The theory and data analysis of the age-stage, two-sex life table have advanced substantially since 1985; however, constructing a complete life table from separately collected group-reared data for immature and adult cohorts remains a methodological challenge. This issue is particularly important because mass rearing of predators is typically conducted under group-rearing rather than individual-rearing conditions. In this study, the predatory stink bug Picromerus lewisi Scott (Hemiptera: Pentatomidae) was used as the model organism, and the widely distributed and economically important pest Mythimna separata (Walker) (Lepidoptera: Noctuidae) was used as prey. Group-reared life table data for immature and adult cohorts of P. lewisi were collected and analyzed using age-stage, two-sex life table theory, set theory, and Cartesian product-based matching. Three types of life table were constructed: bootstrap-matched, simple Cartesian-matched, and constrained Cartesian-matched. No significant differences were detected in developmental durations, preadult survival rate, or total preoviposition period between the bootstrap-match and constrained Cartesian-match methods. In contrast, the egg, first-instar, and fourth-instar estimated using the simple Cartesian-match differed significantly from those obtained using the bootstrap-match. In addition, mean fecundity estimated by the simple Cartesian-match was significantly higher than that from the constrained Cartesian-match. The bootstrap-match produced the greatest variability, whereas the constrained Cartesian-match, by accounting for sex ratio effect, generated more representative life tables and confidence intervals. The logic and equations underlying these matching approaches are presented and implemented in the TWOSEX program. This method is generally applicable to mass-reared natural enemies used in biological control.

The mealybug destroyer Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae) is a globally recognized predator of mealybugs and an important candidate for biological control programs. This study evaluated the demographic characteristics and predation performance of C. montrouzieri fed on Paracoccus marginatus (Hemiptera: Pseudococcidae) under controlled laboratory conditions (27 degrees C +/- 1 degrees C, 70% +/- 5% RH, 16:8 h L:D). Using the age-stage, two-sex life table approach, we quantified stage-specific development, survival, fecundity, and predation rates to provide a comprehensive population-level assessment. The preadult survival rate was 0.586, mean fecundity reached 117.0 eggs/female, and the net reproductive rate (R0), intrinsic rate of increase (r), finite rate of increase (lambda), and mean generation time (T) were 38.5 offspring, 0.1116 day-1, 1.1181 day-1, and 32.7 day, respectively. The net predation rate (C0), transformation rate (Qp), and finite predation rate (omega) were 245.2 preys, 6.38, and 24.9 day-1, respectively. Population projections indicated a rapid increase across three generations and substantial cumulative predation potential. Our results hint that C. montrouzieri exhibits strong demographic performance and high predatory capacity when reared on P. marginatus, highlighting its efficiency as a biological control agent. The integration of life table and predation models provides a precise framework for predicting predator-prey dynamics and optimizing release strategies in integrated pest management (IPM) programs. Future research under field and fluctuating temperature conditions is recommended to validate its large-scale biocontrol efficacy.

The life table data of papaya mealybug, Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae), on the jatropha, Jatropha integerrima (Euphorbiaceae), were collected using individually- and grouprearing and analyzed by using the age -stage, two-sex life table. Because the male individuals have six stages while the female individuals have only five stages, a new method was developed for a correct description of life stages and life table analysis. In general, the developmental durations of individually-reared insects were significantly longer than those of group-reared insects. Although the mean fecundity (F = 167.84 eggs/female) and the net reproductive rate (R0 = 62.10 offspring) of the individually-reared cohort were significantly higher than those of group-reared cohort (F = 66.5 eggs/female and R-0 = 18.62 offspring), there were no significant differences in the population growth rates, i.e., intrinsic rate of increase r and finite rate of increase lambda. Because the age variable x is an exponent in the Euler-Lotka equation, the first reproductive age and total preoviposition period are important factors in the determining the value of population growth rates. The life table data were used to simulate the population growth and timing of the control. Our results demonstrated that for grouplived insects like papaya mealybug, life table data collected using group-reared cohort is a better option for simulating pest population growth and management than data from individually-reared cohort.

