Article

Use of Plant Resin by a Bee Assassin Bug, Apiomerus flaviventris (Hemiptera: Reduviidae)

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Abstract

A bee assassin bug, Apiomerus flaviventris Herrich-Schäffer (Hemiptera: Reduviidae), of the arid or semiarid southwestern North America is known to exploit resins from plants and apply them to the eggs for protection. To elucidate the source and possible functions of the resin, A. flaviventris were collected in the Anza Borrego Desert State Park, California, and observed in the laboratory. Female A. flaviventris collected the resin from a desert perennial shrub, brittlebush, Encelia farinosa Gray ex Torr. (Asteraceae). Bioassays with the predatory ant species Forelius pruinosus (Roger) and Linepithema humile (Mayr) (Hymenoptera: Formicidae) indicated that the brittlebush resin coating is important in preventing A. flaviventris eggs from being picked up by omnivorous predators.

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... While maternal or biparental care occurs in several groups of insects, exclusive paternal care in insects is restricted to true bugs (Gilbert and Manica 2015), where eggcarrying occurs in certain Coreidae (Reguera and Gomendio 1999;Gomendio et al. 2008) and Belostomatidae (Smith and Larsen 1993), and egg guarding in some species of the harpactorine assassin bug Rhynocoris (Gilbert et al., 2010) and Atopozelus Elkins (Tallamy et al. 2004). Maternal care in Heteroptera comprises a variety of different strategies, from the production of oothecae (Kaiwa et al. 2014) or protective coverings of egg batches (Choe and Rust 2007), defence against egg predators and parasitoids through egg guarding (Giffney and Kemp 2014), to provisioning of early instar immatures with food (Nakahira et al. 2013), microbial associates (Kaiwa et al. 2010) or resin used during predation (Weirauch 2006a;Law and Sediqi 2010). Maternal care strategies, including egg guarding, are common in Pentatomomorpha, the so called stink bugs and related groups. ...
... While we did not observe defensive interactions of females with potential egg predators or egg parasitoids, we suspect that this association likely represents a so far undocumented case of maternal egg guarding behaviour in Heteroptera. Egg batches average 21.5 eggs per batch, are loosely organised, and are not covered by either exogenous or endogenous sticky substances, as seen in other Reduviidae that oviposit on the outside of living plant tissues including certain Apiomerini (Choe and Rust 2007;Forero and Weirauch 2017), Harpactorini (Weirauch 2006a), and Phymatinae (Davis 1957). This is consistent with our observation that female Bactrodes do not possess subrectal glands, as previously noted by Davis (1969), a structure that is thought to be involved in the secretion of protective egg batch coverings in Harpactorini. ...
Article
Plants with glandular trichomes have been shown to attract specialist, mutualistic predatory insects. Despite recent advances in understanding the plant component in this association, few sticky plant specialist insects are well documented and their adaptations to the sticky plant environment are understudied. We here describe and illustrate, for the first time, aspects of the natural history and morphology of a small clade of predatory hemipteran insects, the Bactrodinae (Reduviidae). Our study suggests that these insects are exclusively associated with plant species with glandular trichomes. The relationship is not specific as one species of Bactrodes Stål may be associated with multiple species, genera or even families of plants. We document a unique clamp-like structure formed by one of the pretarsal claws and opposing tarsal spine-like setae that enables Bactrodinae to grasp trichomes and walk on leaves densely covered with trichomes. We further present observations of Bactrodes species scavenging on insects entrapped on leaves. Bactrodinae also oviposit on their host plants, and females engage in behaviours that we interpret as maternal egg guarding, a life history strategy that is rare in predatory true bugs. We speculate that instead of or in addition to decreasing egg predation or egg parasitism, female egg guarding may be a response to the limited availability of sticky plants and a strategy against cannibalism.
... Resin bugs in the tribe Apiomerini (Reduviidae: Harpactorinae), also known as bee killers, are known for their striking predation and parental care strategies. They collect plant resins with their forelegs and use this ''sticky trap'' to enhance their performance during prey capture (Miller, 1956; Johnson, 1983; Adis, 1984; Bérenger and Pluot- Sigwalt, 1997).Within the genus Apiomerus Hahn, 1831 females gather sticky resin, transfer it to the abdominal venter, and then remove it during oviposition using a comb on the metatibia to coat their egg clutches (Szerlip, 1980; Eisner, 1988; Choe and Rust, 2007). In addition, females of Apiomerus nigrilobus, Stål, 1872, possess glands on the ventral surface of the abdomen (Barth, 1963) that may interact with the stored plant resin to prevent resin hardening. ...
... Considering these striking natural history phenomena, the lack of detailed descriptions of resin-gathering behaviors is surprising as is the lack of a comprehensive study investigating morphological structures involved in these behaviors. Apiomerini are an exclusively Neotropical tribe of Harpactorinae that comprises 12 extant genera ventral abdominal surfaces (Choe and Rust, 2007). The adults were kept separately in filter paper-lined glass Petri dishes (Pyrex , 10 cm diameter). ...
