Reduviidae Research Articles

Giant assassin in the cave: a new species of the genus Myiophanes from Sri Lanka (Hemiptera: Heteroptera: Reduviidae: Emesinae).

A new thread-legged assassin bug species, Myiophanes (Myiophanes) wygodzinskyi sp. nov. (Hemiptera: Heteroptera: Reduviidae: Emesinae: Emesini), collected from Ravana Cave in Uva Province of Sri Lanka, is described. It is the largest species of the genus described so far.

Annotated list of the assassin bugs (Heteroptera: Reduviidae) of Belize, with the description of two new species.

Fifty-one species of Reduviidae (Hemiptera: Heteroptera) are recorded from Belize; literature citations are provided where relevant, and specimen data are included for examined material. Thirteen previously-described species are reported from Belize for the first time, ten of which represent new generic records: Eupheno histrionicus Stål, 1862 (Cetherinae); Ghinallelia signoreti (Dohrn, 1860) (Emesinae); Rasahus albomaculatus (Mayr, 1865) (Peiratinae); Leogorrus interruptus Champion, 1899; Microlestria laevis Champion, 1899; Nalata quadrituberculata Champion, 1899; Nalata setulosa Stål, 1862; Pseudozelurus superbus (Champion, 1899); Zelurus spinidorsis (Gray, 1832) (all Reduviinae); Oncerotrachelus conformis Uhler, 1894; Saica fuscipes Stål, 1862 (both Saicinae); Gnathobleda litigiosa Stål, 1862; and Stenopoda wygodzinskyi Giacchi, 1969 (both Stenopodainae). Among the ten subfamilies reported, Belizean records for one subfamily, Saicinae, are reported for the first time. Accompanying the checklist are the descriptions of Castolus omega Swanson sp. nov. (Harpactorinae) and Pygolampis aptena Swanson sp. nov. (Stenopodainae).

Insect toxins - selective pharmacological tools and drug/chemical leads.

Insect toxins comprise a diverse array of chemicals ranging from small molecules, polyamines and peptide toxins. Many target nervous system and neuromuscular ion channels and so rapidly affect the behaviour of animals to which the toxin is applied or injected. Other modes of action have also been identified. Wasps, bees, flies, beetles and ants generate a rich arsenal of channel-active toxins, some of which offer selective pharmacological probes that target particular ion channels, while others act on more than one type of channel. Philanthotoxins from the digger wasp have been fruitful in adding to our understanding of ligand-gated ion channels both in the nervous system and at neuromuscular junctions. Fire ants produce the toxic alkaloid solenopsin, a molecule which has stimulated attempts to generate synthetic compounds with insecticidal activity. Apamin from bee venom targets calcium-activated potassium channels, which can in turn influence the release of neuropeptides. Melittin, another bee venom component, is a membrane-acting peptide. The saliva of the assassin bug contains toxins that target the voltage-gated calcium channels of their insect prey. Certain beetles produce diamphotoxin, a haemolytic peptide toxin with traditional use as an arrow poison and others generate leptinotarsin with similar properties. Mastoparan is a powerful peptide toxin present in the venom of wasps. Its toxic actions can be engineered out leaving a potent antimicrobial molecule of interest. In this short review we describe the actions of selected insect toxins and evaluate their potential as neuroactive pharmacological tools, candidate lead molecules for insect control and therapeutic candidates with potential antimicrobial, antiviral and anti-cancer applications.

Pale Damsel Bug Nabis capsiformis Germar (Insecta: Hemiptera: Nabidae)

The pale damsel bug, Nabis capsiformis (Germar), one of the most widespread Nabis species, is a generalist predator that can be found in open areas, including coastal habitats (Lattin 1989). It is commonly reported throughout the southeastern United States, in a variety of ecosystems, it is particularly common in field and row crop agroecosystems. All nympal and adult life stages of Nabis capsiformis are excellent predators and can typically eat one lepidopteran egg or aphid per day when small and as many as two dozen eggs or other prey as later instars and adults. They can survive for up to two weeks without food and become cannibalistic if other prey are unavailable. They use their thickened raptorial front legs that are lined with spines to catch and hold prey, then suck out the body contents with their piercing mouthparts.
 Damsel bugs, including the pale damsel bug, are so named because of the way they hold their front legs up, as though they were lifting a skirt hem to curtsey. At first glance, they appear like a cross between a mantis and an assassin bug. Includes: Introduction - Distribution - Description - Host Plants - Life Cycle - Importance - Selected References.https://edis.ifas.ufl.edu/in1210
 Also published at: https://entomology.ifas.ufl.edu/creatures/VEG/pale_damsel_bug.html

