Instar Larvae Research Articles

Outstretched wing is controlled by intestinal enteroblasts-derived unpaired 2 cytokine signaling in Drosophila.

The outstretched wing phenotype in Drosophila melanogaster can be induced by various genetic mutations and environmental perturbations, yet the role of gut-derived signals in coordinating wing development remains largely unexplored. In this study, we demonstrate that Upd2, secreted from the gut to the wing discs, plays a crucial role in regulating the outstretched wing phenotype. The intestinal precursor cell driver esg-Gal4 exhibits low levels of leaky expression, even in the presence of Gal80ts at room temperature (25°C). This leaky expression of TDP-43, Notch, and Yki in intestinal precursor cells leads to a held-out wing phenotype, shortened lifespan, and impaired locomotor function. Although esg-Gal4 is expressed in imaginal discs, overexpression of TDP-43, Notch, or Yki using the wing-specific driver does not result in the outstretched wing. Furthermore, our data indicate that genetic alterations associated with the spread-out wing phenotype originate in enteroblasts (EBs) during early development. RNA sequencing analysis with guts from third instar larvae revealed that the JAK-STAT pathway ligand Upd2 is among the most significantly downregulated transcripts. Notably, ectopic expression of Upd2 in EBs partially rescued the abnormal held-out wing phenotype induced by TDP-43, Notch, and Yki overexpression. Together, our findings identify gut-derived Upd2 cytokine signaling as a key mediator of the outstretched wing phenotype, providing evidence for gut-to-wing communication axis during Drosophila development.

Active Components of 16 Essential Oils and Their Fumigation Effects on Galleria mellonella (Lepidoptera: Pyralidae)

The greater wax moth (GWM, Galleria mellonella) is a prevalent pest of the honeybee and a significant risk to both honeybee populations and honeycomb storage. Research on the toxicity of essential oils (EOs) to GWM larvae has provided promising results, although their ovicidal effects and active ingredients require further study. Identifying effective plant compounds is essential for developing insecticides for GWM control. This study assessed the fumigation efficacy of 16 EOs on GWM eggs and fifth instar larvae and determined the effectiveness of these EOs and their primary components for fumigating fifth larvae. Wintergreen, star anise, and clove oils demonstrated significant insecticidal effects on GWM eggs and fifth instar larvae, resulting in a mortality rate exceeding 80% within 48 h. Gas chromatography-mass spectrometry analysis identified methyl salicylate (93.26%), trans-anethole (87.75%), and eugenol (77.75%) as the primary compounds in wintergreen, star anise, and clove oils, respectively. Further toxicity testing confirmed that these compounds were responsible for the observed insecticidal properties of the EOs. Notably, trans-anethole exhibited the lowest LC50 value (25.22 μL/L) against the fifth instar larvae of GWM and significant toxicity against GWM eggs and fifth instar larvae, suggesting its potential as a viable option for the future control of GWM populations.

Cost-effectiveness of remote sensing technology for spruce budworm monitoring in Maine, USA

Forest pests are a major disturbance factor in forest ecosystems, which can result in tree mortality and loss of ecosystem services, leading to further negative impacts on the forest economy. Spruce budworm (Choristoneura fumiferana (Clem.); SBW) is a native forest pest in the northeastern USA and Canada, including the state of Maine, which defoliates balsam fir (Abies balsamea (L.) Mill.) and spruce (Picea spp.) trees with cyclical outbreaks every 30-60 years. SBW is typically monitored via ground sampling techniques such as pheromone traps and overwintering second instar larvae (L2) branch sampling. Remote sensing data can also provide information about defoliation patterns across the landscape and forest susceptibility to outbreaks. This study presents a cost-effectiveness analysis comparing remote sensing data, ground sampling techniques, and an integrated monitoring approach, combining remote sensing change detection with field sampling. Over a 10-year project period, Sentinel-2 imagery emerged as the most cost-effective option, ranging from US$33 to US$63/square kilometer (sq km), offering wide spatial coverage and moderate resolution suitable for the identification of defoliation patterns. PlanetScope imagery ranged from US$77 to US$241/sq km, and unmanned aerial vehicle (UAV) imagery had the greatest variation, from US$9,220 to US$58,481/sq km. Labor costs are the most influential in our study, ranging from 30% of total costs for remote sensing approaches to 80% for field sampling. The integrated monitoring approach proposed in this study presents a synergistic strategy for effective and timely SBW monitoring, ranging from US$144 to US$213/sq km. Utilizing this integrated approach leverages both remote sensing and L2 branch surveys to enhance the accuracy and timeliness of monitoring efforts, leading to more effective management strategies for mitigating pest outbreaks for landowners. Our research highlights the importance of adaptive monitoring strategies and integrating remote sensing for forest pest detection.

