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The heavy metal, cadmium (Cd) is an increasingly serious issue in agricultural ecosystems, mediating bottom-up effects on plants, herbivores and natural enemies. We measured how Cd modifies interactions between tomato Solanum lycopersicum, western flower thrips Frankliniella occidentalis, and the predatory bug Orius sauteri by examining Cd effects on the growth of tomato, the fitness of western flower thrips, and the survival and behavior of predators. The photosynthetic parameters of Pn (net photosynthetic rate), Gs (stomatal conductance), Ci (intercellular CO 2 concentration), and Tr (transpiration rate) of tomato plants significantly decreased with the increase of Cd concentration. The total survival number of western flower thrips fed on tomato plants treated with different concentrations of Cd was significantly lower than that of the control, and sex ratios (female/male) gradually increased with the increase of Cd concentration. The numbers of thrips predated by O. sauteri on tomato plants treated with high concentrations of Cd (2.0 or 4.0 mg/L) were significantly reduced by the second day. Cadmium was accumulated and bioconcentrated in the roots, stems, leaves of tomato plants, and transferred to F. occidentalis, and O. sauteri. Cadmium translocated in significant quantities from roots to the stems and leaves of tomato plants, and from the tomato leaf to F. occidentalis. However, there was minimal (non-significant) transfer of Cd from F. occidentalis to O. sauteri. The presence of Cd significantly reduced the growth of tomato plants, the fitness of F. occidentalis, and the predation efficiency of O. sauteri. Collectively, Cd can mediate bottom-up effects on tomato, thrip, and predatory bug along food chain, potentially interrupting pest biological control in tomato in heavy metal-contaminated ecosystems., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Thrips, Frankliniella intonsa, is a highly polyphagous pest with a worldwide distribution. F. intonsa-infested sunflower seeds show marked visual damage. The study findings revealed that significantly more F. intonsa infested confection sunflower compared to oilseed sunflower, via olfactometer bioassay studies, we found that compared with the flower and pollen of oilseed sunflowers, those of confection sunflowers attract F. intonsa. Considering this discrepancy in the preference of F. intonsa on oilseed and confection sunflowers, the volatiles of the flower and pollens of two sunflowers were analysed by gas chromatography-mass spectroscopy. The behavioural responses of F. intonsa were assessed for these compounds using Y-tube bioassays. Geranyl bromide, a unique volatile component of oilseed sunflowers, induced an assertive approach-avoidance behaviour in F. intonsa, whereas the unique component ethyl isovalerate in confection sunflowers attracted F. intonsa. F. intonsa adults demonstrated significant attraction to the blends of confection sunflowers. Furthermore, field verification revealed that intercropping confection and oilseed sunflowers could effectively control F. intonsa. The study provided insights into the chemical cues used by F. intonsa in locating hosts. Therefore, oilseed sunflowers can be used as repellent plants to prevent F. intonsa invasion., (© 2024 John Wiley & Sons Ltd.)

Western flower thrips, Frankliniella occidentalis , is a serious worldwide pest of agriculture and horticulture, and its contact pheromone is 7-methyltricosane. Two enantiomers of 7-methyltricosane were synthesized for the first time. The centra of our strategy were chiral auxiliaries to introduce stereocenter, and Wittig coupling to connect two blocks. The overall yields of our synthesis were 29-30% with seven steps. The electroantennogram (EAG) and the contact behavioral responses revealed that ( R )-, ( S )- and racemic 7-methyltricosane were separately bioactive, and the racemate was the most bioactive in the male arrestant activity and the female EAG test. This result provides valuable insights, showing that the racemate could be used for the support of the control of western flower thrips, which could be more easily prepared relative to more expensive enantiopure pheromone.

Many arthropods carry maternally inherited endosymbionts that cause cytoplasmic incompatibility (CI), manifested as embryonic mortality in matings of infected males with uninfected females. Infected females, however, do not suffer this cost. Therefore, in populations with mixed endosymbiont infections, selection is expected to favour mechanisms that enable hosts to avoid or mitigate CI. This may include changes in mating behaviour, such as reduced female receptivity to mating and/or remating when approached by incompatible males. Here, we investigated mating behavioural traits in haplodiploid thrips naturally associated with two CI-inducing endosymbionts, Cardinium and Wolbachia . Compared with females with both endosymbionts, those with only Cardinium showed reduced receptivity to males carrying both. However, surprisingly, females without endosymbionts were not less receptive to incompatible males. Furthermore, in contrast to females without endosymbionts, females with Cardinium were far less likely to remate with incompatible than compatible males irrespective of the compatibility type of the first mating. Our results suggest that endosymbiont-specific sexual selection processes occur, whereby females carrying only Cardinium recognize Wolbachia in coinfected males to avoid CI. This may hinder a CI-driven Wolbachia spread. Endosymbiont-mediated mating behaviours may be crucial for the dynamics of CI-inducing endosymbionts and their application in pest management strategies.

Although plants harbor a huge phytochemical diversity, only a fraction of plant metabolites is functionally characterized. In this work, we aimed to identify the genetic basis of metabolite functions during harsh environmental conditions in Arabidopsis thaliana. With machine learning algorithms we predicted stress-specific metabolomes for 23 (a)biotic stress phenotypes of 300 natural Arabidopsis accessions. The prediction models identified several aliphatic glucosinolates (GLSs) and their breakdown products to be implicated in responses to heat stress in siliques and herbivory by Western flower thrips, Frankliniella occidentalis. Bivariate GWA mapping of the metabolome predictions and their respective (a)biotic stress phenotype revealed genetic associations with MAM, AOP, and GS-OH, all three involved in aliphatic GSL biosynthesis. We, therefore, investigated thrips herbivory on AOP, MAM, and GS-OH loss-of-function and/or overexpression lines. Arabidopsis accessions with a combination of MAM2 and AOP3, leading to 3-hydroxypropyl dominance, suffered less from thrips feeding damage. The requirement of MAM2 for this effect could, however, not be confirmed with an introgression line of ecotypes Cvi and Ler, most likely due to other, unknown susceptibility factors in the Ler background. However, AOP2 and GS-OH, adding alkenyl or hydroxy-butenyl groups, respectively, did not have major effects on thrips feeding. Overall, this study illustrates the complex implications of aliphatic GSL diversity in plant responses to heat stress and a cell-content-feeding herbivore., (© 2024 The Author(s). The Plant Journal published by Society for Experimental Biology and John Wiley & Sons Ltd.)

