Female Longevity Research Articles

Bioecological Parameters of the Black Fig Fly, Silba adipata (Diptera: Lonchaeidae), Collected from Fig Crops in Mexico

This study assessed several bioecological aspects of the black fig fly, Silba adipata McAlpine (Diptera: Lonchaeidae), the main pest of fig (Ficus carica L.). Figs were collected from eight sites in the Mexican states of Michoacán (Plan de Ayala, Los Tejones, Antúnez, Tangancícuaro, Indaparapeo, El Carrizal, and Charapendo) and Morelos (Telixtac). No infestation was recorded in figs collected in Charapendo, but, in the remaining sites, it was variable (2–33%). Figs from Plan de Ayala and El Carrizal were longer and contained more larvae than those from Telixtac and Los Tejones. Some figs (≤12) collected in Telixtac and Los Tejones contained few pupae or adults. The survival of larval and pupal stages (≤86%) and the proportion of females (40–53%) were determined at the sites where the infestation of figs was >6% (Telixtac, El Carrizal, Plan de Ayala, and Los Tejones). In the second part of this study, the development of individuals collected in Los Tejones was analyzed under constant conditions. The estimated larval duration time was between 13 and 15 d, whereas pupae lasted 11 d. The survival rate and longevity of females and males were very similar. Our results could help design a program for integrated pest management against S. adipata.

Predation affects the evolution of sex-specific longevity.

Predation, a major cause of natural selection, is classically thought to target the weak and sick. However, predators can target animals with condition-dependent sexual traits, and therefore, high-quality individuals can also be the focus of predation. Thus, it is not always clear which individuals are the foci of predators or how this affects trait evolution. Here, we tested for evolutionary effects of sex-specific predation on male and female longevity using replicate populations of the broad-horned flour beetle Gnatocerus cornutus. We found that male-limited predation resulted in the evolution of reduced male and increased female longevity, while female-limited predation had no effects on the longevity of either sex. We also document the costs of reproduction. Coupled with other findings, our results suggest that predation impacts high-quality males and, because of negative intersexual genetic correlations, this increases female longevity.

Biological and population parameters of Telenomus remus and Trichogramma atopovirilia as biological control agents for Spodopterafrugiperda

Maize production faces a significant threat from Spodoptera frugiperda (J. E. Smith) worldwide; historically, Trichogramma pretiosum Riley has served as the primary augmentative egg parasitoid for its biological control. However, since 2004, Telenomus remus Nixon has emerged as a viable global alternative. On a regional scale, in Mexico, Trichogramma atopovirilia (Oatman & Platner) was theorized to outperform T. pretiosum, proving superior in both laboratory and field conditions in 2020. To further the field efficacy of the augmentative use of parasitoids as biological agents of S. frugiperda, we conducted comparisons of biological and population parameters under laboratory-controlled conditions to determine whether T. remus would be more effective than T. atopovirilia, the best Trichogramma parasitoid in Mexico for S. frugiperda. We found that the former parasitoid had statistically significant longer female and male longevity, as well as a higher proportion of female offspring, and greater numerical values in net reproduction rate, intrinsic rate of increase, and finite rate of increase, but no differences were found in the number of days required for both parasitoids to develop from egg to female or egg to male, as well as in the mean generation time and doubling time. Under the conditions of these trials, T. remus had a 47.02% greater intrinsic rate of increase (rm) and may thus be a more effective biological control agent for S. frugiperda than T. atopovirilia. However, these biological and population parameter comparisons are the first execution worldwide; further studies are needed to validate these promising T. remus results.

Trehalose metabolism mediates trade-offs between reproduction and survival in beet webworm, Loxostege sticticalis, under heat stress.