Background This study was conducted to investigate life table characteristics of the parasitoid species, Goniozus legneri Gordh (Hymenoptera: Bethylidae), a major gregarious larval ecto-parasitoids of the carob moth, Ectomyelois ceratoniae Zeller (Lep.: Pyralidae). Demographic parameters of G. legneri reared on two hosts, the carob moth and the flour moth, Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae), were studied under laboratory conditions using age-stage, two-sex life table. Host stage preference and the functional response of this parasitoid were also determined. Results The duration of the immature period, adult pre-ovipositional period and total pre-ovipositional period of G. legneri reared on E. kuehniella was significantly longer than that of those reared on E. ceratoniae , while fecundity and ovipositional days of the wasp were greater/longer in females reared on E. ceratoniae . There were also significant differences in intrinsic and finite rates of increase and mean generation time between wasp parasitoid reared on two hosts. Moreover, population projection indicated that the G. legneri population can grow swifter when reared on E. ceratoniae than on E. kuehniella . Based on the experiments conducted to determine the larval stage preferences of G. legneri , for both hosts, larger larvae were more preferred stages compared to smaller ones, thereby fulfilling the optimal oviposition theory. The functional responses of G. legneri to different population densities of E. kuehniella two last instar larvae were determined as type III at 25 °C and 60% RH. Conclusion The results offer valuable information on some life history attributes of G. legneri . Although G. legneri performed better on E. ceratoniae larvae than on E. kuehniella, as the use of E. ceratoniae larvae as the main host in rearing of G. legneri might be a laborious process and can increase the production costs, E. kuehniella can be used as an alternative host. Further studies are required under greenhouse and field conditions for effective use of this biocontrol agent against the carob moth.

Applying reduced doses of pesticides has advantages such as resistance management, environmental pollution reduction, and control costs. Very few studies show that passing the water used for pesticide applications through a magnetic field can improve the pesticides' efficiency. In this study, the effect of a magnetic field on the acaricidal activity of spirodiclofen was evaluated against Tetranychus urticae. Treatments included distilled water and well water for preparing the suspensions after passing through a constant magnetic field of 0.42 Tesla. Furthermore, additional treatments were made by passing the prepared suspensions through the magnetic field. Mites were counted right before the sprays on days 7, 14, and 21. The treatment efficiencies were calculated by using the Henderson-Tilton formula. Except for 2 of 12 cases in which the efficiencies were negative, in the rest of the experiments, the magnetic field enhanced the efficiency of the studied acaricide. The highest values were recorded for two treatments including magnetizing the mixture of well water and acaricide treatment and magnetized distilled water plus acaricide treatment between days 7 to 21 (approximately 77 %). This study suggests the usefulness of magnetic fields as an environmental -friendly method to increase the effectiveness of the studied plant protection agent.

This paper reviews and introduces innovative research pertaining to the age-stage, two-sex life table. The main topics discussed are: (1) Analysis of data involving group-reared life table studies. We address the rationale behind the data analysis used when constructing a group-reared life table. Proper analysis of grouped-reared life table data enables the collection of realistic and applicable data for ecological studies, devising efficient mass-rearing programs and formulating pest management routines using time-and labor-saving group-rearing methods. (2) The bootstrap-match technique. This novel technique is applicable to those instances when constructing a complete life table involves collecting the immature independently from the adult data. (3) Application of the set theory in life table research. This procedure enables a mathematical description of the population structure and bootstrap samples. (4) Application of the multinomial theorem. Using the multinomial theorem enables calculation of the exact probability of bootstrap samples. (5) Inclusion of infertile bootstrap samples. Because it is impossible to calculate the intrinsic rates of increase for infertile samples, they are normally omitted in life table analysis. Inclusion of these infertile bootstrap samples produces an unbiased life table analysis. (6) The Cartesian product. The Cartesian product of two sets produces the complete coverage of all possible differences. We compared the paired bootstrap test, the Cartesian paired test based on bootstrap results, and the Cartesian paired test based on the multinomial theorem. (7) Integration of life table data with predation data. This procedure, which is especially relevant to biological control programs, enables a comprehensive study of the predator-prey relationship. (8) Computer simulation based on life tables. Population projection based on the age-stage, two-sex life table not only provides the means to predict the dynamics of stage structures of a given pest population, but also provides an insight into the dynamics of predation capacity of the predator population. (9) Problems in life table research. Each of the subjects discussed is crucial for the theoretical advancement and practical applications of scientific demographic research.