Article
Apiomerini (Reduviidae: Harpactorinae) collect plant resins with their forelegs and use these sticky substances for prey capture or maternal care. These behaviors have not been described in detail and morphological structures involved in resin gathering, transfer, and storage remain virtually undocumented. We here describe these behaviors in Apiomerus flaviventris and document the involved structures. To place them in a comparative context, we describe and document leg and abdominal structures in 14 additional species of Apiomerini that represent all but one of the 12 recent genera in the tribe. Based on these morphological data in combination with the behavioral observations on A. flaviventris, we infer behavioral and functional hypotheses for the remaining genera within the tribe Apiomerini. Setal abdominal patches for resin storage are associated with maternal care so far only documented for species of Apiomerus. Based on the occurrence of these patches in several other genera, we propose that maternal care is widespread within the tribe. Ventral abdominal glands are widespread within female Apiomerini. We propose that their products may prevent hardening of stored resins thus providing long-term supply for egg coating. Judging from the diverse setal types and arrangements on the front legs, we predict six different behavioral patterns of resin gathering within the tribe.
... Many species exhibit an unusual method of prey capture in which they collect and apply sticky plant resin to their bodies to ensnare prey (Miller 1956, Bérenger & Pluot-Sigwalt 1997. Female Apiomerus also exhibit maternal care by coating their eggs with resin to anchor them to a substrate, prevent desiccation, and deter predation (Choe & Rust 2007). Szerlip (1980) suggested that all North American Apiomerus species might engage in similar habits of resin gathering to facilitate prey capture. ...
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The Apiomerus maya species group of the genus Apiomerus Hahn, 1831 (Hemiptera: Heteroptera: Reduviidae: Harpactorinae: Apiomerini), the bee assassins, is revised. Four species that are native to parts of Mexico and Central America are recognized and redescribed: Apiomerus maya Dispons, 1971, A. pipil Dispons, 1971, A. venosus Stål, 1872, and A. immundus Bergroth, 1898. Intraspecific polychromatism and male genital morphology are documented for the group. The taxonomy of two previously recognized species is updated: A. tristis Champion, 1899 syn. nov. is here synonymized with A. venosus and A. guatemalensis Dispons, 1971 syn. nov. with A. pipil.
... Esto coincide con lo propuesto por MILLER (1956), BÉRENGER & PLUOT-SIGWALT (1997), quienes describen que este género emplea la resina de las plantas como método de captura de las presas, aplicándosela al cuerpo como trampa adhesiva (ADIS, 1984;GIL-SANTANA & FORERO, 2010). Adicional a lo anterior, este género usa la resina de las plantas para el cuidado parental, cubriendo sus huevos y protegiéndolos contra la depredación y la desecación, además de ayudarle a las ninfas de primeros instares en la captura de sus presas (EISNER, 1988;CHOE & MOHO, 2007;FORERO et al., 2011). Este comportamiento, muy similar dentro de la tribu Apiomerini, fue observado en individuos del género Callioclopus, registrándose una hembra con cinco ninfas de diferentes estadios escondidos en un árbol de M. indica. ...
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... The resinous, aromatic leaves used by European starlings for nest construction may decrease parasite loads and boost immunity among developing nestlings (i.e., Gwinner et al. 2000; Gwinner and Berger 2005; Mennerat et al. 2009). Female assassin bugs also harvest resin and then transfer it to eggs as they are being laid, which inhibits ant predation (Choe and Rust 2007). Among the social insects, many bees, especially in the tropics, collect and use resins as a nest-building material (Roubik 1989). ...
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Diverse animals have evolved an ability to collect antimicrobial compounds from the environment as a means of reducing infection risk. Honey bees battle an extensive assemblage of pathogens with both individual and "social" defenses. We determined if the collection of resins, complex plant secretions with diverse antimicrobial properties, acts as a colony-level immune defense by honey bees. Exposure to extracts from two sources of honey bee propolis (a mixture of resins and wax) led to a significantly lowered expression of two honey bee immune-related genes (hymenoptaecin and AmEater in Brazilian and Minnesota propolis, respectively) and to lowered bacterial loads in the Minnesota (MN) propolis treated colonies. Differences in immune expression were also found across age groups (third-instar larvae, 1-day-old and 7-day-old adults) irrespective of resin treatment. The finding that resins within the nest decrease investment in immune function of 7-day-old bees may have implications for colony health and productivity. This is the first direct evidence that the honey bee nest environment affects immune-gene expression.
