Adult Female Longevity Research Articles

Biology and Ecology of Delia planipalpis (Stein) (Diptera: Anthomyiidae), an Emerging Pest of Broccoli in Mexico.

Delia planipalpis (Stein) (Diptera: Anthomyiidae) is a pest of crucifers, such as broccoli, radish, cauliflower, turnip and cabbage. It has been recently described in Mexico as a significant emerging pest of broccoli. Due the lack of knowledge of this pest, the present study aimed to determine its life cycle, female sexual maturation, copulation, oviposition behavior and adult longevity. The identity of the fly in Mexico was confirmed genetically by sequencing the cytochrome oxidase subunit 1 gene (COI). The mean development time of D. planipalpis was 32-33 days on radish at 24 °C under laboratory conditions. Females became sexually mature 1-2 days after emergence, and the highest incidence of matings was recorded on the second day (60%). Under choice conditions, D. planipalpis females preferred to oviposit on radish plants, rather than broccoli plants, possibly due to the use of radish for rearing the laboratory colony. Oviposition and the mean number of eggs laid varied among the broccoli varieties, with the highest oviposition observed on the Tlaloc variety. Repeated attempts to rear the laboratory colony on broccoli plants failed. Radish-reared insects of both sexes lived longer when individualized in the adult stage (14.5-22.5 days) than when adult flies were maintained in groups (10-11 days). This study contributes to the understanding of D. planipalpis biology and provides information that can be used to establish future control strategies against this pest.

Novel compounds ZK-PI-5 and ZK-PI-9 regulate the reproduction of Spodoptera frugiperda (Lepidoptera: Noctuidae), with insecticide potential.

Trehalase inhibitors prevent trehalase from breaking down trehalose to provide energy. Chitinase inhibitors inhibit chitinase activity affecting insect growth and development. This is an important tool for the investigation of regulation of trehalose metabolism and chitin metabolism in insect reproduction. There are few studies on trehalase or chitinase inhibitors' regulation of insect reproduction. In this study, ZK-PI-5 and ZK-PI-9 were shown to have a significant inhibitory effect on the trehalase, and ZK-PI-9 significantly inhibited chitinase activity in female pupae. We investigated the reproduction regulation of Spodoptera frugiperda using these new inhibitors and evaluated their potential as new insecticides. Compounds ZK-PI-5 and ZK-PI-9 were injected into the female pupae, and the control group was injected with solvent (2% DMSO). The results showed that the emergence failure rate for pupae treated with inhibitors increased dramatically and aberrant phenotypes such as difficulty in wings spreading occurred. The oviposition period and longevity of female adults in the treated group were significantly shorter than those in the control group, and the ovaries developed more slowly and shrank earlier. The egg hatching rate was significantly reduced by treatment with the inhibitor. These results showed that the two new compounds had a significant impact on the physiological indicators related to reproduction of S. frugiperda, and have pest control potential. This study investigated the effect of trehalase and chitin inhibitors on insect reproduction and should promote the development of green and efficient insecticides.

Sublethal Effects of Flonicamid on Life Table of Myzus persicae (Sulzer)

The green peach aphid, Myzus persicae (Sulzer) (Aphididae: Hemiptera) is a cosmopolitan polyphagous pest of more than five hundred plant species belonging to at least forty different plant families including several economically important agricultural crops. The sublethal effect of LC25 concentration of flonicamid on M. persicae was assessed by using an age-stage two-sex life table approach for integrated management of this pest. A leaf-dip bioassay showed that flonicamid was very toxic to the adults of M. persicae at 48 h with the calculated LC25 concentration value of 0.0115 g a.i./L. The adults (parental generation) of M. persicae exposed to the LC25 concentration (sublethal dose) of flonicamid showed inhibitory effects on the life history traits across its generations such as reduction in adult longevity and fecundity of parental generation (F0); shortening the durations of fifth instar nymphs, adult female longevity, oviposition period, total longevity and fecundity of F1 & F2 generations. On the other hand, stimulatory effects were observed on the duration of first, second, third, and fourth instar nymphs; and pre-adults in F2 generation in the flonicamid-treated aphids. Consistently with the effects on individual traits, a higher mean generation time (T) and shorter intrinsic rate of increase (r), finite rate of increase (λ), and net reproductive rate (R0) of F2 generation were observed in the flonicamid treated aphids, although r, λ, R0, T, and gross reproductive rate (GRR) of F1 generation were not significantly affected. The findings revealed the exposure of parental adults of M. persicae to sublethal concentration of flonicamid could induce hormetic (both inhibitory and stimulatory) effects on their succeeding generations. This study is useful for assessing the overall effects of flonicamid on M. persicae. The hormetic effects should be considered when it used flonicamid in the integrated management of M. persicae in crop fields.

