Female Nymphs Research Articles

Neogreenia lonicera sp. nov., a new species of Margarodidae sensu lato (Hemiptera: Coccoidea) from China, with a key to species of Neogreenia MacGillivray and placement of the genus in the family Kuwaniidae

A new species, Neogreenia lonicera Wu & Nan, is described and illustrated based on the adult female, second-instarfemale and first-instar nymph. This new species was collected at Helan Mountain, Inner Mongolia, China, in bark crevicesof Lonicera microphylla (Caprifoliaceae). A key is provided to separate the five species now known in NeogreeniaMacGillivray. A cladistic analysis of morphological data from adult females and first-instar nymphs of 28 archaeococcoidgenera has Neogreenia in a clade with Jansenus Foldi and Neosteingelia Morrison and usually also with KuwaniaCockerell, and thus Neogreenia should be placed in the family Kuwaniidae. A key to distinguish the adult females of the four genera of the Kuwaniidae is provided.

Characterization and comparative analysis of small RNAs in three small RNA libraries of the brown planthopper (Nilaparvata lugens).

BackgroundThe brown planthopper (BPH), Nilaparvata lugens (Stå;l), which belongs to Homopteran, Delphacidae, is one of the most serious and destructive pests of rice. Feeding BPH with homologous dsRNA in vitro can lead to the death of BPH, which gives a valuable clue to the prevention and control of this pest, however, we know little about its small RNA world.Methodology/Principal FindingsSmall RNA libraries for three developmental stages of BPH (CX-male adult, CC-female adult, CY-last instar female nymph) had been constructed and sequenced. It revealed a prolific small RNA world of BPH. We obtained a final list of 452 (CX), 430 (CC), and 381 (CY) conserved microRNAs (miRNAs), respectively, as well as a total of 71 new miRNAs in the three libraries. All the miRNAs had their own expression profiles in the three libraries. The phylogenic evolution of the miRNA families in BPH was consistent with other species. The new miRNA sequences demonstrated some base biases.ConclusionOur study discovered a large number of small RNAs through deep sequencing of three small RNA libraries of BPH. Many animal-conserved miRNA families as well as some novel miRNAs have been detected in our libraries. This is the first achievement to discover the small RNA world of BPH. A lot of new valuable information about BPH small RNAs has been revealed which was helpful for studying insect molecular biology and insect resistant research.

Cissococcus Cockerell (Hemiptera: Coccoidea: Coccidae), a unique gall-inducing soft scale genus on Vitaceae from South Africa, with description of a new species

The gall-inducing genus Cissococcus Cockerell is revised to include two species. The family placement of Cissococcus has been uncertain, but characters of the first-instar nymph and adult male clearly show that Cissococcus is a soft scale insect (Coccidae) and is therefore the only member of the Coccidae known to induce a complex covering gall. All stages of the type species, C. fulleri Cockerell, are described and illustrated, plus the adult and third-instar female and first-instar nymph of a new, closely-related species, C. braini Hodgson & Millar sp. n. Both species are known only from wild vines in the southeast and C. fulleri also in the northeast of South Africa, but each induces a unique gall and each appears to be restricted to a different species of Rhoicissus (Vitaceae). The galls of each species are described and figured, and gall induction in the Coccidae is briefly discussed.

Daily production of spermatophores, sperm number and spermatophore size in two eriophyoid mite species

Under dissociated sperm transfer, (non-pairing) males deposit spermatophores on a substrate, while females seek spermatophores and pick up sperm on their own. Spermatophore expenditures of non-pairing males should be high, due to the increased uncertainty of sperm uptake by a female. In this study I examined spermatophore expenditures in two eriophyoid species that differed in the degree of dissociation between sexes: (1) Aculus fockeui (Nalepa and Trouessart) males rarely visit quiescent female nymphs (QFNs), and mostly deposit spermatophores all over the leaves, whereas (2) Aculops allotrichus (Nalepa) males guard QFNs for many hours and deposit several spermatophores beside them. Males of both species were collected from the field and tested in solitude. Aculus fockeui males deposited on average 19.1 spermatophores per day, whereas A. allotrichus deposited only 3.6 spermatophores per day, and had a very large coefficient of variation. Males and spermatophores of A. allotrichus were significantly smaller and contained less sperm than those of A. fockeui. In both eriophyoids, spermatophore size was fitted to the size of female genitalia and the height of females. The ratio between the diameter of spermatophore head and the width of a female genital coverflap was 0.6, whereas the ratio between the female leg and the length of spermatophore stalk was 0.5. Several factors could be responsible for the discrepancy in spermatophore expenditures between species. Among other factors, the effects of male size, male reproductive strategy and female genitalia size on spermatophore output and size of spermatophores are discussed.