The juvenile hormone binding protein (JHBP) and takeout (TO) genes, mediated by the juvenile hormone (JH), play a crucial role in regulating the reproductive physiology of insects. Our previous study revealed that spinosad-resistant Frankliniella occidentalis (NIL-R) exhibited reduced fecundity and significant changes in JHBP/TO family gene expression. We hypothesized that these genes were involved in regulating the fitness costs associated with resistance. In this study, 45 JHBP/TO genes were identified in F. occidentalis, among which FoTO2 and FoTO10 were duplicates. Additionally, eight genes exhibited significant down-regulation in the NIL-R population. Two genes (FoTO6 and FoTO24) that exhibited the most significant differential expression between the spinosad-susceptible (Ivf03) and NIL-R populations were selected to investigate their roles in resistance fitness using RNA interference (RNAi). Following interference with FoTO6, FoTO24, and their combination, the expression levels of vitellogenin (Vg) were downregulated by 3%-30%, 13%-28%, and 14%-32% from the 2nd day to the 5th day, respectively; Krüppel-homolog 1 (Kr-h1) expression was down-regulated by 3%-65%, 11%-34%, and 11%-39% from the 2nd day to the 5th day, respectively; ovariole length was shortened by approximately 18%, 21%, and 24%, respectively; and the average number of eggs decreased from 407 to 260, 148, and 106, respectively. Additionally, a JH supplementation experiment on the NIL-R population revealed that the expression levels of both FoTO6, FoTO24, Vg and Kr-h1 were significantly upregulated compared with those observed in the Ivf03 population, resulting in increased fecundity. These results suggest that FoTO6 and FoTO24 are involved in JH-mediated regulation of the reproductive fitness cost of resistance to spinosad. Further, FoTO6 and FoTO24 can be considered potential target genes for applying RNAi technology in the scientific management of F. occidentalis., Competing Interests: Declaration of competing interest The authors have declared that no competing interest exists., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Thrips [Megalurothrips usitatus (Bagnall)] (Thysanoptera: Thripidae) is a pest that poses a serious challenge to global crop production and food supply, especially to the cowpea industry. Nano-delivery systems have broad application prospects in the prevention and control of pests in agriculture. Herein, three types of amino acid (AA) modified polysuccinimide nano-delivery carriers (PSI-GABA, PSI-ASP and PSI-GLU) were constructed with a diameter of approximately 150 nm to load thiamethoxam (THX), which enhanced THX effective distribution and use with cowpea plants. Significantly, the PSI-GLU nanocarrier effectively delivered THX to cowpea plant tissues following 6 h of soil application. Compared with commercial THX suspension (SC), the THX content in the leaves of cowpea plants was increased by 2.3 times. Confocal laser scanning microscopy revealed that the FITC-labeled PSI-GLU nanocarrier reached the leaves through the vascular system after being absorbed by the roots of cowpea plants. The PSI-GLU nanocarrier decreased the LC 50 of THX from 11.45 to 7.79 mg/L and significantly enhanced the insecticidal effect. The PSI-GLU nanocarrier also improved the safety of THX to worker bees at 48 h, and moreover showed a growth-promoting effect on cowpea seedlings. These results demonstrated that the PSI-GLU nano-delivery carrier has promising uses on improving the effective utilization of THX for the sustainable control of thrips and reducing the risk to non-target pollutions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The two-spotted spider mite (TSSM), Tetranychus urticae Koch, and the Western flower thrips (WFT), Frankliniella occidentalis (Pergande), are pests commonly found in strawberry crops and pose significant challenges to production. However, the specific dynamics of their interactions with both healthy and infested plants remain poorly understood. In this study, we aimed to investigate the attraction of TSSM and WFT to volatile compounds emitted by healthy plants versus those of plants damaged by either or both species. Plant choice bioassays were conducted under varying conditions, including both healthy and those previously damaged by both TSSM and WFT. Additionally, behavioral tests were carried out using a Y-tube olfactometer, with extracts obtained via dynamic aeration from the plants in different states. The results revealed distinct preferences: TSSM exhibited a strong attraction to both healthy plants and those previously infested by their own specifics, whereas WFT showed a higher preference for healthy plants and those damaged by TSSM. Consistent behaviors were observed in the bioassays conducted with plant extracts. This research sheds light on the intricate interactions between strawberry plants and these pests and offers insights into the probable sequence of attack when both pests are present concurrently. The findings are valuable when implementing management strategies for these two pests in strawberry cultivation, considering the order in which they appear in the crop to help mitigate the damage caused by infestation in a more precise manner and order., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Piercing sucking pests attacking sweet pepper plants cause significant losses to its yield. Considering the undesirable effects of synthetic pesticides, field studies were conducted to evaluate the impact of new pesticides against piercing sucking insect pests of sweet pepper, as well as, their effects on some predators and pepper yield along two seasons of 2021-2022. The obtained results indicated that all tested pesticides effectively suppressed the sucking insect populations (aphids, white fly, thrips) 1,7,14 and 21 days after treatment along two sprays during two seasons. Imidacloprid proved to be the superior one over all other treatments where it recorded mean reduction% (98.91 and 97.27%) & (94.8 and 95.19%), (86.23 and 76.64%) & (80.92 and 88.55%) and (77.68 and 78.44%) & (90.70 and 68.57%) in white fly, aphids and thrips, respectively at 1st and 2nd sprays at 2021 and 2022 seasons, respectively. As for side effects of tested insecticides on natural enemies, Dimethoate induced the highest decrease (60.85 and 69.33%) & (54.02 and 63.41%), (65.52 and 64.74%) & (59.23 and 58.38%) and (64.24 and 59.48%) & (61.66 and 60.8%) on Chrysoperla carnea, Paederus alfierii and Coccinella spp at 1st and 2nd sprays at 2021 and 2022 seasons, respectively. On contrary, Spintoram induced the lowest effects on Chrysoperla carnea, Paederus alfierii and Coccinella spp, recording decrease percent (25.41 and 19.84%) & (15.02 and 12.50%), (11.94 and 11.24%) (16.99 and 18.02%) and (18.73 and15.07%) & (18.35 and18.38%) at1st and 2nd sprays at 2021 and 2022 seasons, respectively. With respect to the effect of tested insecticides on pepper yield, all tested insecticides increased the yield of green pepper fruits compared with control. Imidacloprid achieved the highest fruit yields along two seasons 6.43 and 6.52 (ton / fed.4200 m2) with increase percent 34.53 and 36.04% in yield over control at 2021 and 2022 seasons, respectively.

Megalurothrips usitatus (Bagnall) (Thysanoptera: Thripidae) and Frankliniella intonsa (Trybom) (Thysanoptera: Thripidae) have been detrimental to cowpea production in many countries. Laboratory experiments were conducted to determine the prey stage preference and functional response of 2 predatory mites species, Neoseiulus barkeri (Hughes) (Acari: Phytoseiidae), and Neoseiulus californicus (McGregor) (Acari: Phytoseiidae), towards 2 thrips species (TS), M. usitatus, and F. intonsa, at varying densities and life stages on cowpea. Results shown that Neoseiulus species had a preference for different life stages of prey. Neoseiulus barkeri consumed more M. usitatus nymphs, while N. californicus consumed more F. intonsa (second-instar nymphs). The functional response of the 2 Neoseiulus spp. to nymphs of 2 TS was Type II on cowpea. The higher attack rate coefficient (a') and shorter handling time (Th) values were found on N. barkeri against M. usitatus, and a similar trend was found for those in N. californicus against F. intonsa. Field-caged trials were conducted to evaluate the effectiveness of Neoseiulus spp. in controlling 2 TS. The results have shown that Neoseiulus spp. was effective in controlling the 2 TS, with varying control efficacies at high or low release rates. The study provided valuable information on using Neoseiulus spp. as biological control agents against M. usitatus and F. intonsa in cowpea crops., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Host plants can strongly influence the population performance of insects. Here, we investigated the development, survival, and oviposition of Scirtothrips dorsalis Hood on 6 host plants-Camellia sinensis ( L.) Kuntze (Ericales: Theaceae), Rosa chinensis Jacq. (Rosales: Rosaceae), Capsicum annuum L. (Solanales: Solanaceae), Eustoma grandiflorum (Hook.) G.Don (Gentianales: Gentianaceae), Glycine max (L.) Merr. (Fabales: Fabaceae), and Cucumis sativus L. (Cucurbitales: Cucurbitaceae), and constructed life tables for S. dorsalis on each plant. Significant differences in S. dorsalis development on the host species were observed. The mean developmental period from egg to adult was 11.45 ± 0.12 days, 11.24 ± 0.13 days, 12.08 ± 0.15 days, 12.28 ± 0.12 days, 12.67 ± 0.10 days, and 13.03 ± 0.11 days on C. sinensis, R. chinensis, C. annuum, E. grandiflorum, G. max, and C. sativus, respectively. Significant differences in survival of S. dorsalis were observed, namely, C. sinensis ≈ R. chinensis > E. grandiflorum ≈ C. annuum > G. max > C. sativus. The highest and lowest fecundities of S. dorsalis were recorded on R. chinensis (60.44 ± 1.53) and C. sativus (28.64 ± 1.02), respectively. Both of the net reproductive rate (R0) and intrinsic rate of increase (rm) of S. dorsalis were the highest on R. chinensis, with the values of 27.63 ± 0.58 and 0.142 ± 0.002, respectively; while the lowest on C. sativus, with the values of 8.81 ± 0.12 and 0.092 ± 0.003, respectively. Thus, R. chinensis was found to be the most suitable host, but C. sativus was the least suitable, for population development of S. dorsalis. Our results provide important information for the key control of S. dorsalis among different host plants., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Megalurothrips usitatus Bagnall, an important pest of bean plants, is primarily managed with synthetic insecticides. M. usitatus has developed considerable resistance to various insecticides in multiple cowpea-growing areas in Hainan Province, China, posing challenges to its control in the field. Light control technology is a potentially effective physical control method for M. usitatus. The vision of thrips is highly sensitive to UV light, whereas other biological characteristics remain unknown. Therefore, this study evaluated the effects of ultraviolet light on the biological characteristics of M. usitatus. Results showed that the egg, larval, and pupal stages of M. usitatus were significantly shortened, and the emergence rate (79.59%) and adult survival rate (77.95%) were reduced under a devoid of UV light environment (UV-), compared with the full-spectrum light (control treatment group, CK) (p < 0.05). However, the single spawning quantity and total amount of spawning were significantly higher, and the sex ratio (57%) was the highest under UV- (p < 0.05). Single UV light (UV+) only affected the pupation rate. Also, the antioxidant enzymes, polyphenol oxidase, superoxide dismutase (SOD), and peroxidase activities were significantly and negatively correlated with the progression of generations under UV-, whereas catalase and SOD activities were significantly and positively correlated with the progression of generations under UV+. The UV- light conditions significantly interfered with the behavior selection of M. usitatus. The results of this study showed that the adaptability of M. usitatus populations would be greatly reduced in the absence of ultraviolet light, providing a theoretical basis for the control of M. usitatus populations., (© 2024 Wiley Periodicals LLC.)