Side effects of insecticides alone or in a mixture with acaricide on life history traits and demographic parameters of Brevipalpus yothersi

Brevipalpus yothersi is an important pest to citrus crop due to its ability to transmit the virus that causes citrus leprosis. The exposure of target and non-target organisms to different pesticides is a reality in field conditions. For successful management, it is essential to determine the effects of citrus commonly used pesticides on leprosis mites to determine how pesticides can interfere with the leprosis mite population. Therefore, this study aimed to evaluate the impact of insecticides, alone or associated with spirodiclofen, on B. yothersi life history traits and demographic parameters under laboratory and greenhouse conditions. Results suggest that cypermethrin and imidacloprid, both alone and in a mixture with spirodiclofen, phosmet in a mix with spirodiclofen and spirodiclofen alone did not interfere significantly in the fecundity and fertility of B. yothersi in laboratory conditions. In the same condition, only phosmet at 15.6, 125.0, and 250.0 mg.L-1 reduced the fecundity of the mites. Brevipalpus yothersi population varied with the insecticide and mixture type in the greenhouse condition. Most insecticides and acaricide, alone or in a mixture, decreased pre-adult development, whereas female adult longevity was similar to control. Spirodiclofen combined with phosmet and imidacloprid decreased female adult longevity. Only spirodiclofen in a mixture with cypermethrin and phosmet alone did not interfere significantly with the intrinsic rate of population increase. The other insecticides and mixtures reduced that parameter. The mean time of one mite generation was decreased when the mites were exposed to all insecticides and acaricide combinations, spirodiclofen and phosmet alone. Therefore, cypermethrin, phosmet, imidacloprid, and spirodiclofen, alone or in a mixture, negatively impacted the development time and demographic parameters of B. yothersi.

Comparative life history and demographic parameters of Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) on maize and oat flours

Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), Mediterranean flour moth, is a major pest of stored food products, causing significant economic losses. Understanding the life history and population dynamics of E. kuehniella is crucial for developing effective pest management strategies and improving the sustainability of the food industry. In this study, we conducted an age-stage, two-sex life table analysis of E. kuehniella reared on maize and oat flours. The aim of the study was to compare the demographic parameters of the E. kuehniella populations reared on the two different types of flour including maize in laboratory conditions at 26 ± 1 °C, 60 ± 5% R.H., and a 16:8 (light: dark) photoperiod. Our findings suggest that while the flour type had a minor effect, there was no significant impact on the developmental time, survival rate, fecundity, and population growth rate of E. kuehniella. However, adult female longevity was significantly longer in the maize flour group compared to the oat flour group. The pre-adult survival rate was higher in the maize flour group (83%) than the oat flour group (72%). Additionally, our results indicate that fecundity of the E. kuehniella was slightly higher on oat flour than on maize flour, while the population growth rate was similar on both flours. Our results demonstrated that the larvae fed with maize flour consumed a significantly higher amount of flour (394 mg) than those fed with oat flour (278 mg). Furthermore, after 120 days of simulation the population growth projection of E. kuehniella was twice as high in oat flour compared to maize flour. These findings suggest that both maize and oat flours are susceptible to E. kuehniella infestation, which has important implications for the development of effective pest management strategies and the sustainability of the food industry.

