Predatory Stink Bug Research Articles

Microbial Community Structure and Metabolic Function in the Venom Glands of the Predatory Stink Bug, Picromerus lewisi (Hemiptera: Pentatomidae).

The predatory stink bug, Picromerus lewisi (Hemiptera: Pentatomidae), is an important and valuable natural enemy of insect pests in their ecosystems. While insects are known to harbor symbiotic microorganisms, and these microbial symbionts play a crucial role in various aspects of the host's biology, there is a paucity of knowledge regarding the microbiota present in the venom glands of P. lewisi. This study investigated the venom glands of adult bugs using both traditional in vitro isolation and cultural methods, as well as Illumina high-throughput sequencing technology. Additionally, the carbon metabolism of the venom gland's microorganisms was analyzed using Biolog ECO metabolic phenotyping technology. The results showed 10 different culturable bacteria where the dominant ones were Enterococcus spp. and Lactococcus lactis. With high-throughput sequencing, the main bacterial phyla in the microbial community of the venom glands of P. lewisi were Proteobacteria (78.1%) and Firmicutes (20.3%), with the dominant bacterial genera being Wolbachia, Enterococcus, Serratia, and Lactococcus. At the fungal community level, Ascomycota accounted for the largest proportion (64.1%), followed by Basidiomycota (27.6%), with Vishniacozyma, Cladosporium, Papiliotrema, Penicillium, Fusarium, and Aspergillus as the most highly represented fungal genera. The bacterial and fungal community structure of the venom glands of P. lewisi exhibited high species richness and diversity, along with a strong metabolism of 22 carbon sources. Functional prediction indicated that the primary dominant function of P. lewisi venom-gland bacteria was metabolism. The dominant eco-functional groups of the fungal community included undefined saprotroph, fungal parasite-undefined saprotroph, unassigned, endophyte-plant pathogen, plant pathogen-soil saprotroph-wood saprotroph, animal pathogen-endophyte-plant pathogen-wood saprotroph, plant pathogen, and animal pathogen-endophyte-epiphyte-plant pathogen-undefined saprotroph. These results provide a comprehensive characterization of the venom-gland microbiota of P. lewisi and demonstrate the stability (over one week) of the microbial community within the venom glands. This study represents the first report on the characterization of microbial composition from the venom glands of captive-reared P. lewisi individuals. The insights gained from this study are invaluable for future investigations into P. lewisi's development and the possible interactions between P. lewisi's microbiota and some Lepidopteran pests.

Bottom-up effects of polyethylene microplastics on the growth and development of potato, Colorado potato beetle and Stinkbug predators

Bottom-up effects of polyethylene microplastics on the growth and development of potato, Colorado potato beetle and Stinkbug predators

Insecticidal activities of three recombinant venom proteins of the predatory stink bug, Arma custos.

Widespread resistance of insect pests to insecticides and transgenic crops in the field is a significant challenge for sustainable agriculture, and calls for the development of novel alternative strategies to control insect pests. One potential resource for the discovery of novel insecticidal molecules is natural toxins, particularly those derived from the venoms of insect predators. In this study, we identified three insecticidal proteinaceous toxins from the venom glands (VGs) of the predatory stink bug, Arma custos (Hemiptera: Asopinae). Transcriptomic analysis of A. custos VGs revealed 151 potentially secreted VG-rich venom proteins. Three VG-rich venom proteins (designated AcVP1 ~ 3) were produced by overexpression in Escherichia coli. Injection of the recombinant proteins into tobacco cutworm (Spodoptera litura) larvae showed that all of the three recombinant proteins caused paralysis, liquefaction and death. Injection of recombinant proteins into rice brown planthopper (Nilaparvata lugens) nymphs showed higher insecticidal activities, among which a trypsin (AcVP2) caused 100% mortality postinjection at 1.27 pmol mg-1 body weight. A natural toolkit for the discovery of insecticidal toxins from predatory insects has been revealed by the present study. © 2024 Society of Chemical Industry.

