Rapid comeback of males: evolution of male-killer suppression in a green lacewing population

Evolutionary theory predicts that the spread of cytoplasmic sex ratio distorters leads to the evolution of host nuclear suppressors, although there are extremely few empirical observations of this phenomenon. Here, we demonstrate that a nuclear suppressor of a cytoplasmic male killer has spread rapidly in a population of the green lacewing Mallada desjardinsi An M. desjardinsi population, which was strongly female-biased in 2011 because of a high prevalence of the male-killing Spiroplasma endosymbiont, had a sex ratio near parity in 2016, despite a consistent Spiroplasma prevalence. Most of the offspring derived from individuals collected in 2016 had 1 : 1 sex ratios in subsequent generations. Contrastingly, all-female or female-biased broods appeared frequently from crossings of these female offspring with males derived from a laboratory line founded by individuals collected in 2011. These results suggest near-fixation of a nuclear suppressor against male killing in 2016 and reject the notion that a non-male-killing Spiroplasma variant has spread in the population. Consistently, no significant difference was detected in mitochondrial haplotype variation between 2011 and 2016. These findings, and earlier findings in the butterfly Hypolimnas bolina in Samoa, suggest that these quick events of male recovery occur more commonly than is generally appreciated.

Sublethal and transgenerational effects of thiamethoxam applied to cotton seed on Chrysoperla externa and Harmonia axyridis

BACKGROUND

Thiamethoxam, when applied as a seed treatment, can contaminate plant products, such as extrafloral nectar, and have non-target effects on beneficial arthropods. This study assessed the non-target effects of thiamethoxam applied to cotton seed on the life history parameters of the predators Chrysoperla externa (Neuroptera: Chrysopidae) and Harmonia axyridis (Coleoptera: Coccinellidae).

RESULTS

Exposure of C. externa larvae to plants grown from thiamethoxam-treated seeds caused sublethal and transgenerational effects. Thiamethoxam treatment doubled the proportion of pharate adults and reduced egg fertility in C. externa F0 and F1 generations. In addition, the insecticide prolonged pupal developmental time in the C. externa F1 generation. Thiamethoxam treatment also had a transgenerational effect on exposed H. axyridis larvae, reducing pupal survival in the F1 generation. In the adult bioassay, thiamethoxam treatment reduced egg fertility of C. externa, prolonged the larval period, and reduced both fecundity and egg fertility of the F1 generation. Thiamethoxam also caused transgenerational effect on H. axyridis adults, reducing larval survival of the F1 generation.

CONCLUSION

Thiamethoxam seed treatment was harmful for both predators, but C. externa was more affected by the insecticide than H. axyridis. © 2018 Society of Chemical Industry.

Lethal and Sublethal Toxicity of Insecticides to the Lacewing Ceraeochrysa Cubana

The lethal and sublethal effects of 11 insecticides on the predator Ceraeochrysa cubana (Hagen) were assessed under laboratory conditions. First-instar larvae and adults ≤ 48 h old were sprayed with the highest insecticides doses allowed to control Diaphorina citri Kuwayama in the citrus crop. The survival and duration rates of the different development stages, sex ratio, pre-oviposition period, fecundity, and fertility of the insects were evaluated. In the larval bioassay, chlorpyrifos and malathion had lethal effect which none larvae survived. Azadirachtin, lambda-cyhalothrin + chlorantraniliprole, lambda-cyhalothrin + thiamethoxam, and thiamethoxam had lethal and sublethal effects that did not allow to estimate the life table parameters because the low number of couples formed. Esfenvalerate, imidacloprid WG and SC, phosmet, and pyriproxyfen had sublethal effects which were reflected in the net reproductive rate and in the intrinsic rate of natural increase. In bioassay using adults, none of the individuals survived in the chlorpyrifos, lambda-cyhalothrin + chlorantraniliprole, lambda-cyhalothrin + thiamethoxam, malathion, or thiamethoxam treatments, and the azadirachtin, esfenvalerate, imidacloprid WG and SC, phosmet, and pyriproxyfen treatments were significantly lower compared to the control. None of the insecticides was harmless to first-instar larvae and adults of C. cubana under laboratory conditions showing their potential to reduce the efficiency of this predator.