Frankliniella occidentalis (Pergande) is a typical omnivorous insect that feeds on host plants, pollens and mite eggs, and poses a threat to crops worldwide. The insulin signalling pathway (ISP) is a typical nutrient-sensitive pathway that participates in the regulation of various functions in insects. Serine/threonine kinases (AKTs) and phosphoinositide-dependent kinases (PDKs) are key components of the ISP. In this study, the FoAKT and FoPDK genes in F. occidentalis were cloned, and the effects of three foods on their expression were determined. The expression of FoAKT and FoPDK in the thrips fed on kidney bean leaves supplemented with pine pollen or mite eggs was higher than in those primarily fed on leaves alone. Meanwhile, the fecundity of thrips fed on leaves supplemented with pine pollen was highest. In addition, RNA interference-mediated knockdown of FoAKT and FoPDK decreased vitellogenin (Vg) content and Vg expression in females, shortened ovariole length, delayed egg development and reduced fecundity and offspring hatching rates. Furthermore, the synthesis of juvenile hormone (JH) was reduced, and the contents of glucose, trehalose, glycogen and trehalase were affected. These results suggest that FoAKT and FoPDK regulate the reproduction of F. occidentalis by regulating Vg and JH production as well as carbohydrate metabolism., (© 2024 Royal Entomological Society.)

Although food is produced in aquaponics systems worldwide, no information is available on the occurrence of insect pests and natural enemies in aquaponic lettuce, Lactuca sativa L. In this study, a survey was carried out in an aquaponic system combining lettuce with lambari, Astyanax altiparanae (Garutti & Briski), aiming to determine the insect pests and natural enemies associated with this system. We also determined the predominant insect species and the effect of meteorological factors on their populations. Insect abundance was estimated by visual sampling during 13 cultivation cycles, totaling 27 sampling dates. The meteorological factors considered were air temperature and relative humidity, and their effects were determined using the Pearson correlation. The thrips Frankliniella schultzei (Trybom) and Caliothrips phaseoli (Hood) and the aphid Aphis spiraecola (Patch) predominated. Ambient temperature and relative humidity were essential factors affecting C. phaseoli and F. schultzei. The natural enemies found on the lettuce plants were the thrips Franklinothrips vespiformis (Crawford) and Stomatothrips angustipennis (Hood) and the ladybugs Cycloneda sanguinea L., Eriopis connexa (Germar), and Hippodamia convergens (Guérin-Méneville). These results constitute the first step for a lettuce-integrated pest-management program in aquaponics systems., (© 2024. The Author(s).)

It is essential to correctly identify and keep track of the abundance of thrips species on infested host crops to understand their population dynamics and implement control measures promptly. The current study was conducted to evaluate the performance of sticky traps in monitoring thrips species in exporters' eggplant and chili farms and to assess the impact of weather factors on thrips population dynamics. Thrips species were monitored using blue, yellow, and white sticky traps on chili and eggplant farms in Tuba, respectively, in 2020 and 2021. Each field was divided into 8 blocks, and in each replicate, all colors representing 3 treatments were randomly tied to stakes at the center of the respective crop. Data loggers were installed to record hourly weather variables. Three thrips species [Thrips parvispinus Karny (Thysanoptera: Thripidae), Franklinella schultzei Trybom (Thysanoptera: Thripidae), and Thrips tabaci Lindeman (Thysanoptera: Thripidae)] were identified from both farms and the different species showed varied attractiveness to trap color for both seasons, with white proving more attractive to T. parvispinus. The population dynamics of the species varied significantly with the season and weather but not with the crop. Optimum temperatures (28-31 °C) and relative humidity (60%-78%) showed a positive linear relationship between the trapped insects with temperature and RH, while extreme temperatures (35 °C) negatively affected their abundance. All sticky trap colors attracted several nontarget organisms; however, yellow colors had higher populations, including the predator, Orius insidiosus. White sticky traps are recommended for inclusion in the country-wide monitoring for thrips, especially T. parvispinus., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: Biological control with predatory mites is applied against pests in greenhouse crops. Chemical control with the use of selective, reduced-risk pesticides, is an important component of Integrated Pest Management (IPM) programs, that often needs to be combined with biological control. Here, we evaluated the effect of plant pollen when used as supplementary food on the survival, reproduction and predation of the predatory mite Amblydromalus limonicus (Acari: Phytoseiidae) after exposing young larvae and adults to flonicamid, an insecticide of moderate toxicity to phytoseiids. Pollen is an important alternative food for generalist phytoseiids ensuring survival and supporting populations build-up during periods of prey scarcity. Two regimes of cattail (Typha angustifolia L.) pollen differing in application frequency were used. In the first, the total amount of pollen was supplied once, within 30 min after insecticide application, whereas in the second regime, the same amount of pollen was supplied gradually, i.e., every 48 h., Results: Regardless of the frequency of application, pollen provisioning results in a reduction in prey (thrips) consumption relative to the control (no pollen provisioning). Nevertheless, when adult mites were directly exposed to flonicamid residues, pollen provisioning attenuated the reduction in prey consumption as compared to the control. In addition, the gradual (every 48 h) provisioning of pollen to adult predators exposed to flonicamid residues impacted positively the intrinsic rate of population increase (r m ) of A. limonicus as compared to when feeding on prey., Conclusion: Our results reveal an unexpected role of pollen provisioning in alleviating pesticides side-effects on phytoseiids. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry., (© 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.)

The immature development and reproduction of the predatory mites Amblyseius largoensis (Muma), Proprioseiopsis lenis (Corpuz and Rimando), and Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) were investigated using both thrips eggs and first instars of the western flower thrips, Frankliniella occidentalis Pergande, as prey in a controlled laboratory environment at 25 °C and 60% relative humidity. When provided with thrips eggs as food, A. largoensis exhibited a notably shorter immature development period for both males (7.05 days) and females (6.51 days) as compared with A. swirskii (8.05 and 7.19 days, respectively) and P. lenis (8.10 days and 7.05 days, respectively). Amblyseius largoensis also displayed a higher oviposition rate (2.19 eggs/female/day) than A. swirskii and P. lenis (1.79 and 1.78 eggs/female/day, respectively). Moreover, it exhibited the highest fecundity (25.34 eggs/female), followed by P. lenis (24.23 eggs/female) and A. swirskii (22.86 eggs/female). These variations led to A. largoensis having the highest intrinsic rate of increase (r m ) at 0.209, followed by A. swirskii at 0.188, and P. lenis at 0.165. However, when the predatory mites were provided with first instars of F. occidentalis, A. swirskii demonstrated a faster immature development period for both males (7.67 days) and females (7.59 days) as compared with P. lenis (9.00 days and 7.86 days, respectively) and A. largoensis (8.47 days and 8.61 days, respectively). While the oviposition rates of P. lenis (1.92 eggs/female/day) and A. swirskii (1.90 eggs/female/day) were similar when feeding on this prey, A. largoensis produced fewer eggs (1.83 eggs/female/day). Further, A. swirskii exhibited the highest fecundity (31.93 eggs/female), followed by A. largoensis (25.71 eggs/female) and P. lenis (23 eggs/female). Consequently, the intrinsic rate of increase (r m ) on thrips first instars was highest in A. swirskii (0.190), followed by A. largoensis (0.186), and P. lenis (0.176). In summary, our findings indicate that in terms of life history parameters A. largoensis performs optimally when feeding on thrips eggs, whereas A. swirskii performs best when preying on the mobile first instars of the thrips. These insights into the dietary preferences and reproductive capabilities of the studied predatory mite species have important implications for their potential use as biological control agents against F. occidentalis in agricultural settings., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Iris yellow spot virus (IYSV) poses a significant threat to dry bulb onion, Allium cepa L., production and can lead to substantial yield reductions. IYSV is transmitted by onion thrips, Thrips tabaci (Lindeman), but not via seed. Transplanted onion fields have been major early season sources of IYSV epidemics. As onion thrips tend to disperse short distances, seeded onion fields bordering transplanted onion fields may be at greater risk of IYSV infection than seeded fields isolated from transplanted ones. Additionally, seeded onion fields planted early may be at greater risk of IYSV infection than those seeded later. In a 2-year study in New York, we compared IYSV incidence and onion thrips populations in seeded onion fields relative to their proximity to transplanted onion fields. In a second study, we compared IYSV incidence in onion fields with either small or large plants during midseason. Results showed similar IYSV incidence and onion thrips populations in seeded onion fields regardless of their proximity to transplanted onion fields, while IYSV incidence was over four times greater in large onion plants than in small ones during midseason. These findings suggest a greater risk of onion thrips-mediated IYSV infection in onion fields with large plants compared with small ones during midseason and that proximity of seeded fields to transplanted ones is a poor indicator of IYSV risk. Our findings on IYSV spread dynamics provided valuable insights for developing integrated pest and disease management strategies for New York onion growers., Competing Interests: The author(s) declare no conflict of interest.