Perfect cooperative pest control via nano-pesticide and natural predator: High predation selectivity and negligible toxicity toward predatory stinkbug

The improper use of synthetic pesticides has caused adverse effects on global ecosystems and human health. As a part of sustainable pest management strategy, natural predators, along with nano-pesticides, have made significant contributions to ecological agriculture. The cooperative application of both approaches may overcome their limitations, substantially reducing pesticide application while controlling insect pests efficiently. Herein, the current study introduced a cationic star polymer (SPc) to prepare two types of nano-pesticides, which were co-applied with predatory stinkbugs Picromerus lewisi to achieve perfect cooperative pest control. The SPc exhibited nearly no toxicity against predatory stinkbugs at the working concentration, but it led to the death of predatory stinkbugs at extremely high concentration with the lethal concentration 50 (LC50) value of 13.57 mg/mL through oral feeding method. RNA-seq analysis revealed that the oral feeding of SPc could induce obvious stress responses, leading to stronger phagocytosis, exocytosis, and energy synthesis to ultimately result in the death of predatory stinkbugs. Then, the broflanilide and chlorobenzuron were employed to prepare the self-assembled nano-pesticides via hydrogen bond and Van der Waals force, and the complexation with SPc broke the self-aggregated structures of pesticides and reduced their particle sizes down to nanoscale. The bioactivities of prepared nano-pesticides were significantly improved toward common cutworm Spodoptera litura with the corrected mortality increase by approximately 30%. Importantly, predatory stinkbugs exhibited a strong predation selectivity for alive common cutworms to reduce the exposure risk of nano-pesticides, and the nano-pesticides showed negligible toxicity against predators. Thus, the nano-pesticides and predatory stinkbugs could be applied simultaneously for efficient and sustainable pest management. The current study provides an excellent precedent for perfect cooperative pest control via nano-pesticide and natural predator.

Identification of neuropeptides and their G protein-coupled receptors in the predatory stink bug, Arma custos (Hemiptera: Pentatomidae).

The predatory stink bug Arma custos has been selected as an effective biological control agent and has been successfully massly bred and released into fields for the control of a diverse insect pests. As a zoophytophagous generalist, A. custos relies on a complex neuropeptide signaling system to prey on distinct food and adapt to different environments. However, information about neuropeptide signaling genes in A. custos has not been reported to date. In the present study, a total of 57 neuropeptide precursor transcripts and 41 potential neuropeptide G protein-coupled receptor (GPCR) transcripts were found mainly using our sequenced transcriptome data. Furthermore, a number of neuropeptides and their GPCR receptors that were enriched in guts and salivary glands of A. custos were identified, which might play critical roles in feeding and digestion. Our study provides basic information for an in-depth understanding of biological and ecological characteristics of the predatory bug and would aid in the development of better pest management strategies based on the effective utilization and protection of beneficial natural enemies.

Construction of a nontoxic nano-pesticide and its co-application with natural predators for perfect cooperative pest management: an innovative strategy for pesticide reduction

The current study develops a nano-pesticide that is nontoxic toward the predatory stinkbug but with enhanced bioactivity toward the common cutworm, which proposes to co-apply the nano-pesticide with predator as an innovative pest control technique.

Sublethal effect of chlorpyrifos on predatory behavior and physiology of Eocanthecona furcellata (Hemiptera: Pentatomidae).

Insecticides have been known to reduce the predation efficacy of natural enemies. However, the mechanism of the sublethal effect of insecticides on the functional response of predators remains unclear. This study investigated the sublethal effects of the broad-spectrum insecticide chlorpyrifos on the predatory bug Eocanthecona furcellata (Wolff), which is a potential biological control agent against pests in integrated pest management (IPM) programs. After exposure to a sublethal concentration of chlorpyrifos, the predation capacity and the maximum predatory number of E. furcellata increased by 11.27 and 15.26%, respectively, with prey handling time decreased by 15.07%, and the searching efficiency increased by 5.88-12.61%. Additionally, the intraspecific interference effect was enhanced. Glutathione S-transferase (GST) activity was significantly decreased after 12- to 60-h treatment. At 12 h after treatment, the expression levels of GST gene (GST3), acetylcholinesterase gene (AChE), and cytochrome P450 monooxygenasegene (cyp6B1) were significantly up-regulated by 1.47-, 1.48-, and 2.05-fold, respectively, while GST gene (GST1) was significantly down-regulated by 16.67-fold. These results indicated that a sublethal chlorpyrifos concentration inhibited the GST activity and stimulated the predatory behavior of E. furcellata. The results will advance our understanding of the toxicological mechanism of predatory stink bug responses to insecticides and predict chlorpyrifos' effects on predators in an IPM program.