Histone acetylation and methylation marks in chromatin of Panstrongylus megistus (Hemiptera, Reduviidae)

Panstrongylus megistus, a potential vector of Chagas disease, currently occupies a wider geographic distribution in Brazil than Triatoma infestans, another member of the hemipteran Reduviidae family and a vector of the same disease. A small heterochromatic body (chromocenter) formed by the Y chromosome is evident in the somatic cells of P. megistus, differing in size and chromosome type contribution from the well-studied chromocenters present in T. infestans. While the overall distribution of histone epigenetic marks differ when comparing the heterochromatin and euchromatin territories in T. infestans, no similar data have been established for other hemipteran reduviids, including P. megistus. In the present work, histone acetylation and methylation marks were investigated in cells of Malpighian tubules of P. megistus 5th instar nymphs using immunocytochemical assays and compared to previously published data for T. infestans. Although similarities between these species were found regarding absence of acetylated H3K9, H4K8 and H4K16, and H3K9me and H3K9me2 in the chromocenter, presence of these marks in euchromatin, and presence of H3K9me3 in the chromocenter, no intimate association of acetylated H4K8 and 18S rDNA was revealed in the chromocenter of P. megistus. The elevated abundance of H3K9me2 marks at the nuclear periphery in P. megistus cells, differing from data for T. infestans, is suggested to reflect differences in the interaction of lamina-associated chromatin domains with the nuclear lamina, methyl-transferase modulation and/or association with the last DNA endoreplication step in 5th instar nymphs, which is a matter for further investigation.

Invasion of the assassin bug Agriosphodrus dohrni (Hemiptera: Reduviidae) to Japan: Source estimation inferred from mitochondrial and nuclear gene sequences

A large-sized assassin bug Agriosphodrus dohrni (Signoret), has been recorded from India, Vietnam, China and Japan. It is one of the potential biological control agents against some important agricultural and forest pests. This species is speculated to have invaded Japan from its native range in China about 60 years ago. We used three mitochondrial gene fragments (COI, Cytb, and ND5) and one nuclear gene fragment (EF-1α) to clarify the invasion history of A. dohrni and assess the effects of geographic events and associated ecological adaptation on the distribution pattern. The native populations of A. dohrni in China are divided into three distinct groups, which might be molded by the Early Pleistocene glaciation event and diverged during the Calabrian Stage. However, consistent with the hypothesis of a recent invasion, extremely low level of genetic variation was detected in the Japanese populations, with only two haplotypes for the combined mitochondrial genes. Both the splits network and the ML/BI phylogenetic trees revealed that haplotypes of Japan were more closely-related to those from eastern China. Therefore, we postulate that there has been only one introduction event, probably from somewhere around the Nanjing (NJ) and Lin'an (LA) populations of eastern China.

Characterization of the complete mitochondrial genome of Inara alboguttata (Hemiptera: Reduviidae)

In this study, the complete mitochondrial genome (mitogenome) of the assassin bug Inara alboguttata, is determined using next-generation sequencing. The mitogenome is a typical circular DNA molecule of 15,436 bp long with a high AT bias (72.3%), containing 13 protein-coding genes, two rRNA genes, 22 tRNA genes and a control region. Protein-coding genes all initiate with ATN codons and most of them terminate with TAA or TAG codons, whereas COI, ND3, and ND5 use a single T residue. The lrRNA and srRNA genes are 1247 bp and 766 bp in length, respectively. All tRNA genes have the cloverleaf secondary structure except for the tRNASer(AGN). The control region is 860 bp long with an A + T content of 68.2%. Phylogenetic result supports the sister relationship between I. alboguttata and Acanthaspis ruficeps.