A new Chorizococcus species (Coccoidea, Pseudococcidae) from Taiwan with transferring of Chorizococcus mirzayansi Moghaddam to genus Spilococcus Ferris.

A new mealybug species, Chorizococcus zoysiae sp. n., feeding on Zoysia tenuifolia (Poaceae), is described from Taiwan. Adult female, third-instar female, second-instar female and first-instar nymph were described and illustrated in this article. Keys are provides to (a) separate this new species from similar species of Chorizococcus and those of same genus on zoysia grasses and (b) to identify instars of the new species. In addition, Chorizococcus mirzayansi Moghaddam is transferred to the genus Spilococcus as Spilococcus mirzayansi (Moghaddam), comb. n.

A microsatellite-based test of the Reticulitermes speratus genetic caste determination model in Coptotermes lacteus

Coptotermes lacteus, a termite found in eastern Australia, is a central-site nester that constructs mounds up to 2 m in height. Mature colonies typically contain the primary king and queen, and up to a million or more worker and soldier offspring. Once a year, male and female nymphs are produced in approximately equal numbers and develop into new alates. Experimental removal of the queen in the field and subsequent mating of the king with a replacement queen, results in an unusual phenomenon whereby the production of female nymphs completely ceases, while the production of male nymphs, and workers of both sexes, continues. The proximate cause of this nymph male-bias is yet to be discovered. The production of male nymphs and workers of both sexes in de-queened C. lacteus colonies is equivalent to offspring production patterns in laboratory crosses of male nymphoid (nymph-derived) with female ergatoid (worker-derived) replacement reproductives in the related species Reticulitermes speratus. An X-linked genetically influenced caste determination (GCD) mechanism has been proposed to account for such offspring patterns in R. speratus. We examined microsatellite genotypes in C. lacteus to test a prediction arising from the R. speratus GCD model: that nymphs should result from reproduction by neotenics, rather than the primary pair. In five of six colonies examined, genotypes indicated that all workers and nymphs were derived from a single reproductive pair. In three of these cases, the primary queen was also located and examined; her genotype matched that inferred from worker and nymph genotypes. These results suggest that the GCD model proposed for R. speratus does not apply to C. lacteus, at least under field conditions. The male-nymph bias following queen removal therefore remains an unresolved issue in C. lacteus.

Nymphs in foraging populations of Coptotermes gestroi (Isoptera: Rhinotermitidae)

AbstractFood searching activity by subterranean termites involves workers, soldiers and nymphs. The present study was carried out for elucidating aspects of nymph foraging behavior in Brazil where the species Coptotermes gestroi (Wasmann, 1896) is exotic. Monitoring was conducted through making regular collections from seven different colonies for a period of 22 months, which exhibited the production of forager nymphs all year round. A biometric study was conducted to determine the instars of the forager nymphs collected. The identification of male and female nymphs was also conducted for establishing the sex proportion, which was slightly male-biased. From the 533 forager nymphs collected, 34 were from the 3rd instar, 280 from the 4th instar and 219 from 5th instar. The results suggest that 3rd instar nymphs were not too active in the foraging activities because they were collected only in one colony and in an insignificant quantity.

