Cydnidae Research Articles

Species-specific recognition of the carrier insect by dauer larvae of the nematode Caenorhabditis japonica

Host recognition is crucial during the phoretic stage of nematodes because it facilitates their association with hosts. However, limited information is available on the direct cues used for host recognition and host specificity in nematodes. Caenorhabditis japonica forms an intimate association with the burrower bug Parastrachia japonensis. Caenorhabditis japonica dauer larvae (DL), the phoretic stage of the nematode, are mainly found on adult P. japonensis females but no other species. To understand the mechanisms of species-specific and female carrier-biased ectophoresy in C. japonica, we investigated whether C. japonica DL could recognize their hosts using nematode loading and chemoattraction experiments. During the loading experiments, up to 300 C. japonica DL embarked on male and female P. japonensis, whereas none or very few utilized the other shield bugs Erthesina fullo and Macroscytus japonensis or the terrestrial isopod Armadillidium vulgare. In the chemoattraction experiments, hexane extracts containing the body surface components of nymphs and both adult P. japonensis sexes attracted C. japonica DL, whereas those of other shield bugs did not. Parastrachia japonensis extracts also arrested the dispersal of C. japonica DL released at a site where hexane extracts were spotted on an agar plate; i.e. >50% of DL remained at the site even 60 min after nematode inoculation whereas M. japonensis extracts or hexane alone did not have the same effect. These results suggest that C. japonica DL recognize their host species using direct chemical attractants from their specific host to maintain their association.

Burrower bugs described after the Cydnidae of the Western – Hemisphere catalogue 1960 (Hemiptera: Heteroptera: Cydnidae)

Burrower bugs described after the Cydnidae of the Western – Hemisphere catalogue 1960 (Hemiptera: Heteroptera: Cydnidae)

Diet–consumer nitrogen isotope fractionation for prolonged fasting arthropods

Nitrogen acquisition for cellular metabolism during diapause is a primary concern for herbivorous arthropods. Analyses of naturally occurring stable isotopes of nitrogen help elucidate the mechanism. Relevant articles have cited (58 times up to mid-June 2011) anomalously elevated δ15N (per mil deviation of 15N/14N, relative to atmospheric nitrogen=0 ‰) values (diet–consumer nitrogen isotope fractionation; up to 12 ‰) for a prolonged fasting raspberry beetle (Byturus tomentosus Degeer (Coleoptera: Byturidae)), which feeds on red raspberries (Rubus idaeus: δ15N=∼+2 ‰). Biologists have hypothesised that extensive recycling of amino acid nitrogen is responsible for the prolonged fasting. Since this hypothesis was proposed in 1995, scientists have integrated biochemical and molecular knowledge to support the mechanism of prolonged diapausing of animals. To test the validity of the recycling hypothesis, we analysed tissue nitrogen isotope ratios for four Japanese arthropods: the shield bug Parastrachia japonensis Scott (Hemiptera: Cydnidae), the burrower bug Canthophorus niveimarginatus Scott (Hemiptera: Cydnidae), leaf beetle Gastrophysa atrocyanea Motschulsky (Coleoptera: Chrysomelidae) and the Japanese oak silkworm Antheraea yamamai (Lepidoptera: Saturniidae), all of which fast for more than 6 months as part of their life-history strategy. Resulting diet–consumer nitrogen isotope discrimination during fasting ranged from 0 to 7‰, as in many commonly known terrestrial arthropods. We conclude that prolonged fasting of arthropods does not always result in anomalous diet–consumer nitrogen isotope fractionation, since the recycling process is closed or nearly closed with respect to nitrogen isotopes.

Occurrence of Scaptocoris castanea Perty (Hemiptera: Cydnidae) damaging Azadirachta indica (Meliaceae) seedlings in Brazil

Neem (Azadirachta indica) seedlings were found infested by the brown burrower bug, Scaptocoris castanea Perty, in December 2009, in the county of Tupaciguara, Minas Gerais state. Symptoms observed varied from leaf yellowing and stem drying, reduction in root size and number to plant death. This is the first report of S. castanea attacking neem plants.