A sulfur dioxide treatment is often used to preserve the color and flavor of raisins. We used a life table approach to examine the effects of residual sulfites on Plodia interpunctella (Hubner) when larvae fed on raisins under controlled laboratory conditions. Raisins were fumigated with 66 g/m3 or 133 g/m3 SO2 for either three or six hours, or received no SO2 exposure (control). A two sex life table was constructed for insects in each treatment (n = 70 per treatment). Total immature mortality exceeded 90% in 66 g/m3 SO2 treatments, and 80% in 133 g/m3 SO2 treatments, compared to 28.6% in controls. Sulfur dioxide treatments significantly extended developmental time relative to controls, again more so in the 66 g/m3 SO2 treatments than in the 133 g/m3 treatments, but did not affect the adult longevity of survivors. All SO2 treatments reduced the fecundity of surviving female moths to a small fraction of controls, without significant differences among them. These effects combined to result in significantly diminished life table parameters in all treatments relative to controls, although generation times were increased more in the 66 g/m3 SO2 treatments than in the 133 g/m3 treatments. These inverse dosage-dependent effects may reflect increased feeding avoidance of sulfite residues in the higher dose treatments that resulted in reduced consumption. We conclude that residual sulfur and sulfites deposited on fruit surfaces during SO2 treatment provide substantial control of P. interpunctella, and should effectively suppress the proliferation of moths within bulk stores of dried raisins.

Short note on TWOSEX-MSChart: the key tool for life table research and education.

Amblyseius swirskii (Athias-Henriot) is one of the most important biological control agents and has been used in many countries. In this study, the suitability of Carpoglyphus lactis L. (Acari: Carpoglyphidae), Tyrophagus putrescentiae (Schrank), and their mixture for rearing A. swirskii was evaluated by using the two-sex life table. When reared on C. lactis, the durations of egg, deutonymph, total preadult, total preoviposition period, and adult male longevity of A. swirskii (1.95, 1.17, 6.13, 6.30, and 10.09 d, respectively) were significantly shorter than those reared on the mixed prey (2.05, 1.45, 6.55, 6.64, and 15.56 d, respectively).When reared on the mixed prey, however, the fecundity (110.21 eggs/female) of A. swirskii was significantly higher in comparison with those solely reared on C. lactis (82.17 eggs/female) or on T. putrescentiae (98.23 eggs/female). When reared on the mixed diet, the intrinsic rate of increase (r = 0.3792 d(-1)), finite rate of population increase (lambda = 1.4611 d(-1)), and net reproductive rate (R-0 = 79.69 offspring) of A. swirskii were significantly higher than those on single-species diets. For a daily production of 10,000 eggs of A. swirskii, a smaller population size (2,626 individuals) of A. swirskii is needed when reared on the mixed diet, in contrast to the 4,332 individuals on C. lactis and 3,778 individuals on T. putrescentiae. The population projection and mass-rearing analysis based on life table showed that the mixed diet was the most suitable and economical diet for the mass-rearing of A. swirskii.

The life table is a type of research tool that is frequently used in many studies involving population and community ecology. They are the basis for many comprehensive studies in pest management, pesticide resistance, predator-prey relationships, biological control, mass-rearing and harvesting of insects, plant resistance, etc. Because the morphology, physiology, survival, fecundity, and predation/consumption rate of most arthropods will vary significantly depending on their developmental stage and sex, precise description of stage differentiation and inclusion of both sexes are critical for attaining realistic and accurate life table analyses and correctly evaluating the overall fitness of populations. Since traditional female age-specific life tables ignore the male individuals in a population and are incapable of describing the unique and important feature of stage differentiation (i.e., metamorphosis) that is a defining characteristic of insects and mites, their application to data analysis involving these groups will inevitably result in miscalculations and limit the practical application of these life tables. On the other hand, the age-stage, two-sex life table (hereafter referred to as the two-sex life table whenever appropriate), can precisely delineate stage differentiation and includes both sexes in data analysis, description, and interpretation, and in practical applications. In this review, the problems of female age-specific life tables are examined, followed by a discussion of the advantages of using the two-sex life table. Finally, applications of the two-sex life table in various types of entomological research are discussed and accompanied by examples.

Integrated Pest Management (IPM) aims to combine biological and chemical strategies and measures, hence highlighting the study of acute toxicity and sub-lethal effects of pesticides comprehensively. The present research focused on the side effects of thiamethoxam and pirimicarb sub-lethal concentrations on demographic parameters of Diaeretiella rapae (McIntosh Laboratory) (Hymenoptera: Braconidae). Adult parasitoids were exposed to LC25 of insecticides as well as distilled water as the control. The results showed that thiamethoxam adversely affected population parameters (r, λ, R0, T), adults' longevity, females' oviposition period and mean fecundity, and a similar trend was obtained for pirimicarb with the exception of generation time (T), the latter did not significantly change compared to the control. The intrinsic rate of increase (r) in the control and those treated with pirimicarb and thiamethoxam were 0.2801, 0.2064, 0.1525 days-1, respectively, and the sex ratio was biased toward females in all treatments. Furthermore, none of the insecticides influenced total preoviposition period (TPOP) and offspring emergence rate. In general, these results indicated that both insecticides potentially distort the demographic parameters of the parasitoid even at sub-lethal concentrations, and then they should not be considered for IPM program in the presence of D. rapae. Keywords—Diaeretiella rapae, Lipaphis erysimi, life-table study, pirimicarb, thiamethoxam.

