Instar Research Articles

Morphological ontogeny of Ctenobelba pilosella (Acari: Oribatida: Ctenobelbidae), with comments on Ctenobelba Balogh

The morphological ontogeny of Ctenobelba pilosella Jeleva, 1962 is described and illustrated. This species was investigated from its description mainly in ecological aspect. It was recorded from the forest and meadow soils, with rather low density, and small percent of juveniles.The adult is of medium size and has setiform bothridial seta, with 6–10 anterior spines. Notogaster is covered with asteriform granules and has 10 pairs of medium size, barbed setae. Seta d is absent from genua I–III and all tibia. Bothridial seta of juveniles is setiform and barbed, prodorsal and gastronotal setae are short, except of medium size ro and long, curved inwards lp. Nymphs are quadrideficient and eupheredermous i.e. they carry the exuvial scalps of previous instars. Anal valves of protonymph and deutonymph have two pairs of alveolar setae, which is rare in Brachypylina. The juveniles have seta d on all genua and tibiae.

Estudo comparativo de bioinseticidas a base de Metarhizium anisopliae (Ascomycota: Clavicipitaceae) no controle de Mahanarva fimbriolata (Hemiptera: Cercopidae)

A cigarrinha-das-raízes Mahanarva fimbriolata é uma das principais pragas em cana-de-açúcar e tem causado sérios prejuízos. Objetivou-se avaliar a patogenicidade de diferentes bioinseticidas à base do fungo entomopatogênico Metarhizium anisopliae sobre ninfas de cigarrinhas. Cinco ninfas de 4º instar foram colocadas em placas de Petri contendo folha de cana higienizada. Os bioinseticidas Metarriz®; Metarril®; M. anisopliae JCO®; Metiê® e Gr-Inn CE® foram aplicados sobre as ninfas e folhas de cana com pressão de 15 libras.pol-2 e mantidas à temperatura de 25±1 °C, UR de 70±10% e fotofase de 12h. Foram calculadas a mortalidade acumulada, mortalidade corrigida pela fórmula de Abbott para o 3º dia após pulverização e submetidas à análise de variância pelo teste F, Tukey a P ≤ 0,05, e TL50 (tempo letal). Os bioinseticidas Metarril®, Metarriz® e Gr-Inn CE® apresentaram 91,7, 87,5 e 84,2% de mortalidade corrigida e 93,3, 90,0 e 86,7% de mortalidade acumulada. O bioinseticida Metarriz® apresentou a maior mortalidade com menor TL50 (0,9 dias) no primeiro dia, no segundo dia o Metarriz® e Metarril® obtiveram mortalidades de 86,7 e 80%, respectivamente. No terceiro, quarto e quinto dia os bioinseticidas apresentaram patogenicidade acima de 70%.

Avaliação de fungos no controle da mosca-das-frutas na preservação do mercado brasileiro de frutas

O controle biológico, com a utilização de fungos entomopatogênicos, tem sido umas das promissoras alternativas no controle de moscas-das-frutas. Este estudo teve como objetivo avaliar a patogenicidade dos fungos entomopatogênicos das espécies Metarhizium anisopliae (Metsch.) Sorok. e Beauveria bassiana (Bals.) em larvas de 2º e 3º instar, pupas e adultos da mosca-das-frutas Ceratitis capitata Wiedemann (Diptera: Tephritidae). O experimento foi conduzido nos Laboratórios de Zoologia de Invertebrados e de Fitopatologia do Centro de Ciências Agrárias, Universidade Federal da Paraíba, no município de Areia - PB. Neste estudo foram utilizados dois isolados, Metarhizium anisopliae IDCB425 e Beauveria bassiana IDCB66, em diferentes concentrações. Verificou-se que o potencial de infecção de ambos isolados é maior em larvas de 2º e 3º ínstares e de adultos de C. capitata, do que em pupas. A taxa de mortalidade de C. capitata aumenta à medida que as suspensões se tornam mais concentradas. O isolado de IDCB66 de B. bassiana é mais eficiente à C. capitata, que o isolado IDCB425 de M. anisopliae.