Burrower bugs described after the Cydnidae of the Western–Hemisphere catalogue 1960 (Hemiptera: Heteroptera: Cydnidae)

An update to the catalogue of the Cydnidae (Hemiptera) of the Western Hemisphere (Froeschner 1960) is given. A total of 6 genera and 21 species are listed together with their synonyms. References are given for the original descriptions and the subsequent taxonomic position, the location of types, and the geographic distribution. A comprehensive bibliography is provided.

Trophic eggs compensate for poor offspring feeding capacity in a subsocial burrower bug

Various animals produce inviable eggs or egg-like structures called trophic eggs, which are presumed to be an extended maternal investment for the offspring. However, there is little knowledge about the ecological or physiological constraints associated with their evolutionary origin. Trophic eggs of the seminivorous subsocial burrower bug (Canthophorus niveimarginatus) have some unique characteristics. Trophic eggs are obligate for nymphal survival, and first-instar nymphs die without them. To identify the cause of nymphal death, we hypothesized that first-instar nymphs starve to death because they cannot feed on anything but trophic eggs. Although first-instar nymphs fed on artificially exposed endosperm did survive, nymphs that were provided with intact seed were not able to penetrate the seed vessel and starved to death. Another hypothesis that trophic eggs play a role in transferring the midgut symbiont, essential for survival in heteropteran bugs, from mother to offspring was rejected because almost all nymphs had retained the symbiont without feeding on trophic eggs. These results suggest that poor feeding capacity of the offspring is the cause of nymphal death, and the important constraint that promotes the evolution of the curious trophic egg system in C. niveimarginatus.

A review of burrower bugs (Hemiptera: Heteroptera: Cydnidae sensu lato) of Guam

Five species representing the family Cydnidae sensu lato are recorded from Guam; three of them are reported for the first time from the island: Byrsinus varians (Fabricius, 1803), Fromundus biimpressus (Horváth, 1919), and Rhytidoporus indentatus Uhler, 1877. The widespread species, Fromundus pygmaeus (Dallas), was recorded by Ruckes (1963) and verified by us. The occurrence of a fifth species, previously listed from the island by Ruckes (1963) and Lis (1996), namely Adrisa flavomarginata (Vollenhoven, 1868), is regarded as doubtful. Of four currently known burrower bug species occurring on Guam, three are Oriental and one is American in origin. A key to all burrower bug species known from the island is provided. Additionally, Microporus shiromai Froeschner, 1976 from Hawaii is regarded as a junior synonym of Byrsinus varians (Fabricius, 1803).

A review of burrower bugs (Hemiptera: Heteroptera: Cydnidae sensu lato) of Guam

Five species representing the family Cydnidae sensu lato are recorded from Guam; three of them are reported for the first time from the island: Byrsinus varians (Fabricius, 1803), Fromundus biimpressus (Horvath, 1919), and Rhytidoporus indentatus Uhler, 1877. The widespread species, Fromundus pygmaeus (Dallas), was recorded by Ruckes (1963) and verified by us. The occurrence of a fifth species, previously listed from the island by Ruckes (1963) and Lis (1996), namely Adrisa flavomarginata (Vollenhoven, 1868), is regarded as doubtful. Of four currently known burrower bug species occurring on Guam, three are Oriental and one is American in origin. A key to all burrower bug species known from the island is provided. Additionally, Microporus shiromai Froeschner, 1976 from Hawaii is regarded as a junior synonym of Byrsinus varians (Fabricius, 1803).