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Many insects use tactics to protect their eggs from predation, infection, and water loss, among other risks. Some assassin bugs only in the New World tribe Apiomerini are known to use plant substances, such as resin, instead of secretions to protect their eggs. Here, we report a novel storage mechanism and the utilization of plant resin for egg protection in Asian assassin bugs, Velinus nodipes and Agriosphodrus dohrni (tribe: Harpactorini). Adult females of both species were observed to take in plant resin through their genitalia. We reported on the handling of resin by these species and confirmed that A. dohrni adult females stored resin in their subrectal glands and that the substance covering their egg masses was derived from plant resin. This is the first report on the storage of plant resin inside the bodies of assassin bugs and on resin-protected eggs in Harpactorini. Such internal resin storage was not accompanied by external morphological features, as observed in some Apiomerini assassin bugs, thereby suggesting that this tactic has been overlooked and may have evolved in broader tribes of assassin bugs than previously thought.
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Within the genus Apiomerus Hahn, 1831, the crassipes and the pictipes species groups are described. In the crassipes spe-cies group, three species are redescribed: Apiomerus crassipes (Fabricius, 1803), Apiomerus rufipennis (Fallou, 1889) and Apiomerus spissipes (Say, 1825); one subspecies is raised to species level and redescribed: Apiomerus cooremani Costa Lima, Campos Seabra & Hathaway, 1951; and six species are described as new: Apiomerus californicus Berniker & Sz-erlip, sp. nov., Apiomerus cazieri Berniker & Szerlip, sp. nov., Apiomerus floridensis Berniker & Szerlip, sp. nov., Api-omerus montanus Berniker & Szerlip, sp. nov., Apiomerus peninsularis Berniker & Szerlip, sp. nov. and Apiomerus wygodzinskyi Berniker & Szerlip, sp. nov. In the pictipes species group, two species are redescribed, Apiomerus flaviven-tris Herrich-Schaeffer, 1846 and Apiomerus pictipes Herrich-Schaeffer, 1846, and one subspecies, Apiomerus pictipes pit-tieri Costa Lima, Campos Seabra, & Hathaway, 1951 is synonymized with Apiomerus pictipes. Neotypes are designated for Apiomerus flaviventris, Apiomerus pictipes, and Apiomerus spissipes. Lectotypes are designated for Apiomerus coore-mani and Apiomerus crassipes. The composition of the species groups are different from those originally proposed by Sig-urd Szerlip in his PhD dissertation. The crassipes group has one additional member, Apiomerus rufipennis. Furthermore, Apiomerus barrocoloradoi Forero, Berniker & Szerlip, 2010 and the two manuscript names "Apiomerus panther" and "Apiomerus tigris" were removed from the pictipes group. A key to the species is provided, as well as photographs of habitus and diagnostic features for both males and females. Intraspecific polychromatism is discussed as it relates to spe-cies identification and species delimitation.
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Apiomerini, also called New World resin bugs, are a largely Neotropical tribe of the assassin bug subfamily Harpactorinae, whose members show unique predation and maternal care behaviors. Species in this group collect resins to improve prey capture, and species within Apiomerus also coat their eggs with the accumulated resin to prevent egg predation and desiccation. Current understanding of phylogenetic relationships within the tribe is limited, in part due to the lack of comprehensive comparative morphological studies that would allow for cladistic analyses. Here, the male and female ectodermal genitalic structures are documented for all but one of the 12 extant genera of Apiomerini, including 12 species of the speciose genus Apiomerus. Descriptions and digital micrographs are provided for the pygophore, parameres, and phallus of the male, and for the tergite 8, syntergite 9/10, gonocoxae, gonapophyses, gonoplac, and bursa copulatrix of the female. Primary homologs are identified and their variation among taxa discussed. The wealth of morphological character information uncovered in this comparative analysis will greatly facilitate future cladistic analyses of Apiomerini. Our study also represents one of the first detailed and well-illustrated comparative studies of genitalic features at the tribal level in Reduviidae. Functional morphology of apiomerine genitalia is discussed where appropriate. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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Zhang, G. and Weirauch, C. 2011. Sticky predators: a comparative study of sticky glands in harpactorine assassin bugs (Insecta: Hemiptera: Reduviidae). — Acta Zoologica (Stockholm) 00 : 1–10. For more than 50 years, specialized dermal glands that secrete sticky substances and specialized setae have been known from the legs of New World assassin bugs in the genus Zelus Fabricius (Reduviidae: Harpactorinae). The gland secretions and specialized ‘sundew setae’ are involved in enhancing predation success. We here refer to this predation strategy as ‘sticky trap predation’ and the specialized dermal glands as ‘sticky glands’. To determine how widespread sticky trap predation is among Reduviidae, we investigated taxonomic distribution of sticky glands and sundew setae using compound light microscopical and scanning electron microscopical techniques and sampling 67 species of Reduviidae that represent 50 genera of Harpactorini. We found sticky glands in 12 genera of Harpactorini and thus show that sticky trap predation is much more widespread than previously suspected. The sticky glands vary in shape, size and density, but are always located in a dorsolateral position on the fore tibia. Sundew setae are present in all taxa with sticky glands with the exception of Heza that instead possesses unique lamellate setae. The sticky trap predation taxa are restricted to the New World, suggesting a New World origin of this unique predation strategy.