Low-Temperature-Induced Winter Dormancy in a Predatory Stink Bug Eocanthecona furcellata (Wolff) in the Subtropics

Insects have developed dormancy mechanisms to survive coldness in winters. The specific forms of winter dormancy, however, vary among different geographical and climatic zones and species. While there is extensive research on winter dormancy in insect pests and parasitoids in temperate zones, our understanding of how predatory insects, such as predatory stink bugs in subtropical regions, cope with cold winters and the specific forms of dormancy they undergo remains limited. The effects of winter temperatures on the population dynamics, development, and reproduction of the predatory stink bug Eocanthecona furcellata in the subtropics were investigated through greenhouse and laboratory experiments. E. furcellata exhibits two distinct peaks in population distribution throughout the year: one in April–May and another in October–November. Interestingly, the proportions of adults show an opposite pattern to the population dynamics, with the highest proportions of adults observed during the winter and summer seasons, when temperatures are the lowest and the highest, respectively. Laboratory studies showed that E. furcellata reared at lower temperatures (16 °C, 18 °C, and 20 °C) experienced prolonged development and higher mortality rates for eggs and nymphs compared to higher temperatures (22 °C and 26 °C). Further experiments observed that E. furcellata adults reared at 16 °C, 18 °C, and 20 °C entered into winter dormancy, where ovarian development was either completely halted or slowed down. The observed high proportion of E. furcellata adults and low proportion of nymphs during the cold winter months align well with the dormancy period. This study sheds light on the underlying mechanisms driving the population dynamics of E. furcellata during the subtropical winter. These findings have significant implications in accurately predicting the population dynamics of E. furcellata, implementing effective field release strategies, and optimizing cold storage techniques in the context of biological control programs.

Transcriptome analysis reveals salivary gland-specific neuropeptide signaling genes in the predatory stink bug, Picromerus lewisi.

Predatory stink bugs derive from phytophagous stink bugs and evolved enhanced predation skills. Neuropeptides are a diverse class of ancient signaling molecules that regulate physiological processes and behavior in animals, including stink bugs. Neuropeptide evolution might be important for the development of predation because neuropeptides can be converted to venoms that impact prey. However, information on neuropeptide signaling genes in predatory stink bugs is lacking. In the present study, neuropeptide signaling genes of Picromerus lewisi, an important predatory stink bug and an effective biological agent, were comprehensively identified by transcriptome analysis, with a total of 59 neuropeptide precursor genes and 58 potential neuropeptide receptor genes found. In addition, several neuropeptides and their receptors enriched in salivary glands of P. lewisi were identified. The present study and subsequent functional research contribute to an in-depth understanding of the biology and behavior of the predatory bugs and can provide basic information for the development of better pest management strategies, possibly including neuropeptide receptors as insecticide targets and salivary gland derived venom toxins as novel killing moleculars.

Study of Ecological Diversity of Predatory Asopinae Bugs in the Agro-ecosystem of the Mid-Western Plains

The aim of the present study was to investigate the seasonal abundance of Asopinae predatory stink bugs within an agro-ecosystem. This research was carried out by utilizing sweep nets to collect these insects during the period spanning from May to August in the year 2022. The survey yielded two prominent species of predaceous bugs, specifically Andrallus spinidens and Eocanthecona furcellata. Interestingly, E. furcellata emerged as the dominant species within the field conditions. A noteworthy phenomenon occurred in June when a sudden surge in the population of both species was observed. This population increase was attributed to the presence of lepidopteran larvae in the field, which likely served as a rich food source for these predatory stink bugs. The ecological analysis revealed some important findings regarding the diversity and distribution of these insects in the agro-ecosystem. Specifically, the Shannon Diversity Index was notably low, registering at less than 1.99, indicating a limited variety of species within the sampled population. Similarly, the Simpson Index indicated a low degree of diversity or heterogeneity, falling within the range of 0.01 to 0.04, which further supports the notion of a relatively homogeneous population. Additionally, the Margalef Richness Index signalled a level of disturbance, measuring less than 2.05. This disturbance could be linked to various factors affecting the ecosystem, including changes in agricultural practices or environmental conditions. Lastly, the Dominance Index was relatively high, ranging between 0.5 and 1.0, signifying that a few dominant species, particularly E. furcellata, exerted a significant influence within the ecosystem. In summary, the ecological indices suggested limited diversity, low heterogeneity, disturbance, and dominance within the stink bug population, shedding light on the dynamics of these beneficial insects in the agro-ecosystem.

