New records of species of Nitornus Stål, 1859 (Hemiptera: Reduviidae: Stenopodainae) from French Guiana and Surinam

The occurrences of Nitornus lobulatus Stål, 1859 and Nitornus parkoi (Costa Lima & Campos Seabra, 1945) from French Guiana and of N. parkoi (Hemiptera: Reduviidae: Stenopodainae) from Surinam are reported by the first time. The discovery of these species broadens their known geographic distribution. Brief comments on bionomics information and further discussion of the limited data currently available for these assassin bug species are provided.

Re-description of the assassin bug species Pygolampis striata Miller, 1940 with new distributional records from Japan and Indonesia (Heteroptera, Reduviidae, Stenopodainae)

Pygolampis striata Miller, 1940 was previously described, based on a single male specimen. However, there are no records of the species since then. The females and nymphs were not described and knowledge about their habitat is insufficient. This is the first record of the assassin bug Pygolampis striata Miller, 1940 from Japan and Indonesia. Here, this species has been re-described and, for the first time, the female has been described. The species was collected from the surfaces of dried Poaceae grasslands using the "Gasa-Gasa collecting method".

Hexapod Assassins’ Potion: Venom Composition and Bioactivity from the Eurasian Assassin Bug Rhynocoris iracundus

Assassin bug venoms are potent and exert diverse biological functions, making them potential biomedical goldmines. Besides feeding functions on arthropods, assassin bugs also use their venom for defense purposes causing localized and systemic reactions in vertebrates. However, assassin bug venoms remain poorly characterized. We collected the venom from the assassin bug Rhynocoris iracundus and investigated its composition and bioactivity in vitro and in vivo. It caused lysis of murine neuroblastoma, hepatoma cells, and healthy murine myoblasts. We demonstrated, for the first time, that assassin bug venom induces neurolysis and suggest that it counteracts paralysis locally via the destruction of neural networks, contributing to tissue digestion. Furthermore, the venom caused paralysis and melanization of Galleria mellonella larvae and pupae, whilst also possessing specific antibacterial activity against Escherichia coli, but not Listeria grayi and Pseudomonas aeruginosa. A combinatorial proteo-transcriptomic approach was performed to identify potential toxins responsible for the observed effects. We identified neurotoxic Ptu1, an inhibitory cystin knot (ICK) toxin homologous to ω-conotoxins from cone snails, cytolytic redulysins homologous to trialysins from hematophagous kissing bugs, and pore-forming hemolysins. Additionally, chitinases and kininogens were found and may be responsible for insecticidal and cytolytic activities. We demonstrate the multifunctionality and complexity of assassin bug venom, which renders its molecular components interesting for potential biomedical applications.

Description of the adult of the thread-legged assassin bug Eugubinus araneus (Hemiptera: Reduviidae) from India, with comments on other congeneric species

The thread-legged assassin bug Eugubinus araneus Distant, 1903 (Hemiptera: Heteroptera: Reduviidae: Emesinae: Emesini) was described from India on the basis of two nymphs. This paper provides the first description of the adult with illustrations of both the adult and the nymph. A checklist of and a key to species of Eugubinus Distant, 1903, and images of the type material of six additional species of the genus, i.e., E. intrudans Distant, 1915, E. reticolus Distant, 1915, E. canalanus (Distant,1914), E. annulatus (Villiers, 1948), E. forsteri Wygodzinsky, 1953 and E. papuensis Wygodzinsky, 1966, are provided.

Taxonomic review of Xenorhyncocoris Miller (Heteroptera: Reduviidae: Ectrichodiinae), with description of X. attractivus sp. nov. and notes on sexual dimorphism of the genus

The enigmatic millipede assassin bug genus Xenorhyncocoris Miller, 1938 is revised. Previously known species, X. caraboides Miller, 1938, X. princeps Miller, 1949 and X. schoenitzeri Putshkov & Bérenger, 1999, are diagnosed and photographed. A new species, X. attractivus sp. nov., is described based on male and female specimens from northeastern Borneo. The male of Xenorhyncocoris is reported for the first time, revealing the extreme sexual dimorphism present in the genus. The diagnosis of Xenorhyncocoris is extended in order to make it applicable to the new discovery, and a female-based key to species of the genus is updated. Relationships among Xenorhyncocoris and Vilius Stål, 1863, Neozirta Distant, 1919 and Schottus Distant, 1902 are briefly discussed.