꽃노랑총채벌레 목화진딧물, 점박이응애에 대한 애꽃노린재(Orius sauteri)의 포식반응

애꽃노린재의 먹이로 꽃노랑총채벌레를 주었을 경우, 애꽃노린재 암 수 약충의 온도별 일일포식량은 17, 22, 27, <TEX>$32^{\circ}C$</TEX>에서 전체 약충기간(암/수) 동안 각각 4.2/3.9, 11.4/9.5, 14.3/10.8, 14.7/12.5 마리였고 <TEX>$27^{\circ}C$</TEX>에서 먹이종류별 일일포식량은 먹이로 꽃노랑총채벌레, 목화진딧물 및 점박이응애를 공급하였을 경우 전체 약충기간(암/수) 동안 각각 14.3/10.8, 7.5/7.2, 45.9/38.8마리를 포식하였다. 애꽃노린재 암컷 성충은 <TEX>$27^{\circ}C$</TEX>에서 산란전기간에 42.8마리, 산란기간에 63.2마리를 포식하였다. 애꽃노린재는 꽃노랑총채벌레의 밀도 증가에 띠라 포식량은 점차 증가하였으나 증가율은 차차 감소하는 Holling의 기능반응곡선 제II형(포화형)과 유사한 포식반응을 나타냈고 애꽃노린재 암컷 성충의 탐색율이 5령 약충에 비해 높고 탐색시간도 짧았다. 애꽃노린재의 5령 약충과 암컷 성충은 꽃노랑총채벌레 2령 유충을 가장 선호하였다. Daily predation of female/male O. sauteri during nymphal development were 4.2/3.9, 11.4/9.5, 14.3/10.8, and 14.7/12.5 at 17,22,27, and <TEX>$32^{\circ}C$</TEX>, respectively, and consumed 14.3/10.8 thrips, 7.5/7.2 aphids, 45.9/38.8 mites at <TEX>$27^{\circ}C$</TEX>, respectively. Adult females ate 42.8 thrips daily during preoviposition period and 63.2 thrips during oviposition period at <TEX>$27^{\circ}C$</TEX>. Predation by O. sauteri on F. occidentalis increased as the density of F. occidentalis increased. However, the rate of increase gradually lessened, resembling a Holling's type II functional response. The attack rate of adult female is higher than that of the 5th nymph. Adult female and 5th nymph of O. sauteri appeared to prefer 2nd larva of F. occidentalis.

Scale insect fauna (Hemiptera: Sternorrhyncha: Coccoidea) of New Zealand’s pygmy mistletoes (Korthalsella: Viscaceae) with description of three new species: Leucaspis albotecta, L. trilobata (Diaspididae) and Eriococcus korthalsellae (Eriococcidae)

The scale insect fauna recorded on the pigmy mistletoe genus Korthalsella (Viscaceae) and New Zealand’s loranthaceous mistletoes is reviewed. Three new species from New Zealand discovered on Korthalsella species during this study are described: the adult female, 2nd-instar male and female nymphs of two pupillarial species Leucaspis albotecta sp. nov. and Leucaspis trilobata sp. nov. (Diaspididae); and the adult female, 2nd-instar male and female nymphs and 1st-instar nymph of Eriococcus korthalsellae sp. nov. (Eriococcidae). A distribution map is provided for the three new species. We report the first records of adventive (exotic) scale insects on Korthalsella species in New Zealand – Ceroplastes sinensis Del Guercio, Coccus hesperidum Linnaeus, soft brown scale, Saissetia coffeae (Walker), hemispherical scale, S. oleae (Olivier), black scale (Coccidae), and Aspidiotus nerii Bouché, oleander scale, Hemiberlesia lataniae (Signoret), latania scale, H. rapax (Comstock), greedy scale (Diaspididae), while three native scale insects are also first records: Kalasiris perforata (Maskell) (Coccidae), Eriococcus pallidus Maskell (Eriococcidae) and Paracoccus glaucus (Maskell) (Pseudococcidae). Ten scale insect species are listed for New Zealand’s loranthaceous mistletoes.

A new species of Acanthococcus (Hemiptera, Coccoidea, Eriococcidae) on Leptospermum scoparium (Myrtaceae) from Italy and France

The adult female, 1 st -instar nymph, 2 nd -instar male and 2 nd -instar female nymphs of a new species of felt scale, Acanthococcus mariannae Pellizzari, are described and illustrated. The new species was collected off Leptospermum scoparium (Myrtaceae) in Italy and France. An identification key of Eriococcid species known to occur on Leptospermum spp is also provided.

