to common acaricides in China and risk assessment to spiromesifen

The two-spotted spider mite (Tetranychus urticae Koch) is a widespread, destructive, polyphagous agricultural and horticultural pest. Chemical acaricides are vital for controlling T. urticae, but the mite has developed high resistance to a variety of acaricides in many countries. This study quantifies the resistance to seven acaricides of five field populations of T. urticae collected from roses and vegetables in China and assesses the risk of resistance developing to spiromesifen, which is currently being evaluated for commercialization in this region. Most T. urticae field populations exhibited high resistance to abamectin (154- to 477-fold), etoxazole (158–527), bifenazate (137–239), spirodiclofen (126–263), cyenopyrafen (119–503), and cyflumetofen (140–1360). Notably, all populations had also already developed high resistance to spiromesifen (170–1540). Significant positive correlations were detected between resistance to most of these acaricides, except for spiromesifen. A susceptible population of T. urticae was propagated for 18 generations in the presence of spiromesifen to determine the risk of resistance developing. There was a 9.6-fold increase in resistance. The resistance realized heritability (h2) was 0.1101. Given this degree of heritability and assuming 90% of T. urticae are killed in each generation, a 100-fold increase in resistance to spiromesifen would be expected after only 14 generations. Recent increases in resistance, particularly to cyenopyrafen and cyflumetofen, are also demonstrated. This study illustrates the extent and ongoing development of resistance to acaricides in an economically important pest and demonstrates the importance of evaluating resistance to products that have not yet entered a specific market. Continuous monitoring is necessary to shape resistance management strategies and appropriate choices of acaricide.

Role of phytochemicals and secondary metabolites from Mentha spicata in acetylcholine esterase inhibition for effective pest control of Tetranychus urticae Koch

ABSTRACTThe two-spotted spider mite (Tetranychus urticae Koch) poses a significant threat to global food production. However, the environmental risks associated with synthetic pesticides have necessitated the exploration of eco-friendly alternatives. Plant-based biopesticides utilizing secondary metabolites have emerged as promising strategies for pest management. This study aimed to extract and characterize Mentha spicata L. through biochemical analyses, GC-MS, and LC-QTOF-MS. The extract’s acaricidal, oviposition deterrence, and repellent properties were evaluated against Tetranychus urticae, revealing a pronounced time- and concentration-dependent effect over 96 hours, with an LC50 of 3 µg/mL. Furthermore, the impact of the extract on plant growth was assessed using tomato plants, demonstrating an enhancement in growth rate based on photosynthesis, weight, and oxidative stress markers analyses. Polyphenolics and terpenoids in M. spicata were identified as contributors to its biological activities, including antioxidant and free-radical scavenging properties. Molecular docking experiments targeting acetylcholine esterase (AChE) were conducted on the identified phytocompounds, indicating a high affinity for δ-3-Carene and Isoferuloyl C1 glucuronide. The pesticidal effects of these compounds were attributed to their competitive and synergistic inhibition of AChE. These findings highlight the potential of plant extracts, specifically M. spicata, as effective biopesticides in future pest control strategies. The utilization of secondary metabolites from plant sources offers a sustainable and environmentally friendly approach to combatting T. urticae infestations.

A new spider mite elicitor triggers plant defence and promotes resistance to herbivores.

Herbivore-associated elicitors (HAEs) are active molecules produced by herbivorous insects. Recognition of HAEs by plants induces defence that resist herbivore attacks. We previously demonstrated that the tomato red spider mite Tetranychus evansi triggered defence in Nicotiana benthamiana. However, our knowledge of HAEs from T. evansi remains limited. Here, we characterize a novel HAE, Te16, from T. evansi and dissect its function in mite-plant interactions. We investigate the effects of Te16 on spider mites and plants by heterologous expression, virus-induced gene silencing assay, and RNA interference. Te16 induces cell death, reactive oxygen species (ROS) accumulation, callose deposition, and jasmonate (JA)-related responses in N. benthamiana leaves. Te16-mediated cell death requires a calcium signalling pathway, cytoplasmic localization, the plant co-receptor BAK1, and the signalling components SGT1 and HSP90. The active region of Te16-induced cell death is located at amino acids 114-293. Moreover, silencing Te16 gene in T. evansi reduces spider mite survival and hatchability, but expressing Te16 in N. benthamiana leaves enhances plant resistance to herbivores. Finally, Te16 gene is specific to Tetranychidae species and is highly conserved in activating plant immunity. Our findings reveal a novel salivary protein produced by spider mites that elicits plant defence and resistance to insects, providing valuable clues for pest management.