Revision and phylogenetic analysis of the genus Acanthischium Amyot & Serville, 1843 (Hemiptera: Reduviidae: Harpactorinae)

The Neotropical harpactorine assassin bug genus Acanthischium Amyot & Serville, 1843 (Hemiptera: Reduviidae: Harpactorini) includes four valid species: Acanthischium maculatum Amyot & Serville, 1843 (with ten color varieties proposed by Stål [1872]), Acanthischium haglundi Stål, 1866, Acanthischium superbum Haviland, 1931, and Acanthischium invium Elkins, 1961. A taxonomic revision and a morphological phylogenetic analysis were carried out to test species limits and to propose a hypothesis of evolutionary relationships. As a result of the phylogenetic analysis, Acanthischium is characterized on its external morphology by the elongate postocular region, posterior margin of the pronotum with spines, ventral surface of protrochanter with apical and basal protuberances, profemur wider than mesofemur, and protibia strongly curved. After the taxonomic revision we propose nine valid species, taking into consideration characters of external morphology, male and female genitalia, and color patterns: Acanthischium dimidiatum Stål, 1859 stat. rev.; Acanthischium flaviceps Stål, 1872 stat. rev.; Acanthischium haglundi Stål, 1866; Acanthischium kuna sp. nov. from Panama and Colombia; Acanthischium maculatum Amyot & Serville, 1843; Acanthischium meloae sp. nov. from Suriname; Acanthischium nigrum Stål, 1872 stat. rev.; Acanthischium semiflavum Stål,1872 stat. rev.; and Acanthischium superbum Haviland, 1931. We further synonymize A. invium Elkins, 1961 with A. superbum. All but one of the species ‒ A. flaviceps ‒ were included in the phylogenetic analysis, in which Acanthischium was found to be monophyletic, with the following set of relationships: (A. haglundi + (A. nigrum +(A. dimidiatum (A. maculatum, A. semiflavum, A. kuna, A. meloae, A. superbum)))). The resulting phylogenetic pattern indicate a body color transition from drab to more vivid ones, such as orange or red. The species exhibiting red and orange colorations are found in a clade, suggesting an underlying biological phenomenon, such as wasp mimetism.

Two new species of Abelocephala (Heteroptera: Reduviidae) from Taiwan

The millipede assassin bug genus Abelocephala Maldonado, 1996 (Heteroptera: Reduviidae: Ectrichodiinae: Abelocephalini) is currently comprised of seven Oriental species. Two macropterous males, representing two new species, were recently collected from Taiwan in Malaise trap samples: A. baliensis sp. nov. and A. yilanensis sp. nov. Habitus and structural images are provided for each new species. A revised diagnosis of Abelocephala and an updated identification key to all species of the genus are given.

Age-dependent walking and feeding of the assassin bug Amphibolus venator

Animal behaviours often dependent on age. In many insect species, walking shows an age-dependent decline, and food intake may also be dependent on age. However, few studies have investigated the relationship between age and walking or food intake. In the present study, we compared walking traits and food intake among individuals of different ages in the assassin bug Amphibolus venator (Hemiptera, Reduviidae). The present results showed an age-dependent decline in walking, similar to findings in many animal species. On the other hand, food intake showed a positive correlation with age. Therefore, the decline in walking did not lead to a decline in feeding. The positive relationship between food intake and age may be related to the type of predation, sit-and-wait, used by A. venator via alterations in investment in reproductive traits with age.

Crouching Tiger, Hidden Protein: Searching for Insecticidal Toxins in Venom of the Red Tiger Assassin Bug (Havinthus rufovarius)

Assassin bugs are venomous insects that prey on other arthropods. Their venom has lethal, paralytic, and liquifying effects when injected into prey, but the toxins responsible for these effects are unknown. To identify bioactive assassin bug toxins, venom was harvested from the red tiger assassin bug (Havinthus rufovarius), an Australian species whose venom has not previously been characterised. The venom was fractionated using reversed-phase high-performance liquid chromatography, and four fractions were found to cause paralysis and death when injected into sheep blowflies (Lucilia cuprina). The amino acid sequences of the major proteins in two of these fractions were elucidated by comparing liquid chromatography/tandem mass spectrometry data with a translated venom-gland transcriptome. The most abundant components were identified as a solitary 12.8 kDa CUB (complement C1r/C1s, Uegf, Bmp1) domain protein and a 9.5 kDa cystatin. CUB domains are present in multidomain proteins with diverse functions, including insect proteases. Although solitary CUB domain proteins have been reported to exist in other heteropteran venoms, such as that of the bee killer assassin bug Pristhesancus plagipennis, their function is unknown, and they have not previously been reported as lethal or paralysis-inducing. Cystatins occur in the venoms of spiders and snakes, but again with an unknown function. Reduction and alkylation experiments revealed that the H. rufovarius venom cystatin featured five cysteine residues, one of which featured a free sulfhydryl group. These data suggest that solitary CUB domain proteins and/or cystatins may contribute to the insecticidal activity of assassin bug venom.