Temperature is an important determinant of developmental and reproductive rates in insects. Here, we investigated the physiological responses of adult beet webworm, Loxostege sticticalis L. (Lepidoptera: Crambidae), to three temperatures (16, 23 and 30 °C) focusing on trehalose metabolism. Exposure of moths to 30 °C accelerated eclosion and ovarian development, but shortened the oviposition period and adult longevity, whereas exposure to 16 °C had opposite effects. Transcriptome analysis revealed that vitellogenin (VG) and vitellogenin receptor (VR) genes were up-regulated at 30 °C, as were numerous genes related to energy metabolism, including those involved in the insulin signaling pathway, the tricarboxylic acid (TCA) cycle, and glycolysis. Expression of the trehalose transporter gene TRET1 was also induced at high temperature, primarily in the ovaries, where trehalose content increased, accompanied by lipid degradation in the fat body. Treatment with the trehalase inhibitor validamycin A reduced female fecundity and longevity at 23 °C, but enhanced the expression of genes related to stress resistance and reproduction, mimicking the effect of high temperature. Besides their practical utility for predicting the oviposition behavior and geographic distribution of L. sticticalis in the field, these results elucidate the various physiological roles of trehalose in L. sticticalis during exposure of moths to high temperature and may provide insights into the relationship between stress resistance and reproduction in insects more generally. © 2024 Society of Chemical Industry.

The impact of lethal and sub-lethal exposure of emamectin benzoate on populations of Spodoptera litura (Lepidoptera: Noctuidae) under laboratory conditions

Emamectin benzoate is an avermectin bio-insecticide commonly used for managing several insect pests including Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae), a major polyphagous pest of many cultivated crops. The current study was conducted to evaluate the effects of emamectin benzoate on the fitness of S. litura populations exhibiting differential susceptibility to insecticide. The selection process and all the bioassays were carried out using 6-day-old 2nd instar larvae of S. litura. A field-collected population of S. litura was divided into two groups: one selected with emamectin benzoate for eight generations (EB-Sel) and the other kept unexposed (Unsel-Lab) to insecticide in the laboratory. An increase in resistance ratio from 1.71-fold in the F1 generation to 22.54-fold in the F8 generation of the EB-Sel population was observed compared to the Unsel-Lab (F8) population. The EB-Sel and Unsel-Lab populations were treated with their respective lethal and sub-lethal concentrations which resulted in an extended development period, decreased larval survival, and adult emergence along with increased morphological abnormalities in adults. Significant reductions were observed in both male and female longevity, fecundity, egg hatching, net reproductive rate (R0), intrinsic rate of increase (rm), and finite rate of increase (λ) in EB-Sel and Unsel-Lab populations. Higher concentrations of the insecticide also reduced the relative fitness (Rf) of S. litura larvae, with maximum effect at LC50 of the EB-Sel population where the Rf value was 0.32 compared to the Unsel-Lab population. Both populations have been affected by emamectin benzoate exposure, however, the impact was more pronounced in the EB-Sel population indicating fitness costs. Our results suggested the fitness cost linked to emamectin benzoate resistance in S. litura which might favor managing insecticide resistance by reducing the frequency of resistant alleles by removing selection pressure. Consequently, our research provides significant insights to devise better pest management strategies for S. litura.

Sublethal effects of emamectin benzoate on biological characteristics and the expression of vitellogenin (SgVg) and its receptor in Sclerodermusguani

Emamectin benzoate (EMB) is a commonly used insecticide for controlling agricultural and forest pests. To facilitate its rational use in integrated pest management (IPM), the sublethal effects of EMB on the development and reproduction of Scleroderma guani were evaluated. Sublethal doses of EMB (LD10 and LD30) significantly reduced the longevity and fecundity of F0 females. In the F1 generation, sublethal doses significantly reduced larval development duration and male longevity but significantly extended female longevity. Additionally, the LD30 treatment significantly decreased the number of laid eggs in F1 females by 20.72% compared with the control group. The net reproductive rate (R0) was significantly declined by the LD30 treatment compared with the control group (CK). Furthermore, the mean generation time (T) was significantly extended in both LD10 and LD30 treatment groups. Compared to the control group, the expression of SgVg and SgVgR genes in the LD10 and LD30 groups was significantly lower, which may be a crucial factor for the reduced fecundity of the females. These results indicate that sublethal doses of EMB significantly reduced adult longevity and fecundity of S. guani. The findings are practical for developing IPM strategies for forestry pests using S. guani and EMB.