Life table study of Spodoptera frugiperda at different wheat stages and the effect of larval population density on wheat yield.

Spodoptera frugiperda is an invasive, widespread agricultural pest in China. However, there have been no reports assessing feeding damage on wheat caused by S. frugiperda. To clarify the fitness and potential damage of S. frugiperda to wheat, this study analyzed the population parameters of S. frugiperda fed on wheat in a laboratory and simulated the potential damage in field conditions. The population parameters of S. frugiperda were compared using life tables on wheat at the seedling and adult plant stages. The adult female longevity of S. frugiperda varied from 12.29 days on seedling plants to 16.60 days on adult plants. Egg production was significantly higher when fed on wheat at the seedling stage (646.34 eggs) than when fed on adult plants (495.86 eggs). On wheat at the seedling and adult plant stages, the mean generation times were 35.42 and 38.34 days, respectively, and the intrinsic rates of increase were 0.15 and 0.14, respectively. Spodoptera frugiperda completed development and increased its population in wheat at both plant growth stages. In the field, the effect of different larval densities on the 1000-kernel weight of wheat was significantly different. An action threshold of 40 larvae per m2 was estimated, and the higher population densities caused a yield loss of 17.7%. Spodoptera frugiperda can complete its life cycle on wheat at different stages. Wheat can serve as an alternative host for S. frugiperda. If S. frugiperda reaches 320 larvae per m2 density during wheat growth, it will cause yield loss exceeding 17%. © 2023 Society of Chemical Industry.

Effect of sub-lethal and lethal concentrations of the entomopathogenic fungus Metarhizium anisopliae Sorokin on detoxification enzymes and demographic parameters of Mythimna separata (Walker)

The maize armyworm, Mythimna separata (Walker) (Lepidoptera: Noctuidae), is a polyphagous, destructive, and migratory pest. Improper pesticide application induced resistance may be an alternative mechanism for pest resurgence. In this study, the efficacy of Metarhizium anisopliae (Sorokin) was estimated, while focusing on sub-lethal (LC15) and lethal (LC50) concentration treatments on the F0 and F1 generations of laboratory-reared M. separata. The results indicated an LC50 value of 2.2 × 106 conidia mL−1 against M. separata larvae after infection with M. anisopliae. The sub-lethal and lethal concentrations and trans-generational effects on demographic parameters were estimated using the age-stage, two-sex life table. After treatment with LC15 (2.1 × 105conidia mL−1) and LC50 (2.2 × 106 conidia mL−1) concentrations, the progeny of M. separata exhibited reduced fecundity, larval duration and adult male and female longevity as compared to the control. Subsequently, population growth parameters such as mean generation time (T) and net reproductive rates (Ro) were reduced in these concentrations. Furthermore, activities of the detoxification enzymes glutathione S-transferases (GST), acetylcholinesterase (AChE) and esterases (EST) were significantly different at the LC50 as compared to LC15 and the control. These findings showed pathogenicity of M. anisopliae even at sub-lethal concentration, with negative effects on the fecundity, biological parameters and also altered the detoxifying enzymes of M. separata which enhanced its potential use as a management tool in eco-friendly and long-lasting management programs.

Comparison of the biology of Frankliniella intonsa and Megalurothrips usitatus on cowpea pods under natural regimes through an age-stage, two-sex life table approach.