New record and ecological notes of Phimophorus spissicornis (Hemiptera: Heteroptera: Reduviidae: Phimophorinae) in Colombia

Phimophorus spissicornis, the enigmatic and exclusively Neotropical representative of the Phimophorinae (Heteroptera: Reduviidae), is recorded for the first time from Colombia. Six adult specimens and one nymph were collected in the municipalities of Vegachí and San Carlos, department of Antioquia. In both localities P. spissicornis was collected from palms (Arecaceae) in association with Rhodnius pallescens (Reduviidae: Triatominae). Phimophorus spissicornis was found on the axils of palm fronds of Attalea butyracea and Oenocarpus bataua. Dorsal habitus illustrations of the male, female, and late instar nymph of P. spissicornis are provided.

Fumigant Toxicity of Essential Oils to the German Cockroach (Dictyoptera: Blattellidae)

The fumigant toxicity of 12 essential oil components [carvacrol, 1,8-cineole, trans-cinnamaldehyde, citronellic acid, eugenol, geraniol, S-(-)-limonene, (-)-linalool, (-)-menthone, (+)-alpha-pinene, (-)-beta-pinene, and thymol] to adult male, adult female, gravid female, and large, medium, and small nymphs of the German cockroach, Blattella germanica (L.) (Dictyoptera: Blattellidae), was determined. 1,8-Cineole was the most toxic essential oil component to adult males and females, gravid females, and large nymphs, with LC50 values of 6.8, 8.4, 5.3, and 11.4 mg/liter air at 24 h, respectively. (-)-Menthone and carvacrol were the most toxic essential oil components to medium and small nymphs, with LC50 values of 9.0 and 3.6 mg/liter air at 24 h, respectively. Citronellic acid was the least toxic essential oil component to all stages of the German cockroach. There was not a consistent relationship between body mass and toxicity; the susceptibility of the stages differed for each oil. LC50 values of all stages were correlated negatively with vapor pressure and positively with molecular weight of the essential oil components. The most toxic essential oil components to the majority of cockroach stages were cyclic aliphatic hydrocarbons [1,8-cineole, (-)-menthone, (+)-alpha-pinene, (-)-beta-pinene, and S-(-)-limonene]. Ring size and the presence of a carbonyl functional group also may have contributed to the toxicity of the compounds. Citronellic acid had no effect on ootheca hatch (100% hatch), whereas (-)-menthone had the greatest effect on ootheca hatch (73% hatch). Percentage of hatched oothecae decreased linearly with increasing concentration for (-)-menthone, S-(-)-limonene, (+)-alpha-pinene, and (-)-beta-pinene. No essential oil component prevented ootheca hatch, suggesting that multiple treatments would be required in the field to eliminate infestations.

Functional identity versus species richness: herbivory resistance in plant communities.

The resistance of a plant community against herbivore attack may depend on plant species richness, with monocultures often much more severely affected than mixtures of plant species. Here, we used a plant–herbivore system to study the effects of selective herbivory on consumption resistance and recovery after herbivory in 81 experimental grassland plots. Communities were established from seed in 2002 and contained 1, 2, 4, 8, 16 or 60 plant species of 1, 2, 3 or 4 functional groups. In 2004, pairs of enclosure cages (1 m tall, 0.5 m diameter) were set up on all 81 plots. One randomly selected cage of each pair was stocked with 10 male and 10 female nymphs of the meadow grasshopper, Chorthippus parallelus. The grasshoppers fed for 2 months, and the vegetation was monitored over 1 year. Consumption resistance and recovery of vegetation were calculated as proportional changes in vegetation biomass. Overall, grasshopper herbivory averaged 6.8%. Herbivory resistance and recovery were influenced by plant functional group identity, but independent of plant species richness and number of functional groups. However, herbivory induced shifts in vegetation composition that depended on plant species richness. Grasshopper herbivory led to increases in herb cover at the expense of grasses. Herb cover increased more strongly in species-rich mixtures. We conclude that selective herbivory changes the functional composition of plant communities and that compositional changes due to selective herbivory depend on plant species richness.