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The crassipes and pictipes species groups of Apiomerus Hahn together contain 12 species, many with high intraspecific chromatic variability, which represent the majority of Nearctic species in this New World assassin bug genus. Because of their geographical distribution and their varying degrees of polychromatism, these two species groups provide a unique opportunity to study the evolution of polychromatism and analyse relationships among areas of endemism in the Nearctic, as well as determine the boundary between the Nearctic and Neotropical regions. The results of a morphology based phylogenetic analysis allowed investigation of these questions while also determining relationships among the 12 species in the two species groups. The crassipes and pictipes species groups were each supported as monophyletic and as sister taxa. Apiomerus rufipennis (Fallou) was not included in the original concept of the crassipes species group, but is shown here to be a member of the group. Apiomerus barrocoloradoi Forero, Berniker & Szerlip, which had been hypothesized previously to belong to the pictipes species group, is excluded from this group. Intraspecific polychromatism for each species was identified as being present in one of three states: no polychromatism; limited polychromatism; or polychromatism as discrete colour morphs. Limited polychromatism was here found to be the ancestral state for Apiomerus, and species with discrete colour morphs are restricted to the crassipes and pictipes species groups. Polychromatism appears to be a greatly homoplastic character within the genus. A Brooks parsimony analysis recovered distinct Nearctic and Neotropical clades. The Nearctic clade is divided between areas in the central and eastern U.S.A. and areas in the Western U.S.A. and Mexico. The Nearctic–Neotropical boundary for the taxa included in the analysis is along the Isthmus of Tehuantepec in southern Mexico.
Article
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First observation of alternative food usage (extrafloral nectar) by the assassin bug Atopozelus opsimus (Hemiptera, Reduviidae). Assassin bugs (Reduviidae) are voracious insects that prey on other arthropods. Recent evidences have pointed out that these predators also feed on plant derived substances in rare opportunities. The present study describes the feeding behavior of the reduviid Atopozelus opsimus on extrafloral nectaries of Inga vera (Fabaceae) in a Neotropical savanna area. It was investigated if the insects feed more frequently of extrafloral nectar or prey, and if individuals of different stages of development vary according to feeding behavior. Notably, the results suggest that the diet of all instars and adults consist mainly of extrafloral nectar (N = 1013), in detriment of captured prey ingestion (N = 18). Also, there was no variation on feeding behavior and life stage.
Article
Apiomerus, the charismatic bee-assassins (>108 spp.), belong to the New World resin bugs in the harpactorine tribe Apiomerini (12 extant genera) that is characterized by a novel predation strategy, resin trap predation. Apiomerini also exhibit striking genitalic diversity that has shaped subgeneric classifications within the genus Apiomerus and females of some species of Apiomerus are known to engage in unique maternal care behaviors. The lack of a phylogenetic framework currently hinders evolutionary interpretations of genitalic morphology and maternal care. We here present a molecular phylogeny based on 4, 477bp of six ribosomal and protein coding genes and 95 terminal taxa using parsimony and maximum likelihood approaches as a way of addressing these shortcomings. Apiomerini are monophyletic, with Heniartes being the sistergroup to all remaining taxa that form the monophyletic Manicocoris (Calliclopius, Manicocoris, Micrauchenus, and Ponerobia) and Apiomerus (Agriocoris, Apiomerus, and Sphodrolestes) clades. Previously proposed subgeneric groups are polyphyletic, but several proposed species groups are recovered as monophyletic. Ancestral state reconstruction of the metatibial comb indicates that this structure evolved in the ancestor of all Apiomerini where it was present in males and in females; it became strongly sexually dimorphic (better developed in females than in males) in the Apiomerus clade (Apiomerus+Agriocoris+Sphodrolestes). Genitalic features reveal a pattern of homoplasy, but frequently are nonetheless useful to diagnose supraspecific groups within Apiomerus. The complex genitalia found within Apiomerus are derived for that clade. We conclude that, using the metatibial comb as a proxy, maternal care is relatively common in the tribe Apiomerini and propose that it likely evolved at the base of the Apiomerus clade if not at the base of Apiomerini.