Two thrips, Megalurothrips usitatus (Bagnall) and Frankliniella intonsa (Trybom) are major pests of cowpea in South China. To realistically compare the growth, development and reproductive characteristics of these two thrips species, we compared their age-stage, two-sex life tables on cowpea pods under summer and winter natural environmental regimes. The results showed that the total preadult period of M. usitatus was 8.09 days, which was significantly longer than that of F. intonsa (7.06 days), while the adult female longevity of M. usitatus (21.14 days) was significantly shorter than that of F. intonsa (25.77 days). Significant differences were showed in male adult longevity (10.68 days for F. intonsa and 16.95 days for M. usitatus) and the female ratio of offspring (0.67 for F. intonsa and 0.51 for M. usitatus), and the total preadult period of M. usitatus (16.20 days) was significantly longer than that of F. intonsa (13.66 days) in the winter regime. The net reproductive rate (summer: R0 = 85.62, winter: R0 = 105.22), intrinsic rate of increase (summer: r = 0.3020 day-1, winter: r = 0.2115 day-1), finite rate of increase (summer: λ = 1.3526 day-1, winter: λ = 1.2356 day-1) and gross reproduction rate (summer: GRR = 139.34, winter: GRR = 159.88) of F. intonsa were higher than those of M. usitatus (summer: R0 = 82.91, r = 0.2741, λ = 1.3155, GRR = 135.71; winter: R0 = 80.62, r = 0.1672, λ = 1.1820, GRR = 131.26), and the mean generation times (summer: T = 14.73 days, winter: T = 22.01 days) of F. intonsa were significantly shorter than those of M. usitatus (summer: T = 16.11 days, winter: T = 26.25 days). These results may contribute to a better understanding of the bioecology of different thrips species, especially the interspecific competition between two economically important cowpea thrips with the same ecological niche in a changing environment.

Effects of Temperature and Nutrition during the Larval Period on Life History Traits in an Invasive Malaria Vector Anopheles stephensi.

Anopheles stephensi is an Asian and Middle Eastern malaria vector, and it has recently spread to the African continent. It is needed to measure how the malaria parasite infection in A. stephensi is influenced by environmental factors to predict its expansion in a new environment. Effects of temperature and food conditions during larval periods on larval mortality, larval period, female wing size, egg production, egg size, adult longevity, and malaria infection rate were studied using a laboratory strain. Larval survival and female wing size were generally reduced when reared at higher temperatures and with a low food supply during the larval period. Egg production was not significantly affected by temperature during the larval period. Egg size was generally smaller in females reared at higher temperatures during the larval period. The infection rate of mosquitoes that fed on blood from malaria-infected mice was not affected by rearing temperature or food conditions during the larval period. Higher temperatures may reduce infection. A. stephensi; however, larger individuals can still be infective. We suggest that routinely recording the body size of adults in field surveys is effective in finding productive larval breeding sites and in predicting malaria risk.

Effects of Tebufenozide on Eggs, Larvae and Adults of Chrysoperla carnea (Neuroptera: Chrysopidae).

Quantifying compatibility among control agents is essential for development of integrated pest management (IPM). Chrysoperla carnea (Siemens) and insect growth regulator insecticides are widely used in IPM of Lepidoptera. C. carnea is a generalist predator naturally present in the Mediterranean agroecosystems and bred in insectariums for commercial purposes. Here, we evaluated lethal and sublethal effects of tebufenozide on C. carnea under laboratory conditions. The treatment of eggs with tebufenozide 24 or 48 h after they were laid did not affect the hatching rate or survival of the neonate larvae. Toxic effects of tebufenozide on topically treated larvae was low; development times of surviving larvae and pupae decreased significantly compared with controls. In choice bioassays, a high percentage of third-instar larvae chose prey (Spodoptera littoralis) treated with tebufenozide in preference to untreated prey. Moreover, second-instar larvae of C. carnea that had previously consumed tebufenozide-treated prey (0.75 mL/L) had significantly reduced larval development time compared with controls, while longevity of surviving adults, fecundity and egg viability were unaffected. Ingestion of tebufenozide by adults of C. carnea at the recommended field dose had no significant effect on female fecundity, egg viability or adult longevity. Tebufenozide exhibited low toxicity towards the developmental stages of C. carnea and is therefore a candidate for inclusion in IPM strategies.

