Pupal Stage Research Articles

Compositional, volatile, and structural features of Hermetia illucens (black soldier fly) flours: The effect of population and life stages

The scope of the present study was to study the effect of different populations of Hermetia illucens, commonly known as black soldier fly (BSF), on the major components and volatile composition of the derived freeze-dried flours. Potential differences in the composition of different life cycle stages of BSF, i.e., larvae and pupae, were also investigated. The flours obtained from larvae of two BSF populations from Greece (GR) and Portugal (PO) (L-GR and L-PO, respectively) demonstrated similar major chemical compositions. Pupae (Pu-PO) were richer in chitin compared to larvae. Differences were spotted in their fatty acid profiles and volatile fractions. The saturated/unsaturated lipid fraction ratio was 1.5 in L-GR, higher in L-PO (2.5), and even higher in the case of Pu-PO (4.0). Seventeen (17) compounds were detected in the volatile fraction of the Pu-PO samples and 24 in the volatile fraction of the L-GR and L-PO samples. Notably, dodecanoic acid ethyl ester was the predominant volatile compound in all samples. The proteins of both larvae and pupae were dominated by β-sheet structures. The present study's findings are valuable for designing food or feed products based on BSF components and could be important for applying suitable manufacturing and processing procedures.

Canola bee pollen is an effective artificial diet additive for improving larval development of predatory coccinellids: a lesson from Harmonia axyridis.

Pollen is a common plant-derived food source for predatory ladybird beetles under field conditions, yet the potential for pollen to improve the quality of artificial diets remains largely unexplored. In this study, we developed three pollen diets by incorporating varying proportions of canola bee pollen (7.5%, 15.0% and 22.5% with 2.5%, 5.0%, and 7.5% of water, respectively) into a conventional diet. The feeding efficiency of Harmonia axyridis, an omnivorous predator, was evaluated and compared on three pollen diets, a conventional nonpollen diet and pea aphids. The larvae fed a medium or high pollen diet exhibited significantly higher survival in the 4th instar, pupa and adult stages than those fed a nonpollen diet. These larvae also developed into significantly heavier adults, and their survival rates in adulthood were comparable to those fed pea aphids. Specifically, we revealed the underlying mechanisms through which a high pollen diet enhances pupal development. Consumption of high pollen diet versus nonpollen diet resulted not only in a significant decrease in pupal glycogen content, but also an increase in adult lipid content. Both diet treatments induced similar changes in carbohydrate and glycogen content compared to the aphid diet while exhibiting different alterations in pupal protein content and adult lipid content. Furthermore, the transcriptome analysis revealed that the nutrient metabolism, immune response, and cuticle development pathways were predominantly enriched among the differentially expressed genes (DEGs). Canola bee pollen offers diverse advantages in terms of rearing H. axyridis larvae with an artificial diet, which will advance the development of effective diets for predaceous coccinellids. © 2024 Society of Chemical Industry.

Host Preference of <i>Xanthopimpla</i> Saussure Parasitising <i>Sesamia inferens</i> Walker

Host selection sequence of two parasitoids of under the genus Xanthopimpla Saussure viz., Xanthopimpla flavolineata (Xf) Cameron [Xf] and X. stemmator (Thunberg) (Xs) and suitability of various pupal stages of Sesamia inferens as a factitious host for rearing was investigated. There was no significant difference in egg laying between the single and repeated attempts by both Xf and Xs. The probing time of Xf and Xs in the rice stem with concealed host (2.26± 0.10 and 1.60± 0.13 min) and a hollow stem without a host was found to be 1.19± 0.14 and 0.59± 0.15 min, respectively. However, Xs did not parasitize the naked pupa. The number of ovipositor insertions was 1.50± 0.17 in concealed pupae and 0.92± 0.15 in hollow stem without host. Among the stages of S. inferens pupae tested for acceptance by Xf and Xs, the prepupa was preferred the most followed by one- and two-day-old pupa, while five- and six-day-old pupae were not preferred.