Diapause and Voltinism in Ostrinia furnacalis (Lepidoptera: Crambidae) in Suwon, and Larval Instar Sensitivity to Diapause Induction

Diapause and Voltinism in Ostrinia furnacalis (Lepidoptera: Crambidae) in Suwon, and Larval Instar Sensitivity to Diapause Induction

Single cell transcriptome atlas of the Drosophila larval brain.

Cell diversity of the brain and how it is affected by starvation, remains largely unknown. Here, we introduce a single cell transcriptome atlas of the entire Drosophila first instar larval brain. We first assigned cell-type identity based on known marker genes, distinguishing five major groups: neural progenitors, differentiated neurons, glia, undifferentiated neurons and non-neural cells. All major classes were further subdivided into multiple subtypes, revealing biological features of various cell-types. We further assessed transcriptional changes in response to starvation at the single-cell level. While after starvation the composition of the brain remains unaffected, transcriptional profile of several cell clusters changed. Intriguingly, different cell-types show very distinct responses to starvation, suggesting the presence of cell-specific programs for nutrition availability. Establishing a single-cell transcriptome atlas of the larval brain provides a powerful tool to explore cell diversity and assess genetic profiles from developmental, functional and behavioral perspectives.

Effects of low temperature on trehalose and trehalase contents in Culex pipiens pallens

To examine the effect of low temperature on trehalose and trehalase levels in Culex pipiens pallens. The fourth instar larvae and female adult mosquitoes of Cx. pipiens pallens were exposed at 4 ℃ for 0, 1, 3, 6, 12, 18, 24 h and 0, 1, 3, 6, 12, 18, 24, 36, 48, 72 h, respectively. Then, the trehalose and trehalase contents were detected by enzyme-linked immunosorbent assay (ELISA) in mosquitoes. The contents of trehalose and trehalase significantly increased in the larval and female adult mosquitoes post-exposure to low temperature. The changing trend of trehalose levels was consistent in the larval and female adult mosquitoes, and the highest levels were (2.458 8 ± 0.379 2) mg/g and (2.825 7 ± 0.211 1) mg/g 3 h post-exposure to low temperature, respectively. The trehalose and trehalase levels fluctuated greatly within the first 6 h post-exposure to low temperature. Following adaptation for a period of time, the trehalose and trehalase levels remained at a relatively high level. Low temperature may induce the production of trehalose and trehalase in Cx. pipiens pallens, and the trehalose and trehalase may play an important role in the improvement of the cold resistance.

Spodoptera frugiperda (Lepidoptera: Noctuidae) Strains from Northern Argentina: Esterases, Profiles, and Susceptibility to Bacillus thuringiensis (Bacillales: Bacillaceae)

Fil: Loto, Flavia del Valle. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina

The Biology of Antiteuchus innocens (Hemiptera: Pentatomidae) Under Field Conditions