Identification of metabolizing enzyme genes associated with xenobiotics and odorants in the predatory stink bug Arma custos based on transcriptome analysis

The predatory stink bug, Arma custos, is a highly effective beneficial predator of crop pests. The lack of gene information related to xenobiotic detoxification and odorant degrading enzymes in the predator stink bugs to date has limited our ability for more in-depth studies of biological control. Hence, we conducted de novo assembly of the A. custos transcriptome from guts, antennae, and other tiussue samples of 5th instar larvae using Illumina sequencing technology. A total of 91, 50 and 23 genes of cytochrome P450 monooxygenases (CYPs), carboxyl/choline esterases (CCEs) and glutathione S-transferases (GSTs) genes were identified, respectively. Gene expansions of CYP3 and CYP4 clans and the hormone and pheromone processing CCE class were found in A. custos. Analysis of tissue-specific expression patterns showed that 37 CYPs, 14 CCEs and 8 GSTs were enriched in guts, and 6 CYPs, 5 CCEs and 2 GSTs were up-regulated in antennae, suggesting their potential roles on xenobiotics detoxification and ordorant degradation. Gene information data presented here could be useful for a deeper understanding of the ecology, physiology and behavior of this beneficial species and could be helpful to improve their bio-control efficiency.

First record of the predatory stink bug species Picromerusgriseus (Dallas) (Hemiptera, Heteroptera, Pentatomidae, Asopinae) in Japan, with an illustrated key to the Japanese species of the genus Picromerus Amyot & Serville.

The predatory stink bug genus Picromerus Amyot & Serville, 1843 (Hemiptera, Heteroptera, Pentatomidae, Asopinae) comprises 11 species found in the Northern Hemisphere. In Japan, two species have been recorded to date. However, an easy-to-understand identification method, such as an illustrated key, is lacking. Currently, Picromerusgriseus (Dallas, 1851) has been recorded in Bangladesh, Bhutan, China, Indonesia, Myanmar, Pakistan and Taiwan, but not in Japan. Picromerusgriseus was recorded in Japan for the first time, based on a single individual collected from grasslands around the fields of Ishigaki Island of the Ryukyu Islands, which belong to the Oriental Region. This discovery represents the easternmost record of the species. An illustrated key to the species of Picromerus occurring in Japan is also provided.

The Predatory Stink Bug Arma custos (Hemiptera: Pentatomidae) Produces a Complex Proteinaceous Venom to Overcome Caterpillar Prey.

Predatory stink bugs capture prey by injecting salivary venom from their venom glands using specialized stylets. Understanding venom function has been impeded by a scarcity of knowledge of their venom composition. We therefore examined the proteinaceous components of the salivary venom of the predatory stink bug Arma custos (Fabricius, 1794) (Hemiptera: Pentatomidae). We used gland extracts and venoms from fifth-instar nymphs or adult females to perform shotgun proteomics combined with venom gland transcriptomics. We found that the venom of A. custos comprised a complex suite of over a hundred individual proteins, including oxidoreductases, transferases, hydrolases, ligases, protease inhibitors, and recognition, transport and binding proteins. Besides the uncharacterized proteins, hydrolases such as venom serine proteases, cathepsins, phospholipase A2, phosphatases, nucleases, alpha-amylases, and chitinases constitute the most abundant protein families. However, salivary proteins shared by and unique to other predatory heteropterans were not detected in the A. custos venom. Injection of the proteinaceous (>3 kDa) venom fraction of A. custos gland extracts or venom into its prey, the larvae of the oriental armyworm Mythimna separata (Walker, 1865), revealed insecticidal activity against lepidopterans. Our data expand the knowledge of heteropteran salivary proteins and suggest predatory asopine bugs as a novel source for bioinsecticides.