Detection of Probiotic Bacteria Ligilactobacillus salivarius in the Midgut of Eri Silkworm (Samia ricini, donovan) Collected from Borduar, Assam

Background: Eri silkworm rearing, crucial to Assam’s economy, faces severe productivity threats from disease and crop loss. These challenges impact farmers’ livelihoods, highlighting the urgent need for innovative solutions to boost disease resistance and crop yield, ensuring the industry’s sustainability and profitability. Methods: The study investigated the detection of Lactobacillus species in the midgut of the Eri silkworm (Samia ricini, Donovan) collected from Borduar, Assam. The research involved identifying Ligilactobacillus salivarius in the midgut of 5th instar larvae of the Borduar ecorace of Eri silkworm. The larvae, reared separately on castor and kesseru host plants, were utilized for isolating Lactobacillus on MRS agar. Molecular identification of these isolates was achieved through 16S rRNA sequence analysis. Result: Ligilactobacillus salivarius, a species under the genus Lactobacillus, was identified for the first time in the midgut of Eri silkworm larvae. This bacterium is widely known as a potential probiotic in higher animals, particularly poultry, indicating its possible benefits for silkworm health. The discovery of Ligilactobacillus salivarius in silkworms paves the way for further research aimed at developing novel probiotics tailored specifically for the sericulture industry, potentially improving silkworm health and boosting productivity. Implementing these probiotics presents a promising solution to the challenges facing sericulture in Assam, offering enhanced disease resistance and crop yield.

Effect of photoperiod and 20-hydroxyecdysone on post-embryonic development and diapause disruption in Cirina butyrospermi Vuillet (Lepidoptera: Saturniidae) under laboratory conditions

Abstract Cirina butyrospermi (Lepidoptera: Saturniidae), commonly known as the shea caterpillar, is an edible insect in several West African countries. However, this insect is seasonal due to a long pupal diapause. This study therefore aims to explore the potential for mass rearing of C. butyrospermi by determining the role of photoperiod and 20-hydroxyecdysone in disrupting or shortening diapause. Exposure of larval growth to different photoperiod conditions, i.e. L.D. 6:18, L.D. 8:16, L.D. 10:14 and L.D. 12:12, affected larval weight and adult emergence. With respect to the photoperiod treatments applied to larval growth from neonate to fourth instar, caterpillars reared under L.D. 6:18 conditions weighed more than those reared under the other photoperiods. However, photoperiod treatments did not significantly affect the pupation rate. Adult emergence was only observed under L.D. 6:18 photoperiod conditions for a diapause average duration of 140.85 days. The recorded emergence percentage was 38.46 ± 1.33%, and emergences occurred over a period of ten days. When the L.D. 6:18 photoperiod conditions were applied only on the fourth instar larvae, 24.39 ± 1.41% of pupae developed to adults in 34.50 days on average and emergences were grouped in 4 days. Injections of increasing doses of 20-hydroxyecdysone into diapausing pupae resulted in diapause breaking within 23-28 days in 7-47% of treated pupae, depending on the dose of 20-hydroxyecdysone and the pupal weight. Conversely, diapause remained in non-treated pupae during the study period. Short photoperiod and 20-hydroxyecdysone are key drivers for diapause termination in C. butyrospermi. The possible interaction between 20E doses and treated pupae weight provides new insights into the hormone’s efficacy in breaking pupal diapause in C. butyrospermi. While the results need further clarification, they represent a significant step towards mass breeding of this important food insect.