Antiteuchus innocens Engleman & Rolston (Hemiptera: Pentatomidae) feeds on several species of pines in the highlands of Chiapas, Mexico. The biology and ecology of this species in pine ecosystems is unknown. In this paper, information concerning the life cycle of A. innocens is presented with the objective of providing information that elucidates its role as a pest of pines. Our field observations verified that the first adults of A. innocens typically appear by Apr of each year and reach the highest abundance in May. Afterwards, adults decrease gradually and are undetectable by Nov. Egg masses are laid on abaxial regions of primary branches, and on female strobili of pines. Following egg-hatching, the female remains with its brood, presumably for maternal care. We determined that A. innocens is an oligophagous species, feeding on Pinus oocarpa Shiede, Pinus maximinoi H.E. Moore, and Pinus devoniana Lindley (all Pinaceae). This species is univoltine under the climatic conditions of Chiapas, with a life cycle of about 310 d from egg to adult. Juvenile development of A. innocens is as follows (mean ± SE): 8 (0.66), 8 (0.92), 41 (7.5), 79 (8.1), 122 (5.9), and 52 (6.9) d for egg incubation, first, second, third, fourth, and fifth instar, respectively. The longevity of adults was estimated as 54 d. The longest duration (> 4 mo) of A. innocens occurred in the fourth instar, suggesting the possibility of diapause in this instar; however, this was not verified. ResumenAntiteuchus innocens Engleman & Rolston (Hemiptera: Pentatomidae) es una chinche fitofaga que se alimenta de varias especies de pinos en las montanas de Chiapas, Mexico. Hasta ahora se desconoce la biologia y ecologia de esta especie en los ecosistemas de pinos. En el presente trabajo se presenta informacion relacionada con el ciclo de vida de A. innocens con el objetivo de proporcionar informacion que permita esclarecer su papel como plaga de los pinos. Nuestras observaciones de campo verificaron que, los primeros adultos de A. innocens, tipicamente aparecen en abril de cada ano y alcanzan la abundancia mas alta en mayo. Posteriormente, los adultos disminuyen gradualmente y para noviembre ya no son detectables. Las masas de huevos de esta chinche son puestas en la parte abaxial de las ramas primarias, y sobre los estrobilos femeninos de los pinos. Despues de la eclosion de huevos, la hembra permanece con sus crias, presuntamente para brindarles cuidado maternal. Determinamos que A. innocens es una chinche oligofaga que se alimenta sobre Pinus oocarpa Shiede, Pinus maximinoi H.E. Moore, y Pinus devoniana Lindley (todos Pinaceae). Esta especie es univoltina bajo las condiciones climaticas de Chiapas, con un ciclo de vida de aproximadamente 310 d de huevo a adulto. Los tiempos para el desarrollo de inmaduros de A. innocens son como sigue (media ± ES): 8 (0.66), 8 (0.92), 41 (7.5), 79 (8.1), 122 (5.9), y 52 (6.9) dias, para la incubacion de huevos, primero, segundo, tercero, cuarto, y quinto instar, respectivamente. La longevidad de adultos fue estimada en 54 d. La duracion mas larga (> 4 meses) of A. innocens en el cuarto instar, indica la posibilidad de pasar por una diapausa, sin embargo, este hecho no fue verificado.

Characterization of indigenous silkworm (Bombyx mori L.) breeds on the basis of morphological traits

The morphological characterization among domesticated insect like silkworm (Bombyx mori L.) is an important aspect for selection of suitable parents for breeding programme. The present study was conducted on twenty bivoltine silkworm breeds to estimate the extent relationship by morphological characterization. Eighteen morphological traits both qualitative and quantitative viz., egg shape, chorion colour, colour of the newly hatched larva, larval marking, cocoon colour, cocoon shape, pupa colour and shape, colour of male and female moth, fecundity, hatching, larva weight 5th day, –th instar duration, total larval period, percentage of malformed cocoons, pupation rate, single cocoon weight, single shell weight and shell percent were studied and data revealed significant variability among the breeds. Maximum Euclidean distance was observed between NB4D2 and CSR19 (163.25) followed by CSR19 and UDHEY-5 (145.13) and minimum between UDHEY-1 and UDHEY-3 (4.20). The dendrogram of phenotypic data grouped all breeds in two clusters; Cluster A and B. Cluster A was sub divided into two sub-clusters cluster AI and cluster A II. Cluster A I contained eight breeds and Cluster AII eleven breeds. Cluster B comprised of one breed CSR19. In PCA the genetic divergence was maximum between NB4D2 and CSR19, whereas it was minimum in UDHEY-7 and ND2. PCoA results depicted CSR19 and SPO having greater divergence, whereas it was minimum between UDHEY-7 and ND2. On the basis of Euclidean distance metric the performance of the breeds; CSR19, NB4D2, PO3, UDHEY-8, SPO, UDHEY-4, ND2, CC1, UDHEY-2, UDHEY-5, UDHEY-7, UDHEY-6 have been identified as promising breeds and are recommended for further breeding to boost bivoltine silk production.