Residual Pattern of Chlorantraniliprole, Thiamethoxam, Flubendiamide and Deltamethrin in Tomato Fruit and Soil.

Tomato, Lycopersicon esculentum L. is grown widely as an important day-to-day demand vegetable. The crop is attacked by various polyphagous insect pests like tomato fruit borer, stink bug, cabbage looper, flea beetle, aphids, whitefly, two-spotted spider mite, etc., and oligophagous insects like leaf-miner, five-spotted hawkmoth, etc. To combat the damage and yield loss, various chemical insecticides were sprayed on tomatoes under field conditions. The residual pattern of insecticides like chlorantraniliprole, thiamethoxam, flubendiamide, and deltamethrin residues was studied following applications of chlorantraniliprole 18.5% SC (Coragen) @ 30g a.i./ha, thiamethoxam 25% WG (Actara) @ 50g a.i./ha, flubendiamide 39.35M/M SC (Fame) @ 48g a.i./ha and deltamethrin 2.8% EC (Decis 100) @ 12.5g a.i./ha using Reverse Phase High-Performance Liquid Chromatography (RP-HPLC). Fruit samples were collected at 0 (1h after application), 1, 2, 3, 5, 7 days and at harvest time. All the residues of insecticides such as chlorantraniliprole (0.09mg kg- 1), thiamethoxam (0.03mg kg- 1), flubendiamide (0.02mg kg- 1), and deltamethrin (0.01mg kg- 1) were persisted up to 5th day. There were no residues found at harvest time. The residues of chlorantraniliprole and deltamethrin persisted up to 3rd day of spraying whereas the residues of flubendiamide and thiamethoxam were not detected on the same day in the soil.

The effects of water‐stress, temperature, and plant traits on the outbreak potential of a specialist and generalist spider mite species (Acari: Tetranychidae)

AbstractThe host‐generalist two‐spotted spider mite [Tetranychus urticae (Acari: Tetranychidae); TSM] and host‐specialist Banks grass mite [Oligonychus pratensis (Acari: Tetranychidae); BGM] are common pests of corn (Zea mays L.) in the arid western United States. Climate warming and decreased precipitation may promote conditions favoured by these spider mites. However, rapid evolution of spider mite resistance to commercially available acaricides is driving the need for alternative solutions for managing outbreaks. Planting of drought‐tolerant corn hybrids has been proposed to be a dual‐purpose strategy for mitigating water deficits for irrigation and reducing leaf conditions favourable for BGM outbreaks. However, understanding of the mechanisms responsible for reducing the BGM in the field is lacking and determining whether outbreaks of the TSM can also be averted using drought‐tolerant corn is a pressing concern. We conducted a 2‐year field study testing a drought‐tolerant corn hybrid and an analogous drought‐susceptible hybrid under water‐stress, with artificially infested spider mite populations. Drought‐tolerant corn had larger stem diameter, more massive cobs, and greater leaf water mass compared to the drought‐susceptible corn under water stress. We also found that the BGM populations were reduced on drought‐tolerant plants under water‐stress, as expected, but we found an opposite trend in the TSM. Lastly, water‐stressed leaves were warmer, transpired less, and had higher carbon concentration, which contributed to larger investment in eggs and growth in the BGM. We anticipate that further evaluation of irrigation and crop drought‐tolerance in management of agriculture systems for multiple pest species will be increasingly impactful in arid regions.

A link between energy metabolism and plant host adaptation states in the two-spotted spider mite, Tetranychus urticae (Koch)

Energy metabolism is a highly conserved process that balances generation of cellular energy and maintenance of redox homeostasis. It consists of five interconnected pathways: glycolysis, tricarboxylic acid cycle, pentose phosphate, trans-sulfuration, and NAD+ biosynthesis pathways. Environmental stress rewires cellular energy metabolism. Type-2 diabetes is a well-studied energy metabolism rewiring state in human pancreatic β-cells where glucose metabolism is uncoupled from insulin secretion. The two-spotted spider mite, Tetranychus urticae (Koch), exhibits a remarkable ability to adapt to environmental stress. Upon transfer to unfavourable plant hosts, mites experience extreme xenobiotic stress that dramatically affects their survivorship and fecundity. However, within 25 generations, mites adapt to the xenobiotic stress and restore their fitness. Mites’ ability to withstand long-term xenobiotic stress raises a question of their energy metabolism states during host adaptation. Here, we compared the transcriptional responses of five energy metabolism pathways between host-adapted and non-adapted mites while using responses in human pancreatic islet donors to model these pathways under stress. We found that non-adapted mites and human pancreatic β-cells responded in a similar manner to host plant transfer and diabetogenic stress respectively, where redox homeostasis maintenance was favoured over energy generation. Remarkably, we found that upon host-adaptation, mite energy metabolic states were restored to normal. These findings suggest that genes involved in energy metabolism can serve as molecular markers for mite host-adaptation.