Revision of Heteroscelis Latreille, 1829 (Heteroptera: Pentatomidae: Asopinae) with the description of a new species from Colombia.

The Asopinae comprises about 300 species and 63 genera of predatory stinkbugs, of which around 100 species and 23 genera occur in the Neotropical region. The species of the Neotropical genus Heteroscelis Latreille, 1829 are easily recognized by the small size, vivid and often iridescent colors, the elongated head, and the foretibial foliaceous expansions. In this work we provide a taxonomic revision of Heteroscelis. The genus and its four known species are redescribed, and one new species from Colombia, Heteroscelis vandembergi Sampaio & Campos, sp.nov., is proposed. A distribution map, and a key to the species of Heteroscelis are presented.

Diversity and distribution of predatory stink bugs from India and their role in insect pest management (Hemiptera: Heteroptera: Pentatomidae: Asopinae

Asopinae is the only subfamily among Pentatomidae (Hemiptera: Heteroptera), whose members exhibit predatory feeding habits. They are called predatory stink bugs as they mainly predate on several soft-bodied arthropods. In this study, we compile a consolidated list of the subfamily Asopinae from India, covering 30 species in 17 genera, supplemented with prey information of selected species based on our observations and literature records.

Dietary Association with Midgut Microbiota Components of Eocanthecona furcellata (Wolff)

Eocanthecona furcellata is an important predatory stinkbug that attacks many lepidopteran pests. For mass-rearing, artificial diets are used to rear this predator in the laboratory; however, the fitness of the predators is reduced, and little is known about the cause. Since gut microbiota plays vital roles in the digestion and development of many hosts and can consequently affect host fitness, an understanding of the microbial community composition of E. furcellata may help to solve this unresolved problem. We compared the development and reproduction of E. furcellata reared on an artificial diet, and a natural (Spodoptera litura) or semi-natural (Tenebrio molitor) diet, and then the midgut microbiota were assessed using high-throughput 16S rRNA. The results of the high-throughput 16S rRNA show that the bacterial richness and diversity in the artificial diet gut samples increased considerably compared with the other samples. Proteobacteria and Firmicutes were the dominant phyla in E. furcellata. At the genus level, Serratia (however, the relative abundance was lower in the artificial diet gut samples), Enterococcus, and an uncultured bacterium genus of family Enterobacteriaceae, were dominant. The midgut microbiota components significantly differed among the diets, indicating that the gut bacteria had a dietary association with E. furcellata. This study provides a better understanding of midgut microbiota and the artificial diets that might affect them in E. furcellata.

Defensive thrashing behavior of caterpillars incurs a fatal retaliation from predatory stinkbugs

Thrashing behavior is generally assumed to be an effective means of defense of caterpillars to escape arthropod predators. Yet, scant attention has been paid to subsequent performances of escaped caterpillars. To address this knowledge gap, we conducted experiments with predatory stinkbug Arma chinensis nymphs or adults. As prey, we used armyworm Mythimna separata caterpillar and examined developmental consequences of the prey escaping the predator by thrashing. Surprisingly, we found that caterpillars which escaped from the stylet insertion of the stinkbug by thrashing underwent poor development and were less likely to survive to pupation. This effect did not vary with the life stage of the stinkbug or the duration of its stylet insertion. On the other hand, sham injuries caused by needle puncturing did not significantly affect the caterpillar’s survival. We also examined the overall activities of antioxidant enzymes, immune-related enzymes, and neuroregulatory bioamines as a known insect response to envenomation. We found that these biochemicals were more abundant in caterpillars exercising thrashing behavior. Based on these findings, we speculate that the increased defensive behavior by thrashing results in an increased venom injection by the predator, which is responsible for the observed increased mortality in those caterpillars that practice thrashing.

Bioactivity of essential oils from Croton grewioides and its major compounds: toxicity to soybean looper Chrysodeixis includens and selectivity to the predatory stink bug Podisus nigrispinus.