Temperature-Dependent Biology and Population Performances of the Coffee Berry Borer Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae) on Artificial Diet

At different observation intervals of 1, 5, and 10 days during a trial period of 30 days, the mortality rates of Hypothenemus hampei were 100, 95, and 55%, and the fecundity rates were 0.55, 8.45, and 19.35 eggs/female, respectively. At temperatures of 18, 21, 24, and 27 °C, the development time of the immature stage of H. hampei was significantly shortened with increasing temperature. Furthermore, the lower developmental threshold (T0) and thermal summation (K) of the immature stage were 8.91 °C and 485.44 degree-days, respectively. The greatest longevity of female and male adults reached 115.77 and 26.50 days, respectively, at 18 °C. The highest fecundity was 29.00 eggs/female at 24 °C. The population parameters of H. hampei were analyzed on the basis of the age–stage, two-sex life table theory. According to the data, the parameters were significantly affected by temperature. The highest net reproductive rate (R0) was 13.32 eggs/individual at 24 °C. The highest intrinsic rate of increase (r) and finite rate of increase (λ) were calculated as 0.0401 and 1.0409 day−1, respectively, at a temperature of 27 °C. The shortest mean generation time (T) was 51.34 days at 27 °C. Overall, we provide a discussion on comprehensive biological information regarding H. hampei, thus providing basic knowledge for further research on this pest.

Effects of transgenerational photoperiod experience on the reproduction and development of Anastatus orientalis, an egg parasitoid of the spotted lanternfly.

Transgenerational experience can affect a range of natural enemies' life-history traits and can be involved in the control of developmental plasticity. As a major egg parasitoid of the spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae), the wasp Anastatus orientalis (Hymenoptera: Eupelmidae) is effective at suppressing its host populations. The reproductive and developmental traits of A. orientalis is known to depend on photoperiod conditions, but transgenerational photoperiodic effects have yet to be evaluated. To evaluate the transgenerational photoperiodic effects on A. orientalis, we assessed wasp adult longevity, female fecundity, sex ratio, and diapause rate over three consecutive generations under different experimental photoperiods (L16:D8, L12:D12, and L8:D16), using Antheraea pernyi (Lepidoptera: Saturniidae) eggs as hosts. The results suggest that transgenerational experience significantly impacts several biological parameters of progeny. All parasitoids entered a diapause under the long photoperiod condition (i.e., L16:D8), after which the number of female parasitoids and fecundity of the 2nd and 3rd generations increased significantly as compared to the 1st generation. With the long photoperiod conditions, the female ratio rose from 68.1% (1st generation) to 86.0% (3rd generation) and the progeny per females increased from 35.8 to 75.7. However, adult longevity of females and males were shortened significantly. With the intermediate photoperiod (L12:D12) conditions, fecundity and sex ratio of the 2nd and 3rd generations increased significantly as compared to the 1st generation. With the short photoperiod (L8:D16) conditions, there were no significant differences in fecundity among three generations, but sex ratio of the 2nd and 3rd generations increased significantly as compared to the 1st generation. These results on transgenerational photoperiodic effects can be applied to improve laboratory rearing efficiency of parasitoids and to better understand population dynamics in the field across a latitudinal gradient.

Sublethal effects of emamectin benzoate on development, reproduction, and vitellogenin and vitellogenin receptor gene expression in Thrips hawaiiensis (Thysanoptera: Thripidae).