Effect of Different Host Plants on Life Type Characteristics of Three Spider Mite Pests (Acari: Prostigmata: Tetranychidae).

The present study evaluated the host plant effect on life type characteristics of three important spider mite pest species, Tetranychus urticae Koch, Eutetranychus orientalis (Klein), and E. palmatus Attiah (Acari: Prostigmata: Tetranychidae), based on both field and laboratory observations. The polyphagous species, T. urticae with complicated web (CW-u) life type, occupying unstable habitats, showed variations in the sites for quiescence (SQ), sites for oviposition (SO), sites for defecation (SD), and webbing density (WD) on different annual/perennial host plants. The SQ, SO, and SD of T. urticae were observed either on the leaf, web threads, or trichomes. Tetranychus urticae constructed the lowest WD on tomato plants and the highest WD on maize/mulberry plants. Two spider mite species of the genus Eutetranychus Banks, the polyphagous E. orientalis and the oligophagous E. palmatus, inhabit stable host plants, depicted in the little web (LW-j) life types with persistency in all characteristics on different plants. It is concluded that polyphagous spider mites have restricted their life types, showing their high adaptability to utilize the resources of different host plants for survival with slight variation in some important life type characteristics.

A high epicuticular wax strawberry mutant reveals enhanced resistance to Tetranychus urticae Koch and Botrytis cinerea

Cuticular wax is crucial for plant defense against biotic and abiotic stresses, but its relationship with resistance in strawberries is not well understood. A stable genetic mutant (MT) of ‘Benihoppe’ strawberries with a glossier leaf surface and stronger resistance was identified during cultivation. In this study, we analyzed the anatomical and physiological traits of leaves from ‘Benihoppe’ and its mutant and compared their cuticular wax properties. We also analyzed the differentially expressed genes involved in leaf cuticular wax accumulation and investigated their characteristics against Tetranychus urticae Koch and Botrytis cinerea. Comparisons between morphological and physiological features revealed that the mutant had smaller, darker leaves with a thicker upper epidermis and palisade tissue. GC-MS analysis showed that the total cuticular wax content of the MT leaf (1147.84 μg/dm2) had 1.74 times more total wax content than that of ‘Benihoppe’ (660.66 μg/dm2). The main components of cuticular wax in the MT leaf were primary alcohols (C18, C20, C22, C24, C25 and C26), alkanes (C20 and C31) and fatty acids (C26), whose content increased by 138.37%, 53.69% and 86.80%, respectively, compared with that of ‘Benihoppe’. Based on the comparative transcriptome data, we identified FaKAS2, FaFATA2, FaLACS1, FaKCS12/19, FaPAS2, FaECR, FaCER1 and FAR3/5 as potential key genes involved in wax synthesis of strawberries. Furthermore, MT leaves exhibited lower susceptibility to Tetranychus urticae Koch and its cuticular wax extraction inhibited the growth of Botrytis cinerea more effectively. Therefore, the increase of total cuticular wax and the content of major wax components in MT may be the main contributor to the enhanced resistance. These results not only deepen our understanding of the cuticular wax regulation but also provide potential gene resources for developing more resistant strawberry varieties.

Rhizospheric Bacillus spp. Exhibit Miticidal Efficacy against Oligonychus coffeae (Acari: Tetranychidae) of Tea.

Oligonychus coffeae (Acari: Tetranychidae), popularly known as red spider mite (RSM) is one of the major pests of commercial tea (Camellia sinensis (L.) O. Kuntze) plantation world over. Many attempts have been made in the past to control this devastating pest using a variety of microbial bioagents, however, area-wise field success is very limited. We carried out an in vitro study to explore the potential of rhizospheric Bacillus spp. (B. amyloliquefaciens BAC1, B. subtilis LB22, and B. velezensis AB22) against O. coffeae through adulticidal and ovicidal activity. The 100% adult and egg mortality was observed with bacterial suspension (1 × 109 CFU/mL) by B. velezensis AB22, showing the lowest LC50 values for both adults and eggs of O. coffeae, i.e., 0.28 × 105 and 0.29 × 105, respectively. The study also throws some insights into the underlying mechanism through electron microscopy study and identification of some putative pesticidal metabolites from all the species. The three Bacillus species were observed to have four commonly secreted putative bioactive secondary metabolites, brevianamide A, heptadecanoic acid, thiolutin, and versimide responsible for their bio-efficacy against O. coffeae. The outcome of our study provides a strong possibility of introducing Bacillus spp. as a biological miticide and developing synthetic metabolites mimicking the mechanistic pathway involved in microbial bioefficacy.