Intraguild Predation between Chrysoperla carnea (Neuroptera: Chrysopidae) and Hippodamia variegata (Coleoptera: Coccinellidae) at Various Extraguild Prey Densities and Arena Complexities

Intraguild predation (IGP) is a ubiquitous, important and common interaction that occurs in aphidophagous guilds. The effects of extraguild prey (EGP, i.e., aphids) density, predator life stage combinations and duration of the interaction on the level, asymmetry and direction of intraguild predation between lacewing Chrysoperla carnea and ladybird Hippodamia variegata were examined in simple laboratory arena and more complex microcosm environment. Three initial densities of 50, 150 and 400 Aphis fabae third instar nymphs and a control without aphids were provided to six combinations of predator life stages (2nd and 3rd larval instars of lacewing and 3rd and 4th instars and adult females of ladybird). The remaining aphid density and occurrence of IGP were checked after 24, 48 and 72 h. The IGP intensity (IGP level, IL) was similar in the simple arena (reaching 0.6 between larvae in absence of EGP and 0.3 between lacewing larvae and ladybird females) and microcosm environment (0.3 without EGP). In both environments, increasing EGP density lowered IL according to negative exponential relationship. IGP was asymmetric (general average asymmetry was 0.82 in simple arena and 0.93 in microcosm, the difference was not significant) and mostly in favour of larvae of C. carnea, except in the combination of 2nd larvae of C. carnea with the 4th larvae and adults of H. variegata. The direction of IGP, but not other characteristics, partially changed during the duration of the experiment. The incidence of IGP interactions among aphid predators under real conditions and its consequences on aphid biological control are discussed.

Interactions between Fungal-Infected Helicoverpa armigera and the Predator Chrysoperla externa

The aim of the present study was to evaluate the interactions between Chrysoperla externa (Hagen, 1861) and the eggs and first-instar larvae of Helicoverpa armigera (Hübner 1805) infected by entomopathogenic fungi. The H. armigera eggs and larvae were treated with sterile distilled water + 0.01% Tween 80 (T1, control), Beauveria bassiana (Bals.) Vuill (T2), Metarhizium anisopliae (Metsch.) Sorok (T3), or Metarhizium rileyi (Farlow) Samson. (T4) at different concentrations (1 × 107, 1 × 108, and 1 × 109 con. mL-1). For each treatment, a single third-instar C. externa was offered prey (a combination of 80 eggs and 50 first-instar H. armigera larvae) at 0, 24, and 48 h after inoculation. Ten trials were completed for each treatment, and the entire experiment was repeated three times. Neither the concentrations of fungi nor the application method affected consumption by C. externa. Because all the predator larvae reached the pupal phase, with 100% viability in adults, these results suggest that entomopathogenic fungi and C. externa are compatible and that the simultaneous use of these biological control agents is possible for managing H. armigera.

Attracting Chrysopidae With Plant Volatiles for Lace Bug (Hemiptera: Tingidae) Control in Rhododendrons and Azaleas