Parasitism and predation of the planthopper Tagosodes orizicolus (Homoptera: Delphacidae) by a dryinid parasitoid in Costa Rica

We analyzed the effect of predation and parasitism by the native dryinid Haplogonatopus hernan- dezae as a natural enemy of the rice pest Tagosodes orizicolus under controlled conditions in an insectary in Costa Rica. We found no change in the proportion of T. orizicolus nymphs that were fed upon, parasitized, and that showed no apparent damage throughout the adult stage in H. hernandezae, which favors a stable control of the pest. The percentage of T. orizicolus nymphs that were parasitized (37 %) and preyed upon (36.5 %) was similar, eliminating 73,5 % of the total nymphs causing damage to the rice plants (N = 1 099). Of the total 324 parasitized nymphs, female nymphs were more parasitized than male nymphs (95 % and 5 % respectively) and dryinids developed more successfully in female host nymphs. These tendencies did not change with dryinid age. Survival of dryinids was higher in female T. orizicolus, both for larvae that emerged from the host and pupated, and for pupae that moulted to adults. In cages where the nymphs had no contact with dryinids we found a higher amount of males than females (57.44 ± 28.5 vs 45.22 ± 25.85). In contrast, when the nymphs were in contact with dryinids, the sex ratio was two females to one male reaching adulthood since the dryinids fed more on male nymphs (N = 692). Our results indicate that female dryinids prefer to oviposit in female T. orizicolus nymphs and prey on males. Reproduction by parthenogenesis, acceleration of the development in an insectary with controlled conditions and eficiency of H. hernandezae as a parasitoid and predator indicate that this dryinid is an effective biological control agent of T. orizicolus. Rev. Biol. Trop. 57 (Suppl. 1): 203-211. Epub 2009 November 30.

Jail baits: how and why nymphs mimic adult females of the German cockroach, Blattella germanica

The male German cockroach performs a characteristic courtship behaviour upon contacting a sexually receptive female: he turns away from the female and raises his wings, thereby exposing tergal glands whose reservoirs contain phagostimulatory substances. The female then mounts the male and feeds upon these nuptial secretions; this behaviour places her in the appropriate precopulatory position. The contact sex pheromone on the cuticular surface of the female, responsible for eliciting courtship behaviour in males, consists of a blend of six components that share a common biosynthetic pathway. An excised female antenna can elicit the full courtship display in males. We found that antennae taken from either male or female nymphs of various ages also could elicit the full courtship response in adult males. We extracted lipids from the cuticular surface of nymphs and, guided by behavioural assays, we fractionated the extracts using various chromatography procedures, including flash (column) chromatography, high-performance liquid chromatography and gas chromatography. Mass spectrometry analysis of behaviourally active fractions revealed two classes of courtship-eliciting compounds: all nymphs possessed a novel, still unidentified compound that elicited courtship in adult males. In addition, in last-instar females, we isolated four of the six adult female-specific contact sex pheromone components, consistent with differentiation of the sexes at this stage, and the onset of sexual maturation of the pheromone biosynthetic machinery. Our results support the interpretation that nymphs engage in sexual mimicry to gain access to male-produced nuptial tergal secretions that are exposed and can be secured only during courtship.

A new species of Choroterpes (Ephemeroptera: Leptophlebiidae) from a tropical stream of south India

Choroterpes alagarensis new species (type locality: Alagar hill, Madurai) (Ephemeroptera: Leptophlebiidae) is described from male and female imago, sub imago and nymphs. This species is found in leaf packs, woody debris, pebbles and boulders and occurs in slow flowing stream areas.

Field and laboratory studies in a Neotropical population of the spinose ear tick,Otobius megnini