Article
Bees are known to collect pollen and nectar to provide their larvae and themselves with food. That bees, especially the tropical stingless bees (Apidae: Meliponini), also collect plant resins has, however, been barely addressed in scientific studies on resource use in bees. Resins are used for nest construction, nest maintenance and nest defence. Furthermore, some South-East Asian species transfer resin-derived terpenes to their cuticular profiles. The resin requirement of bees is in turn used by certain plant species, which attract bees either for pollination by providing resin in their inflorescences, or for seed dispersal by providing resin in their seed capsules (mellitochory). Mellitochory is found in the eucalypt tree Corymbia torelliana, the resin of which is collected by Australian stingless bees. We investigated how the interaction between C. torelliana and resin-collecting bees affects the chemical ecology of two Australian stingless bee genera by comparing the chemical profiles of eight bee species with resin from C. torelliana fruits. The two bee genera differed significantly in their chemical profiles. Similar to South-East Asian stingless bees, 51% of all compounds on the body surfaces of the five Tetragonula species were most likely derived from plant resins. Up to 32 compounds were identical with compounds from C. torelliana resin, suggesting that Tetragonula species include C. torelliana compounds in their chemical profiles. By contrast, few or none resinous compounds were found on the body surfaces of the three Austroplebeia species sampled. However, one prominent but as yet unknown substance was found in both C. torelliana resin and the chemical profiles of all Tetragonula and four Austroplebeia colonies sampled, suggesting that most colonies (76%) gathered resin from C. torelliana. Hence, C. torelliana resin may be commonly collected by Australian stingless bees and, along with resins from other plant species, shape their chemical ecology.
Article
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The constant pressure posed by parasites has caused species throughout the animal kingdom to evolve suites of mechanisms to resist infection. Individual barriers and physiological defenses are considered the main barriers against parasites in invertebrate species. However, behavioral traits and other non-immunological defenses can also effectively reduce parasite transmission and infection intensity. In social insects, behaviors that reduce colony-level parasite loads are termed "social immunity." One example of a behavioral defense is resin collection. Honey bees forage for plant-produced resins and incorporate them into their nest architecture. This use of resins can reduce chronic elevation of an individual bee's immune response. Since high activation of individual immunity can impose colony-level fitness costs, collection of resins may benefit both the individual and colony fitness. However the use of resins as a more direct defense against pathogens is unclear. Here we present evidence that honey bee colonies may self-medicate with plant resins in response to a fungal infection. Self-medication is generally defined as an individual responding to infection by ingesting or harvesting non-nutritive compounds or plant materials. Our results show that colonies increase resin foraging rates after a challenge with a fungal parasite (Ascophaera apis: chalkbrood or CB). Additionally, colonies experimentally enriched with resin had decreased infection intensities of this fungal parasite. If considered self-medication, this is a particularly unique example because it operates at the colony level. Most instances of self-medication involve pharmacophagy, whereby individuals change their diet in response to direct infection with a parasite. In this case with honey bees, resins are not ingested but used within the hive by adult bees exposed to fungal spores. Thus the colony, as the unit of selection, may be responding to infection through self-medication by increasing the number of individuals that forage for resin.
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Article
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The present work shows the occurrence of an intense predatory activity on adults working Meliponinae bees (Hymenoptera, Apidae), by Apiomerus pilipes (Fabricius, 1787) (Hemiptera, Reduviidae, Harpactorinae, Apiomerini) at a meliponary in the Instituto Nacional de Pesquisas da Amazônia (INPA, Manaus), Amazonas State, Brazil.O presente trabalho registra a ocorrência de intensa atividade predatória de Apiomerus pilipes (Fabricius, 1787) (Hemiptera, Reduviidae, Harpactorini, Apiomerini) sobre operárias adultas de meliponíneos (Hymenoptera, Apidae), no meliponário experimental do Instituto Nacional de Pesquisas da Amazônia (INPA, Manaus), Estado do Amazonas, Brasil. O meliponário se encontra num fragmento de vegetação secundária no próprio INPA.
Article
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Scanning electron microscopy observations are presented for freshly hatched nymphs and adults of Zelus longipes L., an hemipteran species of the family Reduviidae (assassin bugs). The emphasis is on the structure and distribution of pores and different types of hairs covering the tibiae of the forelegs in relation to a viscous substance associated with them. The substance is instrumental in catching prey. In both developmental stages of the animal, the legs are abundantly covered with two major types of hairs. There are the so-called sundew hairs characterized by spines on their upper part. The legs also carry smooth peg-like setae. In addition, the adult animals show a few smooth, needle-shaped hairs. At this developmental stage, the surface of the legs has developed ring-like invaginations. The animals catch prey using their raised forelegs that are covered with a layer of sticky substance. It is assumed that the sundew hairs in combination with the peg-like setae play a role in mechanically stabilizing the film of stick)' substance covering the legs in both developmental stages. The ring-like invaginations found only in the adult animals are interpreted as the external openings of integumental glands, responsible for the production of the substance. The openings are missing in freshly hatched nymphs, and it is assumed that they use the sticky substance deposited by the female at the bases of the laid eggs to set up their sticky traps.