Structural and functional studies reveal the molecular basis of substrate promiscuity of a glycosyltransferase originating from a major agricultural pest

The two-spotted spider mite, Tetranychus urticae, is a major cosmopolitan pest that feeds on more than 1,100 plant species. Its genome contains an unprecedentedly large number of genes involved in detoxifying and transporting xenobiotics, including 80 genes that code for uridine diphosphate (UDP) glycosyltransferases (UGTs). These enzymes were acquired via horizontal gene transfer (HGT) from bacteria after loss in the Chelicerata lineage. UGTs are well-known for their role in phase II metabolism, however, their contribution to host adaptation and acaricide resistance in arthropods, such as T. urticae, is not yet resolved. TuUGT202A2 (Tetur22g00270) has been linked to the ability of this pest to adapt to tomato plants. Moreover, it was shown that this enzyme can glycosylate a wide range of flavonoids. To understand this relationship at the molecular level, structural, functional, and computational studies were performed. Structural studies provided specific snapshots of the enzyme in different catalytically relevant stages. The crystal structure of TuUGT202A2 in complex with UDP-glucose was obtained and site directed-mutagenesis paired with molecular dynamic simulations revealed a novel lid-like mechanism involved in the binding of the activated sugar donor. Two additional TuUGT202A2 crystal complexes, UDP-(S)-naringenin and UDP-naringin, demonstrated that this enzyme has a highly plastic and open-ended acceptor binding site. Overall, this work reveals the molecular basis of substrate promiscuity of TuUGT202A2 and provides novel insights into the structural mechanism of UGTs catalysis.

Enhancing the Biological Control of Mite Species Infesting Olive Trees through Application of Predatory Mite Agistemus exsertus Gonzalez (Acari: Stigmaeidae) and Eco-Friendly Natural Compounds.

Olive (Olea europaea L.) is a subtropical tree cultivated in arid, dry and temperate regions. Olive orchards in Al-Jouf of Saudi Arabia are the largest worldwide and currently face harmful pest infestation. The present study aimed at evaluating the efficiency of the predatory mite Agistemus exsertus Gonzalez (Acari: Stigmaeidae) and the exogenously applied melatonin (MT), glycine betaine (GB) and 5-aminolevulinic acid (ALA) as eco-friendly approaches for enhancing the biological control of four mite species (Tegolophus hassani, Oxycenus niloticus, Aceria olivi and Tetranychus urticae) infesting olive trees in Al-Jouf under laboratory and field conditions. Field experiment was conducted on 6-year-old Manzanillo olive trees grown in a private orchard farm in Al-Jouf during two seasons, 2020 and 2021. Results revealed that A. exsertus developed successfully from egg to adult. The females of T. hassani, O. niloticus, A. olivi, and T. urticae required 7.36, 8.89, 9.98 and 8.38 days, respectively, to develop from egg to adult at 28°C and 65 ± 5% relative humidity. O. niloticus was the most preferred prey of A. exsertus. The net reproductive rate (R0 ) was 42.1, 38.7, 34.6 and 36.8 females/female/generation, the intrinsic rate of increase (rm ) was 0.27, 0.26, 0.23 and 0.20 females/female/day, and the mean generation time (T) was 16.2, 17.1, 18.6 and 17.2 days when a predator consumed T. hassani, O. niloticus, A. olivi and T. urticae, respectively. The adult female consumed daily about 114 O. niloticus, 105 A. olivi, 95 T. hassani and 15.2 T. urticae individuals, respectively. A. exsertus proved to be an effective biocontrol agent against mites infesting olive trees. In addition, the exogenous application of 1 mM MT, 15 mM GB and 25 mg/L ALA, alone or in combination, caused significant mortality for the four mites. Application of these natural compounds, alone or in combination, also significantly enhanced the growth, relative water content, relative chlorophyll, content of flavonoid and nutrients, antioxidant enzymes activities, stress-related genes expression and fruit yield and quality of the infested olive trees compared to non-treated infested trees. This study is the first that demonstrates the efficiency of these eco-friendly approaches for controlling mites infesting olive trees, and could be used as a replacement for the harmful chemical acaricides.