우리나라 주요 항구주변에서 매미나방 발생과 령기별 약제 반응 비교

우리나라 주요 항구주변에서 매미나방 발생과 령기별 약제 반응 비교

Revision of genus Hellica Stål, 1867 and description of three new genera of South American Lanopini (Hemiptera: Acanthosomatidae: Blaudusinae)

Fil: Carpintero, Diego Leonardo. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales Bernardino Rivadavia; Argentina

In-vitro study on the larvicidal activity of Manihot glaziovii peel extract against Aedes aegypti larvae

Use of chemical method to control Aedes aegypti population in the Dengue endemic areas caused the emergence of a resistant strain of this species to insecticide compounds, including temephos. Exploration of the alternative compounds that have larvicidal effects is needed, such as natural products derivate from plants. The current study was designed to evaluate the effective dosage of methanolic extract of Manihot glaziovii peel against the third instar larvae of Aedes aegypti. Bioassay test was performed based on the WHO procedure to occupy the 24 hours exposure of five levels dosages of Manihot glaziovii peel extract, namely 1,800, 2,400, 3,000, 3,600 and 4,200 ppm respectively. As many as 25 of healthy Aedes aegypti larvae were subjected into each group, five-time replicated and compared with tap water control group. The mortality rate of Aedes aegypti larvae has increased due to the increase in treatment groups dosages, ranged from 44–97.6%. It is significantly different in larvae mortality rate between different treatment groups. There was no observation of killed larvae in the control group. LD50 and LD90 of methanolic extract of Manihot glaziovii peel were measured 2,027 ppm and 3,772 ppm, respectively. This result suggests the possible use as an ecofriendly larvicide against Aedes aegypti larvae. Further investigation is needed to obtain secondary metabolites of this plant.

The first fossil free-living late instar larva of Strepsiptera (Insecta)

The first fossil free-living late instar larva of Strepsiptera (Insecta)

Fumigant toxicity of Haplophyllum tuberculatum (Rutaceae) and Nepeta crispa (Lamiaceae) on the Indian meal moth

The insecticidal activity of essential oil vapors of Haplophyllum tuberculatum (Sapindales: Rutaceae) and Nepeta crispa (Lamiales: Lamiaceae) were evaluated on third instar larvae of Plodia interpunctella (Lepidoptera: Pyralidae) as one of the major insect pests of stored products. Essential oils of the plants were obtained using Clevenger-type water distillation. GC-MS analyses of the oils demonstrated that the main compounds of H. tuberculatum were ρ-menth-2-en-1-ol-cis (20.15 %), ρ-menth-2-en-1-ol-trans (16.92 %), trans-Piperitol (13.23 %), Piperitone (7.34 %) and cis-Piperitol (6.72 %). It is an important plant that has many medicinal properties. 1,8- Cineole (32.98 %), s-Pinene (8.70 %), 4aa,7a,7aa-Nepetalactone (8.08 %) and 4as,7a,7as-Nepetalactone (6.1 %) were detected as the predominant component in N. crispa. The aerial parts of that are used in traditional medicine. The LC50 values were estimated after 24 hours for H. tuberculatum and N. crispa as 4.301 and 5.579 µl L-1 air, respectively. LC50 values were projected using probit analysis. Results on H. tuberculatum showed more toxicity against the Indian meal moth compared to the N. crispa. In conclusion, the essential oil of the two plants could have potential for application to stored grain and agricultural commodities to control of stored crop pests in IPM programs.

The potential of host-specific volatiles from Tribolium confusum larval faeces for luring the ectoparasitoid Holepyris sylvanidis : Presentation

The ectoparasitoid Holepyris sylvanidis (Bethylidae) attacks larvae of different stored product pest beetles. Previous studies on the olfactory host search of H. sylvanidis revealed that female parasitoids are strongly attracted to volatiles released from Tribolium confusum larval faeces, in particular to (E)-2-nonenal and 1-pentadecene. We suggested that these host-specific key compounds may serve the parasitoid as long-range attractants for host location. In this context, we propose that the attractive volatile blend could be used to establish a new approach within the biological control of stored product pests by guiding the parasitoid to its host and thus, increasing the host finding success. We investigated the potential of the identified host-indicating volatile cues to attract H. sylvanidis from a distance by offering the two key compounds to female parasitoids. Their walking behaviour and the covered distance were analysed on a Kramer sphere. Moreover, in semi-field trials both attractive volatiles were loaded onto rubber septa which were placed next to 4th instars of T. confusum at 1.5 m distance from the parasitoids. We studied the host finding success of H. sylvanidis by (i) measuring the mean time to locate and parasitise T. confusum larvae and (ii) counting the number of parasitised and unparasitised host larvae as well as the number of newly hatched parasitoids compared to the control without additional olfactory cues. First results showed that H. sylvanids females can locate the provided host larvae from a distance. Parasitistion of host larvae started four days after the release of parasitoids. No effect of the additionally offered hostspecific key volatiles ((E)-2-nonenal and 1-pentadecene) on the parasitoid´s host finding success was observed at the given conditions and used amounts of compounds. Further studies are required to determine the right odour blend and concentrations for attraction of parasitoids over a distance and finally to show that the addition of host-derived kairomones may support the host finding success of H. sylvanidis.