One ear of each of five cows on a property close to Dean Funes, province of Córdoba, Argentina, was inspected monthly from December 2004 to November 2006 to determine the presence of Otobius megnini (Dugès) and to ascertain its seasonality. Ticks were collected to study the biological parameters of larvae, nymphs and adult ticks. Groups of nymphs were also maintained at three different photoperiods at 25 degrees C. The abundance of immature stages was greatest during January-April and August-October in the first and second years of the study, respectively. No larvae successfully moulted. Nymphs weighing < 17 mg also failed to moult, but 89% of heavier nymphs moulted into adults. Nymphs moulting to males weighed less (49.5 +/- 16.09 mg) than nymphs moulting to females (98.1 +/- 34.08 mg). The pre-moult period was similar for nymphs moulting to either sex and significantly longer (P < 0.01) for female nymphs maintained at 25 degrees C compared with nymphs kept at 27 degrees C. No effect of photoperiod on the pre-moult periods of nymphs was detected. Female ticks produced a mean of 7.0 +/- 1.94 egg batches after a preoviposition period of 16.4 +/- 8.41 days for the first batch. The mean oviposition period was 61 +/- 20.8 days and the duration of oviposition for each batch varied from 1 to 6 days. The mean number of eggs per batch was 93.1 +/- 87.53. The minimum incubation period for the first egg batch was 13.6 +/- 2.77 days. The total number of eggs laid by each female was 651.6 +/- 288.90. Parthenogenesis was not observed. The reproductive efficiency index (REI) (number of eggs laid/weight of female in mg) was 5.5 +/- 1.26. Pearson's correlations showed a significant direct relationship between the weight of the female and number of eggs laid (P < 0.01) and REI (P < 0.05). Several of the biological values presented above for the tick population from the Neotropical zoogeographic region showed marked differences to equivalent values for O. megnini populations from the U.S.A. (Nearctic) and India (Oriental). Nevertheless, the only two sequences of 16S rDNA deposited in GenBank from ticks originating in Argentina and allegedly in the U.S.A. indicate that they are conspecific (99.8% agreement). We tentatively consider the biological differences among populations of this tick species to represent adaptations for survival at different conditions.

A new species of Crypticerya Cockerell (Hemiptera: Monophlebidae) from Colombia, with a key to species of the tribe iceryini found in South America

The adult female and first-instar nymph of a new species of iceryine scale insect, Crypticerya multicicatrices Kondo & Unruh sp. n., are described and illustrated. The new scale insect is polyphagous and was collected on 13 plant species distributed in seven botanical families, including fruit trees of economic importance such as mango and soursop. A taxonomic key to the species of the tribe Iceryini known from South America is provided. Previous records of C. brasiliensis (Hempel) from Colombia are confirmed to be misidentifications of this new species.

Target of Rapamycin (TOR) Mediates the Transduction of Nutritional Signals into Juvenile Hormone Production

Anautogeny is a reproductive strategy by which females do not reproduce until they feed. Therefore, nutritional signals must inform the reproductive tissues, and cells that the organism has reached a nutritional status suitable for triggering reproductive processes. One of the possible pathways involved in anautogeny is the "target of rapamycin" (TOR) pathway, which has been described as connecting the nutritional status with growth, proliferation, and cancer. The German cockroach, Blattella germanica, is an anautogenous species whose vitellogenesis is governed by juvenile hormone. In the present report, we describe the cloning of TOR cDNA from B. germanica (BgTOR). Expression studies showed that BgTOR is expressed in adult female corpora allata and fat body. BgTOR knockdown using systemic RNAi in vivo produced a severe inhibition of juvenile hormone synthesis in adult female corpora allata, together with a reduction of mRNA levels corresponding to 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase-1, HMG-CoA synthase-2, and HMG-CoA reductase. In addition, there was a reduction of vitellogenin mRNA in the fat body, and ovaries did not grow. Analysis of TOR expression in corpora allata of fed and starved females suggested that TOR is not regulated at the transcriptional level. Nevertheless, there was a reduction in HMG-CoA synthases and reductase mRNA in corpora allata (but not in the fat body) of starved females, together with a dramatic reduction of juvenile hormone production and ovary development. Taken together, our results indicate that TOR knockdown mimics starvation in terms of corpora allata activity, and suggest that nutritional signals that activate juvenile hormone biosynthesis and vitellogenin production are mediated by the TOR pathway.

Neoperlops vietnamellus, a rare stonefly from Vietnam (Plecoptera: Perlidae)

A rare perlid stonefly, Neoperlops vietnamellus, sp. nov., is described from Vietnam. Descriptions and figures of key characters are provided for the male and female adult, nymph, and egg stages. The male adult of N. vietnamellus can be distinguished from other congeners by its unique distribution of patches of sensilla basiconica posteromesally on the abdominal terga VII–IX, by the absence of sensilla basiconica on the anterior processes of the hemiterga, and by the absence of prominent spines along ventral edge of the hemiterga. The female adult has a slightly protruding subgenital plate on the abdominal sternum VIII as a strongly sclerotized mesal tab. The nymphs can be distinguished by the distinct M-line marking on the head, relatively long cerci, and a lack of dense swimming hairs on cerci. The egg chorion surface is completely smooth, and the anchor features a number of long filaments.