Thrips hawaiiensis (Morgan) (Thysanoptera: Thripidae) is a sap-sucking pest that seriously damages several crops and reduces their economic value. Exposure to low concentrations of insecticides may have a sublethal effect on surviving insects. In order to provide a reference for the rational application of emamectin benzoate, its sublethal effects on the development and reproduction of T. hawaiiensis were evaluated. Pupal development time was significantly shorter in T. hawaiiensis treated with sublethal concentrations of emamectin benzoate (LC10 and LC20) than in control. Female adult longevity and female total longevity were significantly longer following LC20 treatment than in the control and LC10 treatment groups. Nevertheless, male adult longevity and male total longevity were significantly shorter in the LC10 treatment group than in the control and LC20 treatment groups. The sublethal concentration of emamectin benzoate (LC20) significantly shortened the preadult stages and the mean generation. Meanwhile, it significantly increased the finite rate of increase, intrinsic rate of increase, and net reproductive rate. The fecundity was significantly higher after LC20 treatment than after LC10 and control treatments. Compared with the control group, the LC10 and LC20 groups of T. hawaiiensis adults showed a significantly higher expression of the vitellogenin (Vg) and vitellogenin receptor (VgR) genes, which played a key role in increasing their fecundity. These findings suggest that short-term exposure to sublethal concentrations of emamectin benzoate may lead to a resurgence and secondary outbreak of T. hawaiiensis infestation. The results have practical applications for the management of this important and noxious pest.

Effects of temperature, relative humidity, and illumination on the entomological parameters of Aedes albopictus: an experimental study.

Aedes albopictus (Diptera: Culicidae) is a mosquito from Asia that can transmit a variety of diseases. This paper aimed to explore the effects of temperature, relative humidity, and illumination on the entomological parameters related to the population growth of Aedes albopictus, and provide specific parameters for developing dynamic models of mosquito-borne infectious disease. We used artificial simulation lab experiments, and set 27 different meteorological conditions to observe and record mosquito's hatching time, emergence time, longevity of adult females, and oviposition amount. We then applied generalized additive model (GAM) and polynomial regression to formulate the effects of temperature, relative humidity, and illumination on the biological characteristics of Aedes albopictus. Our results showed that hatchability closely related to temperature and illumination. The immature stage and the survival time of adult female mosquitoes were associated with temperature and relative humidity. The oviposition rate related to temperature, relative humidity, and illumination. Under the control of relative humidity and illumination, ecological characteristics of mosquitoes such as hatching rate, transition rate, longevity, and oviposition rate had an inverted J shape with temperature, and the thresholds were 31.2°C, 32.1°C, 17.7°C, and 25.7°C, respectively. The parameter expressions of Aedes albopictus using meteorological factors as predictors under different stages were established. Meteorological factors especially temperature significantly influence the development of Aedes albopictus under different physiological stages. The established formulas of ecological parameters can provide important information for modeling mosquito-borne infectious diseases.

Population growth of Tetranychus truncatus (Acari: Tetranychidae) on different drought-tolerant potato cultivars.

Tetranychus truncatus Ehara (Acari: Tetranychidae) has become one of the major phytophagous pests in China in recent years, and is found on a wide range of host plants. However, little information is available on the population performance of this arthropod pest on potatoes. In this study, we explored the population growth of T. truncatus on two drought-tolerant potato (Solanum tuberosum L.) cultivars under laboratory conditions using the age-stage, two-sex life table. Tetranychus truncatus completed its entire life history on both potato cultivars tested, Holland 15 and Longshu 10. There was no significant difference between two potato cultivars in developmental duration. Tetranychus truncatus had shorter adult longevity (20.61 days), adult female longevity (20.41 days), and total female longevity (33.66 days) on Longshu 10 than Holland 15 (21.16 days, 21.19 days, and 34.38 days, respectively). However, it exhibited a higher preadult survival rate, higher fecundity (F = 88.32 eggs per female), and relatively higher population parameters when reared on Longshu 10 than on Holland 15 (F = 75.70 eggs per female). Growth projection also showed that the population size of T. truncatus on Longshu 10 (expand 750-fold) was larger than that on Holland 15 (expand 273-fold) after 60 days. Our results demonstrate that the drought-sensitive potato variety, Holland 15, is relatively resistant to T. truncatus compared with the drought-tolerant variety, Longshu 10, and suggest that T. truncatus exhibited a trade-off between longevity and reproduction on both potato cultivars. Our findings provide information on population prediction, which may aid the management of this pest mite species of potatoes.