Infection with pathogenic fungi is a major threat to the mass production of the parasitoid wasp Habrobracon hebetor: 20 generations under surveillance

Pathogen infection is one of the most important challenges threatening the success of mass rearing of natural enemies either in insectaries or in augmentative biological control programs. In this investigation, we studied the biological and population growth parameters of a naturally infected colony of the parasitoid wasp Habrobracon hebetor (Say) (Hymenoptera: Braconidae) over 20 generations (G1inf − G20inf) of rearing on Ephestia kuehniella (Zeller) (Pyralidae: Lepidoptera) under laboratory conditions. Based on morphological characteristics and ITS sequences, two types of fungal colonies were isolated from the diseased females and identified as Thermothielavioides terrestris and Aspergillus flavus. The results showed that although no significant differences were found in the female longevity and fecundity of H. hebetor on E. kuehniella up to G15inf, the duration of the immature period was extended as the number of generations increased. In addition, the intrinsic rate of increase (r) and finite rate of increase (λ) had no significant differences up to G8inf. The net reproductive rate (R0) of G15inf had no significant differences with G2inf, G8inf, and G10inf. On the other hand, in G15inf, R0 was significantly higher than G4inf, G6inf, and G20inf. The findings underscore the negative impact of fungal infection on population growth parameters compared with uninfected population. This study showed that naturally fungal infection of the parasitoid affected the population growth and life table parameters through mass rearing, compared and discussed with the healthy parasitoid.

Differential longevity in free-living smooth snakes Coronella austriaca

During a 31-year study (1992–2022) of reptiles inhabiting a 10 ha area of lowland heath, within a planted coniferous forest in southern England, UK, smooth snakes Coronella austriaca Laurenti, 1768, were individually marked with passive integrated transponder tags. New-born smooth snakes were also captured, measured and weighed to estimate size at birth. Growth curves were estimated for females and males which, combined with their estimated size at birth, provided an estimate of age at the time of death. The estimated mean age at death of females (7.8 years) was significantly lower than that of males (10.1 years), with females and males reaching a maximum age of 15 and 25 years respectively. Reproductive effort was considered as a possible explanation for the observed reduced longevity of females compared to males. Female reproductive success increased between 4 and 10 years of age and then declined in the largest breeding individuals, regardless of age. This finding suggested the possible presence of size/growth-related reproductive senescence. This is the first known study to provide reliable estimates of longevity in free-living smooth snakes. It demonstrated a significant difference between females and males in both mean and maximum ages attained, and the potential impact of breeding stress as an explanatory factor for increased female mortality and reproductive senescence. Keywords: predicted age, body size, SVL, reproductive output, senescence

Unveiling the female experience through adult mortality and survivorship in Milan over the last 2000 years

This study challenges historical paradigms using a large-scale integrated bioarchaeological approach, focusing on the female experience over the last 2,000 years in Milan, Italy. Specifically, 492 skeletons from the osteological collection of Milan were used to elucidate female survivorship and mortality by integrating bioarchaeological and paleopathological data, paleoepidemiological analyses, and historical contextualization. Findings revealed changes in female longevity, with a notable increase from Roman to contemporary eras, albeit plateauing in the Middle Ages/modern period. Significant sex-specific differences in mortality risk and survivorship were observed: females had higher mortality risk and lower survivorship in the Roman (first-fifth century AD) and Modern (16th-18th century AD) eras, but this trend reversed in the contemporary period (19th-20th century AD). Cultural and social factors negatively impacted female mortality in Roman and modern Milan, while others buffered it during the Middle Ages (sixth-15th century AD). This study underscored the importance of bioarchaeological inquiries in reconstructing the past, providing answers that may challenge historical assumptions and shedding light on how the interplay of cultural, social, and biological factors shaped the female experience across millennia.