Maternal-care behaviour inAdomerus variegatus(Hemiptera: Cydnidae)

AbstractSubsociality involving provisioning for offspring has been reported for one shield bug and three burrower bug species (Hemiptera: Pentatomoidea: Parastrachiidae and Cydnidae: Sehirinae). We present the first report of subsocial behaviour in the burrower bugAdomerus variegatus(Signoret), focusing on manifestations of maternal care, specifically the production of trophic eggs, guarding of offspring, and progressive provisioning. In our study, each female produced an egg mass that included some trophic eggs. Prior to nymphal hatch, females remained in their nests and showed egg mass guarding behaviour. Mothers started provisioning behaviour a few hours after nymphal hatch. Each mother dragged a seed (larger than her body) with her proboscis to the nest as food for the nymphs. These findings suggest thatA. variegatusshows maternal-care behaviours similar to those reported in some other pentatomoid species and that trophic egg production and nest provisioning have evolved as interrelated processes.

Two new species of Amnestus from Guatemala, with new records for some other Guatemalan burrower bugs (Hemiptera: Heteroptera: Cydnidae)

Two new species of Amnestus from Guatemala, with new records for some other Guatemalan burrower bugs (Hemiptera: Heteroptera: Cydnidae)

Two new species of Amnestus from Guatemala, with new records for some other Guatemalan burrower bugs (Hemiptera: Heteroptera: Cydnidae)

In this paper we describe two new species in the genus Amnestus, Amnestus henryi and Amnestus zacki, and we register new localities for 10 species of burrowing bugs for the fauna of Guatemala; two of these species correspond to new records, Amnestus pusio (Stål), and Dallasiellus reflexus Froeschner. We include a brief description of the 28 species known for Guatemala, mentioning old and new records; new species are fully described and illustrated, and drawings of the male genitalia, scent gland opening, fore, and hind legs of males are also presented. A key to separate the 28 Guatemalan species of burrower bugs is provided.

Lactistes obesipes Signoret, 1879 (Hemiptera: Cydnidae) — the burrower bug enigma: redescription, synonymy, and remarks on its distribution and taxonomic status

Lactistes obesipes Signoret, 1879 (Hemiptera: Cydnidae) — the burrower bug enigma: redescription, synonymy, and remarks on its distribution and taxonomic status

Lactistes obesipes Signoret, 1879 (Hemiptera: Cydnidae)—the burrower bug enigma: redescription, synonymy, and remarks on its distribution and taxonomic status

The genus Lactistes Schiødte, 1847 (Cydnidae: Cydninae: Geotomini sensu lato – for a new classification of the Cydnidae, see Pluot-Sigwalt & J.A. Lis, 2008) comprises 15 species distributed in the Palaearctic, Afrotropical, and Oriental Regions, and only a single species reported from the Australian Region (J.A. Lis 1996, 1999; Cassis & Gross 2002). This species, named Lactistes obesipes, was described three times by Signoret in three different papers (1879, 1880, 1881) from an unknown locality in Australia (firstly as “Nouvelle-Hollande”, then as “Australie”) on the basis of the same single female specimen.

Pre- and post-hatch trophic egg production in the subsocial burrower bug, Canthophorus niveimarginatus (Heteroptera: Cydnidae)

In recent years, three terrestrial bugs, Adomerus triguttulus and Sehirus cinctus (Cydnidae) and the closely related Parastrachia japonensis (Parastrachiidae), have been the focus of several fascinating studies because of the remarkable, extensive parental care they were found to display. This care includes egg and nymph guarding, production of trophic eggs, unfertilized, low cost eggs that are used as food by newly hatched nymphs, and progressive provisioning of the host seed. In this study, we have investigated yet a third related Asian cydnid, Canthophorus niveimarginatus, with regard to the possible occurrence of some or all of these complex traits in order to assess how widespread these maternal investment patterns are in this group of insects and to better understand the implications of their manifestations from an evolutionary context. Manipulative experiments were carried out in the lab to determine whether females provision nests. Observational and egg removal studies were carried out to determine whether trophic eggs are produced, and, if they are, their possible impact on nymphal success. The findings revealed that C. niveimarginatus does, in fact, progressively provision young, and this species also displays all of the other behaviors associated with extended parental care in subsocial insects. Moreover, unlike the other two related species, which place trophic eggs on the surface of the original egg mass, C. niveimarginatus produces both pre- and post-hatch trophic eggs. Nymphs deprived of access to post-hatch trophic eggs had significantly lower body weight and survival rate than those that fed on them. To our knowledge, this is the first time the production of both pre- and post-hatch trophic eggs has been demonstrated in insects outside the Hymenoptera. In this paper, we qualitatively and quantitatively demonstrate the provisioning behavior and patterns of trophic egg production in C. niveimarginatus. When and how trophic eggs are produced and delivered to young should have important correlations with the ecological and life history constraints under which a species has evolved. Thus, we also discuss the possible ecological and life history factors that favor the evolution of post-hatch trophic eggs.

