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Background: Herbivorous insects are one of the main biological threats to crops. One such group of insects, stink bugs, do not eat large amounts of tissue when feeding on soybean, but are damaging to the quality of the seed yield as they feed on green developing seeds leading to poorly marketable harvests. In addition to causing physical damage during sucking-feeding activities, the insects can also transmit microbial pathogens, leading to even greater yield loss. Conducting surveys of the insect intestinal microbiome can help identify possible pathogens, as well as detail what healthy stink bug digestive systems have in common.Methods: We used the conserved V4 region of the 16S rRNA gene to characterize the bacterial microbiome of the red-banded stink bug Piezodorus guildinii collected in Brazil and the United States, as well as the neotropical brown stink bug Euschistus heros collected in Brazil.Results: After quality filtering of the data, 192 samples were kept for analyses: 117 samples from P. guildinii covering three sites in Brazil and four sites in the United States, and 75 samples for E. heros covering 10 sites in Brazil. The most interesting observations were that the diversity and abundance of some bacterial families were different in the different ecoregions of Brazil and the United States.Conclusion: Some families, such as Acetobacteraceae, Bacillaceae, Moraxellaceae, Enterobacteriaceae, and Rhodocyclaceae, may be related to the better adaptation in some localities in providing nutrients, break down cellulose, detoxify phytochemicals, and degrade organic compounds, which makes it difficult to control these species.

Stink bugs communicate while mating on a plant by means of the substrate-borne component of the species and sex-specific calling, courtship and rival signals, produced by vibration of the abdomen. Courtship conducted over a close visual distance, chemical contact and mechanical exchange of information terminates in copulation. Here we describe characteristics, differences between species, transmission properties and the behavioral context of the stink bugs Chinavia impicticornis, C. ubica and Euschistus heros in relation to their buzzing signals, produced by vibration of lifted wings. Comparison between species reveals their species' non-specific temporal parameters, characterized by irregular repetition rate and highly variable duration. Frequency spectral bands extend to several kHz above approximately 100 Hz, which is the fundamental frequency and significantly higher in E. heros compared with both Chinavia species. Buzzing signals, recorded predominantly in the very early phase of mating behavior, precede emission of signals produced by abdomen vibration. Males and females emit signals spontaneously when alone on a plant or together with conspecific or alien species mates. Transmission of wing-produced signals along the plant shows characteristics similar to those produced by abdomen vibration. We suggest that amplitudes, measured on distant plants in direct contact or through soil and roots, together with the high sensitivity of relevant vibrational receptors, enable stink bugs to communicate between plants, using substrate-borne vibratory signals outside the limits of the single plant. [ABSTRACT FROM AUTHOR]

Plant growth-promoting fungi belonging to genus Trichoderma are known to help plants when dealing with biotic stressors by enhancing plant defenses. While beneficial effects of Trichoderma spp. against plant pathogens have long been documented, fewer studies have investigated their effect on insect pests. Here, we studied the impact of Trichoderma root colonization on the plant defense responses against stink bug feeding attack. For this purpose, a model system consisting of tomato plant, Solanum lycopersicum cv Dwarf San Marzano, Trichoderma harzianum strain T22 and the southern green stink bug, Nezara viridula, was used. We firstly determined stink bug performance in terms of relative growth rate and survival on tomato plants inoculated by T. harzianum T22. Then, we evaluated relative expression of plant defense-related genes on inoculated plants induced by stink bug feeding. We found evidence that T. harzianum T22 affects tomato defense responses against N. viridula nymphs leading to reduction of growth rate. Our results also showed that T. harzianum T22 enhances plant direct defenses by an early increase of transcript levels of jasmonic acid marker genes. Yet this effect was time-dependent and only detected 8 h after herbivore induction. Taken together, our findings provide better understanding on the mechanisms underlying tomato induced resistance against herbivorous stink bugs. [ABSTRACT FROM AUTHOR]