Larvae of Trogoderma respond behaviorally to whole body extracts

Behavioral responses to semiochemicals by Trogoderma (Coleoptera: Dermestidae) stored product pests were assayed in a small arena. Hexane extracts were obtained from Khapra beetle, Trogoderma granarium, warehouse beetle, Trogoderma variable, and the larger cabinet beetle Trogoderma inclusum that were killed by being frozen for 48 hours at -20° C. These extracts were analyzed using gas chromatography coupled with mass spectrometry (GC/MS), and it was confirmed that they contain several cuticular hydrocarbons, fatty acids and sterols. Two choice experiments were performed inside Petri dish arenas, with filter paper fully covering the bottom surfaces. Two smaller 3cm filter papers were placed on opposite ends within each arena. Each of the smaller papers were folded three times in parallel to present a corrugated surface that the insects could move underneath if they chose. In each case, one paper had a 100µl aliquot of one of the extracts, and the other 100µl of hexane as a control. 10 late instar larvae of the same species as the treatment extract were placed in the arena and allowed to acclimate overnight in a dark room. For all three species, it was found that larvae were more likely to be found on the side of the Petri dish with the hexane control rather than the conspecific larval extract. They were also more likely to be on or near the smaller corrugated filter paper treated with the control as opposed to the filter paper treated with the larval extract. Thus repellency of the conspecific extract was demonstrated at that particular dose. Further assays using different doses of the raw extracts and their individual chemical components are planned. The use of these semiochemicals in novel management strategies will be considered.

Molecular characterization and tissue expression analysis of five genes for chitinase in the red palm weevil, Rhynchophorus ferrugineus (Coleoptera: Curculionidae)

Insect chitinases are hydrolytic enzymes that cleave chitin of the cuticle and peritrophic membrane during molting. Multiple genes encode insect chitinases, which are characterized as having diverse chemical and enzymatic properties depending on the time and the site of expression. This work was done to isolate and characterize chitinase genes from the red palm weevil (RPW), Rhynchophorus ferrugineus (Oliver), a cryptic pest of many palm trees. The isolated five genes were phylogenetically clustered into five different groups (I, II, III, VI, and VII) of the glycoside hydrolase family 18 (GH18). Domain structure analysis revealed that RfCht1 (group I), RfCht3 (group VI), and RfCht5 (group VII) each retained a single catalytic domain of the GH18, whereas RfCht2 (group III)) and RfCht4 (group II) possessed two and five GH18 catalytic domains, respectively. RfCht1, RfCht2, and RfCht3 each retained a single chitin-binding domain (CBD) and RfCht4 retained five CBDs, but RfCht5 lacked CBD. Developmental and tissue expression profiles showed high levels of transcripts of the five genes in the newly hatched first instar larvae. RfCht1 and RfCht2 transcripts were expressed constitutively almost with high levels in young and mature eggs, in all tested larval instars, pre-pupae, pharate pupae, and adults; whereas RfCht3 and RfCht5 transcripts were expressed as low levels in the early instars larvae few hours before molting. In late developmental stages and mature eggs, RfCht3, RfCht4, and RfCht5 were expressed as low levels mainly in the cuticle. This study presents the first report on chitinase genes in the RPW and suggests that these genes have additional roles in the weevil development, which require further elucidation. Key words: Chitinase, conserved motifs, cuticle, domain structure, expression profile, Rhynchophorus ferrugineus