Effect of Azadirachta indica Leaf Extract on the Toxicity Induced by Ethyl Methanesulphonate (EMS) in the Third Instar Larvae of Transgenic Dro-sophila melanogaster (hsp70-lacZ) Bg9

Background: Neem, known for its medicinal benefits, such as anti-inflammatory, antioxidant, and anti-cancer properties, can serve as a complementary or al-ternative treatment. Research has also indicated that neem extracts lessen the harmful ef-fects of the chemotherapy drug cisplatin on healthy cells while still preserving its ability to target cancer cells effectively. Different parts of the Neem tree, such as leaves, bark, fruit, flowers, oil, and gum, have been traditionally used in herbal medicine for treating various health conditions, including cancer, hypertension, heart disease, and diabetes. Objective: The effect of neem extract was studied on the Ethyl methanesulphonate (EMS) (an anti-cancerous drug)-induced toxicity in the third instar larvae of transgenic Drosophi-la melanogaster (hsp70-lacZ) Bg9. Methods: The third instar larvae were exposed to 25 μM of EMS alone and along with 4×10-3g/ml, 8×10-3g/ml, 12×10-3g/ml, and 16×10-3g/ml of neem extract (NE) mixed in diet for 24 hrs. Results: A significant increase in toxicity was observed in the larvae exposed to 25 μM of EMS. A dose-dependent significant decrease in the toxic effects was observed in the lar-vae exposed to various doses of neem extract. The GCMS analysis of the neem extract showed the presence of Phytol and α-tocopherol as major compounds. Conclusion: The reduction in the toxicity induced by EMS is mainly attributed to phytol and α-tocopherol. conclusion: The reduction in the toxicity induced by EMS is mainly attributed to phytol and α-tocopherol.

Do more food choices lead to bad decisions? A case study in predaceous ladybird beetle, Propylea dissecta.

Understanding why animals choose one food over another is one of the key questions underlying the fields of behaviour ecology. This study aims to test if ladybird beetle, Propylea dissecta Mulsant (Coleoptera: Coccinellidae) can forage selectively for nutrients in order to redress specific nutritional imbalances to maximise their fitness. We hypothesised that the presence of more food choices leads to bad decisions in terms of their food selection which ultimately negatively affects the mating and reproductive parameters of P. dissecta. To test this, we first manipulated the predator's nutritional status by rearing them in five separate dietary groups from first instar larvae to newly emerged adult stage. Thereafter, we tested their food choice between five different foods, i.e. Aphis craccivora Koch, Aphis nerii Boyer de Fonsclombe, conspecific eggs, heterospecific eggs and mixed pollen grains, equidistantly placed in a Petri dish. Based on the food choice of the newly emerged adults, they were reared on the chosen diet for 10 days. Thereafter, adults were paired with their opposite sex (collected from stock culture reared on A. craccivora) and mating and reproductive parameters were recorded. Our results suggested that the variety of food did not affect the food choice of ladybird beetle, P. dissecta. They tend to choose their natural diet, i.e. aphid in each dietary regime. We found that previous dietary regime, i.e. larval dietary regime, significantly influences the mating and reproductive parameters of both the male and female except for the time to commence mating by the male. Food choices of adult beetles were found to significantly influence the time to commence mating, average fecundity and per cent egg viability in males and only mating duration in females. Our findings suggest that P. dissecta consistently made optimal decisions when facing various food choices. They consistently preferred their natural and preferred food choice over others, indicating a strong food selection behaviour.

Effects of low temperature stress on cold-resistant substances and gene expression in Spodoptera frugiperda (Lepidoptera: Noctuidae)

The fall armyworm Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) is a major agricultural pest. Low temperature is an important factor that limits S. frugiperda survival and reproduction. The physiological cold tolerance indexes of S. frugiperda larvae from October 2022 to February 2023 were investigated. The results showed that the cold-resistant substances in S. frugiperda differed significantly among different months. The water content was the lowest in January. Lipids were the highest in December and January, trehalose and protein contents were the highest in December, and glycerol content was the highest in January. The contents of lipid, protein, trehalose, and glycerol were the highest in the 6th instar larvae, whereas the water content did not differ among the larva stages. The functions of two genes, including endothelial lipase (Eol1) and gastric lipase (Epl1) that were extracted from the transcriptome analysis of S. frugiperda in the cold resistance were assessed. After 24 h of cold stress, the mRNA levels of Eol1 and Epl1 RNA interference were significantly down-regulated by 60.76% and 82.53%, and the survival rate of S. frugiperda larvae decreased. Additionally, Eol1 and Epl1 silencing significantly decreased the lipid content and pupal weight of S. frugiperda. The results indicate that S. frugiperda larvae can change the contents in winter to response the cold conditions and the lipids plays an important role in the cold resistance of S. frugiperda.