Natural biological control is a key factor that ensures the regulation of insect pest populations in agroecosystems. However, the indiscriminate use of pesticides has compromised this environmental service. Thus, the search for environmentally safe pesticides is an increasing requirement for sustainable food production. In this study, we analyzed the toxicity of essential oils from two accessions (CGR112 and CGR126) of Croton grewioides and its major compounds, methyl eugenol and eugenol, on the soybean pest Chrysodeixis includens. In addition, we investigated the sublethal effects of these compounds on the predatory bug Podisus nigrispinus, analyzing its developmental, reproduction and life table parameters. Essential oils and their major compounds were toxic to C. includens and P. nigrispinus. In general, the presence of eugenol made the essential oil more toxic to the pest and selective to the natural enemy. Eugenol was the most toxic compound for 2nd instar larvae of C. includens at LD50, followed by CGR126 essential oil from C. grewioides which was equally toxic at higher doses. The estimated lethal times for essential oils to cause mortality in 50% of the population of C. includens were less than 15h. There was selectivity of the essential oil of CGR126 accession of C. grewioides at lethal doses above 90%. Although the treatments showed little effect on the development of P. nigrispinus, body mass and reproductive parameters were negatively affected, with the exception of the essential oil of CGR126 accession of C. grewioides. The essential oil of C. grewioides may be a promising active ingredient for the synthesis of new insecticides, which are efficient against C. includens and at the same time are safer for the natural enemy P. nigrispinus.

A full-length transcriptome and gene expression analysis of three detoxification gene families in a predatory stink bug, Picromerus lewisi.

The predatory stink bug P. Lewisi shows potential for Integrated Pest Management programs for controlling Lepidoptera pest insects in crops and forests. The importance of this insect for biological control has stimulated several studies into its biology and ecology. However, P. lewisi has little genetic information available. In the present study, PacBio single-molecule real-time (SMRT) sequencing and Illumina RNA-seq sequencing technologies were used to reveal the full-length transcriptome profiling and tissue-specific expression patterns of P. lewisi. A total of 12,997 high-quality transcripts with an average length of 2,292 bp were obtained from different stages of P. lewisi using SMRT sequencing. Among these, 12,101 were successfully annotated in seven public databases. A total of 67 genes of cytochrome P450 monooxygenases, 43 carboxylesterase genes, and 18 glutathione S-transferase genes were identified, most of which were obtained with full-length ORFs. Then, tissue-specific expression patterns of 5th instar nymphs were analyzed using Illumina sequencing. Several candidate genes related to detoxification of insecticides and other xenobiotics as well as the degradation of odors, were identified in the guts and antennae of P. lewisi. The current study offered in-depth knowledge to understand the biology and ecology of this beneficial predator and related species.

Host instar susceptibility and stage specific predatory potential of stink bug Eocanthecona furcellata on tasar silkworm Antheraea mylitta

Aim: The study was conducted to find out the susceptible stage of tasar silkworm larvae to predation by stink bug and stage dependent feeding potential of stink bug over different instars of tasar silkworm. Methodology: Susceptibility of silkworms was studied by recording the daily larval mortality of all silkworm stages (1st to 5th instar) due to predation by E. furcellata. Stage specific predatory potential was estimated by recording the number of larvae required to complete each developmental stages (2-5th Nymphal instars and adult male and female). Results: Experimental results revealed that 1st and 2nd instar silkworms were most susceptible towards the attack of both nymphal and adult stages of stink bug whereas 3rd instar silkworms were moderately susceptible, however, third instar onwards susceptibility of tasar silkworm towards E. furcellata was negligible. Further stage specific cumulative predatory potential revealed that adult females of predatory bug were significantly more damaging to first instar silkworms (F= 125.20; df=5, 24; P= ≤ 0.0001) as compared to other stages by recording more larval consumption. Observations were also made on the second instar silkworms and it was observed that female adults were again superior over other stages of predatory stink bug (F= 135.30; df=5, 24; P= ≤ 0.0001). Similar trend of feeding potential was also recorded on 3rd instar silkworms; however, the rate of feeding was comparatively lesser than the first and second instar silkworms. Interpretation: Early instar silkworms were less defensive to predators attack, and were highly vulnerable to stink bug, however, as silkworm reached third instar, larvae started depending themselves by rapid head/thoracic movement to ward off the stink bugs. Significant difference in the feeding potential between different developmental stages was observed and adults being superior in feeding indicates their higher nutritional requirements as they need to be fit for reproductive performance to continue their progeny. Key words: Eocanthecona furcellata, Larval susceptibility, Predatory potential, Tasar silkworm