Background: The stick tea thrips, Dendrothrips minowai Priesner, is one of the most important sucking pests that seriously infest tea plants (Camellia sinensis) in China. Given that D. minowai exhibit aggregation behaviors in tea plantations, this study evaluated the potential of aggregation pheromones for their control., Results: H-tube olfactometer assays showed that D. minowai larvae, adult females and adult males were significantly attracted to larvae rather than adult females and males under laboratory conditions. Subsequent gas chromatography-mass spectrometry analysis of volatiles from larvae, identified two larva-specific components: dodecyl acetate and tetradecyl acetate. Electrophysiological and behavioral experiments confirmed the positive response of females and males to dodecyl acetate, tetradecyl acetate, and their blend (1:1.5). Deployment of these aggregation pheromones on sticky traps resulted in a 1.2- to 3.0-fold increase in the capture of D. minowai adults compared with control traps. In addition, deployment of sticky traps baited with these aggregation pheromones within tea plantations resulted in a noteworthy reduction in the population of adult thrips per 100 leaves, 10 days following trap deployment. The reduction ranged from 29% to 59%, in comparison with the control., Conclusion: D. minowai larvae produce aggregation pheromones, dodecyl acetate and tetradecyl acetate, that can be useful for controlling tea thrips. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

With a continuous increase in world population and food production, chemical pesticide use is growing accordingly, yet unsustainably. As chemical pesticides are harmful to the environment and developmental resistance in pests is increasing, a sustainable and effective pesticide alternative is needed. Inspired by nature, we mimic one defense strategy of plants, glandular trichomes, to shift away from using chemical pesticides by moving toward a physical immobilization strategy via adhesive particles. Through controlled oxidation of a biobased starting material, triglyceride oils, an adhesive material is created while monitoring the reactive intermediates. After being milled into particles, nanoindentation shows these particles to be adhesive even at low contact forces. A suspension of particles is then sprayed and found to be effective at immobilizing a target pest, thrips, Frankliniella occidentalis . Small arthropod pests, like thrips, can cause crop damage through virus transfer, which is prevented by their immobilization. We show that through a scalable fabrication process, biosourced materials can be used to create an effective, sustainable physical pesticide., Competing Interests: Competing interests statement:A patent pertaining to this research has been filed with the European Patent Office Application No. EP22202752.

Past research has characterized the induction of plant defenses in response to chewing insect damage. However, little is known about plant responses to piercing-sucking insects that feed on plant cell-contents like thrips (Caliothrips phaseoli). In this study, we used NMR spectroscopy to measure metabolite changes in response to six days of thrips damage from two field-grown soybean cultivars (cv.), known for their different susceptibility to Caliothrips phaseoli. We observed that thrips damage reduces sucrose concentration in both cultivars, while pinitol, the most abundant leaf soluble carbohydrate, is induced in cv. Charata but not in cv. Williams. Thrips did not show preference for leaves where sucrose or pinitol were externally added, at tested concentration. In addition, we also noted that cv. Charata was less naturally colonized and contained higher levels of trigonelline, tyrosine as well as several compounds that we have not yet identified. We have established that preference-feeding clues are not dependent on the plants major soluble carbohydrates but may depend on other types of compounds or leaf physical characteristics., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Zavala reports financial support was provided by University of Buenos Aires. Zavala Jorge reports financial support was provided by Fund for Scientific and Technological Research. Zavala reports a relationship with University of Buenos Aires that includes: employment., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Development of advanced pest control methods that do not rely on insecticides is an important issue for sustainable agriculture. Particularly with regards to micro pests that are not only highly resistant to various insecticides but also because we are running out of options for which insecticide to use against them, resulting in enormous economic damage worldwide. Here we report that the effectiveness of the conventional insect net can be greatly advanced by changing their color to red that helps significantly reduce pesticide use. We demonstrate the red effect using Onion thrips, Thrips tabaci a main vector of Iris Yellow Spot Virus (IYSV) and Tomato Spotted Wilt Virus (TSWV) that cause serious damage to various vegetables. New red nets succeeded in suppressing the invasion rates and damages (white spots on the leaves) in a Welsh onion greenhouse with minimum use of pesticides. We discuss how red nets are compatible with labor-saving, sustainable agriculture and the future potential of "optical pest control" based on insect color vision and its behavioral response., (© 2024. The Author(s).)

Frankliniella occidentalis Pergande (Thysanoptera: Thripidae) is an agricultural pest threatening various horticultural crops worldwide. Inducing plant resistance is an ecologically beneficial and potentially effective method for controlling F. occidentalis. As an essential nutrient element, exogenous calcium enhances plant-induced resistance. This study investigated the effects of CaCl2 on the secondary metabolites of kidney bean plants and detoxifying and digestive enzymes in F. occidentalis. We found that treatment of plants and treatment time and also the interactions of the 2 factors significantly affected secondary metabolites contents (tannin, flavonoids, total phenol, alkaloid, and lignin) of kidney bean leaves, which indicated that that the effect of treatment of plants on secondary metabolites varied with treatment time. Moreover, when thrips fed on CaCl2-treated plants, the activities of detoxifying enzymes, enzymes glutathione S-transferase and cytochrome P450 substantially increased compared to those in which thrips fed on control plants. However, the activity of carboxylesterase significantly decreased. The detoxifying enzyme genes CL992.contig6, CYP4PN1, and CYP4PJ2 were significantly upregulated at 24 and 48 h. The activities of digestive enzymes (α-amylase, chymotrypsin, and lipase) increased substantially in F. occidentalis. The digestive enzyme gene, FoAMY-1, was significantly upregulated at 24 and 48 h after treatment. The pupation rate and pupal weight of F. occidentalis were significantly reduced. The results indicated that exogenous CaCl2-induced metabolic changes in kidney bean plants and altered the enzymatic activity and development of F. occidentalis that fed upon them., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The transmission of insect-borne viruses involves sophisticated interactions between viruses, host plants, and vectors. Chemical compounds play an important role in these interactions. Several studies reported that the plant virus tomato spotted wilt orthotospovirus (TSWV) increases host plant quality for its vector and benefits the vector thrips Frankliniella occidentalis . However, few studies have investigated the chemical ecology of thrips vectors, TSWV, and host plants. Here, we demonstrated that in TSWV-infected host plant Datura stramonium , (1) F. occidentalis were more attracted to feeding on TSWV-infected D. stramonium ; (2) atropine and scopolamine, the main tropane alkaloids in D. stramonium , which are toxic to animals, were down-regulated by TSWV infection of the plant; and (3) F. occidentalis had better biological performance (prolonged adult longevity and increased fecundity, resulting in accelerated population growth) on TSWV-infected D. stramonium than on TSWV non-infected plants. These findings provide in-depth information about the physiological mechanisms responsible for the virus's benefits to its vector by virus infection of plant regulating alkaloid accumulation in the plant.