Effect of Ibicella lutea (Staph.) Van Eselt. (Martyniaceae) Leaves Extracts in Some Biological Aspects of False Armyworm Insect Lucania loreyi (Dup.) (Lepidoptera: Noctuidae)

The present study included test the effectiveness of Turbinoid and Alkaloid compounds extracts from pure leaves of Devil's Claw Ibicella lutea on life performance of false armyworm insect Lucania loreyi, the Turbinoid compounds extract had a clear effect on the various insect lifestyle, the percentage of eggs destruction in the Turbinoid and Alkaloid compounds extract at a concentration of 2.0 mg/ ml reached (50.0 and 46.7%), respectively, compared with the control treatment that reach (0.0%), The percentage of the destruction of first and sixth larval instar was (90.3 and 73.3%) when transacted with Turbinoid compounds extract respectively at the concentration of 2.0 mg/ ml, while the percentage of destruction of first and sixth larval instar that transacted with Alkaloid compounds extract was reach (90 and 56.7 %) respectively at the concentration of 2.0 mg/ ml, the highest percentage for pupa destruction was reached about 80% when transacted with Turbinoid compounds extract at concentration of 2.0 mg/ ml compared with Alkaloid compounds extract which reached 43.3% at concentration of 2.0 mg/ ml, and the percentage of adult destruction reached 63.3% when transacted with Turbinoid compounds extract at a concentration of 2.0 mg/ ml and reached 40.0% with alkaloid extract, The accumulative percentage of immature phases destruction, when transacted with Turbinoid and Alkaloid compounds, extract reached about (100 and 83.3%), respectively, at a concentration of 2.0 mg/ ml.

Plant and herbivore ontogeny interact to shape the preference, performance and chemical defense of a specialist herbivore.

The amount of damage that herbivorous insects impose on plants varies as a function of plant ontogenetic trajectories in tissue quality and defenses, and the herbivores' own developmental trajectories in body size, mandible shape and detoxification enzymes, among others. However, little is known about how host plant and herbivore ontogeny interact. Using four ontogenetic stages of Plantago lanceolata (Plantaginaceae) and three to five larval stages of the specialist caterpillar Junonia coenia (Nymphalidae), we evaluated how ontogenies in both of these trophic levels shape: (i) caterpillar feeding choice, (ii) performance, and (iii) sequestration of plant allelochemicals. Plant physical (leaf toughness) and chemical (iridoid glycosides) defenses increased, while nutritional quality (water and nitrogen content) decreased, as plants aged. These plant ontogenetic trajectories strongly altered the behavior and physiology of this specialist herbivore, but the magnitude of the response varied with larval stage. In feeding experiments, while first instar larvae showed little preference among plant stages, older larvae significantly preferred juvenile over reproductive stages. In turn, larval consumption increased and digestive efficiency decreased, potentially explaining their decrease in relative growth rate, as larvae and host plant aged, but differences were greater for younger than older caterpillars. Finally, sequestration of plant allelochemicals increased through plant and larval development; however, the major differences due to diet occurred earlier during larval development. Our results highlight that changes in plant ontogeny most strongly influence early herbivore instars, emphasizing the need to consider the developmental stage of both trophic levels to better understand temporal variation in herbivore damage.

Evaluation the Toxicity of Honey Bee Venom on Achroia grisella Developmental Stages

The common control method used to control the lesser wax moth A. grisella was fumigation with toxic gases; however, many insect pests of honey bees have developed resistance to the conventional control methods. This study aimed to study the toxicity of crude bee venom on developmental stages of A. grisella as safer alternative and replacement of these chemicals. The bee venom was collected by placing the electric bee venom collector device at the entrance of the beehive. Newly deposited eggs of A. grisella were assayed to evaluate the crude honey bee venom effect on the viability of eggs. Dried crude honey bee venom was diluted with pure acetone to concentrations of 50, 25, 12.5 and 6.25 µg/µl. Egg hatchability was significantly (p50) of 52.89 µg /µl. The topical application of crude honey bee venom was applied on 3rd instar larvae with concentrations of 0, 6.25, 12.5, 25, 50 µg. The calculated mortality percentages for all treatments were 8% at the lower concentration and 52% at the high concentration. The calculated lethal median concentration LC50 was 38.27 µg /µl.