The azalea lace bug (Stephanitis pyrioides Scott) (Hemiptera: Tingidae) is an invasive pest of rhododendrons and azaleas (Ericaceae: Rhododendron), which feeds on the underside of leaves causing chlorosis, reduced photosynthesis, and even plant death. While insecticides can control this pest, growers, landscape managers, and homeowners have requested softer alternatives. Augmentative release of predatory green lacewing Chrysoperla sp. (Neuroptera: Chrysopidae) eggs and larvae has reduced S. pyrioides, but large-scale implementation may not be practical nor cost-effective. Attracting naturally occurring Chrysopidae with plant volatiles may be an economical and convenient option. In this study, we tested whether volatile blends 1) attracted Chrysoperla sp., and 2) controlled S. pyrioides populations on Rhododendron spp. in farm or urban landscapes. Experimental plots contained different multicomponent lures placed aboveground next to infested plants. Adult Chrysoperla sp., other natural enemies, and S. pyrioides from egg to adult stages were monitored in both farm and urban landscapes for two summers. Overall, two out of three volatile blends consistently attracted Chrysoperla sp. to sticky traps near baited plants. Methyl salicylate + acetic acid + 2-phenylethanol (methyl salicylate blend) and acetophenone + acetic acid + 2-phenylethanol (acetophenone blend) captured more adult Chrysoperla sp. than control traps in farm landscapes. However, only the acetophenone blend was associated with a slight reduction of S. pyrioides. Additional research is needed to determine whether the phenology of the first generation of both species are synchronized for effective season biological control in the Pacific Northwest.

Selectivity of Entomopathogenic Fungi to Chrysoperla externa (Neuroptera: Chrysopidae)

Simple Summary

Agricultural crop systems have adopted integrated management as a model of success in pest control; however, chemical control is still prioritized. The use of pesticides incorrectly and excessively has provided a reduction in natural enemies, selection of resistant populations and resurgence of pests. Chrysoperla externa is a predator found in several regions in Brazil that preys on different pest insects. Entomopathogenic fungi Beauveria and Metarhizium also stand out for causing epizootics on pests. Both predators and entomopathogens can simultaneously act as pest control; thus, verifying the selectivity of entomopathogenic fungi to predators increases the potential for biological control through synergism and conservation of natural enemies in the agroecosystem. Considering the control potential of these different biological control agents, in this study we evaluated the selectivity of Beauveria bassiana, Metarhizium anisopliae and Metarhizium rileyi to the larvae of this predator. The results provide evidence that the biological development of larvae of C. externa is not influenced by the entomopathogenic fungus. These species of fungi can be recommended, aiming at a management of populations of arthropod pests, with low effect on C. externa when it is present in the agrosystem.

Abstract

We aimed to evaluate the selectivity of entomopathogenic fungi to larvae of Chrysoperla externa (Neuroptera: Chrysopidae). For this purpose, Beauveria bassiana (strain ESALQ PL63), Metarhizium anisopliae (strain ESALQ E9) and Metarhizium rileyi (strain UFMS 03) were assessed at different concentrations (1 × 10⁷, 1 × 10⁸ and 1 × 10⁹ conidia mL⁻¹). The control treatment consisted of distilled water and Tween80 0.01. The treatments were applied with a Potter spray tower using two different methodologies: direct application (DA) and dry film (DF). Up to 96 h after application, no treatment provided a larval mortality above 3%. After 120 h, only B. bassiana induced significant mortality in all instars, with rates of 26%, 17% and 10% for first, second and third instar larval periods, respectively. There was no difference regarding to the application method or concentration of conidia. The percentage of individuals that revealed changes in the length of the larval and pupal periods varied among different treatments with entomopathogenic fungi and control treatments, application methodologies and concentrations. Despite B. bassiana revealing a higher mortality than M. anisopliae and M. rileyi on larvae of C. externa, these three entomopathogenic fungi may be used in association with C. externa for sustainable pest management.

Morphology of the male and female reproductive tracts of virgin and mated Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae)

