Stilt Bug Research Articles

Two New Species of Hoplinine Stilt Bugs (Heteroptera: Berytidae: Gampsocorinae) from Brazil, with New Country Records for Three Other Species

The hoplinine stilt bugs (Heteroptera: Berytidae: Gampsocorinae) Hoplinus cincospinus Henry, new species from Minas Gerais, Brazil, and Parajalysus brunneus Henry, new species from Pará, Brazil, are described. A diagnosis, description, and digital images of the adult and selected structures are provided for each species and a revised key to the species of Hoplinus and a partial key to the species of Parajalysus are given to aid identification. New country records are given for Parajalysus punctipes Van Duzee, P. tenuicornis Henry, and P. verucosus Štusák.

New genus and species of stilt bug (Hemiptera: Berytidae) from Western Australia

AbstractA new genus and new species of stilt bug (Hemiptera: Heteroptera: Berytidae) are described from Western Australia. Arideneides cocosdiaspora gen. et sp. nov., of the subfamily Berytinae, tribe Berytini, is based on two male and two female specimens. Habitus photographs, scanning electron micrographs and X‐ray microtomography (micro‐CT) are used to document the morphology of this species. DNA sequence data for COI and 16S gene regions are provided.

Annotated checklist of the stilt bugs (Hemiptera: Heteroptera: Berytidae) of Guatemala, with new country records

The stilt bugs (Hemiptera: Heteroptera: Berytidae) of Guatemala are reviewed. Previously, seven species were recorded from the country. Three species are recorded as new to Guatemala: Oedalocanthus ornatus Henry, 1996; Pronotacantha concolor Henry, 1997; and Metacanthus multispinus (Ashmead, 1887). Four additional species have not been recorded from Guatemala but have ranges that make their occurrence likely. Label data is presented for all examined specimens.

Revision of the Neotropical Stilt Bug Genus emMetajalysus/em Štusák (Hemiptera: Heteroptera: Berytidae), with Descriptions of Three New Species.

The stilt bug genus Metajalysus Štusák is revised and three new species are recognized. A neotype of the type species, M. horvathi Štusák, is designated and the new species M. clavatus, n. sp. from Argentina, M. graziae, n. sp. from Argentina and Bolivia, and M. pilosus, n. sp. from Ecuador are described. Digital images of the adult male and female and male genitalia are provided and a key to the species of the genus is given.

Continent-Scale Sampling Reveals Fine-Scale Turnover in a Beneficial Bug Symbiont.

Many members of animal-associated microbial communities, including the gut flora, are acquired from their host’s environment. While many of these communities are species rich, some true bugs (Hemiptera) in the superfamilies Lygaeoidea and Coreidae allow only ingested Burkholderia to colonize and reproduce in a large portion of the midgut. We studied the spatial structuring of Burkholderia associated with a widespread omnivorous bug genus, Jalysus (Berytidae). We sampled Wickham’s stilt bug, Jalysus wickhami, across the United States and performed limited sampling of its sister species, the spined stilt bug Jalysus spinosus. We asked: (1) What Burkholderia strains are hosted by Jalysus at different locations? (2) Does host insect species, host plant species, or location influence the strain these insects acquire? (3) How does Burkholderia affect the development and reproductive fitness of J. wickhami? We found: (1) Sixty-one Burkholderia strains were present across a sample of 352 individuals, but one strain dominated, accounting for almost half of all symbiont reads. Most strains were closely related to other hemipteran Burkholderia symbionts. (2) Many individuals hosted more than one strain of Burkholderia. (3) J. wickhami and J. spinosus did not differ in the strains they hosted. (4) Insects that fed on different plant species tended to host different Burkholderia, but this accounted for only 4% of the variation in strains hosted. In contrast, the location at which an insect was collected explained 27% of the variation in symbiont strains. (5) Burkholderia confers important fitness benefits to J. wickhami. In laboratory experiments, aposymbiotic (Burkholderia-free) insects developed more slowly and laid fewer eggs than symbiotic (Burkholderia-colonized) insects. (6) In the lab, nymphs sometimes acquired Burkholderia via indirect exposure to adults, indicating that horizontal symbiont transmission can occur via adult insect-mediated enrichment of Burkholderia in the local environment – a phenomenon not previously reported in bug-Burkholderia relationships. Taken together, the results suggest that for these bugs, critical nutritional requirements are outsourced to a highly diverse and spatially structured collection of Burkholderia strains acquired from the environment and, occasionally, from conspecific adults.