Function of PxGrp78 in the Reproduction of Plutella xylostella.

Glucose-regulated protein 78 (Grp78), a crucial molecular chaperone in the endoplasmic reticulum, has been extensively investigated in vertebrates. However, its functional exploration in insects remains limited. This study cloned the full-length cDNA sequence of Grp78 in Plutella xylostella (L.), which is 2583 bp long. The open reading frame (ORF) is 2004 bp in length and encodes a total of 667 amino acids, including three conserved characteristic sequences of the HSP70 family. PxGrp78 is expressed in various developmental stages of P. xylostella, with the highest expression observed in third instar larvae and higher expression in female adults compared to male adults. The interference with PxGrp78 in female adults was found to significantly reduce the quantity of egg laying and the hatching rate, as well as shorten the oviposition period and down-regulate the expression of the PxVg gene. These results suggested an important role for PxGrp78 in the reproduction of P. xylostella.

Exploring the ameliorative potential of rutin against High-Sucrose Diet-induced oxidative stress and reproductive toxicity in Drosophila melanogaster

Sucrose is a vital ingredient in numerous food items consumed regularly. However, exposure to excessive sucrose for a prolonged period can promote health issues. The reproductive system has a delicate physiology that can be targeted by various chemical stressors, including sucrose. Hence, the present in vivo study aims to unveil the impacts of the High-Sucrose Diet (HSD) on the reproductive fitness of Drosophila melanogaster. In addition, the present work has also assessed the protective potential of a bioactive compound, rutin, against it. Here, 1st instar larvae were exposed to HSD (30%) alone and in combination with rutin (100-300µM) till their adult stage. HSD disturbed sex comb morphology in adult males, while fecundity and hatchability of eggs in females. Moreover, HSD triggered gonadal ROS production, oxidative stress, and modulated endogenous antioxidants such as SOD, catalase, and glutathione in both sexes. Nuclear fragmentation and tissue injuries, along with protein and lipid oxidation, were also apparent. Elevated levels of cytosolic Iron suggested an active Fenton reaction in adults. Further, HSD modulated the activities of reproductive and metabolic mediators, including vitellogenin, malate dehydrogenase, glucose-6-phosphate dehydrogenase, and angiotensin-converting enzymes that are critical to overall reproductive fitness. Interestingly, co-treatment with rutin, mainly at 200µM, mitigated these adverse effects and restored reproductive fitness. The protective potential of rutin might be attributed to its ability to normalize redox homeostasis, reduce oxidative stress, and optimize critical enzymes involved in reproductive physiology. These findings suggest that rutin has potential therapeutic implications to counteract the reproductive hazards induced by HSD.

Density-dependent fitness and mass-rearing of Habrobracon hebetor (Say) (Hymenoptera: Braconidae) incorporating life table variability

The ectoparasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae) is an important natural enemy insect deployed for controlling lepidopteran larvae in warehouses and fields. However, there is limited information on mass-rearing methods of H. hebetor. This study investigated the effects of different Ephestia elutella (Hübner) (Lepidoptera: Pyralidae) and parasitic egg densities on the fitness and mass-rearing efficiency of H. hebetor, aiming to determine the optimal conditions for developing an economically viable and sustainable mass-rearing system for this parasitoid. Our results showed that the average number of eggs laid per host dropped below 7.54 eggs when the number of hosts exceeded five. H. hebetor exhibited significantly increased preadult survival rate (67.41%-81.00%), female and male body size (2224.55-2379.83 μm, 2213.39-2324.65 μm), fecundity (443.98-492.43 eggs), net reproductive rate (R0=154.57-216.67 offspring), intrinsic rate of increase (r=0.2776-0.3223 d-1), net paralyzed rate (C0=72.37-93.17 larvae), and net parasitism rate (Z0=43.55-55.04 larvae) at a density of 5-15 eggs per host than at 20 eggs per host. Meanwhile, considering rearing costs and production rate, a density of 5-15 eggs per host proved to be the most economical for mass-rearing H. hebetor, achieving a daily harvest rate of 10,000 newly emerged female adults. Therefore, for an efficient mass-rearing system for H. hebetor, maintaining a density of 5-15 eggs per host is recommended considering variability in life table and discarding aged individuals (after 36 days old). In summary, providing 5-10 5th instar larvae of E. elutella per day per pair of male and female parasitoid wasps is advised for effective mass-rearing of H. hebetor.