Article
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Comprehensive laboratory baiting studies with the 4 insecticides abamectin, boric acid, fipronil, and hydramethylnon were conducted against Argentine ant, Linepithema humile (Mayr). Serial dilutions of each insecticide prepared in a 25% sucrose solution were provided for 24 h or 14 d to groups of workers and queens. Sucrose-water baits containing 1 x 10(-5)% fipronil and 0.1% hydramethylnon provided complete mortality of L. humile workers baited for 24 h. Baits containing 1 x 10(-4) and 1 x 10(-5)% fipronil provided 100% kill of queens. In the continuous baiting, 0.5% boric acid, 1 x 10(-6)% fipronil, and 0.025% hydramethylnon provided 100% mortality of workers. The queens and workers provided baits containing 1 x 10(-5)% fipronil and 0.5% boric acid all died within 14 d. Low concentrations of fipronil and boric acid in sucrose may be promising candidates for Argentine ant control.
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Partial sequences are reported for the mitochondrial genes for cytochrome oxidase subunits 2 and 3 and for cytochrome b, and the entire sequence of the gene for tRNA(Leu)(UUR) for species from 14 genera of dolichoderine ants and from three outgroup genera. Considerable variation was observed between tRNA genes in the size of the TPsiC arm and the DHU and anticodon loops and whether or not the TPsiC stem possesses a GC pair. The outgroup taxa showed complete TAA CO1 stop codons, but dolichoderines have either TA or T. The outgroup taxa showed a noncoding gap between the CO1 and the tRNA(Leu)(UUR) genes. A phylogeny-independent compatibility test using the amino acid sequences showed differences between the genes consistent with variation in evolutionary rates, according with other studies. Base compositions proved heterogeneous between species, hence phylogenetic analysis was restricted to the protein sequences using maximum likelihood and the mtREV24 replacement matrix. A maximum-likelihood consensus tree has similarities to those from morphological studies with some exceptions such Leptomyrmex falling within the dolichoderine genera rather than basally, and the accretion of genera formerly included under Iridomyrmex. Features of the tRNA genes and the CO1 termination codons agree quite well with the molecular phylogeny.
Article
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Horizontal transfer of three contact insecticides, bifenthrin, beta-cyfluthrin, and fipronil, was tested in laboratory colonies. Donor ants were exposed for 1 min to insecticide-treated sand substrates and placed with unexposed ant colonies at two different temperatures. Mortality was monitored to compare the ability of donors to transfer lethal doses of these insecticides to untreated individuals. Treated donor insects, live or dead, were added into colonies to determine the importance of donor behavior on lethal transfer. Fipronil was readily transferable between individuals, resulting in high mortality rates. Bifenthrin and beta-cyfluthrin were less transferable, exhibiting moderate-to-low mortality rates similar to the controls. Greater mortality occurred at 27-29 degrees C than at 21-23 degrees C for bifenthrin, but not the other treatments or controls. Colony mortality did not significantly increase when adding live donors, suggesting that necrophoresis was probably an important donor behavior in addition to grooming and trophallaxis on horizontal transfer.
Article
The Argentine ant, Linepithema humile (Mayr), is an economically important tramp ant species that displaces native ants and other arthropods in agricultural, urban and natural settings. Even though Argentine ants are frequently described as aggressive, little research has been conducted on their agonistic behavior towards homopterans and parasitoids. An ethogram of the responses to scales and parasitoids was constructed that included antennating, lunging, opening mandibles and grabbing. Linepithema humile workers did not respond aggressively towards brown soft scale, Coccus hesperidum L., after they had tended them. They readily attacked the parasitoid, Metaphycus flavus (Howard), killing 33% of them within 1 h. The cuticular extracts of scales, aphids, and parasitoids applied to dead fruit flies triggered agonistic responses.
Article
Foraging in trees by the Argentine ant,Iridomyrmex humilis (Mayr), was disrupted by a variety of synthetic chemicals, with the most effective chemical being farnesol. Testing of substrates for presentation of the disruptant chemicals gave some success with rubber or Tygon tubing, although best results were obtained through incorporation of the material into Stikem, which was then banded around tree trunks. Amounts of farnesol used for effective, long residual ant control were between 0.8 and 2 g per tree.
Article
Article
A variety of chemicals that are identical or similar to known ant alarm pheromone components or ant-defensive allomones produced by organisms other than ants were evaluated for effectiveness in disrupting the foraging activities of Formica aerata(Francoeur). The chemicals were applied as bands around the trunks of plum trees oraround wooden stakes holding ant feeding stations at their tops. Some of the chemicals were highly effective in excluding ants from the trees or feeding stations. Long-duration(up to 53 d) disruption of foraging was obtained with farnesol when incorporated in Stickem as a slow-release substrate.
Article
The egg and 5 nymphal instars of Apiomerus crassipes (F.) are described and illustrated. A. crassipes overwinters as 4th or 5th instars and there is one generation a year. The developmental period for eggs averaged 16.7 days and nymphal development averaged 123.8 days. All nymphs and adults employed protibial combs to groom the antennae. The number of setae composing the combs increased from 15 in the 1st instars to 38 in the adults. Females also employed a metatibial comb to groom the venter of the abdomen during oviposition. Eggs were parasitized by Anastatus reduvii (Howard). The following new prey records were obtained: Apis mellifera L. (Apidae), Chauliognathus marginatus (F.) (Cantharidae), Podabrus rugulosus LeConte (Cantharidae), and Photinus pyralis (L.) (Lampyridae).