Background: Different thrips species can co-occur on the same flowers with different dominance degrees. To accurately evaluate the population performance on different thrips species on Magnolia grandiflora flowers, we investigated the diversity of thrips species and their population dynamics both in the field and laboratory. In addition, the activities of detoxifying and protective enzymes in thrips were also measured., Results: Field investigations revealed that four thrips species (Thrips hawaiiensis, Thrips flavidulus, Frankliniella occidentalis, and Thrips coloratus) coexisted on M. grandiflora flowers. They were ranked, from highest population density to lowest, as follows: T. hawaiiensis > T. flavidulus > F. occidentalis > T. coloratus. In laboratory investigations, the species were ranked, from fastest developmental rates to slowest, as follows: F. occidentalis > T. hawaiiensis > T. flavidulus > T. coloratus; and from largest population size to smallest, as follows: T. hawaiiensis > F. occidentalis > T. flavidulus > T. coloratus. Biochemistry assays showed that the four species differed in their activities of detoxifying enzymes (carboxylesterase, glutathione-S-transferase, and cytochrome P450) and protective enzymes (superoxide dismutase, peroxidase) in both laboratory and field strains., Conclusion: Differences in population performance among these four thrips on M. grandiflora may be related to their activity levels of physiological enzymes. The variations in thrips population performance between the field and the laboratory could be due to differences in environmental conditions. T. hawaiiensis showed a strong host preference for M. grandiflora, and thus it has the potential to be a dangerous pest in horticultural plants. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

Background: The tobacco thrips (Frankliniella fusca Hinds; family Thripidae; order Thysanoptera) is an important pest that can transmit viruses such as the tomato spotted wilt orthotospovirus to numerous economically important agricultural row crops and vegetables. The structural and functional genomics within the order Thysanoptera has only begun to be explored. Within the > 7000 known thysanopteran species, the melon thrips (Thrips palmi Karny) and the western flower thrips (Frankliniella occidentalis Pergrande) are the only two thysanopteran species with assembled genomes., Results: A genome of F. fusca was assembled by long-read sequencing of DNA from an inbred line. The final assembly size was 370 Mb with a single copy ortholog completeness of ~ 99% with respect to Insecta. The annotated genome of F. fusca was compared with the genome of its congener, F. occidentalis. Results revealed many instances of lineage-specific differences in gene content. Analyses of sequence divergence between the two Frankliniella species' genomes revealed substitution patterns consistent with positive selection in ~ 5% of the protein-coding genes with 1:1 orthologs. Further, gene content related to its pest status, such as xenobiotic detoxification and response to an ambisense-tripartite RNA virus (orthotospovirus) infection was compared with F. occidentalis. Several F. fusca genes related to virus infection possessed signatures of positive selection. Estimation of CpG depletion, a mutational consequence of DNA methylation, revealed that F. fusca genes that were downregulated and alternatively spliced in response to virus infection were preferentially targeted by DNA methylation. As in many other insects, DNA methylation was enriched in exons in Frankliniella, but gene copies with homology to DNA methyltransferase 3 were numerous and fragmented. This phenomenon seems to be relatively unique to thrips among other insect groups., Conclusions: The F. fusca genome assembly provides an important resource for comparative genomic analyses of thysanopterans. This genomic foundation allows for insights into molecular evolution, gene regulation, and loci important to agricultural pest status., (© 2023. The Author(s).)

Many herbivorous insects rely on plant volatiles to locate their host plants. Vector-borne viral infections induce changes in plant volatiles, which render infected plants more attractive to insect vectors. However, the detailed mechanisms underlying the olfactory responses of insect vectors induced by the volatiles produced by virus-infected plants are poorly understood. Here, we show that volatiles emitted by pepper (Capsicum annuum) plants infected with tomato zonate spot virus (TZSV), particularly the volatile cis-3-hexenal, which is recognized by chemosensory protein 1 of the thrips Frankliniella intonsa (FintCSP1), are more attractive to F. intonsa than the volatiles emitted by non-infected pepper plants. FintCSP1 is highly abundant in the antenna of F. intonsa. Silencing of FintCSP1 significantly decreased electroantennogram responses of F. intonsa antennae to cis-3-hexenal and impaired thrips' responses to TZSV-infected pepper plants and cis-3-hexenal, as assessed using a Y-tube olfactometer. Three-dimensional model predictions indicated that FintCSP1 consists of seven α-helixes and two disulfide bridges. Molecular docking analysis suggested that cis-3-hexenal is positioned deep inside the binding pocket of FintCSP1 and binds to residues of the protein. We combined site-directed mutagenesis and fluorescence binding assays and identified three hydrophilic residues, Lys26, Thr28, and Glu67, of FintCSP1 as being critical for cis-3-hexenal binding. Furthermore, CSP of F. occidentalis (FoccCSP) is also a key olfactory protein involved in modulating the behaviour of F. occidentalis to TZSV-infected pepper. This study revealed the specific binding characteristics of CSPs to cis-3-hexenal and confirmed the general hypothesis that virus infections induce changes in host volatiles, which can be recognized by the olfactory proteins of the insect vector to enhance vector attraction and this may facilitate viral spread and transmission., Competing Interests: The authors declare that they have no conflict of interests., (Copyright: © 2023 Li et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Plant viruses can facilitate their transmission by modulating the sex ratios of their insect vectors. Previously, we found that exposure to tomato spotted wilt orthotospovirus (TSWV) in the western flower thrips, Frankliniella occidentalis, led to a male-biased sex ratio in the offspring. TSWV, a generalist pathogen with a broad host range, is transmitted primarily by F. occidentalis in a circulative-propagative manner. Here, we integrated proteomic tools with RNAi to comprehensively investigate the genetic basis underlying the shift in vector sex ratio induced by the virus., Results: Proteomic analysis exhibited 104 differentially expressed proteins between F. occidentalis adult males with and without TSWV. The expression of the fiber sheath CABYR-binding-like (FSCB) protein, namely FoFSCB-like, a sperm-specific protein associated with sperm capacitation and motility, was decreased by 46%. The predicted FoFSCB-like protein includes 10 classic Pro-X-X-Pro motifs and 42 phosphorylation sites, which are key features for sperm capacitation. FoFSCB-like expression was gradually increased during the development and peaked at the pupal stage. After exposure to TSWV, FoFSCB-like expression was substantially down-regulated. Nanoparticle-mediated RNAi substantially suppressed FoFSCB-like expression and led to a significant male bias in the offspring., Conclusion: These combined results suggest that down-regulation of FoFSCB-like in virus-exposed thrips leads to a male-biased sex ratio in the offspring. This study not only advances our understanding of virus-vector interactions, but also identifies a potential target for the genetic management of F. occidentalis, the primary vector of TSWV, by manipulating male fertility. © 2022 Society of Chemical Industry., (© 2022 Society of Chemical Industry.)

Insects are an astonishingly successful and diverse group, occupying the gamut of habitats and lifestyle niches. They represent the vast majority of described species and total terrestrial animal biomass on the planet. Their success is in part owed to their sophisticated visual systems, including colour vision, which drive a variety of complex behaviours. However, the majority of research on insect vision has focused on only a few model organisms including flies, honeybees and butterflies. Especially understudied are phytophagous insects, such as diminutive thrips (Thysanoptera), in spite of their damage to agriculture. Thrips display robust yet variable colour-specific responses despite their miniaturized eyes, but little is known about the physiological and ecological basis of their visual systems. Here, we review the known visual behavioural information about thrips and the few physiological studies regarding their eyes. Eye structure, spectral sensitivity, opsin genes and the presence of putative colour filters in certain ommatidia strongly imply dynamic visual capabilities. Finally, we discuss the major gaps in knowledge that remain for a better understanding of the visual system of thrips and why bridging these gaps is important for expanding new possibilities for applied pest management strategies for these tiny insects. This article is part of the theme issue 'Understanding colour vision: molecular, physiological, neuronal and behavioural studies in arthropods'.