Simuliids from Madrid Autonomous Region (Spain): update and new contributions

Simuliidae family in Spain has been studied irregularly: some enclaves have been widely investigated by both national and foreign experts, while others have been merely mentioned or addressed indirectly for various reasons. The Madrid Region in Spain has been recurrently investigated in this respect, yet many geographical areas remain to be studied regarding Simuliidae taxonomy, geographical distribution, and ecology. In this study, a thorough sampling was conducted based on searching for preimaginal stages of larva and pupa attached or fixed to any suitable support in different lotic water systems. The latter were chosen for their favourable conditions for hosting new and valuable information. The collected material was identified based on morphological characteristics. A total of 16 species were identified. The following is an update of the simuliid fauna and its altitudinal ranges from Spain’s central geographical area, including seven new records for the Madrid Region: Prosimulium rufipes (Meigen, 1830); Simulium (Nevermannia) naturale Davies, 1966; Simulium (Nevermannia) quasidecolletum Crosskey, 1988; Simulium (Nevermannia) urbanum Davies, 1966; Simulium (Simulium) trifasciatum Curtis, 1839; Simulium (Simulium) maximum (Knoz, 1961); Simulium (Simulium) variegatum Meigen, 1818. Following the update, the species with the narrowest altitudinal distribution were: S. (N.) naturale and S. (N.) urbanum: 1843-1844 meters (m), while Simulium (Nevermannia) cryophilum (Rubtsov, 1959) and Simulium (Simulium) intermedium Roubaud, 1906 presented the widest distribution: 870-2000 m. In this study, S. (N.) naturale and S. (N.) urbanum also displayed the narrowest altitudinal range, with 1 m, whereas S. (N.) cryophilum presented the broadest, with 603 m. The present study contributes to the knowledge of Spanish blackflies generally and from the Madrid Region in particular, providing new insights into the species composition and their altitudinal distribution. It thus lays the foundations for future works.

BmSLC7A5 is essential for silk protein synthesis and larval development in Bombyx mori.

Insects produce silk to form cocoons, nests, and webs, which are important for their survival and reproduction. However, little is known about the molecular mechanism of silk protein synthesis at the translation level. The solute carrier family7 (SLC7) genes are involved in activating the target of rapamycin complex1 (TORC1) signaling pathway and protein translation process, but the physiological roles of SLC7 genes in silk-producing insects have not been reported. Here, we found that amino acid signaling regulates silk protein synthesis and larval development via the L-type amino acid transporter1 (LAT1; also known as SLC7A5) in Bombyx mori. A total of 12 SLC7 homologs were identified in the silkworm genome, among which BmSLC7A5 was found to be a silk gland-enriched gene and may be involved in leucine transport. Bioinformatics analysis indicated that SLC7A5 displays high homology and a close phylogenetic relationship in silk-producing insects. Subsequently, we found that leucine treatment significantly increased silk protein synthesis by improving the transcription and protein levels of silk genes. Furthermore, systemic and silk gland-specific knockout of BmSLC7A5 led to decreased silk protein synthesis by inhibiting TORC1 signaling, and somatic mutation also resulted in arrested development from the 5th instar to the early pupal stage. Altogether, our study reveals that BmSLC7A5 is involved in regulating silk protein synthesis and larval development by affecting the TORC1 signaling pathway, which provides a new strategy and target for improving silk yield.

Distinct developmental patterns in Anopheles stephensi organ systems

Anatomical profiles of insects inform vector biology, comparative development and evolutionary studies with applications in forensics, agriculture and disease control. This study presents a comprehensive, high-resolution developmental profile of Anopheles stephensi, encompassing larval, pupal, and adult stages, obtained through microCT scanning. The results indicate in situ anatomical changes in most organ systems, including the central nervous system, eyes, musculature, alimentary canal, salivary glands, and ovaries, among other organ systems, except for the developing heart. We find significant differences in the mosquito gut, body-wall, and flight muscle development during metamorphosis from other dipterans like Drosophila. Specifically, indirect flight muscle specification and growth can be traced back at least to the 4th instar A. stephensi larvae, as opposed to post-puparial development in other Dipterans like Drosophila and Calliphora. Further, while Drosophila larval body-wall muscles and gut undergo histolysis, changes to these organs during mosquito metamorphosis are less pronounced. These observations, and raw data therein may serve as a reference for studies on the development and the genetics of mosquitoes. Overall, the detailed developmental profile of A. stephensi presented here illuminates the unique anatomy and developmental processes of Culicidae, with important implications for vector biology, disease control, and comparative evolutionary studies.

Metarhizium spp. isolates effective against Queensland fruit fly juvenile life stages in soil.