Bajacanthus immaculatus: A New Hoplinine Genus and Species of Stilt Bug (Hemiptera: Heteroptera: Berytidae) from Baja California Sur, Mexico, with a Revised Key to Genera of the Tribe

The new stilt bug genus Bajacanthus, n. gen., and new species B. immaculatus, n. sp. are described from the Vizcaino Peninsula in Baja California Sur, Mexico. The berytid was discovered on the recently described endemic plant, Bajacalia moranii B. L. Turner (Asteraceae). A diagnosis, description, digital images of the adult male and female, the male genitalia capsule, and parameres are provided to facilitate recognition. A discussion of relationships is given and a revised key to the genera of the tribe Hoplinini (Gampsocorinae) is provided.

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.

Domestication of tomato has reduced the attraction of herbivore natural enemies to pest‐damaged plants

AbstractPlant domestication can alter species interactions and influence novel associations among crops and insects. We performed a series of preference and performance experiments to test predator and herbivore attraction to domesticated and wild plants and to evaluate the efficacy of herbivore‐induced plant volatiles (HIPVs) across a domestication gradient in tomato, including wild relatives, landraces and domesticated commercial cultivars.We employed a tri‐trophic system consisting of the specialist lepidopteran herbivoreManduca sextaand two of its natural enemies: an egg predator, the stilt bugJalysus wickhami, and a larval parasitoid, the waspCotesia congregata.In olfactometer trials, natural enemies consistently preferred HIPVs of wild tomatoes over domesticated cultivars, with landraces in between. Plant‐domestication effects were also apparent in terms of decision speed: predators were slower to orient towards damaged crops than to damaged wild relatives.By contrast,M. sextamoths were more likely to oviposit on domesticated than on wild or landrace tomatoes, indicating that insect responses to plant odours vary with trophic level. Field trials confirmed olfactory preference tests: caterpillars recovered from wild tomato relatives were more likely to be parasitized than those recovered from landraces or domesticated tomatoes.The results of the present study suggest that tomato domestication has reduced the efficacy of HIPVs in attracting predators compared with wild relatives and also that this decreased attraction leads to lower attack rates by enemies in the field. This outcome has implications for understanding the specificity of tri‐trophic plant defences and the compatibility of natural enemies for biocontrol in agro‐ecosystems.

First record of Metatropis rufescens (Hemiptera: Heteroptera: Berytidae) from Turkey

The stilt bug Metatropis rufescens (Herrich-Schaeffer, 1835) (Hemiptera: Heteroptera: Berytidae) is reported as a new record for Turkey and also represents the first record of the tribe Metatropini Henry, 1997 for the Turkish fauna. The specimens of the species were collected from its host plant, Circaea lutetiana L. (Onagraceae), in the forest area of Rize Province. The biology and habitat characteristics of the species are briefly discussed.

Cuscohoplininus pagoreni: a new genus and species of Hoplinini stilt bug from Peru (Heteroptera: Berytidae)

The Berytidae or stilt bugs are a cosmopolitan family of lygaeoid bugs, which are slender, elongate insects, with generally cylindrical bodies and very long, slender antennae and legs. Members of the tribe Hoplinini are characterized by the lack of a distinct metapleural scent channel and the possession of a dorsally directed process on the caudal edge of the male genitalia capsule (absent in Xenoloma and Cuscohoplininus). In this paper, we described the new genus and species Cuscohoplininus pagoreni from Peru. Scanning electron micrographs are provided to illustrate taxonomically important structures. Among the eight genera known in the tribe Hoplinini, the new genus Cuscohoplininus resembles Parajalysus in general aspect and size, but can be easily distinguished by the following characters: Parajalysus is characterized by the four large, erect pronotal spines, one centered on the anterior lobe, and on the posterior lobe, one at each humeral angle and one at the base of the meson; whereas, Cuscohoplininus has a single spine on the anterior pronotal lobe, an elongate scutellar spine (a tubercle is present in Parajalysus), and lacks a process on the caudal edge of the male genitalia capsule.