The Morphology, Effects of Temperature and Photoperiod on Pseudopupal Diapause and Low Temperature Storage of Epicauta impressicornis (Coleoptera: Meloidae)

The gross morphology of each phase of the hypermetamorphic development of Epicauta impressicornis Pic (Coleoptera: Meloidae) was observed. The effects of temperature and photoperiod on pseudopupal (5th instar larva) diapause and low temperature storage on eggs and pseudopupae were determined. Low temperatures had a dominant effect on diapause incidence, regardless of the photoperiod. Pseudopupae stored at temperatures lower than 18 °C entered diapause, but completed their development without entering diapause at 21, 24, and 27 °C. The critical temperature for inducing diapause was between 16 °C and 16.5 °C, regardless of the photoperiod. The viability of low temperature storage of eggs and pseudopupae decreased with prolongation of storage time. The optimal storage condition for both eggs and pseudopupae was 4 °C for 30 days. Our results will provide a theoretical basis for additional studies on the biological characteristics of E. impressicornis and will also function as a prerequisite basic reference for the artificial large-scale rearing of E. impressicornis.

Synergistic Effect of Three Medicinal Plant Extracts and Their Nutritional Indices on the Tribolium castaneum Herbst and Ephestia kuehniella Zeller

Chemical control of stored pests causes environmental pollution, contamination of stored products and endangering human health. Botanical compounds are one of the suitable alternatives for this aim. In this study effects of eucalyptus, rosemary and mentha extracts alone and in mixed of them on T. castaneum and E. kuehniella were evaluated. Due to our research, the most effect of rosemary extract on the T. castaneum adult, and eucalyptus on the 3rd and 4th instars larvae of E. kuehniella observed. The most significant synergetic on the T. castaneum adult was the combination of ME, MR and ER. Also, the most synergetic effect of extracts on the 3rd and 4th instar larvae of E. kuehniella were related to ME, and MR and ME respectively. The lowest amount of T. castaneum adult Feeding deterrence percentage indices (FDI) and Approximately Digestibility (AD) were observed in rosemary extract and the lowest amount of Efficiency of conversion of ingested food (ECI), Relative consumption rate (RCR) and The Relative growth rate (RGR) was related to eucalyptus extract. The lowest amount of E. kuehniella larvae FDI was observed in rosemary extract and the lowest amount of ECI, RGR and AD was related to eucalyptus extract. Therefore, these botanical extracts can be used to control these two important stored pests.

Microinjection-enabled gene silencing in first instar larvae of western flower thrips, Frankliniella occidentalis, reveals vital genes for larval survival.

The western flower thrips (Frankliniella occidentalis) is a significant agricultural pest, causing severe global yield losses due to extensive feeding damage and the transmission of plant pathogenic viruses. Despite recent advancements in RNA interference (RNAi) in thrips species, its application has been mostly limited to the adult stage. Given the crucial role of first instar larval thrips in acquiring and transmitting orthotospoviruses, achieving gene silencing in these larvae is critical for studying virus entry and acquisition. While thoracic and abdominal injections have proven effective in adult thrips, the low post-injection survival rate hinders their use in larval thrips. This study addresses this challenge by presenting a microinjection methodology to deliver dsRNA into the hemolymph of first instar larval thrips through the coxa, the first proximal segment of the foreleg. This method significantly improved larval survival rate by preventing detrimental damage to the internal tissues. Significant knockdown of V-ATPase-B, cytochrome P450 (CYP3653A2), and apolipophorin-II/I (ApoLp-II/I) transcripts was confirmed after 48 and/or 72 h post injection (hpi), corresponding to the first and second instar larval stages, respectively. Silencing CYP3653A2 or ApoLp-II/I significantly increased larval mortality. These findings demonstrate proof-of-principle of gene silencing and associated silencing phenotype (mortality) for first instar larval thrips and highlight the essential role of CYP3653A2 and ApoLp-II/I in larval vitality. Our RNAi-based tool offers an opportunity to investigate the molecular mechanisms of thrips-orthotospovirus interactions, as the virus must be acquired by young larval thrips for successful transmission to plants, thus presenting potential targets for thrips pest management.