Abundance of natural enemies of Nezara viridula (Hemiptera: Pentatomidae) on three cultivars of sweet alyssum

AbstractThe southern green stink bug, Nezara viridula is one of the most serious pests of tomatoes in Florida. During 2014 and 2015 tomato cropping seasons, three cultivars of sweet alyssum, Lobularia maritima (Brassicales: Brassicaceae) were evaluated in north Florida to determine their effectiveness in conserving the natural enemies of the southern green stink bug in open field conditions. The experimental refuge crops were cultivated on two outer rows and one center row of the tomato crop. Each section of the rows of trap crops and refuge crops was 20 × 3 ft. (6 × 0.91 m) in size. Pest insects and their natural enemies were collected weekly and identified. On refuge crops, big‐eyed bug, Geocoris punctipes (Hemiptera: Geocoridae); minute pirate bug, Orius insidiosus (Hemiptera: Anthocoridae), ladybird beetles (Coleoptera: Coccinelidae), assassin bugs (Hemiptera: Reduviidae), damsel bugs (Hemiptera: Nabidae), hover flies (Diptera: Syrphidae) and spiders (Arachnida) were collected. All cultivars of L. maritima attracted the natural enemies of the southern green stink bug; however ‘carpet of snow’ was the most effective cultivar followed by ‘tall white’ in attracting G. punctipes in the tomato crop. N. viridula population first peaked in July and declined in week 11 and then had a sharp increase in weeks 12 and 13 when G. punctipes population was comparatively high. Data on the availability of suitable refuge crops which provide nectar and shelter to natural enemies are useful for integrated pest management of the southern green stinkbug, because these plants provide necessary resources to conserve beneficial species.

<b>A first report and additional description of the assassin bug <I>Neostaccia plebeja</I> (Stål) (Heteroptera: Reduviidae) from India with comparative notes on <I>Staccia diluta</I> Stål from Assam, India</b>

The assassin bug, Neostaccia plebeja (Stål, 1866) (Hemiptera: Heteroptera: Reduviidae: Stenopodainae) is being reported for the first time from India. It is redescribed with many illustrations. Comparative photos of the salient characters of Staccia diluta Stål, 1859 are also provided.

Phylogenetic comparative analysis supports aposematic colouration-body size association in millipede assassins (Hemiptera: Reduviidae: Ectrichodiinae).

The diversity of colour patterns and its importance in interactions with the environment make colouration in animals an intriguing research focus. Aposematic colouration is positively correlated with body size in certain groups of animals, suggesting that warning colours are more effective or that crypsis is harder to achieve in larger animals. Surprisingly, this relationship has not been recovered in studies investigating insects, which may have been confounded by a focus on aposematic taxa that are also gregarious. Millipede assassin bugs (Hemiptera: Reduviidae: Ectrichodiinae) comprise species with cryptic and aposematic colour patterns across a range of body sizes, are typically solitary as adults and are thus an excellent model for investigating a possible association between colouration and body size. Here, we use a comprehensive phylogeny for Ectrichodiinae, ancestral state reconstruction of colouration, and phylogenetic comparative methods to test for a colouration-body size association. The ancestor of Ectrichodiinae is reconstructed as cryptically coloured, with multiple subsequent transitions between aposematic and cryptic colouration. Aposematic colouration is positively associated with male body length and supports the hypothesis that selection on Ectrichodiinae body size may influence evolutionary transitions between aposematic and cryptic colouration or alternatively that selection for aposematic colouration influences body size evolution.

A new species of Klabonosa Bouček (Hymenoptera: Pteromalidae) reared from eggs of Endochus sp. (Hemiptera: Reduviidae) from India.

The genus Klabonosa Bouček(Hymenoptera: Pteromalidae) is recorded for the first time from the Oriental region, with both sexes of K. indica Gupta, Sureshan Yeshwanth sp. n. reared from eggs of the assassin bug Endochussp. (Hemiptera: Reduviidae) on Artocarpus heterophyllus Lam. (Moraceae). The male is formally described and illustrated for the first time for the genus.

Harvesting Venom Toxins from Assassin Bugs and Other Heteropteran Insects.