REVIEW OF THE STILT BUG GENUS HOPLINUS, WITH THE DESCRIPTION OF A NEW SPECIES AND NOTES ON OTHER HOPLININI (HETEROPTERA: BERYTIDAE: GAMPSOCORINAE)

The new stilt bug Hoplinus paulai is described from Minas Gerais, Brazil. Habitus photographs, scanning electron micrographs of selected structures, illustrations of male parameres, and a revised key are provided to help distinguish this species from other members of the genus. New distribution and/or host records are given for Hoplinus scutellatus Henry, Oedalocanthus ornatus Henry, and Xenoloma princeps Harris, and a discussion pertaining to the rediscovered name-bearing type of Neides spinosissimus Signoret, the type species of Hoplinus Stål, is provided.

Populations of Predaceous Natural Enemies Developing on Insect-Resistant and Susceptible Tomato in North Carolina

Abstract Naturally occurring populations of immature and adult Geocoris punctipes, adult Coleomegilla maculata and immature coccinellids were monitored on field-grown tomato lines susceptible and resistant to Manduca sexta and Helicoverpa zea. Helicoverpa zea and Heliothis virescens eggs and small larvae that serve as prey for these predators also were monitored. More H. zea and H. virescens eggs and small larvae were found on resistant than on susceptible plant lines. However, similar populations of large H. zea and H. virescens larvae were found on resistant and susceptible plants. The number of adult Geocoris punctipes, adult Coleomegilla maculata and immature coccinellids on resistant plants was always as high or higher than the number on susceptible plants. The data demonstrate no incompatibility of host-plant resistance with biological control provided by these predaceous insects, but indicate that the number of G. punctipes and coccinellids required to provide effective biological control may develop too late in the season to be of practical value. Large populations of stilt bugs ( Jalysus wickhami, Hemiptera: Berytidae) and spiders were observed to occur earlier in the growing season than either G. punctipes or coccinellids and may be a significant source of mortality for H. zea eggs and small larvae.

Chromosomes in two stilt bug speciesMetatropis rufescensHerrich-Schaeffer ssp.linneaeWagner andBerytinus minorHerrich-Schaeffer (Berytidae, Heteroptera)

SUMMARYThe karyotypes of two stilt bug species Metatropis rufescens (Herrich- Schaeffer) ssp. linneae Wagner and Berytinus minor (Herrich-Schaeffer) (Heteroptera, Berytidae) were reinvestigated by an improved method to analyze chromosomes and their meiotic behaviour. The chromosome formula 2n (♂) = 18 + XY for M. rufescens ssp. linneae was confirmed and a novel chromosome formula for B. minor, 2n (♂) = 42 + X1X2X3Y, was given. This is the first finding of multiple sex chromosome system in this family. Male meiosis is chiasmatic for autosomes. Sex chromosomes undergo post-reductional meiosis. C-banding method revealed heterochromatic bands near one of the telomeres in some but not in all chromosomes in M. rufescens ssp. linneae. The present data on chromosomes in the family Berytidae are discussed.