BACKGROUND: Recently, in temperate and neotropical regions of South America the generalist stink bug Dichelops furcatus (Hemiptera: Pentatomidae) became a new pest of corn (Zea mays) seedlings. Implementation of no‐tillage cultivation system left organic matter covering the soil, which shelters adults of stink bugs during winter. In spring, corn is sowed under soybean stubble and D. furcatus adults start to feed on seedlings. To determine corn‐derived volatile organic compounds (VOCs) that attract this stink bug species, we evaluated stink bug preferences from two corn hybrids with contrast germplasm backgrounds, a temperate and a tropical hybrid. RESULTS: Stink bugs preferred to feed on temperate seedlings rather than on the tropical ones. GC–MS and PCA analysis of VOCs suggested that hybrids emitted contrasting blends. Linalool represented 68% of total VOCs emitted from temperate corn, while in the tropical hybrid this compound represented 48%. Olfactometer experiments demonstrated that linalool was attractive to stink bugs. However, 2 h of D. furcatus attack induced emission of 14 additional VOCs in temperate seedlings, and olfactometer bioassay and blend of VOCs emission suggested that perceived volatiles by stink bugs induced feeding avoidance. The increment of VOCs emission was associated with the induction of JA, JA‐Ile, ABA, and IAA, and decreasing of SA concentrations. CONCLUSION: This is the first time showing a complete profile of defensive phytohormones induced by stink bugs feeding on corn, and further demonstrating that a blend of corn seedling‐associated VOCs, mainly composed by linalool, modulates D. furcatus adults' behavior and feeding preferences. © 2021 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The gradual increase in kernel (nut) size as the macadamia seed develops, appears to play a role in the decline of kernel susceptibility to feeding by insects of the suborder Heteroptera. In some cultivars the kernel becomes resistant to feeding before others due to differences in husk and shell thickness (e.g. feeding by Nezara spp.), but species with a long proboscis (e.g. Bathycoelia spp.) could still feed on the kernel after maximum fruit size was reached. The thickness of the husk and shell, and not the hardness of the shell, was the limiting factor in kernel feeding. Bathycoelia distinct a Distant (Pentatomidae) and Pseudotheraptus wayi Brown (Coreidae) were the most damaging heteropteran species with respect to the size of the kernel lesions caused. A single feeding incident during early fruit development could cause large necrotic lesions, which totally malformed the kernel. Farnya sp. and Nezara sp. caused only small shallow lesions. During the fruit maturation period, only B. distincta was able to damage the kernel significantly due to its long proboscis. The extent of fruit damage was dependent on the stage of fruit development and the species concerned. A tolerance index was developed to express the relative tolerance of macadamia cultivars to the damage caused by kernel-feeding Pentatomidae at the later stages of fruit development. Parameters for the index were the number of pentatomids attacking macadamia, their proboscis length and the combined thickness of the husk and shell of the fruit. [ABSTRACT FROM AUTHOR]

Riptortus pedestris (Fab.) is an important pest on soybean plants in East Asia. Females lay eggs scattered not only on host plants, but also on non-host plants, probably for avoiding detection by natural enemies. Newly hatched nymphs can develop to the second instar without the need of food except water. Second instar nymphs, the first-feeding stage with a strong locomotion, need to find suitable feeding sites on host plants. The mechanism is still not well understood. Here, we found second instars were attracted by both male and female adults, but generally repelled by second and fifth instar nymphs, wherein their responses were little affected by food volatiles (soybean seeds or seedlings). Nymphs distinctly differed from adults in chemical composition of the whole-body extracts. 4-oxo-(E)-2-Hexenal was the major component in nymph's extracts, but it was not found in adults, whereas some ester compounds, such as (E)-2-hexenyl esters, were exclusively found in adults and accounted for the main part in their extracts. The three esters, (E)-2-hexenyl (Z)-3-hexenoate (E2-6:Z3Hx), (E)-2-hexenyl (E)-2-hexenoate (E2-6:E2Hx) and myristyl isobutyrate, were male specific and had been reported as an aggregation pheromone. Synthetic 4-oxo-(E)-2-hexenal strongly repelled second instars, while (E)-2-hexenyl hexanoate emitted by both males and females attracted them. The main component of the aggregation pheromone, myristyl isobutyrate, also strongly attracted second instars. How the findings may improve the efficiency of chemical traps in fields was discussed. [ABSTRACT FROM AUTHOR]

Damage generated by insects is one of main restricting factors for soybean production. Stink bugs are a great threat within pests because, by feeding mainly on pods, they cause direct and irreversible damage to developing seeds. Thus, plant resistance is an important management strategy to reduce insect population impact on yield losses. Association mapping can be used as a powerful tool for dissecting resistance mechanisms in soybean, more specifically to recover functional loci involved in plant defense against herbivorous insects; and can also provide valuable markers for the development of soybean cultivars with resistance. The purpose of this study was to identify molecular markers associated with resistance genes to stink bugs in a collection of soybean germplasm, using the association mapping strategy. According to the decline value in the linkage disequilibrium, an accurate power of mapping resolution was predicted in this population. Four associated markers located in chromosomes 6 and 15 were identified. Out of the 112 candidate genes close to them, 31 would encode proteins related to defense pathways triggered by the attack of herbivorous insects. The proteins encoded by these candidate genes could be associated to the jasmonic acid pathway. The main contribution of this study was the identification of molecular markers associated with resistance genes to stink bugs. These markers will be a useful tool for marker-assisted selection applied to soybean genetic breeding. [ABSTRACT FROM AUTHOR]