To better understand the effect of individual- and group-rearing conditions on predator performance, we studied the life table and predation rate of the predatory mite, Phytoseiulus persimilis Athias-Henriot, after the mites had been individually- or group-reared on two-spotted spider mites, Tetranychus urticae, eggs at 25±1°C, 65±5% RH and a photoperiod of 16: 8 (L:D) h. The net reproductive rate (R0), intrinsic rate of increase (r), net predation rate (C0), finite predation rate (ω) in the individually-reared predators were 40.61 offspring, 0.2594 d-1, 437.3 T. urticae eggs, and 4.8668 preys/d, respectively. Similar values were obtained when the predators were reared in groups (R0 = 43.10 offspring, r = 0.2837 d-1, C0 = 420.9 T. urticae eggs, and ω = 5.9054 preys/d). Mean adult longevities were 28.42 and 25.29 d for group-reared male and female predators, respectively; these values were significantly shorter than those of individual-reared mites (49.87 d for male and 36 d for female). Our results showed that P. persimilis mites could be group-reared in biological control programs without negative effect on their growth and predation potential.

Colorado potato beetles (CPB) overwinters as adults in the soil, thus, their survival is related with their energy reserves. The present study examined the biochemical changes in adults treated with sub-lethal concentrations (≤LC30) of pyriproxyfen. First, both the plants and overwintered adults were sprayed with different levels of pyriproxyfen (0, 250, 500 and 750 μl/l) under field conditions and were tested at 3, 6 and 12 days after treatment. Next, the adults from the first experiments were re-sprayed 1 week later with pyriproxyfen at the same concentrations and were re-sampled at 3, 6 and 12 days after the second treatment. The lipid, sugar, glycogen and protein levels of 4 males and 4 females were determined (mg/g; w/w). Results revealed a significant decline in lipid (87.7%), glycogen (50%) and caloric contents (75%) levels with respect to controls. Sugar and protein levels increased 7.89 and 5.79 times with respect to the controls. The best results were obtained at 250 μl/l of pyriproxyfen. The second round of testing demonstrated the additive effects of pyriproxyfen on bioenergetic reserves. Only the protein level showed a significant difference by sex.

The two-spotted spider mite, Tetranychus urticae Koch, is a polyphagous pest that causes considerable damage to field, horticultural and greenhouse crops. Currently, many plant essential oils and their active compounds have received attention because of their lethal effect against arthropod pests such as herbivorous mites. In this study, contact toxicity of three formulated compositions based on synthetic thymol and menthol including menthol 5%, thymol 5%, and a mixture of menthol 5% + thymol 5% tested against eggs and female adults of T. urticae . Adulticidal results showed that menthol 5% + thymol 5% had the lowest LC 50 value (656.77 µl/l) 24 hours after the treatment. Likewise, the mixture was highly effective against T . urticae eggs and had the lowest LC 50 value (967.24 µl/l). Although, the LC 50 value of menthol 5% and menthol 5% + thymol 5% were not significantly different from each other but both of them had a significant difference with the thymol 5% in manner of adulticide and ovicidal. Results also showed that a combination of thymol and menthol increased lethal effects compared to these two compounds.

Colorado potato beetles (CPB) overwinters as adults in the soil, thus, their survival is related with their energy reserves. The present study examined the biochemical changes in adults treated with sub-lethal concentrations (<= LC30) of pyriproxyfen. First, both the plants and overwintered adults were sprayed with different levels of pyriproxyfen (0, 250, 500 and 750 mu l/l) under field conditions and were tested at 3, 6 and 12 days after treatment. Next, the adults from the first experiments were re-sprayed 1 week later with pyriproxyfen at the same concentrations and were re-sampled at 3, 6 and 12 days after the second treatment. The lipid, sugar, glycogen and protein levels of 4 males and 4 females were determined (mg/g; w/w). Results revealed a significant decline in lipid (87.7%), glycogen (50%) and caloric contents (75%) levels with respect to controls. Sugar and protein levels increased 7.89 and 5.79 times with respect to the controls. The best results were obtained at 250 mu l/l of pyriproxyfen. The second round of testing demonstrated the additive effects of pyriproxyfen on bioenergetic reserves. Only the protein level showed a significant difference by sex.