Queensland fruit fly, Bactrocera tryoni, Froggatt (Diptera: Tephritidae) is Australia's primary fruit fly pest species. Integrated Pest Management (IPM) has been adopted to sustainably manage this polyphagous species with a reduced reliance on chemical pesticides. At present, control measures are aimed at the adult stages of the fly, with no IPM tools available to target larvae once they exit the fruit and pupate in the soil. The use of entomopathogenic fungi may provide a biologically-based control method for these soil-dwelling life stages. The effectiveness of fungal isolates of Metarhizium and Beauveria species were screened under laboratory conditions against Queensland fruit fly. In bioassays, 16 isolates were screened for pathogenicity following exposure of third-instar larvae to inoculum-treated vermiculite used as a pupation substrate. The best performing Metarhizium sp. isolate achieved an average percentage mortality of 93%, whereas the best performing Beauveria isolate was less efficient, with an average mortality of 36%. Susceptibility to infection during different development stages was investigated using selected fungal isolates, with the aim of assessing all soil-dwelling life stages from third-instar larvae to final pupal stages and emerging adults. Overall, the third larval instar was the most susceptible stage, with average mortalities between 51-98% depending on the isolate tested. Moreover, adult mortality was significantly higher when exposed to inoculum during pupal eclosion, with mortalities between 56-76% observed within the first nine days post-emergence. The effect of temperature and inoculum concentration on insect mortality were assessed independently with candidate isolates to determine the optimum temperature range for fungal biological control activity and the rate required for application in field conditions. Metarhizium spp. are highly efficacious at killing Queensland fruit fly and have potential for use as biopesticides to target soil-dwelling and other life stages of B. tryoni.

Systemic pesticides in a solitary bee pollen food store affect larval development and increase pupal mortality

Solitary bees are often exposed to various pesticides applied for pest control on farmland while providing pollination services to food crops. Increasing evidence suggests that sublethal toxicity of agricultural pesticides affects solitary bees differently than the social bees used to determine regulatory thresholds, such as honey bees and bumblebees. Studies on solitary bees are challenging because of the difficulties in obtaining large numbers of eggs or young larvae for bioassays. Here we show the toxic and sublethal developmental effects of four widely used plant systemic pesticides on the Japanese orchard bee (Osmia cornifrons). Pollen food stores of this solitary bee were treated with different concentrations of three insecticides (acetamiprid, flonicamid, and sulfoxaflor) and a fungicide (dodine). Eggs were transplanted to the treated pollen and larvae were allowed to feed on the pollen stores after egg hatch. The effects of chronic ingestion of contaminated pollen were measured until adult eclosion. This year-long study revealed that chronic exposure to all tested pesticides delayed larval development and lowered larval and adult body weights. Additionally, exposure to the systemic fungicide resulted in abnormal larval defecation and increased mortality at the pupal stage, indicating potential risk to bees from fungicide exposure. These findings demonstrate potential threats to solitary bees from systemic insecticides and fungicides and will help in making policy decisions to mitigate these effects.

Identification of insect cuticular protein genes LCP17 and SgAbd5 from Helicoverpa armigera and evaluation their roles in fenvalerate resistance

Insect cuticular protein (ICP) plays an important role in insect growth and development. However, research on the role of ICP in insecticide resistance is very limited. In this study, insect cuticular protein genes LCP17 and SgAbd5 were cloned and characterized in Helicoverpa armigera based on previous transcriptome data. The functions of LCP17 and SgAbd5 genes in fenvalerate resistance were assessed by RNA interference (RNAi), and their response to fenvalerate was further detected. The results showed that LCP17 and SgAbd5 were overexpressed in the fenvalerate-resistant strain comparing with a susceptible strain. The open reading frames of LCP17 and SgAbd5 genes were 423 bp and 369 bp, encoding 141 and 123 amino acids, respectively. LCP17 and SgAbd5 genes were highly expressed in the larval stage, but less expressed in the adult and pupal stages. The expression level of LCP17 and SgAbd5 genes increased significantly after fenvalerate treatment at 24 h. When the cotton bollworms larvae were exposed to fenvalerate at LD50 level, RNAi-mediated silencing of LCP17 and SgAbd5 genes increased the mortality from 50.68% to 68.67% and 63.89%, respectively; the mortality increased to even higher level, which was 73.61%, when these two genes were co-silenced. Moreover, silencing of these two genes caused the cuticle lamellar structure to become loose, which led to increased penetration of fenvalerate into the larvae. The results suggested that LCP17 and SgAbd5 may be involved in the resistance of cotton bollworm to fenvalerate, and LCP17 and SgAbd5 could serve as potential targets for H. armigera control.