Lethal and sublethal effects of carlina oxide on Tetranychus urticae (Acari: Tetranychidae) and Neoseiulus californicus (Acari: Phytoseiidae).

Tetranychus urticae Koch, is a polyphagous and damaging pest, presenting several resistant populations worldwide. Among new and more environmentally friendly control tools, botanical pesticides represent a valuable alternative to synthetic ones within integrated pest management strategies. Accordingly, we investigated the lethal and sublethal effects of carlina oxide isolated from Carlina acaulis (Asteraceae) roots on T. urticae and its natural enemy, the predatory mite, Neoseiulus californicus (McGregor). Carlina oxide (98.7% pure compound) was used for acaricidal tests on eggs, nymphs, and adult females of T. urticae (concentrations of 312.5, 625, 1250, 2500 and 5000 μL L-1 ), and eggs and females of N. californicus (1250 and 5000 μL L-1 on eggs and females, respectively). Behavioral two-choice tests were also conducted on phytoseiid females. Carlina oxide toxicity was higher on T. urticae females than nymphs (median lethal dose 1145 and 1825 μL L-1 , respectively), whereas egg mortality and mean hatching time were significantly affected by all tested concentrations. A decreasing daily oviposition rate for T. urticae was recorded with concentrations ranging from 625 to 5000 μL L-1 , whereas negative effects on the population growth rate were recorded only with the three higher concentrations (1250, 2500 and 5000 μL L-1 ). No toxic effect on N. californicus females was found, but a strong repellent activity lasting for 48 h from application was recorded. Carlina oxide reduced longevity and fecundity of T. urticae adults, but not of N. californicus. This selective property allows us to propose it as a novel active ingredient of ecofriendly acaricides for T. urticae management. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Parental exposure to heat waves improves offspring reproductive investment in Tetranychus urticae (Acari: Tetranychidae), but not in its predator, Phytoseiulus persimilis (Acari: Phytoseiidae).

The more frequent and intense occurrence of heat waves is a challenge for arthropods because their unpredictable incidence requires fast adaptations by the exposed individuals. Phenotypic plasticity within and across generations might be a solution to cope with the detrimental effects of heat waves, especially for fast-developing, small arthropods with limited dispersal abilities. Therefore, we studied whether severe heat may affect the reproduction of a pest species, the spider mite Tetranychus urticae, and its counterpart, the predatory mite Phytoseiulus persimilis. Single offspring females with different parental thermal origins (reared under mild or extreme heat waves) of both species were exposed to mild or extreme heat waves on bean leaves over 10 days, and the oviposition, egg sizes, survival, and escape behavior of the females were evaluated daily. The total losses of predators mainly via escapers were very high compared to prey, which makes a separation between selective and plastic effects on shifted reproductive traits impossible. Predator females laid smaller eggs, while their consumption and oviposition rates were unaffected during extreme heat waves. In comparison, larger prey females fed more and produced more, but smaller, eggs due to within- and trans-generational effects. These advantages for the prey in comparison to its predator when exposed to extreme heat waves during the reproductive phase support the trophic sensitivity hypothesis: higher trophic levels (i.e., the predator) are more sensitive to thermal stress than lower trophic levels (i.e., the prey). Furthermore, the species-specific responses may reflect their lifestyles. The proactive and mobile predator should be selected for behavioral thermoregulation under heat waves via spatiotemporal avoidance of heat-exposed locations rather than relying on physiological adaptations in contrast to the more sessile prey. Whether these findings also influence predator-prey interactions and their population dynamics under heat waves remains an open question.