Development, survivorship and reproduction of Gryon aetherium Talamas (Hymenoptera: Scelionidae), an egg parasitoid of Bagrada hilaris (Burmeister) (Hemiptera: Pentatomidae), under eight constant temperatures

Environmental temperature is fundamental determinant of insect physiology and behavior, and the success of an importation biocontrol program often relies on the acclimatization capacity of the introduced biocontrol agent. Co-evolved natural enemies of a target pest that share the same climatic range are expected to be suitable candidates for introduction. The stink bug Bagrada hilaris (Burmeister) is an invasive pest in the USA which damages mainly brassica crops in California and other Southwest states. An egg parasitoid from Pakistan, Gryon aetherium Talamas (Hymenoptera: Scelionidae), is currently being evaluated as a classical biocontrol agent. In order to determine the range of temperatures suitable for G. aetherium, its development, reproduction and survivorship were evaluated in the laboratory under eight regimes of constant temperature, ranging from 15 to 40 °C. Gryon aetherium was able to develop successfully between 18 °C (46.9 ± 0.6 d) and 37.5 °C (7.3 ± 0.09 d) with a maximum emergence rate of 95.5 ± 1.9 % at 25 °C. The parasitoid reproduced under all tested temperatures, with maximum fecundity at 30 °C (104.5 ± 21.2 progeny/female). The mean longevity of adult females was 151.3 ± 6.8 days at 15 °C and declined to 4.3 ± 0.3 days at 40 °C. Our results suggest that G. aetherium should establish in the warmest regions of USA, but would not likely control B. hilaris in crucifer crops of the Californian coastal regions where lower temperatures are likely to limit its developmental success.

Sublethal Effects of Beauveria bassiana Strain BEdy1 on the Development and Reproduction of the White-Backed Planthopper, Sogatella furcifera (Horváth) (Hemiptera: Delphacidae).

Rice (Oryza sativa) is the most important food crop all over the world, while white-backed planthopper (WBPH), Sogatella furcifera (Horváth) (Hemiptera: Delphacidae) is an important pest causing rice yield reduction. The purpose of this study is to evaluate the sublethal effects of strain BEdy1 Beauveria bassiana (Bals.-Criv.) Vuill. (Hypocreales: Cordycipitaceae) on S. furcifera using the two-sex life table analytical method, compare the life tables of the F0 and F1 generations of WBPHs which were treated with sublethal concentrations (LC10, LC25) of B. bassiana BEdy1 with a control group. The results showed that the duration of the egg, 4th-instar and 5th-instar nymph, pre-adult, total pre-oviposition (TPOP) and mean generation time (T) for the LC25 treatment were significantly longer than those of the control and LC10 treatment. However, the duration of the adult, the longevity of male and female adults and the oviposition days of female adults for the LC25 treatment were significantly shortened. The fecundity of female adults, intrinsic rate of increase (r), net reproductive rate (R0) and finite rate of increase (λ) for the LC25 treatment were significantly decreased compared with those of other treatments. The duration of the egg and pre-adult stage for the LC10 treatment were longer than those of the control group, but the population parameters showed no significant difference. Therefore, the LC25 of B. bassiana BEdy1 can inhibit the population growth of S. furcifera.

The Effect of Sex Ratio and Population Density on Adult and Female Egg-Laying Behavior and Female Longevity of Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae)

This study was conducted to determine the effects of sex ratio and population density on Plodia interpunctella (Hübner) adult and female egg laying behavior. This study was conducted to determine the effects of sex ratio and population density on Plodia interpunctella (Hübner) adult and female egg laying behavior. The studies were carried out in the laboratory of the Department of Plant Protection of the Faculty of Agriculture of Selçuk University and in the climate room at 28±1ºC, 70±5% relative humidity and dark environment. Experiments were carried out in 1 Liter jars with 4 replications. Seven for the sex ratio in the trials (1/1.2/1.3/1.4/1.5/1.6/1.7/1 Male/Female), five for the population density (2/1.4/2) .6/3.8/4.10/5 Male/Female) (in a fixed sex ratio of 2 male/female) different parameters were used. According to the results obtained, an increase was observed in the number of eggs laid by a female from the early stages to the intermediate levels in the sex ratio and population density. When we look at the effect of the sex ratio, the number of eggs laid by the female in the ratio of 5 males / 1 females reached the highest level with 312 eggs. In the population density, the female left the largest number of eggs (360 eggs) at a density of 9 adults. In mass production of P. interpunctella, the highest number of eggs will be obtained from females if the adult population density is 9, the sex ratio is 5 males / 1 female and adult food is provided.