Responses of two Anastrepha species' immature stages infesting preferential hosts to different temperature exposures.

Anastrepha fraterculus (Wiedemann) and A. obliqua (Macquart) are important pests of fruit crops. In Brazil, these species cause damage to fruit growing in the South (annual average temperature of 20.9°C) and Northeast (average yearly temperature of 24°C). We evaluated the effect of temperature on the viability and development time of A. fraterculus and A. obliqua immature stages in their respective preferred hosts, guava (Psidium guajava L., Myrtaceae) and mango (Mangifera indica L., Anacardiaceae). The duration of egg and pupal stages, egg to pre-pupa, and viability of egg and pupal stages under different temperatures (15, 20, 25, 30, and 35°C) were assessed. For both species, development time decreased with increasing temperature. Viability in the evaluated stages was only observed between 15 and 30°C. However, the species responded differently to the exposure temperatures (15 and 30°C), especially in the pupal stage and from egg to pre-pupa. Anastrepha fraterculus showed a lower tolerance to high temperatures, especially in the pupal stage and from egg to pre-pupa, which may explain its lower importance and economic impact in warmer Brazilian regions. Anastrepha obliqua had a lower tolerance at 15°C, indicating greater adequacy for temperatures above 20°C, characteristic of Northeast Brazil, suggesting the capacity to spread to cooler areas with rising temperatures.

Deliquescence‐induced release of ethyl formate and chlorine dioxide from their precursors‐loaded sachets for in‐package fumigation of spotted wing drosophila (Drosophila suzukii Matsumura)

AbstractThe toxicity and environmental concerns of methyl bromide (MB) have been a significant impetus for research into environmentally benign fumigant alternatives. Ethyl formate (EF) and chlorine dioxide (ClO2) are FDA‐approved agents with potential as alternatives to MB. However, both are chemically unstable and pose considerable end‐use challenges. In this study, we developed moisture‐activated sachets for EF and ClO2 to facilitate their end‐use deployment for in‐package fumigation. The sachets were loaded with EF or ClO2 metastable precursors, citric acid (CA), and a deliquescent salt carrier (e.g., CaCl2 or NaCl). When placed in an elevated relative humidity environment, these combinations activate the release of EF or ClO2 gases, separately. The deliquescence lowering phenomenon and its effect on fumigants release rate were investigated when mixing CA with CaCl2 or NaCl. The mutual deliquescence relative humidity for CA–CaCl2 and CA–NaCl mixtures were 40% and 63%, respectively. CaCl2 enhanced the release rate of fumigants from their sachets, whereas NaCl resulted in a slower release rate. EF and ClO2 sachets were evaluated for fumigation of different life stages of spotted wing drosophila (SWD). Complete control of SWD adults was achieved after exposure to 10.1 mg·h/L EF, while eggs, larval, and pupal stages were more tolerant toward EF vapour and required 110.2 mg·h/L EF to achieve control. ClO2 at low concentrations was more effective than EF against all SWD life stages, excluding pupae. Complete mortality was achieved after fumigating SWD adults, eggs, and larvae with 0.73, 2.39, and 1.21 mg·h/L ClO2, respectively. These results indicated that both EF and ClO2 sachets could be employed safely for EF and ClO2 in‐packaging fumigation to control produce pests.

The Pupa Stage Is the Most Sensitive to Hypoxia in Drosophila melanogaster.

Hypoxia not only plays a critical role in multiple disease conditions; it also influences the growth and development of cells, tissues and organs. To identify novel hypoxia-related mechanisms involved in cell and tissue growth, studying a precise hypoxia-sensitive time window can be an effective approach. Drosophila melanogaster has been a useful model organism for studying a variety of conditions, and we focused in this study on the life cycle stages of Drosophila to investigate their hypoxia sensitivity. When normoxia-grown flies were treated with 4% O2 at the pupa stage for 3, 2 and 1 day/s, the eclosion rates were 6.1%, 66.7% and 96.4%, respectively, and, when 4% O2 was kept for the whole pupa stage, this regimen was lethal. Surprisingly, when our hypoxia-adapted flies who normally live in 4% O2 were treated with 4% O2 at the pupa stage, no fly eclosed. Within the pupa stage, the pupae at 2 and 3 days after pupae formation (APF), when treated for 2 days, demonstrated 12.5 ± 8.5% and 23.6 ± 1.6% eclosion, respectively, but this was completely lethal when treated for 3 days. We conclude that pupae, at 2 days APF and for a duration of a minimum of 2 days, were the most sensitive to hypoxia. Our data from our hypoxia-adapted flies clearly indicate that epigenetic factors play a critical role in pupa-stage hypoxia sensitivity.