When good bugs go bad: intraguild predation by Jalysus wickhami on the parasitoid, Cotesia congregata

AbstractWe report a case of direct intraguild predation involving an insect predator and parasitoid in an agricultural system. The spined stilt bug, Jalysus wickhami Van Duzee, feeds on eggs of the tobacco hornworm, Manduca sexta L., and also on prepupal and pupal stages of the gregarious hornworm parasitoid, Cotesia congregata (Say). In two separate trials, mean mortality of attached parasitoids was significantly lower (66%, 73%) than that of their detached siblings (97%, 96%) after a 3 day exposure to stilt bugs, demonstrating that attachment to the host offered some protection against predation. In no‐choice experiments, prepupal parasitoids suffered greater mortality (0 day‐old = 61%, 1 day‐old = 65%) than pupal parasitoids (2 day‐old = 50%, 3 day‐old = 14%). When offered in combination with 0 or 2 day‐old hornworm eggs, respective mortality of 0,1,2 and 3‐day‐old pupal parasitoids showed a similar pattern (67%, 63%, 33% and 23%). In another experiment, mortality of 0‐day‐old pupal parasitoids (64%) was greater than that of 3 day‐old pupal parasitoids (38%). Mortality of pupal parasitoids was not affected by the availability of hornworm eggs, a highly acceptable food. Younger pupal parasitoids (= prepupae) probably suffered greater mortality because they were more easily fed on by stily bugs than older (pupated) ones. Because C. congregata overwinters in the prepupal stage, it may be particularly vulnerable to attack late in the season when stilt bug populations are large and hornworm eggs are relatively uncommon.

Effects of diet on longevity and fecundity of the spined stilt bug, Jalysus wickhami

AbstractWe evaluated the suitability of selected food items for the adult spined stilt bug, Jalysus wickhami Van Duzee (Hemiptera: Berytidae), by providing one of seven diet treatments: (1) prepupae of the parasitoid, Cotesia congregata (Say) (Hymenoptera: Braconidae), on a leaf of tobacco (Nicotiana tabacum L., ‘NC 2326’) (Solanaceae); (2) C. congregata prepupae alone (i.e., no tobacco leaf); (3) eggs of the parasitoid's host, Manduca sexta (L.) (Lepidoptera: Sphingidae), on a tobacco leaf; (4) M. sexta eggs alone; (5) tobacco aphids, Myzus nicotianae Blackman (Homoptera: Aphididae), on a tobacco leaf; (6) a tobacco leaf alone; and (7) no prey and no tobacco. A tobacco leaf was necessary for the long‐term survival of stilt bugs, but prey source did not affect longevity. Regardless of the prey type, stilt bugs with access to a tobacco leaf lived 21–23 days, while stilt bugs without access to tobacco lived less than 12 days. Animal prey provided a protein source required for egg deposition in J. wickhami, and prey species differed in their relative nutritive values. Female stilt bugs that fed on M. sexta eggs or on C. congregata prepupae were significantly more fecund (102 and 106 nymphs per female, respectively) than females that fed on tobacco aphids (24 nymphs per female). Results suggest that stilt bugs may feed on tobacco aphids and C. congregata prepupae when other prey are unavailable.

Jalysus wickhami (Hemiptera: Berytidae): Toxicity of Pesticides Applied to the Soil or in the Transplant Water of Flue-Cured Tobacco

The effects of 13 pesticides applied to soil or in water at transplantation of flue-cured tobacco on spined stilt bug, Jalysus wickhami Van Duzee, survival were evaluated. The experiments were done in the laboratory and field at Oxford, N.C., from 1981 to 1984. Because spined stilt bugs probe tobacco leaves and suck plant juices, they are vulnerable to systemic pesticides. The systemic materials aldicarb, carbofuran, and phenamiphos were especially toxic to these beneficial predators of tobacco pests. All other pesticides were not toxic to spined stilt bugs in field experiments, although some were toxic when applied on tobacco in glass lantern globes in the laboratory.