Two new Ophiocordyceps species from Thailand, which belong to Ophiocordyceps nutans species complex and attack adult and nymph of stink bugs, are described: Ophiocordyceps asiana and O. tessaratomidarum. Molecular phylogenetic analyses of ITS and a combined sequence data of LSU, RPB1 and TEF1 revealed that these two new species are distinct from other known species in Ophiocordyceps nutans species complex. Based on the findings on morphological studies, they further support the naming of these two novel species. Ophiocordyceps asiana is parasitic on adult and nymph stink bugs, members of Coreidae and Pentatomidae which were recorded from China, Japan and Thailand, while O. tessaratomidarum is reported from Thailand for the first time and is only found as a parasite on adult stink bug, Tessaratoma papillosa (Tessaratomidae, Hemiptera). The fertile heads of O. asiana are shorter than reported for O. tessaratomidarum, and the colours of fertile heads producing teleomorph of these two species differs from each other by having strong reddish orange or light yellowish pink in O. asiana and pale yellow in O. tessaratomidarum. [ABSTRACT FROM AUTHOR]

The subfamily Pentatominae is the most diverse within Pentatomidae, with about 120 genera and 680 species recorded in the Neotropics. The genera Euschistus Dallas, 1851 and Glyphepomis Berg, 1891 and the species Banasa dolabrata Thomas, 1988, B. peruana Thomas, 1990, B. testacea Thomas, 1990, Glyphepomis setigera Kormilev & Pirán, 1952, and Euschistus taurulus Berg, 1878 are recorded for the first time in Paraguay; and two monotypic genera, Berecynthus Stål, 1862 and Nocheta Rolston, 1980, are recorded for the first time in Bolivia and Ecuador, respectively. These new records increase the known country level diversity of Pentatominae in the Neotropics.

Consumption of edible insects as alternative animal protein-source is a potential long-term solution to curb protein deficiency in resource-limited communities where diets lacking in protein are predominant. Entomophagy has been expressed in both developed and developing countries, and previous studies have proven that edible insects are high in protein. However, there is paucity of information on protein quality of edible insects to adequately guide populations on their utilization as good alternative protein sources. The aim of this study was to evaluate protein quality of three edible insects commonly consumed in most regions of Zimbabwe, namely Imbrasia belina (mopane worms), Locusta migratoria (locust) and Encosternum delegorguei (stinkbug). Kjeldahl method was used to evaluate crude protein of edible insects and a 20-day mice-feeding trial was conducted to evaluate protein efficiency ratio and protein digestibility in comparison to a control protein (casein). Crude protein was higher in Locusta migratoria (71.2%) compared to Imbrasia belina (57.7%) and Encosternum delegorguei (31.3%). Protein efficiency ratio was lower in insect samples L. migratoria (2.3), I Belina (1.96), E. delegorguei (2.0) compared to control casein (2.5). There was a significant difference (p0.05) in protein digestibility between the three insect protein sources and casein. The results showed high protein quality of three edible insects commonly consumed in Zimbabwe comparable to casein, a high quality animal protein. High protein digestibility of edible insects indicated ease in absorption and improved utilisation in the body. The lower PER values for I. Belina and E. delegorguei could possibly indicate that these edible insects may be limiting in the amino acids that support body tissue building and growth. Edible insects are a good source of quality protein that could meet protein requirements in resource-limited populations to curb protein deficiency. There is a strong need to further promote edible insects as a good alternative animal protein source. Key words: Protein Efficiency Ratio, Digestibility, Protein quality, Edible Insects, INTRODUCTION The human practice of consuming insects as food, (entomophagy) is common in many parts of the world, especially in resource-limited countries (RLCs) [1]. It has been estimated that approximately [...]

Hexacladia hilaris Burks (Hymenoptera: Encyrtidae) is a parasitoid associated to several stink bug species in Costa Rica, Porto Rico and United States. In April 2018, at the Passo Fundo (28º15’46” S / 52º24’24” O), Rio Grande do Sul state, Brazil, specimens of H. hilaris were collected from Chinavia erythrocnemis (Berg) (Heteroptera: Pentatomidae). This is the first record of this parasitoid in South America as well as its association with C. erythrocnemis.

Over the past two decades, management practices within Louisiana soybean production have shifted. Successful application of an integrated pest management (IPM) strategy requires an understanding of how these changes have affected predator-pest dynamics. Surveys monitoring foliage-foraging arthropod populations in soybean took place across six locations within Louisiana over six years (2012–2014 and 2015–2018). Temporal associations of pest groups, defoliating and piercing-sucking, and predator groups relating to soybean phenology were observed. Additionally, soybean maturity groups (III, IV, and V) were also evaluated to delineate potential differences. Results indicated higher abundances of piercing-sucking pests compared to defoliating pests across both datasets (2012–2014 and 2015–2018). Pest groups were more abundant in later soybean reproductive periods, mainly attributed to Chrysodeixis includens and Piezodorus guildinii. Predator populations were mainly comprised of Araneae and Geocoridae throughout the survey periods. From 2015 to 2018, soybean growth had a significant effect on total predator abundance with more predators present at the pod-fill and soybean maturity stage. Correlations between total pest abundance and total predators exhibited a moderate positive linear relationship. Soybean maturity groups only influenced piercing-sucking pest abundance, with later maturing groups (IV and V) having higher numbers. Thus, control tools and tactics aimed at controlling late season pests should be modified to avoid reducing predator populations.