Maternal Care in the Burrower Bug Adomerus triguttulus: Defensive Behavior

Some burrower bugs (Heteroptera: Cydnidae) show complex patterns of maternal care, including defense against predators and the provisioning of food to nymphs. Recently, the subsocial cydnid bugs have attracted the interest of researchers as model systems to study the behavioral ecology of parental investment. However, there have been few attempts to quantify the fitness benefits of maternal behavior other than provisioning. Here, we examined the maternal behavior of Adomerus triguttulus and its adaptive significance in terms of offspring survival in the field. A. triguttulus young depend on fallen nutlets of myrmecophorous mints, Lamium spp. Under field conditions, females attend offspring, from eggs to second instar nymphs, in nests on the ground under the litter. When disturbed, the females showed aggressive responses against the source of disturbance. The females often carried spherical clutches of eggs away from the nest when heavily disturbed. Female-removal experiments in the field demonstrated a defensive function of the female behavior; predators, such as ants, attacked egg clutches without females and the clutches often disappeared during the experiment. Egg clutches without females sometimes also suffered from fungal infection. Selective factors on maternal defensive behavior in A. triguttulus are discussed in terms of habitat properties possibly emerging from insect-plant associations.

Naktodemasis bowni: New ichnogenus and ichnospecies for adhesive meniscate burrows (AMB), and paleoenvironmental implications, Paleogene Willwood Formation, Bighorn Basin, Wyoming

Adhesive meniscate burrows (AMB) are common in alluvial paleosols of the Paleogene Willwood Formation, Bighorn Basin, Wyoming. AMB are sinuous, variably oriented burrows composed of a nested series of distinct, ellipsoidal packets containing thin, tightly spaced menisci subparallel to the bounding packet. Menisci are non-pelleted and texturally homogeneous with each other and the surrounding matrix. AMB were constructed most likely by burrower bugs (Hemiptera: Cydnidae), cicada nymphs (Hemiptera: Cicadae), and less likely by scarabaeid (Coleoptera: Scarabaeidae) or carabid beetles (Coleoptera: Carabidae), based on burrow morphology and comparison to similar structures produced by these organisms in modern soils. Extant burrowing insects excavate backfilled burrows in well-rooted A and upper B horizons of soils generally below field capacity depending on soil type. This study demonstrates that AMB are distinct morphologically from such previously described ichnofossils asBeaconites, Laminites, Scoyenia, Taenidium, andAncorichnus. Naktodemasis bowni, a new ichnogenus and ichnospecies, represents burrows composed of nested ellipsoidal packets backfilled with thin, tightly spaced, menisci subparallel to the bounding packet. The presence ofN. bowniindicate periods of subaerial exposure associated with pedogenic modification under moderately to well-drained soil conditions, or during periods of better drainage in imperfectly drained soils.N. bowni, therefore, can differentiate alluvial paleoenvironments from marine and lacustrine paleoenvironments, as well as periods of subaerial exposure of sediments deposited in aquatic settings.

The first fossil Cydnidae (Hemiptera: Pentatomoidea) from the Late Mesozoic of China

Two new genera and two new species of fossil amnestine burrower bugs, Cilicydnus robustispinus gen. & sp. nov. and Orienicydnus hongi gen. & sp. nov., are described and illustrated. They were collected from the Late Mesozoic nonmarine sedimentary strata of Northeast China. This finding represents the first record of fossil cydnids from China. The fossil cydnid localities and the distribution of extant taxa are summarized in a map.