Effect of Transplantation Date on the Seasonal Abundance of the Green Peach Aphid (Homoptera: Aphididae) and Two Aphid Predators on Flue-Cured Tobacco

The effects of flue-cured tobacco transplantation date on the seasonal abundance of the green peach aphid, Myzus persicae (Sulzer), a stilt bug, Jalysus wickhami Van Duzee, and the convergent lady beetle, Hippodamia conoergens Guerin-Memeville, were investigated in south-central Virginia during 1979–1981. Tobacco was transplated ca. 10 days apart on three dates from 10 to 29 May 1979 and on five dates from 28 April to 9 June 1980 and 1981. Aphid populations were highest on the first two transplantings (10 and 20 May) in 1979, the first three (29 April, 9 and 19 May) in 1980, and the third and fourth (18 and 28 May) in 1981. Populations were lowest on late-transplanted tobacco. In 1981, tobacco transplanted on the first two dates matured 14 to 29 days earlier and, thereafter, had lower aphid populations than comparable treatments in 1979 and 1980. Populations usually declined on tobacco after topping (removal of terminal floral branch) was initiated. Lady beetle populations were closely related to aphid abundance in 1980, but the relationship was less distinct in 1981. Stilt bug populations peaked in all trans plantings during the first half of August, and they were significantly more abundant in the last two transplantings than the first three during the last half of August and early September. In 1980 and 1981 yields, returns (dollars per hectare), and values (dollars per kilogram) were similar for the first three trans plantings, but all were significantly reduced in the fourth and fifth transplantings during at least 1 year.

Review of Stilt Bug (Hemiptera: Berytidae) Host Plants

A list of host plants of the world Berytidae (Hemiptera-Heteroptera) is given. Species of the stilt bug subfamily Berytinae are largely ground dwellers associated with the Fabaceae (Berytinus spp.), or they feed on viscid plants of the Geraniaceae, Scrophulariaceae, and other families (Neides spp.) and show various tendencies toward carnivory. Many stilt bugs in the Metacanthinae are specialists on “glandular-hairy” plants of the Cucurbitaceae, Fabaceae, Lamiaceae, Malvaceae, Onagraceae, Scrophulariaceae, and Solanaceae. Several species feed on insects entrapped in plant secretions or on lepidopteran eggs or aphids, e.g., Jalysus wickhami Van Duzee. In contrast to several other narrowly elongate groups of Heteroptera (e.g., chorosomine rhopalids, leptocorisine alydids) which are adapted to feeding on grasses, only a few berytids [Aknisus multispinus Ashmead, Jalysus spinosus (Say)] feed on grasses or any monocot.

Collection and Storage of an Insect Predator, Jalysus spinosus , 1 from Tobacco Plants 23

Two tractor-mounted devices collected about 83,500 stilt bugs, Jalysus spinosus (Say) from ca. 25 ha of tobacco during the fall of 1972 and 1973. Due to rapid growth of microorganisms collected with the bugs, only 1% of the stilt bugs stored at 12.8°C survived 83 days. However, 19% of the stilt bugs stored in outside cages at ambient temperature survived 160 days.

Insect Predators and Pests on Tobacco Following Applications of Systemic Insecticides

Soil incorporated systemic insecticides applied to flue-cured tobacco were evaluated for their effects on beneficial insects. Tobacco treated with aldicarb, aldoxycarb, disulfoton 15G, and fosthietane had significantly fewer spined stilt bugs than the untreated checks during at least one of the 2 yr of the experiment. During 1977, the disulfoton 6EC and ethoprop treatments had as many or more stilt bugs than the check, while oxamyl had the most stilt bugs of the chemical treatments during 1978. There were serious outbreaks of the tobacco hornworm, Manduca sexta (L.), and the tomato hornworm, M. quinquemaculata (Haworth), in the aldoxycarb and aldicarb plots during 1977 and 1978 and in the disulfoton 15G plots during 1978. Stilt bug to hornworm ratios for aldicarb and aldoxycarb treatments were 14–25% of the untreated check during 1977 and 31 – 46% of the check during 1978. Carbofuran treated tobacco had stilt bug to hornworm ratios of 1.7 – 2.6 times higher than the check during 1977 and 2.6 – 49 times higher than the check during 1978. The high stilt bug to hornworm ratios in the carbofuran treatments were due to the excellent hornworm control. Geocoris spp., Nabis spp., and the convergent lady beetle, Hippodamia convergens Guerin-Meneville, were most abundant in the treatments with poor green peach aphid, Myzus persicae (Sulzer), control including oxamyl, ethoprop, and a1doxycarb broadcast.