Host plant species will influence the population and physiological performance of insects. Frankliniella occidentalis is a well-known invasive pest commonly found on flowering plants. Herein, the population development of F. occidentalis was investigated on the flowers of different Rosa chinensis cultivars (Ruby, Love, Parade, Pink Peace, and Mohana), and the digestive enzyme activities in thrips were measured after feeding on these flowers. The developmental times of F. occidentalis from egg to adult were 10.07, 10.37, 11.64, 10.66, and 10.90 d on Ruby, Love, Parade, Pink Peace, and Mohana, respectively. Significant differences in fecundity were also observed, with the greatest fecundity levels of F. occidentalis on Ruby (82.96) and the lowest on Mohana (63.40). F. occidentalis showed the greatest R0 on Ruby (43.57), followed by Love (36.46), Parade (33.00), Pink Peace (27.97), and Mohana (23.21). The rm showed a similar trend, with values of 0.156, 0.145, 0.141, 0.134, and 0.130, respectively. There were significant differences in digestive enzyme activities in F. occidentalis on different flowers, and different digestive enzymes showed different performance among these plants. The highest amylase and lipase activities in F. occidentalis were on Ruby, on which F. occidentalis had the fastest development rate and the highest R0, whereas the highest trypsin activity was on Pink Peace. All three digestive enzymes in thrips showed the lowest activities on Mohana. The varied population development of F. occidentalis associated with R. chinensis cultivars may be related to their digestive enzyme performance, which plays important roles in nutrient metabolism and insect growth., (© The Author(s) 2022. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The western flower thrips, Frankliniella occidentalis, is one of the most devastating insect pests with explosive reproductive potential. However, its reproductive physiological processes are not well understood. This study reports the ovarian development and associated transcriptomes of F. occidentalis. Each ovary consisted of four ovarioles, each of which contained a maximum of nine follicles in the vitellarium. The germarium consisted of several dividing cells forming a germ cell cluster, presumably consisting of oocytes and nurse cells. The nurse cells were restricted to the germarium while the subsequent follicles did not possess nurse cells or a nutritive cord, supporting the neo-panoistic ovariole usually found in thysanopteran insects. Oocyte development was completed 72 h after adult emergence (AAE). Transcriptome analysis was performed at mid (36 h AAE) and late (60 h AAE) ovarian developmental stages using RNA sequencing (RNASeq) technology. More than 120 million reads per replication were matched to ≈ 15,000 F. occidentalis genes. Almost 500 genes were differentially expressed at each of the mid and late ovarian developmental stages. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that these differentially expressed genes (DEGs) were associated with metabolic pathways along with protein and nucleic acid biosynthesis. In both ovarian developmental stages, vitellogenin, mucin, and chorion genes were highly (> 8-fold) expressed. Endocrine signals associated with ovarian development were further investigated from the DEGs. Insulin and juvenile hormone signals were upregulated only at 36 h AAE, whereas the ecdysteroid signal was highly maintained at 60 h AAE. This study reports the transcriptome associated with the ovarian development of F. occidentalis, which possesses a neo-panoistic ovariole., Competing Interests: The authors have declared that no competing interests exist.

Nazonothrips toshifumii gen. et sp. n. is described from unidentified fungus in Taiwan. This fungus-feeding species probably belongs to the tribe Plectrothripini of the subfamily Phlaeothripinae. The males of the new species exhibit a strange allometric growth that appears to involve two patterns of variation, but it is not possible to be certain due to the small number of available specimens.

Background: Brood pollination mutualism is a special type of plant-pollinator interaction in which adult insects pollinate plants, and the plants provide breeding sites for the insects as a reward. To manifest such a mutualism between Stellera chamaejasme and flower thrips of Frankliniella intonsa, the study tested the mutualistic association of the thrips life cycle with the plant flowering phenology and determined the pollination effectiveness of adult thrips and their relative contribution to the host's fitness by experimental pollinator manipulation., Results: The adult thrips of F. intonsa, along with some long-tongue Lepidoptera, could serve as efficient pollinators of the host S. chamaejasme. The thrips preferentially foraged half-flowering inflorescences of the plants and oviposited in floral tubes. The floral longevity was 11.8 ± 0.55 (mean ± se) days, which might precisely accommodate the thrips life cycle from spawning to prepupation. The exclusion of adult thrips from foraging flowers led to a significant decrease in the fitness (i.e., seed set) of host plants, with a corresponding reduction in thrips fecundity (i.e., larva no.) in the flowers., Conclusions: The thrips of F. intonsa and the host S. chamaejasme mutualistically interact to contribute to each other's fitness such that the thrips pollinate host plants and, as a reward, the plants provide the insects with brooding sites and food, indicating the coevolution of the thrips life cycle and the reproductive traits (e.g., floral longevity and morphology) of S. chamaejasme., (© 2021. The Author(s).)

Many species of thrips (Thysanoptera) in the family Thripidae form mating aggregations, but the adaptive significance of these aggregations and the extent of male and female mate choice is poorly understood. We studied the mating behaviour of the bean flower thrips Megalurothrips sjostedti (Trybom) (Thysanoptera: Thripidae), which forms male aggregations and occurs across sub-Saharan Africa. We tested whether males choose mates by female age or mating status. No-choice mating bioassays with one male and one female were used to simulate the way males usually encounter only one female at a time in aggregations in the field. Virgin females violently resisted mating attempts by males, but we found no compelling evidence to establish whether this was indiscriminate or was screening suitable males. Younger males (1-2 days old) did not discriminate females by age (1-2 or 7-10 days old), but older males (7-10 days old) avoided mating with older females. Any male choice by female mating status (virgin or mated) was weak or absent. The mating behaviour of M. sjostedti shows broad similarities with that of other thrips species that form aggregations, but also shows some distinct and novel differences, which can help our understanding of the adaptive significance of aggregations., (© 2021. The Author(s).)

Background: Plant-produced specialised metabolites are a powerful part of a plant's first line of defence against herbivorous insects, bacteria and fungi. Wild ancestors of present-day cultivated tomato produce a plethora of acylsugars in their type-I/IV trichomes and volatiles in their type-VI trichomes that have a potential role in plant resistance against insects. However, metabolic profiles are often complex mixtures making identification of the functionally interesting metabolites challenging. Here, we aimed to identify specialised metabolites from a wide range of wild tomato genotypes that could explain resistance to vector insects whitefly (Bemisia tabaci) and Western flower thrips (Frankliniella occidentalis). We evaluated plant resistance, determined trichome density and obtained metabolite profiles of the glandular trichomes by LC-MS (acylsugars) and GC-MS (volatiles). Using a customised Random Forest learning algorithm, we determined the contribution of specific specialised metabolites to the resistance phenotypes observed., Results: The selected wild tomato accessions showed different levels of resistance to both whiteflies and thrips. Accessions resistant to one insect can be susceptible to another. Glandular trichome density is not necessarily a good predictor for plant resistance although the density of type-I/IV trichomes, related to the production of acylsugars, appears to correlate with whitefly resistance. For type VI-trichomes, however, it seems resistance is determined by the specific content of the glands. There is a strong qualitative and quantitative variation in the metabolite profiles between different accessions, even when they are from the same species. Out of 76 acylsugars found, the random forest algorithm linked two acylsugars (S3:15 and S3:21) to whitefly resistance, but none to thrips resistance. Out of 86 volatiles detected, the sesquiterpene α-humulene was linked to whitefly susceptible accessions instead. The algorithm did not link any specific metabolite to resistance against thrips, but monoterpenes α-phellandrene, α-terpinene and β-phellandrene/D-limonene were significantly associated with susceptible tomato accessions., Conclusions: Whiteflies and thrips are distinctly targeted by certain specialised metabolites found in wild tomatoes. The machine learning approach presented helped to identify features with efficacy toward the insect species studied. These acylsugar metabolites can be targets for breeding efforts towards the selection of insect-resistant cultivars.

In females of haplodiploid animals, female production requires fertilization, whereas male production does not. Therefore, haplodiploid species can display extraordinary sex ratios. Constrained sex allocation occurs when a female cannot produce daughters. This can be due to virginity but may also occur after mating due to insemination failure, selfish genetic elements or physiological constraints. Here, we investigated the mechanism underlying constrained sex allocation in Pezothrips kellyanus. In this species some mated females produce highly female-biased broods, yet, for unknown reasons, others produce extremely male-biased broods. Using crossing experiments controlled for maternally inherited endosymbionts we confirmed that constrained females were successfully inseminated. Furthermore, male-biased offspring production was not paternally inherited, ruling out paternal sex ratio elements previously identified as sex ratio distorters in some parasitoid wasps. Next, we excluded mating time and paternal fitness effects (male size) on sex allocation. However, we found that constrained sex allocation only occurred in small females producing smaller eggs than large females producing larger eggs and female-biased broods. Consequently, the bimodal sex allocation pattern correlates with maternal condition, and may have arisen (adaptively or non-adaptively) in association with an egg size-mediated fertilization mechanism recently detected in some haplodiploids, with egg size positively affecting fertilization success., (© 2021 The Authors. Evolution © 2021 The Society for the Study of Evolution.)