Biodiversity of spider mites of Ankara, with a checklist of the Tetranychinae and first report of Schizotetranychus ibericus Reck for Turkey (Acari: Prostigmata)

The samples were collected at weekly intervals between April and October from 2011 to 2014 on rosaceous plants and Quercus trees in Ankara, Turkey. Twelve spider mite species (Acari: Tetranychidae), Amphitetranychus viennensis (Zacher), Schizotetranychus ibericus Reck, Tetranychus urticae Koch, T. turkestani (Ugarov & Nikolskii), Eoteteranychus populi (Koch), E. pruni (Oudemans), E. coryli Reck, E. tiliarium (Hermann) Panonychus ulmi (Koch) (Tetranychinae), Bryobia rubrioculus (Scheuten), B. praetiosa Koch and B. sp. (Bryobiinae) were identified in Ankara. Schizotetranychus ibericus Reck, 1947 is a new record for Turkey. Tetranychus urticae and A. viennensis occurred in all the sampling localities, while S. ibericus was collected only on a Quercus sp. (Fagaceae). Tetranychus urticae Koch (Tetranychidae) was the most abundant and common species while some other species were represented by only two specimens such as Eotetranychus populi and E. tiliarum (Hermann). Apple harbored the highest number of spider mite species (9) while Prunus mahaleb and Quercus had only 2 and 1 species, respectively. The preferred hosts plants were Malus domestica (1007), Prunus domestica (749) and Prunus avium (479), while Prunus armeniaca (164), Prunus mahaleb (66) and Quercus sp. (17) were less preferred hosts. Collection data and geographical distribution of these species are provided. The checklist of the previous identified Tetranychinae species of Turkey is provided.

Bird-of-paradise, thorn apple and maize pollens are promising alternative diets for the long-term rearing of predatory mite Amblyseius swirskii (Acari: Phytoseiidae)

Pollen grains can provide important nutrients for reproduction of different predators such as phytoseiid mites. Since mass rearing of phytoseiid predatory mites may be facilitated by feeding on alternative diets, the current study evaluated the utility of plant pollen as diet for mass rearing of the predatory mite Amblyseius swirskii Athias-Henriot, which is a commercially available biocontrol agent of phytophagous mites and insects. Demographic parameters of A. swirskii fed on pollens of bird-of-paradise (Caesalpinia gilliesii), thorn apple (Datura stramonium), and maize (Zea mays) were determined over 10 continuous generations. In addition, the pollens of common hibiscus (Hibiscus syriacus), and velvetleaf (Abutilon theophrasti) were assessed, but the predatory mite was unable to reach adulthood when fed on these pollens, and most of them died in nymphal stages. This study also evaluated the preying ability of A. swirskii on the natural prey Tetranychus urticae Koch before and after 10 generations. All experiments were conducted in the laboratory under controlled conditions of 25±1°C, 60±5% RH, and a photoperiod of 16:8 (L: D) h. According to the life table parameters, the pollen grains of bird-of-paradise, followed by maize and thorn apple, were shown to be promising diets for the long-term rearing of A. swirskii. Furthermore, the study found that A. swirskii reared on bird-of-paradise pollen had a high predation capability, with a mean of 677 prey per generation after 10 generations. Overall, it is concluded that while bird-of-paradise pollen was the most suitable alternative diet for the predatory mite, both maize and thorn apple pollen grains were also found to be promising diets for A. swirskii. These diets can be used for mass rearing of this predatory mite.

Effect of temperature on the life history and development of Typhlodromus athiasae Porath and Swirski (Acari: Phytoseiidae) as a predator of Tetranychus urticae Koch (Acari: Tetranychidae)

The present study determined the effects of different temperatures on the life history parameters and development of Typhlodromus athiasae Porath and Swirski (Acari: Phytoseiidae) for the first time. The study was conducted at 20, 25 and 30°C and the predators fed on Tetranychus urticae Koch (Acari: Tetranychidae) under laboratory conditions. Our results show that temperature significantly affected pre-adult and adult durations of T. athiasae. The adult longevity was calculated as 47.90, 22.88, 19.50 days for females, 26.11, 19.90, 20.46 days for males at 20, 25 and 30°C, respectively. The adult females of T. athiasae laid 15.80 (eggs/female), 17.20 (eggs/female) and 12.38 (eggs/female) eggs at the respective temperatures tested. The highest net reproductive rate (R0= 8.90 offspring/individual) determined at 25°C but no significant difference was found among the other temperatures. The highest intrinsic rate of increase (r= 0.12 day-1) was observed at 25°C and 30°C. Although the highest finite rate of increase (λ= 1.13 day-1) was determined at 25°C, no significant difference was observed between this temperature and 30°C. Also, the shortest mean generation time (T=14.97 day) was obtained at 30°C whereas the longest mean generation time (T=28.39 day) was observed at 20°C. Our results revealed that 25°C was more suitable for mass production even if the female and male of T. athiasae survived and reproduced at all temperatures. Consequently, our present results and the data to be obtained in greenhouse and field conditions will reveal the potential of T. athiasae as a biological control agent of T. urticae.