Predatory insects have reproductive organs rich in complex changes that may be responsible for the success of their population growth. The species Chrysoperla externa is a predator used in biological control programs in Latin America. However, there is no morphological data about the morphology of the reproductive tract in this insect. This study describes the morphology of the reproductive organs of virgin and mated C. externa male and female. The male has a pair of testes yellow in color and five pairs of accessory glands closely associated with the seminal vesicles. The testis follicles are twisted filled with cysts in different developmental stages. The pair of ovaries in the females shows asymmetry with 9-11 ovarioles per ovary with oocytes in different developmental stages and a spherical spermatheca. Virgin and mated males have no differences in the size of the testes, seminal vesicle, and accessory glands. C. externa females show morphological changes in the reproductive tract according to sexual maturation, which is triggered by mating. The ovary activation occurs after female mating. The ovaries are of merotistic polytrophic type. The spermathecal reservoir is lined by a flattened epithelium with a thin cuticular intima and associated with well-developed muscles. It is concluded that the reproductive tract of C. externa is similar in virgin and mated males and females. Egg production is activated only after mating and the development of reproductive tract structures is faster in mated females.

Rearing Chrysoperla externa Larvae on Artificial Diets

We tested three artificial diets for rearing larvae of Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae), aiming at reducing the production costs of this predator. Two of the diets come from studies with other species of lacewings, and the third is a modification described in this paper. All diets were based on animal protein and were supplied to 2nd and 3rd instar larvae, whereas 1st instar larvae received eggs of Anagasta kuehniella (Zeller) (Lepidoptera: Pyralidae). We evaluated the preimaginal duration and survival, adult size, longevity and fecundity, egg hatchability, and predatory capacity of larvae produced. The performance of the diets was followed for seven generations. The diet we describe showed to be the best among the artificial diets tested. Our results show that C. externa can be successfully reared on artificial diets during second and third instars, reducing in 90% the dependency on eggs of A. kuehniella.

Pollen Ingestion by Chrysoperla externa (Hagen) Adults in a Diversified Organic Agroecosystem

Chrysoperla externa (Hagen) larvae prey on pest insects and mites in agroecosystems, and adults mainly feed on pollen, nectar, and honeydew. Therefore, preserving this lacewing in crop systems depends on having plants that provide these resources. The objectives of this research were to identify pollen grains ingested by Ch. externa adults collected in a diversified organic agroecosystem and to evaluate whether there is a difference in the amount of ingested pollen grains between males and females. The adults of Ch. externa were collected in four different crops during 13 months in Seropédica, state of Rio de Janeiro, Brazil, using a collecting net. The adults were killed and underwent acetolysis, in order to recover the pollen in the gut. A total of 37,441 pollen grains from 19 Angiospermae families were found, besides 16 Pteridophyte spores. Among the recognized pollen grains, those of Poaceae were the majority, both in frequency of occurrence (87.5%) and in quantity (33496), and were found and recovered in every month of collection. Females and males ingested, respectively, 71.9 and 28.1% of the total number of Angiospermae pollen grains consumed by both sexes. The highest number of Poaceae pollens was obtained from the females (72.1% of the total number of Poaceae pollen, recovered from females + males). Taken as a whole, this study showed that adults of Ch. externa find possibilities to maintain throughout the year, in different crops, but the main source of pollen to males and females was Poaceae plants.

Distribution and Biology of Mallada desjardinsi (Neuroptera: Chrysopidae) in India and Its Predatory Potential Against Aleurodicus dispersus (Hemiptera: Aleyrodidae)

In this study, we report the prevalence of Mallada desjardinsi (Navas) in seven geographical regions of India and provide the first report of its kind outlining the preying of all stages of the spiraling whitefly, Aleurodicus dispersus Russell, by M. desjardinsi Sampling was conducted in seven regions of two provinces in India, Bengaluru (Karnataka) and Tiruppur (Tamil Nadu), which demonstrated that M. desjardinsi populations were most dense at the former and least at the later. To the best of our knowledge, this is the first report of its kind outlining observations regarding the biology and feeding potential of M. desjardinsi on A. dispersus under laboratory conditions. It was observed that the second nymphal stadium of A. dispersus was most preferred prey for M. desjardinsi and the least preferred was the A. dispersus adult. It was also seen that the third stadium of M. desjardinsi consumed more A. dispersus individuals than any other life stages. The longevity of female and the total developmental period of M. desjardinsi were computed as 27.6 ± 1.69 and 24.1 ± 0.99 d, respectively. The average total number of eggs laid by the M. desjardinsi female was 211.1 ± 6.35 eggs. M. desjardinsi was observed to be extremely efficient in terms of prey searching and predatory potential with respect to A. dispersus The results of this study indicate strongly that M. desjardinsi has the potential to be used for the control of A. dispersus.