Toxicity and fitness evaluation of Chrysoperla carnea resistant strains on cotton mealy bug Phenacoccus solenopsis Tinsely

Research was conducted to select chlorantraniliprole and bifenthrin resistant strains of Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) at Bahauddin Zakariya University, Multan, Pakistan. Moreover, fitness parameters of resistant C. carnea were evaluated after feeding on 2nd instars nymph of Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae). Two to three day old C. carnea larvae were used in each topical bioassay. The raw data of biological parameters were analysed using an age stage, two sex life table. After 16 and 13 rounds of selection, the Chlo-Sel and Bife-Sel strains of C. carnea developed 91- and 2.19-fold resistance level, respectively compared with the UN-Sel strain. Biological parameters such as larval duration (days), pupal duration (days), female longevity (days), male longevity (days), adult pre-oviposition period (APOP) (days), total pre-oviposition period (TPOP) (days), oviposition (days), reproductive female ratio (RepF/Fn), and fecundity/female (F) were significantly different while pre-adult female (days), pre-adult male (days), and female ratio (Nf/N) was not significantly different among all strains. Demographic parameters such as finite rate of increase (λ), mean generation time (T), intrinsic rate of increase (r), net reproductive rate (Ro), and gross reproductive rate (GRR) were significantly different while doubling time (DT) was significantly similar among all strains of C. carnea. This information could be helpful in developing and promoting the use of insecticide resistant strains of C. carnea for the management of P. solenopsis under field conditions. Moreover, knowledge of fitness advantages will be helpful in IPM for the development of control strategies against P. solenopsis. In order to explore the practical relevance of our findings, more research ought to be conducted.

Effects of the symbiotic bacteria, Caballeronia insecticola, on the life history parameters of Riptortus pedestris (Hemiptera: Alydidae) and their implications for the host population growth.

This study aimed to investigate the effects of symbiosis on the life history of host insects and address their implications at the host population level. We evaluated the effects of symbiotic bacteria Caballeronia insecticola on its host Riptortus pedestris (Fabricus) (Hemiptera: Alydidae) from cohorts for nymphal development, adult survivorship, and female reproduction. Then, life table parameters were compared between symbiotic and apo-symbiotic groups, and the effects of symbiosis on the abundance of R. pedestris were simulated for varying proportions of symbiotic individuals in host populations. We found that symbiosis significantly accelerated the nymphal development and reproductive maturation of females. However, symbiosis incurred survival cost on adult females, reducing their longevity by 28.6%. Nonetheless, symbiotic females laid significantly greater numbers of eggs than the apo-symbiotic during early adult ages. This early reproductive investment negated the adverse effect of their reduced longevity, resulting in the mean lifetime fecundity to not significantly differ between the 2 groups. Indeed, total cohort fecundity of the symbiotic group was 1.3-fold greater than that of the apo-symbiotic group. Life table analysis demonstrated shorter generation time and greater population growth rate in the symbiotic population. Finally, the simulation model results indicate that an increase in the proportion of symbiotic R. pedestris favored the population growth, increasing the population size by 1.9 times for every 25% increase in the proportion of symbiotic individuals. Our study demonstrates that symbiont-mediated changes in the life history parameters of host individuals favor the host population growth, despite substantial reduction in the female longevity.

Age structure of the Japanese treefrog – <i>Dryophytes japonicus</i> (Amphibia, Anura, Hylidae) in the south of the Primorsky krai (Russian Far East)

The article presents the results of age structure studying in a population of the Japanese treefrog (Dryophytes japonicus) by skeletochronology. Animals were caught in the vicinity of Fokino town and Dunay settlement (Primorsky Krai, Russian Federation) in the third decade of July, 2022–2023. Cross sections of a finger’s phalanges were used as a registering structure. To es- timate age, preparations from 59 individuals (12 females and 47 males) were used. The body length of females and males was in a range of 29.40–44.80 mm (on average 38.50 ± 5.69) and 34.16–44.16 mm (on average 38.30 ± 2.36), respectively. The age of females and males varied in a range of 1–4 years (on average 2.7 ± 1.3) and 1–5 years (on average 2.2 ± 1.1), respectively. The modal age in females and males was 4 years (41.6 % of all studied individuals) and 1–2 years (63.8 %), respectively. The average age of males and females did not differ statistically significant- ly. Body length depended on age, in both females (r = 0.82, p < 0.05) and males (r = 0.54, p < 0.05). The expectancy longevity in females and males was 4.41 years (S = 0.744) and 3.76 years (S = 0.693), respectively. The growth of males stops after reaching puberty. Females continue to grow after maturation; that is why the most adult individuals are the largest ones. The growth rate coefficient (k) was higher in males (2.22) than in females (0.89). The authors note that in the south of the Primorsky Krai, D. japonicus is characterized by the minimum age of puberty and life longevity among all studied populations.