Analysis of Genes Associated with Feeding Preference and Detoxification in Various Developmental Stages of Aglais urticae.

Herbivorous insects and host plants have developed a close and complex relationship over a long period of co-evolution. Some plants provide nutrients for insects, but plants' secondary metabolites also influence their growth and development. Urtica cannabina roots and leaves are poisonous, yet Aglais urticae larvae feed on them, so we aimed to clarify the mechanism enabling this interaction. At present, studies on the detoxification mechanism of the A. urticae are rare. In our study, first, we used the A. urticae larval odor selection behavior bioassay and choice feeding preference assay to analyze the feeding preferences of A. urticae on its host plant, U. cannabina. Next, we used transcriptome sequencing to obtain the unigenes annotated and classified by various databases, such as KEGG and GO. In this study, we found that U. cannabina could attract A. urticae larvae to feed via scent, and the feeding preference assay confirmed that larvae preferred U. cannabina leaves over three other plants: Cirsium japonicum, Cannabis sativa, and Arctium lappa. The activity of detoxifying enzymes GST and CarE changed in larvae that had consumed U. cannabina. Furthermore, through transcriptomic sequencing analysis, 77,624 unigenes were assembled from raw reads. The numbers of differentially expressed genes were calculated using pairwise comparisons of all life stages; the expression of detoxification enzyme genes was substantially higher in larvae than in the pupal and adult stages. Finally, we identified and summarized 34 genes associated with detoxification enzymes, such as UDP-glucose 4-epimerase gene, 5 Glutathione S-transferase genes, 4 Carboxylesterase genes, 4 Cytochrome P450 genes, 10 ATP-binding cassette genes, 4 Superoxide dismutase, and Peroxidase. Moreover, we identified 28 genes associated with the development of A. urticae. The qRT-PCR results were nearly consistent with the transcriptomic data, showing an increased expression level of four genes in larvae. Taken together, this study examines the correlation between A. urticae and host plants U. cannabina, uncovering a pronounced preference for A. urticae larvae toward host plants. Consistent with RNA-seq, we investigated the mechanism of A. urticae's interaction with host plants and identified detoxification-related genes. The present study provides theoretical support for studying insect adaptation mechanisms and biological control.

Ecdysone receptor strongly influences larval–pupal–adult transition and melanization in Tuta absoluta

Abstract Background Tomato leaf miner (Tuta absoluta) is a quarantined pest that damages Solanaceae crops worldwide. The overuse of traditional pesticides negatively affects both human health and the environment. RNA interference (RNAi), based on double-stranded RNA (dsRNA) induction, can be beneficial in the control of Tuta absoluta; one of the key points of using this technique is the selection of target genes. Exploring the ecdysone receptors (EcR) associated with the growth and development of tomato leaf miners is an important research topic and the primary aim of this study. Methods In this study, RNA extraction, cDNA synthesis, gene cloning, bioinformatics analysis, and quantitative real-time polymerase chain reaction were used to obtain the full length, conserved domain, and relative expression levels of the EcR. RNAi was used to explore the effects of EcR on larval growth and development, pupal weight, and emergence rate. Results The full-length cDNA of T. absoluta TaEcR was 1859 bp, and the coding region including the ZnF_C4 and HOLI domains was relatively conserved. The relative expression of EcR in the early pupal stage was substantially higher than that in the other instars. Approximately 70% of TaEcR RNAi larvae died or pupated abnormally. In the few successful pupations, the pupa weights were substantially lower (36.44%) than those of the control group. The color of the pupae was abnormal, and they did not enter their normal black state; the emergence rate of pupae was reduced by 43.45% compared to that of the control group. Conclusion These results indicate that TaEcR inhibition can affect larval metamorphosis, pupation, melanism, eclosion abnormalities, and, ultimately, lead to death. The results of this study suggest that TaEcR may be a candidate factor for developing environmentally-friendly RNAi pesticides that have practical value in field control.