Pest Management Systems and Insecticide Tolerance of Lacewings (Neuroptera: Chrysopidae)

Lacewings (Neuroptera: Chrysopidae) are part of the beneficial fauna found in citrus orchards under both organic and conventional pest management. Due to their importance, knowledge about susceptibility of these predators to insecticides is a key element for their use as biological control agents. We studied the inter- and intraspecific susceptibility of the following lacewing species to bifenthrin, chlorpyrifos, and imidacloprid: Ceraeochrysa cincta (Schneider) (Neuroptera: Chrysopidae), Ceraeochrysa cubana (Hagen), Ceraeochrysa paraguaria (Navás), and Chrysoperla externa (Hagen). Different concentrations of these insecticides were sprayed on first instar larvae of these lacewing species from six orchards (three organic and three conventional), and LC50s were estimated. Development and reproduction of the most common lacewing, C. cincta, from both organic and conventional management systems were also studied. Lacewings from conventional management areas do not always have greater tolerance to insecticides. Chrysoperla externa was the most susceptible species to insecticides. Ceraeochrysa cincta displayed the highest LC50 and its populations from the conventional system showed lower egg hatching but shorter egg and larval developmental time. Adults collected from orchards managed conventionally lived longer, exhibited a higher population growth rate and a reduced doubling time. Ceraeochrysa cincta was the more tolerant species to insecticides better coping with systems that rely on chemical control as the main pest management tactic used.

Krüppel homolog 1 mediates juvenile hormone action to suppress photoperiodic reproductive diapause-related phenotypes in the female Chrysoperla nipponensis (Neuroptera: Chrysopidae)

Juvenile hormone (JH) has been revealed to be a critical factor in regulating photoperiod reproductive diapause in various insect species, however, little information is known about the detailed mechanisms. In this study, we investigated the roles of JH signaling in photoperiod reproductive diapause in a green lacewing, Chrysoperla nipponensis (Okamoto), which is a potentially important biological control predator. Our results showed that the short-day condition induces a diapause state including JH synthesis suppression, ovarian development arrest, and triglyceride accumulation. The interference of JH response genes, Krüppel homolog 1 (Kr-h1), in reproductive females exhibited a diapause-related phenotype such as ovarian development arrest and larger triglyceride storage. Exogenous JH III suppresses diapause to promote ovarian development and inhibit triglyceride synthesis. However, exogenous JH III fails to rescue the Kr-h1-silenced phenotype. Accordingly, our results demonstrate the critical role of Kr-h1 in regulating JH signaling to promote reproduction.

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.

The genome sequence of a green lacewing, Nineta flava (Scopoli, 1763)

We present a genome assembly from an individual Nineta flava (green lacewing; Arthropoda; Insecta; Neuroptera; Chrysopidae). The genome sequence spans 732.30 megabases. Most of the assembly is scaffolded into 7 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 16.16 kilobases in length.

Abundance and Seasonal Migration Patterns of Green Lacewings (Neuroptera: Chrysopidae) across the Bohai Strait in Eastern Asia