Heteropteran insects such as assassin bugs (Reduviidae) and giant water bugs (Belostomatidae) descended from a common predaceous and venomous ancestor, and the majority of extant heteropterans retain this trophic strategy. Some heteropterans have transitioned to feeding on vertebrate blood (such as the kissing bugs, Triatominae; and bed bugs, Cimicidae) while others have reverted to feeding on plants (most Pentatomomorpha). However, with the exception of saliva used by kissing bugs to facilitate blood-feeding, little is known about heteropteran venoms compared to the venoms of spiders, scorpions and snakes. One obstacle to the characterization of heteropteran venom toxins is the structure and function of the venom/labial glands, which are both morphologically complex and perform multiple biological roles (defense, prey capture, and extra-oral digestion). In this article, we describe three methods we have successfully used to collect heteropteran venoms. First, we present electrostimulation as a convenient way to collect venom that is often lethal when injected into prey animals, and which obviates contamination by glandular tissue. Second, we show that gentle harassment of animals is sufficient to produce venom extrusion from the proboscis and/or venom spitting in some groups of heteropterans. Third, we describe methods to harvest venom toxins by dissection of anaesthetized animals to obtain the venom glands. This method is complementary to other methods, as it may allow harvesting of toxins from taxa in which electrostimulation and harassment are ineffective. These protocols will enable researchers to harvest toxins from heteropteran insects for structure-function characterization and possible applications in medicine and agriculture.

Harvesting Venom Toxins from Assassin Bugs and Other Heteropteran Insects

Harvesting Venom Toxins from Assassin Bugs and Other Heteropteran Insects

First record of the genus Ptilocerus in the Australian Region, with the description of two new species (Hemiptera: Heteroptera: Reduviidae).

The assassin bugs of the genus Ptilocerus Gray, 1831 (Hemiptera: Heteroptera: Reduviidae: Holoptilinae) occurring in the Australian Region are reviewed for the first time, resulting in the description of two new species, viz., P. spangenbergi sp. nov. (Queensland and Northern Territory, Australia) and P. papuensis sp. nov. (Papua New Guinea). The latter species differs from P. fuscus Gray, 1831 (the type-species of genus Ptilocerus) in a couple of major external morphological characters, hence its tentative placement in the genus Ptilocerus is discussed. A key for the separation of the two new species is provided.

Redescription of the thread-legged assassin bug Ploiaria anak (Hemiptera: Heteroptera: Reduviidae: Emesinae) from India, with notes on its biology.

The thread-legged assassin bug species Ploiaria anak Distant, 1909 (Hemiptera: Heteroptera: Reduviidae: Emesinae) from India is redescribed based on recently collected material from Pune District, India. Notes on the biology of the species and a key to species of the genus from India are provided. A lectotype is designated for P. anak. Both P. nuda and P. nude appear in the original description of the Ploiaria species described by Ravichandran Livingstone (1989); nuda is selected as the correct original spelling. As this name is a junior homonym of P. nuda Miller, 1950, it is replaced by the new name P. raviaspinosa nom. nov.

The assassin bug Pristhesancus plagipennis produces two distinct venoms in separate gland lumens

The assassin bug venom system plays diverse roles in prey capture, defence and extra-oral digestion, but it is poorly characterised, partly due to its anatomical complexity. Here we demonstrate that this complexity results from numerous adaptations that enable assassin bugs to modulate the composition of their venom in a context-dependent manner. Gland reconstructions from multimodal imaging reveal three distinct venom gland lumens: the anterior main gland (AMG); posterior main gland (PMG); and accessory gland (AG). Transcriptomic and proteomic experiments demonstrate that the AMG and PMG produce and accumulate distinct sets of venom proteins and peptides. PMG venom, which can be elicited by electrostimulation, potently paralyses and kills prey insects. In contrast, AMG venom elicited by harassment does not paralyse prey insects, suggesting a defensive role. Our data suggest that assassin bugs produce offensive and defensive venoms in anatomically distinct glands, an evolutionary adaptation that, to our knowledge, has not been described for any other venomous animal.

Entrapped carrion increases indirect plant resistance and intra‐guild predation on a sticky tarweed

Many plants employ indirect defenses against herbivores; often plants provide a shelter or nutritional resource to predators, increasing predator abundance, and lessening herbivory to the plant. Often, predators on the same plant represent different life stages and different species. In these situations intraguild predation (IGP) may occur and may decrease the efficacy of that defense. Recently, several sticky plants have been found to increase indirect defense by provisioning predatory insects with entrapped insects (hereafter: carrion). We conducted observational studies and feeding trials with herbivores and predators on two sticky, insect‐entrapping asters, Hemizonia congesta and Madia elegans, to construct food webs for these species and determine the prevalence of IGP in these carrion‐provisioning systems. In both systems, intraguild predation was the most common interaction observed. To determine whether IGP was driven by resource abundance, whether it reduced efficacy of this indirect defense and whether stickiness or predator attraction was induced by damage, we performed field manipulations on H. congesta. Carrion supplementation led to an increase in predator abundance and IGP. IGP was asymmetric within the predator guild: assassin bugs and spiders preyed on small stilt bugs but not vice versa. Despite increased IGP, carrion provisions decreased the abundance of the two most common herbivores (a weevil and a mealybug). Overall seed set was driven by plant size, but number of seeds produced per fruit significantly increased with increasing carrion, likely because of the reduction in the density of a seed‐feeding weevil. Observationally and experimentally, we found that carrion‐mediated indirect defense of tarweeds led to much intraguild predation, though predators effectively reduced herbivore abundance despite the increase in IGP.