Sublethal effects of the cis-nitromethylene neonicotinoid insecticide cycloxaprid on the white-backed planthopper, Sogatella furcifera (Hemiptera: Delphacidae)

Cycloxaprid is a novel cis-nitromethylene neonicotinoid insecticide which shows high insecticidal activity against a wide range of sap-feeding insect pests. Studies were carried out to investigate the sublethal effects of cycloxaprid on the white-backed planthopper, Sogatella furcifera (Horváth) (Hemiptera: Delphacidae). When the third-instar nymphs were treated with LC25 of cycloxaprid, the female adult longevity and fecundity were significantly decreased in both the F0 and F1 generations. Moreover, the oviposition days and egg hatchability in the F1 generation were decreased. However, no significant differences were observed for the adult preoviposition period (APOP), total preoviposition period (TPOP), intrinsic rate of increase (ri), finite rate of increase (λ), net reproductive rate (R0) and mean generation time (T) of the F1 individuals. Additionally, the P450 activity and the mRNA expression levels of CYP4CE3, CYP417A4, CYP439A3, CYP6FJ3, CYPSF01 and CYP4FD2 were significantly induced by LC25 of cycloxaprid exposure in the third-instar nymphs. In contrast, the expression level of vitellogenin (Vg) in the female adults was significantly decreased after being treated with cycloxaprid at their nymph stage. These results indicate that cycloxaprid has potential as a good alternative insecticide for the sustainable control of S. furcifera field populations.

Integrative analysis of transcriptomics and metabolomics reveals the toxic mechanism of spirobudiclofen on Panonychus citri (Acari: Tetranychidae)

After insecticides are used in the field, their toxicity will gradually decrease to sublethal concentration with the passage of time and environmental factors, and some pest individuals will be exposed to sublethal concentrations, which will result in the sublethal effects. Therefore, understanding the sublethal effects of pesticides is the key to examine their efficacy and evaluate pesticide risk management. Panonychus citri McGregor (Acari: Tetranychidae) is a key citrus pest in the world and its control is largely based on the use of acaricides, such as spirobudiclofen In this study, the sublethal effects of spirobudiclofen on population parameters of Panonychus citri adult females were evaluated. The results showed that sublethal concentration of spirobudiclofen significantly reduced in the longevity and fecundity of female adults, and the effects increased with increasing tested concentrations (LC30, LC50). In order to characterise the spirobudiclofen molecular mechanism, the transcriptomes and metabolomics of spirobudiclofen-treated (two sublethal concentrations LC30 and LC50) and untreated adult females were compared using RNA-sequencing and LC-MS. The RNA-seq results revealed that the immune defense, antioxidative system, cuticle formation and lipid metabolic pathway of P. citri were involved in the responses to spirobudiclofen stress. Moreover, based on the disordered lipid metabolic pathways obtained from transcriptomic studies, the sublethal effects of spirobudiclofen on P. citri were examined by LC-MS; the results showed that the tolerance metabolism of P. citri exposed to spirobudiclofen was regulated by enhancing the metabolism of glycerophospholipid and glycine, serine and threonine. In the present study, transcriptomics and metabolomics-based approaches were employed to examine the molecular mechanism of spirobudiclofen-induced sublethal effects on P. citri, and the results provide new insights into the defense mechanisms at the molecular and biochemical level, and valuable information for pest control strategy development.