Many insects, including green lacewings, migrate seasonally to exploit suitable breeding and winter habitats. Green lacewings are important natural enemies of insect pests worldwide. Here, four dominant green lacewing species, Chrysoperla nipponensis (Okamoto), Chrysopa pallens (Rambur), Chrysoperla furcifera (Okamoto), and Chrysopa formosa Brauer, were investigated for their ability to migrate between northern and northeastern China across the Bohai Strait from late May to late October each year. Furthermore, there were significant interannual and seasonal differences in the number of migratory green lacewings collected. The number of green lacewings in spring was significantly lower than that in summer and autumn, and the highest average number of green lacewings occurred in June. In addition, there were differences in the sex ratio of migrating green lacewings between months, with a greater proportion of females than males. Finally, the seasonal migration trajectories simulated by the HYSPLIT model revealed that the green lacewings captured on Beihuang Island primarily originated from Shandong Province. Accordingly, these findings contribute to our understanding of green lacewing migration in eastern Asia and aid its incorporation within integrated pest management (IPM) packages for several crop pests. Furthermore, long-term tracking of migrant insect populations can reveal ecosystem services and trophic dynamic processes at the macroscale.

Genetic Variability of Ceraeochrysa cincta, Ceraeochrysa claveri, and Ceraeochrysa cubana (Neuroptera: Chrysopidae) Populations in Agroecosystems of Southeast Brazil

The species of the genus Ceraeochrysa, known as green lacewings or trash-carriers, are widely distributed along the Americas and its islands. In Brazil, 28 species are found, including Ceraeochrysa cincta (Schneider), Ceraeochrysa claveri (Navás), and Ceraeochrysa cubana (Hagen). These species are recorded on many crops, where they are often used for biological control. For this use, knowledge of the genetic features of the species is extremely important because they are associated to the species' ability to withstand different conditions in new environments, such as variations of temperature and presence of pathogens. However, little is known about the genetic features of Ceraeochrysa species. Here, we analyze and compare the distribution of the genetic variability of C. cincta, C. claveri, and C. cubana in agroecosystem populations of southeast Brazil. We found a high genetic diversity in each of the three species, and no strong genetic structure was detected, such that genetic diversity is broadly shared among the crops and localities analyzed. We can conclude that there was a high gene flow among the sampled Ceraeochrysa populations (natural or driven by anthropic action) since the exchange of seedlings among crops can lead to the distribution of the specimens.

Azadirachtin-Based Biopesticide Affects Fitness and Ovarian Development of the Natural Enemy Ceraeochrysa claveri (Neuroptera: Chrysopidae)

Plant-derived biopesticides have gained attention in agriculture as a pest control method that minimizes the negative effects caused by conventional synthetic insecticides to natural enemies. Azamax™ is one of the most commercialized biopesticides in Brazil, but little is known about its effects on non-target insects such as Ceraeochrysa claveri, a non-target insect that is economically important as a pest predator, used in this study. To evaluate the toxic effects of azadirachtin on fitness and ovarian development, a total of 450 C. claveri larvae were exposed by ingestion to subdoses (36 mg/L (0.3%) and 60 mg/L (0.5%) of azadirachtin for 15 days and after that, biological parameters and ovarian development were analyzed. The doses tested corresponded to the minimum and maximum concentrations used in the field. The results demonstrated that both tested doses of the biopesticide significantly reduced survival rates, delayed and extended larval and pupal development times, caused malformations in the body, altered the ultrastructure of adult ovaries, and induced cell death in ovarian follicles. Azamax™, a biopesticide marketed as a reduced-risk insecticide, was shown to have detrimental effects on the lifespan and ovarian development of C. claveri.

Testing the Effects of Prey Type on the Life History and Population-Level Parameters of Chrysoperla externa (Neuroptera: Chrysopidae)