Patterned apoptosis has an instructive role for local growth and tissue shape regulation in a fast-growing epithelium

What regulates organ size and shape remains one fundamental mystery of modern biology. Research in this area has primarily focused on deciphering the regulation in time and space of growth and cell division, while the contribution of cell death has been overall neglected. This includes studies of the Drosophila wing, one of the best-characterized systems for the study of growth and patterning, undergoing massive growth during larval stage and important morphogenetic remodeling during pupal stage. So far, it has been assumed that cell death was relatively neglectable in this tissue both during larval stage and pupal stage, and as a result, the pattern of growth was usually attributed to the distribution of cell division. Here, using systematic mapping and registration combined with quantitative assessment of clone size and disappearance as well as live imaging, we outline a persistent pattern of cell death and clone elimination emerging in the larval wing disc and persisting during pupal wing morphogenesis. Local variation of cell death is associated with local variation of clone size, pointing to an impact of cell death on local growth that is not fully compensated by proliferation. Using morphometric analyses of adult wing shape and genetic perturbations, we provide evidence that patterned death locally and globally affects adult wing shape and size. This study describes a roadmap for precise assessment of the contribution of cell death to tissue shape and outlines an important instructive role of cell death in modulating quantitatively local growth and morphogenesis of a fast-growing tissue.

Evaluation of Insect Growth Regulators (IGRs) as biological pesticides for control of Aedes aegypti mosquitoes

Background & objectives: Insect growth regulators (IGRs) are biological hormone analogue or mimics used as pesticides to inhibit the growth of larva during their molting and skin shedding. This study aimed to test the effect of IGRs on the eggs hatching and post-hatching inhibition of Aedes mosquitoes and understanding its effect in the mosquito breeding habitats for reduction in adult emergence. Methods: Experiments on the evaluation of three insect growth regulators (IGRs) for the control of different stages of Aedes aegypti was carried out during 2020-21. Each experiment consisted of four treatments viz., Pyriproxyfen, Novaluron, and Larvicol at 1.0 ppm and distilled water as a control. All experiments were carried out in completely randomized design (CRD) except eggs which were carried out in factorial design each with three replications. Results: All tested IGRs performed better in affecting eggs, larval and pupal stages of Ae. aegypti. Highest eggs hatching inhibition (80%) of fresh eggs occurred in Pyriproxyfen followed by Novaluron (66%) and lowest in Larvicol (62%). Eggs hatch inhibition of embryonated eggs was lower than fresh eggs. Pyriproxyfen caused 69%, Novaluron 59% and Larvicol 39% eggs hatch inhibition of embryonated eggs. Both Pyriproxyfen and Novaluron performed better in causing 98–100% larval mortality followed by Larvicol (39%). Larval development to pupal stage was completely prevented by both Pyriproxyfen and Novaluron. Although Larvicol resulted in lowest eggs hatch and larval inhibition but prevented pupae to emerge as adults. Results further showed 70–89% mortality of 3rd instar larvae of Ae. aegypti when exposed to Pyriproxyfen and Novaluron solutions after 30 days storage at lab. temperature (27±2°C), RH 70±5. Interpretation & conclusion: None of the IGRs was more effective at the pupal stage but showed carry-on activity of growth inhibition and mortality of the successive stages of development when used against eggs stages. Therefore, we recommend early application of IGRs at mosquito habitats during the beginning and onset of the season when very early stages of mosquitoes are available in the field.

Cell wall epitope distribution in the functional compartments of galls induced by Palaeomystella oligophaga (Lepidoptera) in Macairea radula (Melastomataceae)

Context The parasitic interaction between the galling insect Palaeomystella oligophaga (Lepidoptera) and the host plant tissues of Macairea radula (Melastomataceae) leads to the formation of globoid galls. These galls have storage and typical nutritive tissues (outer and inner compartments, respectively), whose functions may be related to differential cell wall component distributions and to the stage of development of the gall inducer. Aims We evaluated whether the cell wall composition of the gall compartments (storage and nutritive tissues) changes according to the developmental stage of the gall inducer P. oligophaga. Methods The galls occupied by the gall inducer in different stages of development (i.e. larval and pupal stages, as well as empty galls) were collected and submitted to histological examination, immunocytochemical analyses using monoclonal antibodies for pectins, hemicelluloses, and glycoproteins, and histochemical analyses using phloroglucinol for lignins. Key results The histological results showed that nutritive tissues have smaller cells compared with storage ones when the galling insect is in the larval stage. Immunocytochemical analyses also showed the occurrence of both methyl-esterified and unesterified pectins, as well hemicelluloses in the nutritive tissue during the larval stage. The dynamic of some cell wall components changes when the gall inducer is in the pupal stage, or the galls are empty. Conclusions The changes in the composition of the cell walls, especially regarding homogalacturonans and xyloglucans, support the high metabolism and resource availability in cell walls of nutritive tissue for the gall inducer. Implications The cell wall composition may indicate important metabolic steps during gall formation and galling insect diet.