Giant fish-killing water bug reveals ancient and dynamic venom evolution in Heteroptera.

True Bugs (Insecta: Heteroptera) produce venom or saliva with diverse bioactivities depending on their feeding strategies. However, little is known about the molecular evolution of the venom toxins underlying these biological activities. We examined venom of the giant fish-killing water bug Lethocerus distinctifemur (Insecta: Belostomatidae) using infrared spectroscopy, transcriptomics, and proteomics. We report 132 venom proteins including putative enzymes, cytolytic toxins, and antimicrobial peptides. Over 73% (96 proteins) showed homology to venom proteins from assassin bugs (Reduviidae), including 21% (28 proteins from seven families) not known from other sources. These data suggest that numerous protein families were recruited into venom and diversified rapidly following the switch from phytophagy to predation by ancestral heteropterans, and then wereretained over>200 my of evolution. In contrast, trophic switches to blood-feeding (e.g. inTriatominae and Cimicidae) or reversions to plant-feeding (e.g., inPentatomomorpha) were accompanied by rapid changes in the composition of venom/saliva, including the loss of many protein families.

A New Cretaceous Insect with a Unique Cephalo-thoracic Scissor Device

Insects use different parts of their body to cling to mating partners, to catch prey, or to defend themselves, in most cases the mouthparts or the legs. However, in 400 million years of evolution [1, 2], specialized devices were independently acquired in several groups to adopt these tasks, as for instance modified legs in mantids, assassin bugs or stick insects [3-5], or clasping antennae of the globular springtails [6]. So far, no known species used the neck region between the head and thorax in one of these functional contexts. Here we describe females of †Caputoraptor elegans, a very unusual, presumably predacious insect discovered in approximately 100-million-year-old [7] Burmese amber. Based on several morphological features, we conclude that this species lived in the foliage of trees or bushes. A unique feature of the new taxon is a scissor-like mechanism formed by wing-like extensions on the posterior head and corresponding serrated edges of the dorsal sclerite of the first thoracic segment. Based on the specific structure of the apparatus, we conclude that it was probably used by females to hold on to males during copulation. A defensive or prey-catching function appears less likely. A similar mechanism did not evolve in any other known known group of extant or extinct insects.

A Dipteran's Novel Sucker Punch: Evolution of Arthropod Atypical Venom with a Neurotoxic Component in Robber Flies (Asilidae, Diptera).

Predatory robber flies (Diptera, Asilidae) have been suspected to be venomous due to their ability to overpower well-defended prey. However, details of their venom composition and toxin arsenal remained unknown. Here, we provide a detailed characterization of the venom system of robber flies through the application of comparative transcriptomics, proteomics and functional morphology. Our results reveal asilid venoms to be dominated by peptides and non-enzymatic proteins, and that the majority of components in the crude venom is represented by just ten toxin families, which we have named Asilidin1–10. Contrary to what might be expected for a liquid-feeding predator, the venoms of robber flies appear to be rich in novel peptides, rather than enzymes with a putative pre-digestive role. The novelty of these peptides suggests that the robber fly venom system evolved independently from hematophagous dipterans and other pancrustaceans. Indeed, six Asilidins match no other venom proteins, while three represent known examples of peptide scaffolds convergently recruited to a toxic function. Of these, members of Asilidin1 closely resemble cysteine inhibitor knot peptides (ICK), of which neurotoxic variants occur in cone snails, assassin bugs, scorpions and spiders. Synthesis of one of these putative ICKs, U-Asilidin1-Mar1a, followed by toxicity assays against an ecologically relevant prey model revealed that one of these likely plays a role as a neurotoxin involved in the immobilization of prey. Our results are fundamental to address these insights further and to understand processes that drive venom evolution in dipterans as well as other arthropods.