Green lacewings are valuable predators, utilized in augmentative biological control against various agricultural pests. However, further studies are required to comprehend the performance of these predators when consuming natural prey. We investigated the capacity of Chrysoperla externa (Hagen) to utilize the following three distinct prey types: the pupae of the coffee leaf miner Leucoptera coffeella (Guérin-Mèneville & Perrottet), the eggs of the sugarcane borer Diatraea saccharalis (F.), and the eggs of the Mediterranean flour moth Ephestia kuehniella (Zeller). The first two of these species are naturally occurring prey found in field crops, while the last serves as a factitious prey species for the mass rearing of natural enemies. We hypothesized that the type of prey would differentially affect the life history and population-level parameters of C. externa. Laboratory experiments were conducted to compare the pre-imaginal survival and developmental times, adult longevity and reproduction, and population growth of C. externa when larvae were provided with each of the three prey items. Results indicated that C. externa utilized the two natural prey items, L. coffeella pupae and D. saccharalis eggs, for its development, reproduction, and population growth. However, larvae developed significantly faster and females exhibited higher reproductive parameters, including fecundity and daily oviposition, when consuming the factitious prey, E. kuehniella eggs. This resulted in a higher intrinsic rate of population increase, as well as shorter times for the population to double in size. Understanding the population dynamics of C. externa when consuming different prey items is crucial for optimizing their utilization in augmentative biological control programs.

Fitness effect and transcription profile reveal sublethal effect of nitenpyram on the predator Chrysopa pallens (Neuroptera: Chrysopidae)

Although neonicotinoids are widely used and important insecticide, there are growing concerns about their effect on nontarget insects and other organisms. Moreover, the effects of nitenpyram (NIT), a second generation of neonicotinoid insecticides, on Chrysopa pallens are still unclear. Therefore, this study purposed to investigate the acute toxicity of NIT to C. pallens using the spotting method. To examine the potential effects of a sublethal dose of NIT (LD30 , 1.85 ng of active ingredient per insect) on C. pallens, we constructed the life tables and analyzed the transcriptome data. The life table results showed that the period of second instar larvae, adult pre-oviposition period and total pre-oviposition period were significantly prolonged after exposure to sublethal dose of NIT, but had no significant effects on the other instars, longevity, oviposition days, and fecundity. The population parameters, including the preadult survival rate, gross reproduction rate, net reproductive rate, the intrinsic rate of increase, and finite rate of increase, were not significantly affected, and only the mean generation time was significantly prolonged by NIT. Transcriptome analysis showed that there were 68 differentially expressed genes (DEGs), including 50 upregulated genes and 18 downregulated genes. Moreover, 13 DEGs related to heat shock protein, nose resistant to fluoxetine protein 6, and prophenoloxidas were upregulated. This study showed the potential effects of sublethal doses of NIT on C. pallens and provided a theoretical reference for the comprehensive application of chemical and biological control in integrated pest management.

Functional response of 3 green lacewing species (Neuroptera: Chrysopidae) to Leucoptera coffeella (Lepidoptera: Lyonetiidae)

Green lacewings (Neuroptera: Chrysopidae) are predators commonly found in coffee plantations in Brazil that can serve as important biological control agents against insect pests such as the coffee leaf miner, Leucoptera coffeella (Lepidoptera: Lyonetiidae). However, the efficacy of different lacewing species in controlling L. coffeella needs to be evaluated before they are used in augmentative biological control programs. Here, laboratory experiments were conducted to investigate the effects of the L. coffeella developmental stage on the functional response of 3 species of green lacewings: Chrysoperla externa, Ceraeochrysa cincta, and Ceraeochrysa cornuta. The attack rate, handling time, and the number of prey attacked during 24 h with different densities (1, 2, 4, 8, 16, 32, and 64 individuals) of either L. coffeella larvae or pupae were recorded for each of the 3 lacewing species. Based on logistic regression models, all 3 predators showed a Type II functional response when consuming both larvae and pupae of L. coffeella. All 3 species also had similar attack rates (0.0091 larva/h and 0.0095 pupa/h), handling times (3.5 and 3.7 h for larvae and pupae, respectively), and estimated number of prey attacked during the observation period (6.9 larvae and 6.6 pupae) for L. coffeella larvae and pupae. Therefore, our laboratory studies show that the 3 green lacewings Ch. externa, Ce. cincta, and Ce. cornuta have potential for the biological control of L. coffeella, although these results need to be confirmed under field conditions. These findings have implications for the selection of lacewings for augmentative L. coffeella biocontrol.