Article
The nesting behavior of Megachile prosopidis Cockerell, Megachile chilopsidis Cockerell, and Megachile discorhina Cockerell was studied in trap nests placed near Tucson, Arizona. Quantitative differences among the five distinct nest plugs made by M. prosopidis are described. The nest plugs fall into three structural types. The first layer of capping material deposited in the first structural type is sand and an unidentified oral secretion mixed to form a hard layer. In the second structural type, the first layer is made of soft resin mixed with sand or organic matter. A third, less common, structural type includes those nests capped with pure resin. The dominant pollen host plant species was identified as Cercidium microphyllum (Torr.) Rose and Johnston (Fabaceae). Two other legumes, Prosopis velutina Wooton and Olneya tesota A. Gray, became important pollen sources late in the nesting season. Resin samples taken from the nest caps were indistinguishable, by gas chromatography, from resin of Encelia farinosa A. Gray (Asteraceae). The following parasites and predators were reared from the nests: Tricrania stansburyi Haldeman (Coleoptera: Meloidae), Lecontella gnara Wolcott (Coleoptera: Cleridae), Anthrax cintalpa Cole (Diptera: Bombyliidae), Stelis (Dolichostelis) perpulchra Crawford (Hymenoptera: Megachilidae), and Sapyga sp. Latreille (Hymenoptera: Sapygidae). New host records are reported for T. stansburyi, L. gnara, and A. cintalpa.
Article
Scanning electron microscopy observations are presented for freshly hatched nymphs and adults of Zelus longipes L., an hemipteran species of the family Reduviidae (assassin bugs). The emphasis is on the structure and distribution of pores and different types of hairs covering the tibiae of the forelegs in relation to a viscous substance associated with them. The substance is instrumental in catching prey. In both developmental stages of the animal, the legs are abundantly covered with two major types of hairs. There are the so-called sundew hairs characterized by spines on their upper part. The legs also carry smooth peg-like setae. In addition, the adult animals show a few smooth, needle-shaped hairs. At this developmental stage, the surface of the legs has developed ring-like invaginations. The animals catch prey using their raised forelegs that are covered with a layer of sticky substance. It is assumed that the sundew hairs in combination with the peg-like setae play a role in mechanically stabilizing the film of sticky substance covering the legs in both developmental stages. The ring-like invaginations found only in the adult animals are interpreted as the external openings of integumental glands, responsible for the production of the substance. The openings are missing in freshly hatched nymphs, and it is assumed that they use the sticky substance deposited by the female at the bases of the laid eggs to set up their sticky traps.
Article
A survey of pretarsal structures in Reduviidae of 22 higher-level taxa and several outgroup representatives is conducted using scanning electron microscopy (SEM) and light microscopy. Based on histology and SEM, pretarsal structures are described in detail for Rhodnius prolixus. Structures of the distal tarsomer, which appear to be functionally correlated with the pretarsus, are documented for the first time in Heteroptera. These comprise lateral oval sclerites, two campaniform sensilla and two marginal setae, observed in Reduviidae and other heteropteran taxa. The presence of a peg-like dorsomedian sensillum medially between the claws in Reduviidae and Nabidae is demonstrated. As a result of its structure and position, homology of this sensillum with the ‘dorsal arolium’ in other heteropteran groups is proposed. Within Reduviidae, the transformation of the peg-like dorsomedian sensillum to a campaniform sensillum, as seen in most representatives of the harpactoroid complex, is hypothesized. The first record of parempodia other than setiform within Reduviidae is noted in nymphs of Harpactorinae, which may possess lamellate parempodia. Several characters that are possibly useful for clarifying relationships among the harpactoroid groups are described and discussed. The pretarsal structures, including the unguitractor plate and the tarsal marginal setae among reduviid groups are discussed in a phylogenetic context.
Article
1. There is growing evidence that granivorous ants compete for seeds in desert ecosystems. But ants that diverge in diet may still interact strongly if existing colonies deter foundress queens. Granivores (seed eaters) and omnivores (ants that scavenge and feed on plant exudates) are common components of desert ecosystems. 2. The results of a 15-year granivore reduction experiment to explore the responses of two common omnivorous ants, Forelius cf pruinosus and Dorymyrmex insana, in a desert grassland were analysed. The food competition hypothesis predicts that granivore removal will have no net effect on omnivores. The spatial competition hypothesis predicts compensatory increases in omnivores on granivore removal plots. 3. A grain-based gut poison significantly reduced the densities of three of the four common granivorous ants. Densities of the large-colony (105-worker) omnivore Forelius did not increase with granivore removal. In contrast, and consistent with the hypothesis of competition for space, densities of the small-colony omnivore (102−103 worker) Dorymyrmex increased on granivore removal plots; however, this effect was only observed in years of high Dorymyrmex abundance.