Assessment of non-target toxicity of insecticides on Ganaspis brasiliensis (Ihering) in laboratory and field conditions.

G1 strain Ganaspis brasiliensis (Ihering) has been recently released in both Europe and America as a biological control agent of the spotted wing drosophila, Drosophila suzukii (Matsumura). In initial phases of classical biological control programs, it becomes imperative to evaluate the susceptibility of parasitoids to insecticides, to identify the best alternatives to adopt in an integrated pest management and organic perspective. In this study, we evaluated lethal and sublethal effects of topical application of five different insecticides classes: neonicotinoids, diamides, pyrethroids, organophosphates and spinosyns. Additionally, we tested residual toxicity in field trials in vineyards and sweet cherry orchards. Adult wasps' susceptibility to different insecticides' classes were consistent between laboratory and field. Spinosad exhibited the highest toxicity, with a median lethal concentration (LC50) of 0.00372 of the maximum field dose, and the highest knock-down effect in field trials, causing 92.5 ± 5% of mortality at T0. λ-cyhalothrin showed sublethal effects on both male and female insects' longevity when applied at LC30. In field trials, deltamethrin showed the highest persistence, causing significant parasitoid mortality up to 14 days after treatment. Conversely, cyantraniliprole was the least toxic active ingredient according to both topical and residual bioassays, even though its residues caused mortality up to 7 days after the treatment in the field. Our results indicate that spinosad and λ-cyhalothrin are highly toxic to G. brasiliensis, making them incompatible with classical biological control programs. Cyantraniliprole exhibited lower toxicity, and may be considered a selective pesticide for the integrated management of D. suzukii. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

A comparative approach for life history and functional response demonstrates similar survival strategies for Trichogramma evanescens and T. pintoi.

Egg parasitoids are important biological control agents of lepidopteran pests of agricultural crops. Trichogramma evanescens Westwood and T. pintoi Voegele (Hymenoptera: Trichogrammatidae) are egg parasitoids with worldwide importance. The parasitoid selection necessitates comparative assessment of the life table traits and functional response analysis to provide insights into their effectiveness in pest control. In this study, we examined theirlife table traits including survivorship and reproductivity, and functional response and associated parameters i.e., attack coefficient and handling time. Life table parameters, using age-stage, two-sex theory, revealed similar survival and reproductive strategies for both species. For example, the female longevity, oviposition days and fecundity did not differ between both species. Exceptionally, the male longevity of T. evanescens was shorter than that of T. pintoi. The population growth parameters such as gross reproductive rate (GRR), net reproductive rate (R0), intrinsic rate of increase (r), finite rate of increase (λ), and mean generation time (T) did not differ between species. The polynomial logistic regression yielded a type III functional response and a non-linear least square analysis revealed different attack coefficient and similar handling time. However, their parasitism rate differed between the lowest (five eggs) and highest (80 eggs) initial host egg densities such that T. evanescens had a lower parasitism rate at the lowest density and higher parasitism rate at the highest density. The similarity in survival strategies and minor differences in host handling of both parasitoids are discussed in terms of relevance to applied biological control applications and evolutionary traits. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Silence of Aminopeptidase N 2gene reveals the trade-offs for acquiring Cry1Ac resistance in Plutella xylostella.