Integrated Pest Management (IPM) is endorsed as the future standard for crop protection worldwide. This holistic concept integrates preventative and curative measures amongst which host plant resistance (HPR) plays an essential role. Up to now HPR has been a somewhat under-utilized tool in pest management due to widespread use of pesticides and technological hindrance. Thrips are key pests in agriculture and horticulture worldwide. Here we provide an overview on the current status of research on constitutive and induced HPR including thrips-host relationships and thrips as virus vectors. We stress modulation of plant defense responses by abiotic and biotic elicitors to increase HPR and provide an outlook on the increasing potential of HPR inspired by the fast advancement of -omics techniques., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Key Message: A major thrips resistance QTL in Capsicum was fine-mapped to a region of 0.4 Mbp, and a multidisciplinary approach has been used to study putative underlying mechanisms. Resistance to thrips is an important trait for pepper growers. These insects can cause extensive damage to fruits, flowers and leaves on field and greenhouse grown plants worldwide. Two independent studies in Capsicum identified diterpene glycosides as metabolites that are correlated with thrips resistance. In this study, we fine-mapped a previously defined thrips resistance QTL on chromosome 6, to a region of 0.4 Mbp harbouring 15 genes. Two of these 15 candidate genes showed differences in gene expression upon thrips induction, when comparing plants carrying the resistance allele in homozygous state to plants with the susceptibility allele in homozygous state for the QTL region. Three genes, including the two genes that showed difference in gene expression, contained a SNP that was predicted to lead to changes in protein structure. Therefore, these three genes, i.e. an acid phosphatase 1 (APS1), an organic cation/carnitine transporter 7 (OCT7) and an uncharacterized locus LOC107874801, are the most likely candidates for playing a role in thrips resistance and are a first step in elucidating the genetic basis of thrips resistance in Capsicum. In addition, we show that the diterpene glycoside profiles did not differ between plants with the resistance and susceptibility allele for the chromosome 6 QTL, suggesting that these compounds do not play a role in the resistance conferred by the genes located in the major thrips resistance QTL studied.

Heliothrips (Parthenothrips) octarcticulatus was originally described by Schmutz (1913) from Sri Lanka. Subsequently, Hood (1954) described from Taiwan a new genus and species Copidothrips formosus, and then Stannard and Mitri (1962) described a further new genus and species, Mesostenothrips kraussi, from Kiribati and Gibert Islands. Bhatti (1967, 1990), recognized that only a single genus and species was involved amongst these names, established the resultant synonymies, and recorded the species octarcticulatus from various localities between the Seychelles and five different Pacific Island groups. It has also been recorded from Northern Australia, and Thailand (ThripsWiki 2021) as well as Christmas Island in the Indian Ocean (Mound 2019). Despite these records, there is little reliable information about host plants and biology apart from Piper myristicum on Pohnpei island (Micronesia), and also damage caused to the leaves of Aglaonema and Spathoglottis at Darwin in Australia (Mound Tree 2020). In this note, we add a further interesting host record and describe the previously unknown male as well as the larvae of this species.

The human enteric bacterial pathogen Salmonella enterica causes approximately 1.35 million cases of food borne illnesses annually in the United States. Of these salmonellosis cases, almost half are derived from the consumption of fresh, raw produce. Although epiphytic S. enterica populations naturally decline in the phyllosphere, a subset of phytophagous insects have recently been identified as biological multipliers, consequently facilitating the growth of bacterial populations. We investigated whether tomato leaves with macroscopic feeding damage, caused by infestation of adult Western flower thrips (Frankliniella occidentalis), support higher S. enterica populations. To explore this hypothesis, we assessed S. enterica populations in response to thrips feeding by varying insect density, plant age, and the gender of the insect. As a reference control, direct leaf damage analogous to thrips feeding was also evaluated using directed, hydraulic pressure. In a supplementary set series of experiments, groups of F. occidentalis infested tomato plants were later inoculated with S. enterica to determine how prior insect infestation might influence bacterial survival and persistence. Following an infestation period, leaves visibly damaged by adult F. occidentalis supported significantly higher S. enterica populations and resulted in greater amounts of electrolyte leakage (measured as electrical conductivity) than leaves lacking visible feeding damage. Plant age did not significantly influence S. enterica populations or estimates of electrolyte leakage, independent of initial infestation. Additionally, the gender of the insect did not uniquely influence S. enterica population dynamics. Finally, applications of aggressive water bombardment resulted in more electrolyte leakage than leaves damaged by F. occidentalis, yet supported comparable S. enterica populations. Together, this study indicates that F. occidentalis feeding is one of the many potential biological mechanisms creating a more habitable environment for S. enterica., Competing Interests: The authors have declared that no competing interests exist.

Background: The western flower thrips, Frankliniella occidentalis (Pergande), is a globally invasive pest and plant virus vector on a wide array of food, fiber, and ornamental crops. The underlying genetic mechanisms of the processes governing thrips pest and vector biology, feeding behaviors, ecology, and insecticide resistance are largely unknown. To address this gap, we present the F. occidentalis draft genome assembly and official gene set., Results: We report on the first genome sequence for any member of the insect order Thysanoptera. Benchmarking Universal Single-Copy Ortholog (BUSCO) assessments of the genome assembly (size = 415.8 Mb, scaffold N50 = 948.9 kb) revealed a relatively complete and well-annotated assembly in comparison to other insect genomes. The genome is unusually GC-rich (50%) compared to other insect genomes to date. The official gene set (OGS v1.0) contains 16,859 genes, of which ~ 10% were manually verified and corrected by our consortium. We focused on manual annotation, phylogenetic, and expression evidence analyses for gene sets centered on primary themes in the life histories and activities of plant-colonizing insects. Highlights include the following: (1) divergent clades and large expansions in genes associated with environmental sensing (chemosensory receptors) and detoxification (CYP4, CYP6, and CCE enzymes) of substances encountered in agricultural environments; (2) a comprehensive set of salivary gland genes supported by enriched expression; (3) apparent absence of members of the IMD innate immune defense pathway; and (4) developmental- and sex-specific expression analyses of genes associated with progression from larvae to adulthood through neometaboly, a distinct form of maturation differing from either incomplete or complete metamorphosis in the Insecta., Conclusions: Analysis of the F. occidentalis genome offers insights into the polyphagous behavior of this insect pest that finds, colonizes, and survives on a widely diverse array of plants. The genomic resources presented here enable a more complete analysis of insect evolution and biology, providing a missing taxon for contemporary insect genomics-based analyses. Our study also offers a genomic benchmark for molecular and evolutionary investigations of other Thysanoptera species.

The effect of five photoperiods (0:24, 6:18; 12:12, 18:6, and 24:0 light:dark (L:D)) on the development, reproduction, and survival of the predatory thrips Scolothrips longicornis Priesner fed on the two-spotted spider mite, Tetranychus urticae Koch, was tested under laboratory conditions at 60% RH and 25°C. Development time of almost all immature stages in S. longicornis was the shortest under long day lengths (18:6 and 24:0 L:D). The adult duration of both sexes decreased with increasing light length from 6 to 24 h. The longevity of male and female decreased with increasing light length. Under a 12:12 L:D photoperiod, S. longicornis females had the longest oviposition period and longevity, highest net reproductive rate (R0 = 15.37), intrinsic rate of natural increase (r = 0.141), and finite rate of increase (λ = 1.151). Life table parameters showed a significant difference with various photoperiods. The consequences of the present research demonstrated that a 12:12 L:D photoperiod is the most favorable for the reproduction and development of S. longicornis fed on T. urticae, and that for mas rearing for augmentative biological control programs, would be the ideal photoperiod to maximize production.

Transgenic cotton expressing Cry51Aa2.834&#95;16 Bt toxin (hereafter referred to as MON 88702) has the potential to be an important tool for pest management due to its unique activity against tobacco thrips, Frankliniella fusca. Unlike other Bt toxins targeting lepidopteran cotton pests, MON 88702 does not cause direct mortality but has an antixenotic effect that suppresses F. fusca oviposition. Previous work has shown neonicotinoid seed treated (NST) crops have similar behavioral effects on thrips. This study used non-choice and common garden experiments to examine how the presence of MON 88702 cotton and soybean (another F. fusca host) with and without NSTs might alter F. fusca infestation distributions. In a no-choice environment, significant larval establishment differences were observed, with untreated soybean plants becoming most heavily infested. In choice experiments, plants expressing MON 88702 or were neonicotinoid treated had significantly lower larval establishment. Larval density decreased as dispersal distance increased, suggesting reproductive decisions were negatively related to distance from the release point. Understanding how F. fusca responds to MON 88702 in an environment where adults can choose among multiple host plants will provide valuable context for projections regarding design of MON 88702 resistance refuges. Reduced larval establishment on NST cotton and soybean suggests that area-wide use of NSTs could reduce the number of susceptible F. fusca generated in unstructured crop refuges for MON 88702. These results also suggest that although the presence of NST MON 88702 could suppress reproduction and resistance selection, over time this benefit could erode resulting in increased larval establishment on NST cotton and soybean due to increased frequency of neonicotinoid resistant F. fusca populations., Competing Interests: The authors have read the journal’s policy and have the following potential competing interests: AH and GK received support from Bayer Crop Science in the form of crop seed and initial funding to generate information for this study. This does not alter our adherence to PLOS ONE policies on sharing data and materials. There are no patents, products in development or marketed products associated with this research to declare.