Article
The dolichoderine ant Iridomyrmex pruinosum and the formicines Myrmecocystus mimicus and M. depilis overlap widely in their niches. Although a worker of I. pruinosum is about four times smaller than a forager of Myrmecocystus, Iridomyrmex usually succeeds in displacing Myrmecocystus from the bait and often successfully blocks the nest entrance of its competitors, thus preventing Myrmecocystus foragers from leaving their nest. Iridomyrmex achieves this by quickly channeling large numbers of workers to food sources and nest entrances of Myrmecocystus, employing an effective chemical mass recruitment system, and chemicall repelling its competitors with secretions from the pygidial (anal) gland.
Article
Chemical analysis of leaves from 12 different localities of Encelia farinosa (including var. phenicodonta and var. radians) collected on the peninsula of Baja California (Mexico) revealed the presence of various chemotypes that differed with regard to the concentrations of chromenes and sesquiterpene lactones. Localities of E. farinosa collected in the northern part of Baja California were characterized by high concentrations of the chromene encecalin (up to 252 μmol g−1 dry wt.), whereas the sesquiterpene lactone farinosin was not detected. Localities of E. farinosa collected at the southern tip of the peninsula lacked encecalin, but were shown to accumulate farinosin (up to 85 μmol g−1 dry wt.) instead. On the mainland of Mexico, as well as in Arizona (U.S.A.), farinosin concentrations varied from 18 to 44 μmol g−1 dry wt. for 10 different localities analyzed. Chromenes were not detected or present only in minor amounts (up to 13 μmol g−1 dry wt.), when compared to the samples from northern Baja California. Chemical variation within localities was small when compared to variation between different localities. Accumulation of encecalin and aridity seem to coincide at least on the peninsula of Baja California, as localities of E. farinosa that receive the least amount of rainfall contained the largest amounts of encecalin in their leaves. Leaves of E. farinosa that contained sufficiently large amounts of either encecalin or farinosin were both detrimental to neonate larvae of the polyphagous pest insect Spodoptera littoralis as shown by addition of the respective crude leaf extracts to artificial diet. Possible advantages of the observed intraspecific chemical variability of E. farinosa with regard to adaptation by generalist insect herbivores are discussed.
Article
Ithomiine butterflies (Nymphalidae) have long-lived, aposematic, chemically protected adults. However, little is known about the defense mechanisms in larvae and other juvenile stages. We showed that larvae Mechanitis polymnia are defended from ants by a chemical similarity between their cuticular lipids and those of the host plant, Solanum tabacifolium (Solanaceae). This is a novel defense mechanism in phytophagous insects. A field survey during one season showed that larval survivorship was up to 80%, which is high when compared with other juvenile stages. In a laboratory bioassay, live larvae on their host plant were not attacked by the predatory ant Camponotus crassus (Formicidae). Two experiments showed that the similarity between the cuticular lipids of M. polymnia and S. tabacifolium protected the larvae from C. crassus: (a) when the caterpillar was switched from a host plant to a non-host plant, the predation rate increased, and (b) when a palatable larva (Spodoptera frugiperda, Noctuidae) was coated with the cuticular lipids of M. polymnia and placed on S. tabacifolium leaves, it no longer experienced a high predation rate. This defensive mechanism can be defined as chemical camouflage, and may have a double adaptive advantage, namely, protection against predation and a reduction in the cost of sequestering toxic compounds from the host plant.
The Argentine ant
  • W Newell
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Newell, W. and T. C. Barber. 1913. The Argentine ant. U. S. Dep. Agric. Bur. Entomol. Bull. 122.
Observations upon the heteropterous Hemiptera of lower California, with descriptions of new species
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Uhler, P. R. 1894. Observations upon the heteropterous Hemiptera of lower California, with descriptions of new species. Proc. Calif. Acad. Sci. (Ser. 2) 4: 223Ð295.
Harzwanzen or "resin bugs" in Thailand
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Usinger, R. L. 1958. Harzwanzen or "resin bugs" in Thailand. Pan-Pac. Entomol. 34: 52.
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Apiomerus pictipes (Reduvio, Chinche Asesina, Assassin Bug), pp. 684 Ð 687
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Johnson, L. K. 1983. Apiomerus pictipes (Reduvio, Chinche Asesina, Assassin Bug), pp. 684 Ð 687. In D. H. Janzen [ed.], Costa Rican natural history. University of Chicago Press, Chicago, IL.
STATISTIX 7 userÕs manual
  • Analytical Software
Analytical Software. 2000. STATISTIX 7 userÕs manual. Analytical Software, Tallahassee, FL.