Bacillus thuringiensis (Bt) is widely used as a biopesticide worldwide. To date, at least eight pest species have been found to be resistant to Bt in the field. As the first pest that was reported having resistance to Bt in the field, considerable research has been done on the mechanisms of Bt resistance in Plutella xylostella. However, whether the acquisition of Bt resistance by P. xylostella comes at a fitness cost is also a valuable question. In this study, Aminopeptidase-N 2 (APN2), a Cry toxin receptor gene of P. xylostella, was knocked down by RNA interference, resulting in improved resistance to Cry1Ac. It was also found that larval mortality of APN2 knockdown P. xylostella was significantly higher than that of the control, while the pupation rate, pupal weight, eclosion rate, fecundity (egg/female), hatchability, and female adult longevity were significantly lower in APN2 knockdown P. xylostella than in the control. These results illustrate that if Cry1Ac resistance was obtained only through the reduction of APN2 expression, P. xylostella would need to incur some fitness costs for it.

Biology and Morphometrics of Fall armyworm (Spodoptera frugiperda) in Chitwan, Nepal

The Fall armyworm (FAW) Spodoptera frugiperda, native to the Americas, is an important invasive and polyphagous pest threatening cereal production. Abiotic and biotic factors, including climatic uncertainty and insect pests like S. frugiperda, pose threats. Detected in East Africa in 2016 and reported in Nawalpur, Nepal, on May 9, 2019, FAW has led to a 34% decline in maize yields. Studying FAW's biology and morphometrics is crucial for understanding its habitat and ecology, essential prerequisites for adopting integrated management strategies. Biological parameters such as incubation period, larval and pupal duration, pre-oviposition and, oviposition periods, male and female adult longevity, larval and pupal mortality, sex ratio (male: female), and morphometrics of egg, larvae, pupa, and adult were measured. The incubation period (2-3 days), larval and pupal periods (13-18 and 9-12 days) with overall life duration (31-45 days) were recorded in maize. Head capsule width of the first, second, third, fourth, fifth, and sixth instar were recorded as 0.52±0.05, 0.73±0.05, 1.1±0.05, 1.74±0.12, 2.04±0.15, and 2.91±0.23 mm respectively. Mean body length of different larval instars were recorded as 3.33±0.26, 6.92±1.07, 13.11±1.45, 16.82±1.57, 28.68±1.75, and 34.56±1.99 mm for the first, second, third, fourth, fifth, and sixth instar respectively.

The Effect of Different Thiamethoxam Concentrations on Riptortus pedestris Development and Fecundity.

The stink bug, Riptortus pedestris (Fabricius) (Hemiptera: Alydidae), is a highly destructive pest that significantly damages legume crops in East and South Asia. Neonicotinoid insecticides containing thiamethoxam are widely used to control R. pedestris in soybean fields. However, the current knowledge on the impact of different thiamethoxam concentrations on R. pedestris growth and reproduction is lacking and insufficient. The present study investigated the effects of thiamethoxam on the biological traits of R. pedestris after treatment with LC10 (19.8 mg/L), LC20 (31.6 mg/L), LC30 (44.2 mg/L), LC40 (58.9 mg/L), and LC50 (77.0 mg/L) concentrations. These five thiamethoxam concentrations (LC10~LC50) reduced adult longevity and fecundity in the F1 generation females. Thiamethoxam treatment also significantly decreased the population trend index, intrinsic rate of increase, net reproductive rate, gross reproductive rate, and finite rate of increase and increased the mean generation time. These results show that thiamethoxam hinders and suppresses the development and growth of the F1 population of R. pedestris. Thiamethoxam is recommended for spray control during peak adult emergence, as it not only has a controlling effect on the parental generation but also a negative impact on the F1 generations.

Effect of storage period on trichocards parasitized by Trichogramma chilonis Ishii under laboratory conditions

The present study aimed to find the suitable storage duration for parasitized trichocards without affecting much the biological parameters of T. chilonis adults such as adult emergence, adult longevity and egg parasitization. The results revealed that biological parameters viz., adult emergence, adult longevity and egg parasitization were inversely proportional to the storage period. Maximum adult emergence (87.63%), female longevity (5.57 days), male longevity (4.53 days) and egg parasitization (85.67%) were observed at 5 days storage period. Further, adult emergence declines to 56.13 per cent when trichocards are stored for 25 days. Whereas, less than 50 per cent egg parasitization in F1 generation was observed when trichocards were stored for 35 days. However, there was no egg parasitization by a female in the F1 generation noticed for 45 and 50 days storage period this might be due to short adult female longevity and lowest adult emergence. Hence, it can be concluded that trichocard could be effectively stored for up to 25 days at low temperatures under refrigerator conditions(4°C temperature and 50-60% relative humidity) by considering at least 50 per cent adult emergence with 4.13 days of female longevity as well as 63.00 per cent egg parasitization during the mass production program. Therefore, effective and right time augmentation of T. chilonis could be achieved under field conditions.