The toxicity of thiamethoxam and pirimicarb on Diaeretiella rapae (Mc'Intosh) as a parasitoid of Lipaphis erysimi (Kaltenbach), exposed to residues on glass vials, was investigated under laboratory conditions at 23 ± 2 °C, 70 ± 5% RH and 16:8 h (L: D). Moreover, in order to find the negative impacts of both insecticides on the efficiency of D. rapae, the functional response of the exposed parasitoids were assessed. The newly emerged parasitoids were exposed to LC25 of the insecticides and distilled water as control. Host densities of 2, 4, 6, 8, 16, 32 and 64 were placed on canola seedlings in a transparent cylindrical container and were offered to the treated parasitoids. Type of functional response was determined by means of logistic regression method and the parameters, attack rate (a) and handling time (Th) were calculated by nonlinear regression model using SAS software. The parasitoid exhibited type II functional response in all experiments. Attack rates in control, pirimicarb and thiamethoxam were 0.057 ± 0.01,0.059 ± 0.013 and 0.040 ± 0.01 h -1 , and handling times were 1.097 ± 0.1, 1.86 ± 0.02, 2.81 ± 0.296 h, respectively. Maximum rates of parasitism (T/Th) were estimated 21.87, 12.9, 8.53 aphids, respectively. These observations suggest that pirimicarb with less harmful effects is the preferred candidate for controlling the mustard aphid.

The effect of fenpyroximate on life table parameters of Phytoseiulus persimilis (Athias-Henriot 1957) was evaluated under laboratory conditions (25 ± 2 °C, 60 ± 5 % RH and 16:8 (L:D) h). To take both sexes and the variable developmental rate among individuals into consideration, the raw data were analyzed based on the age stage, two sex life tables. The estimated value of LC50 for P persimilis is found to be 270 ppm. The preoviposition period of P persimilis treated with fenpyroximate (1.67 d) was signifi cantly longer than for the control treatment (1 d). The lifetime fecundity of P persimilis treated with fenpyroximate was 0.997 (egg/female) and for control treatment was 23.881 (egg/female). The intrinsic rate of increase (r), fi nite rate of increase (λ), net reproductive rate (R0), the mean generation time (T) and gross reproduction rates (GRR) of P persimilis treated with fenpyroximate were obtained as -0.023 d-1, 0.977 d-1, 0.724 offspring, 12.812 d and 3.981 offspring, respectively. Results showed that fenpyroximate had a signifi cant negative effect on life table parameters of P persimilis and indicate that fenpyroximate in combination with P persimilis should not be used together at the same time in integrated pest management programs aimed at control of Tetranychus urticae (Koch 1836).

The life table and parasitism rate of Diadegma insulare (Cresson) (Hymenoptera: Ichneumonidae), a larval parasitoid of the diamondback moth Plutella xylostella (L.) (Lepidoptera: Plutellidae), were studied at 25 +/- 1 degrees C, 65 +/- 10% RH, and a photoperiod of 16:8 (L: D) h. The data were analyzed based on the age-stage, two-sex life table theory. Because the sex ratio of offspring varies with the age of the female parent, we used only female offspring to calculate the intrinsic rate of increase (r), finite rate of increase (lambda), net reproductive rate (R-0), and mean generation time (T) by using the jackknife technique, the values of which were 0.18407 d(-1), 1.2021 d(-1), 17.94 offspring, and 15.69 d, respectively. We also calculated these parameters by using bootstrap technique. They were not significantly different from those estimated by using the jackknife technique. We included both male and female offspring in the calculation of the parasitism rate. The net parasitism rate (C-0) was 42.63 aphids. Moreover, population projection showed differences between simulated population based on total offspring and female offspring. Because both the offspring sex ratio and the parasitism rate depend on female age, it is necessary to use the age-stage, two-sex life table for a correct analysis. Frequency of the net reproductive rate estimated by using bootstrap technique fit normal distribution well, whereas frequency data estimated by using jackknife technique failed the normality test. We suggest that the jackknife technique should not be used for the estimation of population parameters.