Development, survival and description of the life stages of Zatrephina lineata (Coleoptera: Chrysomelidae) fed on Ipomoea pes-caprae leaves.

Zatrephina lineata (Coleoptera: Chrysomelidae) is a phytophagous insect, mainly of plants of the genera Ipomoea and Mikania. The objective was to study the development, survival and to describe the life stages of Z. lineata fed on leaves of Ipomoea pes-caprae. Biological observations were made daily with the aid of a stereoscopic microscope and the instars of this insect identified by the exuvia left between one moulting and the next. The duration of development and survival of the egg, larva and pupa stages and the first, second, third, fourth and fifth instars and of the nymph stage of Z. lineata differed, but not between sexes of this insect. The duration of development of Z. lineata was longer in the larval stage and in the fifth instar, and its survival greater in the egg and pupa stages and in the first and fifth instars. Zatrephina lineata eggs, cream-colored, are ellipsoid and deposited in groups on the adaxial surface of older I. pes-caprae leaves. The larvae of this insect go through five instars, with the first three being gregarious with chemo-behavioral defenses. The exarated pupae of Z. lineata, light yellow in color and with an oval shape flattened dorsoventrally, attach to the abaxial surface of the I. pes-caprae leaves. The shape of adults of this insect is oval, straw yellow in color with lighter longitudinal stripes and females are slightly larger than males.

Caracterização da Antixenose e antibiose em cultivares de soja a Anticarsia gemmatalis (Lepidoptera: Erebidae)

ABSTRACT: Anticarsia gemmatalis (Lepidoptera: Erebidae) is distributed in tropical and subtropical regions of America, and is an important pest of Fabaceae, such as: soybean, peanut, common bean, cowpea, pea, chickpea and kudzu. In soybean, the velvet bean caterpillar is important due to the plant defoliation in their larval stage. This study evaluated soybean cultivars as source of resistance to A. gemmatalis by antixenosis (attractiveness and non-preference for feeding) and antibiosis (biological parameters of the insect). The parameters evaluated were: antixenosis: attractiveness and non-preference, dry mass consumed and attractiveness index and antibiosis: duration of larval and pupal stages, adult longevity, total cycle, larval and pupal weights and larval, pupal and total viability. Considering antixenosis and antibiosis the least suitable cultivars for A. gemmatalis were found to be BRS 8383 IPRO, BRS 1074 IPRO, BRS 1061 IPRO, BRS 7180 IPRO, BRS 9383 IPRO, BRS 8980 IPRO and BRS 1003 IPRO due to high mortality in the larval phase. The cultivars BRS 523 and BRS 543 RR “block technology” suggest displays antixenosis and or antibiosis to A. gemmatalis. These cultivars can be used by soybean producers in combination with other control tactics in soybean IPM.

Hormonal control of <i>fruitless</i> expression and male sexual orientation in <i>Drosophila</i>

<p>Sex determination genes control the differentiation of gonads that synthesize and secret sex hormones to remotely control sexual development and behaviors in mammals. In contrast, sex determination genes in insects directly control sexual development and behaviors in a cell-autonomous way, which is largely independent of hormones. In this study, we find that two important hormones, juvenile hormone (JH) and 20-hydroxyecdysone (20E), oppositely regulate the dynamic expression of Fru<sup>M</sup>, the male-specific product of the sex determination gene <i>fruitless</i> in <i>Drosophila</i>. 20E signaling is essential to the high-level expression of Fru<sup>M</sup> proteins in the pupal stage, while JH suppresses larval Fru<sup>M</sup> expression through inhibiting 20E signaling. We further show that 20E signaling regulates both the development and physiological function of the male-specific P1 neurons to mediate sexual orientation in male flies. Our results demonstrate both conserved and diversified functions of hormones in sexual development and behaviors in flies and mice.</p>