Evaluation of key factors for mass rearing the egg parasitoid Telenomus remus Nixon (Hymenoptera: Scelionidae)

BackgroundTelenomus remus is an egg parasitoid used as a biocontrol agent to control the invasive pest Spodoptera frugiperda. The use of high-quality factitious hosts is needed for efficient mass rearing of high-fitness parasitoids for biological control releases. To improve the efficiency and quality of parasitoid production for mass rearing, we evaluated host perference, supplemental nutrition, ultraviolet (UV) irradiation, parasitoid density, and exposure duration. Quality control for the mass rearing of Te. remus has not been conducted previously. This study determined the conditions and quality control factors necessary for the effective mass rearing of Te. remus.MethodsThe preferred host of Te. remus was determined and the effects of supplemental nutrition on Te. remus adults, as well as those of ultraviolet (UV) irradiation on host eggs were evaluated. The subsequent impact on the quality of Te. remus were also assessed. The optimal parasitoid-to-host eggs ratio and exposure duration were studied.ResultsTelenomus remus preferred S. frugiperda eggs as the host. Nutrition supplementation prolonged female longevity and increased fecundity of Te. remus. UV irradiation caused S. frugiperda eggs to shrivel, having a negative effect on Te. remus reproduction. When the ratio of Te. remus to S. frugiperda eggs ranged from 1:4 to 1:10 and the exposure duration was 48 h, a lower wizened egg rate, higher emergence rate, and greater female proportion was obtained.ConclusionsThe use of S. frugiperda eggs as the host for mass rearing of Te. remus was indicated, and it was found Spodoptera litura eggs could sever as an alternative host. Nutrition supplementation and non-UV-irradiated S. frugiperda eggs should be provided. The suitable ratio of Te. remus to S. frugiperda eggs ranges from 1: 4 to 1:10, and the exposure duration should be 48 h, as determined by the ratio of parasitoid to host eggs.

Effect of zinc fortified, arid and irrigated wheat varieties flour upon life history parameters of red flour beetle, Tribolium castaneum (Herbest) (Coleoptera: Tenebrionidae)

Red flour beetle, Tribolium castaneum (Herbest) (Coleoptera: Tenebrionidae) is a stored grain pest. Various fortified wheat varieties have been produced but data about the impact of different wheat varieties flour on life history parameters of T. castaneum are poorly understood. This study evaluated the effect of fortified (Zincol-16 T1), arid zone [(BARS-09 T2), and (Fatehjang-2016 T3)] and irrigated zone [(Faisalabad-2008 T4), (Gold-2016 T5), (Manthar-03 T6), (Fareed-06 T7), (Mairaj-08 T8)] wheat varieties flour upon some life history parameters of T. castaneum in the laboratory using age-stage two sex life table. The egg incubation period, adult male and female longevities, and total male and female longevities of T. castaneum were shortest in T5 and T6 as compared to all other treatments. The T5 presented shorter larval and pre-adult duration. Egg incubation, larval, and pupal durations and total male and female longevities were higher in T1. Total longevity (egg to adult) of T. castaneum was lowest in T1 as compared to T3 and T4 but similar to other treatments. Pre-adult duration was longer in T1 as compared to all other treatments. Pre-adult survival was significantly lower in T1 (53%) than all the treatments in which it remained at par. Lowest proportion of female adult (Nf/N) was found in T1 as compared to T3, T4, and T7. Age stage specific survival rate (sxj) was lower on T1, whereas life expectancy (exj) was higher than other varieties. These results suggest that T. castaneum develop poorly upon zinc fortified wheat variety, Zincol as compared to other varieties thus it can be a good integrated pest management tool against this pest.