Transmission of stridulatory signals of the burrower bugs, Scaptocoris castanea and Scaptocoris carvalhoi (Heteroptera: Cydnidae) through the soil and soybean

Abstract Males and females of the burrower bug species Scaptocoris castanea Perty and Scaptocoris carvalhoi Becker emit stridulatory signals when on the roots of soybean. The substrate‐borne components of the signal can be recorded on the plant but not on the surrounding soil surface. The stridulatory apparatus is composed of the tergal plectrum (lima) and the stridulitrum (stridulatory vein) on the underside of the hind wings. The male plectrum has one ridge and the female lima has 13 ridges. Stridulitra of different species differ in the length and in the number of teeth. Rubbing of plectrum (lima) ridges over the stridulitrum in one or both directions produces pulse trains. The velocity of signals that are recorded less than 0.5 cm from the bug is below 0.013 mm s−1 on the soil and below 0.066 mm s−1 on the leaf surface. Broadband spectra have a dominant frequency of less than 1 kHz and subdominant peaks extending up to 7 kHz. The dominant frequency of the stridulatory signal transmitted through a plant decreases together with the proportion of its higher frequency spectral components. Signals are attenuated for 3–9 dB cm−1 when transmitted through the soil or soybean leaf and for approximately 1 dB cm−1 when transmitted through soybean stem.

Morphology of trophic eggs and ovarian dynamics in the subsocial bug Adomerus triguttulus (Heteroptera: Cydnidae)

In the subsocial burrower bug, Adomerus triguttulus (Motschulsky, 1886), females produce trophic eggs, which are inviable and serve as a food supply for hatched nymphs, and add them onto egg masses during maternal care. Trophic eggs are expected to be less costly for females to produce and for offspring to consume than viable eggs. Such specialization may be reflected in the size, structure, and developmental process of the eggs. Inviable trophic eggs were smaller than viable eggs, and the intraclutch size variation of the former was larger than that of the latter. The viable eggs always had approximately five micropylar processes at a pole, whereas the trophic eggs mostly lacked them. Active oogenesis was maintained during the maternal egg care period; oocyte development continued after the deposition of viable eggs and declined close to the hatching time of the clutches. Mature chorionated eggs were consistently observed in ovaries. It is strongly suggested that at least some trophic eggs contained in clutches at hatching are those that have matured and been deposited during the maternal care of eggs. We discuss possible selective factors leading to the specialization of these unusual heteropteran trophic eggs and the ecological significance of their ovarian dynamics.

Maternal food provisioning in relation to condition-dependent offspring odours in burrower bugs (Sehirus cinctus)

The sensory modalities used for communication among family members have at least partly evolved within an organism's pre-existing sensory context. Given the well-known general importance of chemical communication in insects, we hypothesized in sub-social insects with parental care that chemical signals emitted by larvae to influence parental care (i.e. solicitation pheromones) would have evolved. To test this hypothesis, we performed an experiment in the burrower bug Sehirus cinctus (Hemiptera: Cydnidae) where nymphs were hand-reared under high- or low-food conditions. These hand-reared clutches were used as a source of volatiles. The volatiles were collected for chemical analysis and delivered to caring mothers to quantify their behavioural response. As predicted, mothers exposed to volatiles from nymphs in poor condition provisioned significantly more food than those exposed to air (controls) or volatiles from high-condition nymphs. Chemical analysis revealed that nymphs emitted a blend of eight compounds of which alpha-pinene and camphene showed the strongest relationship with food treatment. Exposure to pure synthetic alpha-pinene and camphene did not affect maternal provisioning, however, suggesting that the functional significance of alpha-pinene and/or camphene may occur in a blend with other compounds. This study shows a clear effect of condition-dependent offspring odours on maternal food provisioning and identifies, for the first time, candidate compounds for a potential chemical offspring begging signal.