Western flower thrip, Frankliniella occidentalis (Pergande), is among the most economically important agricultural pests globally, attacking a wide range of vegetable and horticultural crops. In addition to causing extensive crop damage, the species is notorious for vectoring destructive plant viruses, mainly belonging to the genera Orthotospovirus, Ilarvirus, Alphacarmovirus and Machlomovirus. Once infected by orthotospoviruses, thrips can remain virulent throughout their lifespan and continue transmitting viruses to host plants when and wherever they feed. These irruptive viral outbreaks in crops will permanently disrupt functional integrated pest management systems, and typically require a remedial treatment involving insecticides, contributing to further development of insecticide resistance. To mitigate against this continuing cycle, the most effective management is early and comprehensive surveillance of the pest species and recognition of plant viruses in the field. This review provides information on the pest status of F. occidentalis, discusses the current global status of the viruses vectored by this thrip species, examines the mechanisms involved in transmitting virus-induced diseases by thrips, and reviews different management strategies, highlighting the potential management tactics developed for various cropping systems. The early surveillance and the utilization of potential methods for control of both F. occidentalis and viruses are proposed., (© 2019 The Authors. Insect Science published by John Wiley & Sons Australia, Ltd on behalf of Institute of Zoology, Chinese Academy of Sciences.)

In view of the common use of the herb basil ( Ocimum basilicum ) in nutrition and in phytomedicine, the contents of its leaves are of obvious interest. In extracts of fresh yellowish-green basil leaves, phyllobilins (PBs), which are bilin-type catabolites of chlorophyll (Chl), were detected using high-performance liquid chromatography (HPLC). Two such PBs, provisionally named Ob -nonfluorescent chlorophyll catabolite (NCC)-40 and Ob -YCC-45, exhibited previously unknown structures that were delineated by a thorough spectroscopic characterization. When basil leaves were infested with aphids or thrips or underwent fungal infections, areas with chlorosis were observed. HPLC analyses of the infested parts of leaves compared to those of the healthy parts showed a significant accumulation of PBs in the infested areas, demonstrating that the senescence-associated pheophorbide a oxygenase/phyllobilin (PAO/PB) pathway is activated by herbivore feeding and fungal infection.

Melon yellow spot orthotospovirus (MYSV), a member of the genus Orthotospovirus, is an important virus in cucurbits. Thrips palmi is considered the most serious pest of cucurbits because it directly damages and indirectly transmits MYSV to the plant. The effects of MYSV-infected plants on the development time, fecundity, and preference of the thrips were analyzed in this study. Our results showed that the development time of male and female thrips did not differ significantly between MYSV-infected and non-infected cucumbers. The survival rate of thrips in non-infected and MYSV-infected cucumbers were not significantly different. In a non-choice assay, T. palmi adults were released on non-infected and MYSV-infected cucumbers and allowed to lay eggs. The number of hatched larvae did not significantly differ between non-infected and MYSV-infected cucumbers. In a choice assay, MYSV had no detectable effect on the number of adult thrips and preceding hatched larvae. In a pull assay, the settling rate of thrips on the released plant did not differ significantly when the adult thrips were released to non-infected or MYSV infected cucumbers for any cucumber cultivar. Based on our results, we propose that the effects of MYSV-infected cucumbers on the development time, fecundity, or preference of T. palmi may not be an important factor in MYSV spread between cucumbers., Competing Interests: The authors have declared that no competing interests exist.

The onion thrips, Thrips tabaci (Lindeman, 1889), is a cosmopolitan pest of economic importance on a wide range of crops. Despite being one of the most studied thrips species, there is very limited knowledge available about its ability to perceive light. The T. tabaci cryptic species complex consists of a tobacco-associated (T) and two leek-associated (L1, L2) biotypes. We made electroretinogram recordings on the most widespread thelytokous (where unfertilized eggs produce females) T. tabaci L2 biotype and measured attraction to light sources in this biotype as a function of wavelength in behavioural experiments. The spectral sensitivity of the T. tabaci L2 biotype shows a unimodal curve peaking at λ max  = 521 nm. Contrary to this spectral sensitivity curve, L2 biotype attraction in an arena is bimodal with local maxima at 368 nm (UV) and 506-520 nm (green) being practically of the same magnitude. Although being similar to the arrhenotokous (where unfertilized eggs produce males) L1 biotype in phototaxis, significant differences regarding photoreceptor cell responses emerged. This study contributes to our understanding of light perception in Thysanoptera as well as to the development of more effective monitoring tools for this economically important pest species., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Western flower thrips, Frankliniella occidentalis , first arose as an important invasive pest of many crops during the 1970s-1980s. The tremendous growth in international agricultural trade that developed then fostered the invasiveness of western flower thrips. We examine current knowledge regarding the biology of western flower thrips, with an emphasis on characteristics that contribute to its invasiveness and pest status. Efforts to control this pest and the tospoviruses that it vectors with intensive insecticide applications have been unsuccessful and have created significant problems because of the development of resistance to numerous insecticides and associated outbreaks of secondary pests. We synthesize information on effective integrated management approaches for western flower thrips that have developed through research on its biology, behavior, and ecology. We further highlight emerging topics regarding the species status of western flower thrips, as well as its genetics, biology, and ecology that facilitate its use as a model study organism and will guide development of appropriate management practices.

The objective of this study was to evaluate the Holopothrips fulvus Morgan (Thysanoptera: Phlaeothripidae) population dynamics and to identify dwarf cashew genotypes less infested by the pest in 2015 and 2016, under field conditions. H. fulvus population evaluations were carried out by monthly observations in the plants and using a score scale varying from 0 to 4. H. fulvus infestation occurred from October to December, and in the cashew genotypes CAP 112/8, CAP 121/1, CAP 131/2, CAP 145/2, CAP 145/7, CAP 128/2, CAP 120/4, CAP 123/6, CAP 130/1, and CAP 157/2 was dependent on the flowering period of the crop in 2015. In 2016, there was dependence in all evaluated genotypes between H. fulvus infestation and the cashew flowering period. In 2015, no significant differences were observed between the evaluated genotypes regarding H. fulvus infestation. In 2016, genotypes CAP 105/5, CAP 143/7, CAP 150/3, CAP 155/2, CAP 158/8, CAP 161/7, CAP 163/8, CAP 31, CAP 71, CAP 92, CAP 113, CAP 120, CAP 155, CAP 165, CAP 106/1, CAP 111/2, CAP 127/3, CAP 157/2, and BRS 226 were less infested. H. fulvus occurs from October to December and we could identify the dwarf cashew genotypes less infested by the pest.

Western flower thrips (WFT), Frankliniella occidentalis, has become an important pest of vegetables worldwide, due to its economic damage to crop production. In order to control WFT, chemical insecticides are widely used. However, WFT has developed a high resistance against many kinds of insecticides. Na + , K + -ATPase, playing an important role in the ionic transmission across the membrane, is commonly considered to be the target of several xenobiotic compounds. However, whether the Na + , K + -ATPase can be used as one of the target sites for controlling WFT is still unknown. In this study, resistance levels of WFT to four insecticides (chlorpyrifos, beta cypermethrin, abamectin, and thiamethoxam) were measured. It was found that all four insecticides exhibited significant inhibitory effects on WFT, especially on nymphs. The activity of Na + , K + -ATPase was estimated after the treatment of four insecticides. Additionally, mRNA expression levels of three Na + , K + -ATPase α-subunit isoforms (X1, X2 and X3) were detected using RT-qPCR. The transcription profile of three Na + , K + -ATPase α-subunit isoforms were diverse after treatment by these four insecticides, which indicated that these isoforms might play different roles in the tolerance to insecticides. The results suggested that Na + , K + -ATPase can obviously be inhibited by these four classes of insecticide, and may serve as the new target for controlling WFT.