Titanium Dioxide Nanoparticles-Induced Genotoxic Effects in Mosquito Culex quinquefaciatus

Titanium dioxide (TiO2) nanoparticles are being extensively used in a wide range of industrial applications for producing a variety of different consumer products, including medicines and even food items. The consumption of these products is increasing at an alarming rate, and this results in the release of these nanoparticles in the environment, causing a threat to organisms thriving in aquatic as well as terrestrial ecosystems. That is why screening such materials for their genotoxic effects, if any, becomes essential. A toxicity assay was performed to determine the LD20 of these nanoparticles for the mosquito Culex quinquefaciatus by Probit analysis. Early fourth instar larvae were exposed to the selected dose of 50 µg/mL, which is <LD20 value, for 24 h treatment. Chromosomal slides were prepared from lacto-aceto-orcein-stained gonads of adult mosquitoes developed from treated and control larvae. These nanoparticles were reported cytotoxic as a statistically significant decline in mitotic index in treated mosquitoes than controls were observed. The nanoparticles were also found to induce various structural and numerical chromosomal aberrations in the treated lot. In the end, it can be concluded that these nanoparticles do have a genotoxic effect. The present study provides a caution against further use of these nanoparticles. There must be the development of strategies for the safe, sustainable use as well as proper disposal of these nanoparticles so as to protect both biotic and non-biotic components of the environment.

ROS-responsive supramolecular antimicrobial peptides-based nanoprodrugs for cervical cancer therapy

Although antimicrobial peptides (AMPs) as a promising natural drugs can efficiently inhibit cervical cancer, poor bioavailability, low tumor selectivity, and non-selective toxicity still hinder its further application in vivo. In order to effectively address these challenges, we have developed a reactive oxygen species (ROS)-responsive targeting nanoprodrug designed for selective therapy of cervical cancer. Such nanoprodrugs (CEC-OxbCD) are fabricated by the supramolecular self-assembly of the modified β-cyclodextrin (β-CD) and AMPs. Antimicrobial peptide, CecropinXJ (CEC), is a cationic antibacterial peptide isolated from 3rd instar larvae of Bombyx mori from Xinjiang, China. OxbCD is an oxidation-responsive β-cyclodextrin material. CEC-OxbCD were synthesized using the nanoprecipitation/self-assembly method. Subsequently, the particle size distribution, morphology, drug loading efficiency, and release behaviour of CEC-OxbCD were characterised. In vitro and in vivo anti-cancer activities were also evaluated. Nanoprodrugs can be effectively disassembled under stimuli of the tumor- endogenous ROS, resulting in a rapid and on-demand release of antimicrobial peptides (AMPs) with a release rate of 90 %. Furthermore, both in vitro and in vivo experimental results demonstrate that our nanoprodrugs exhibit remarkable therapeutic efficacy against cervical cancer. This work not only provides an effective and promising therapeutic strategy for cervical cancer, but also explores a novel application for AMPs.

Morphology of the egg-case and larva of Paracymus aeneus (Germar) (Coleoptera: Hydrophilidae).

The generic and species identity of previously described larva of Paracymus aeneus (Germar, 1824), the type species of the genus Paracymus Thomson, 1867, has been a subject of controversy owing to their morphological similarity to the genus Anacaena Thomson, 1859. In this study, we describe morphology of the egg-case and all three instar larvae of P. aeneus based on Japanese specimens obtained through rearing and provide the biological information on the species under rearing conditions. The morphology of the larvae corresponds with that of known Paracymus larvae rather than Anacaena. Consequently, larvae previously described as P. aeneus do not belong this species. Therefore, this is the first description of the immature stages of P. aeneus.

From Egg to Adult: A Developmental Table of the Ant Monomorium pharaonis.

Ants are one of the most ecologically and evolutionarily successful groups of animals and exhibit a remarkable degree of phenotypic diversity. This success is largely attributed to the fact that all ants are eusocial and live in colonies with a reproductive division of labor between morphologically distinct queen and worker castes. Yet, despite over a century of studies on caste determination and evolution in ants, we lack a complete ontogenetic series from egg to adult for any ant species. We, therefore, present a developmental table for the Pharaoh ant Monomorium pharaonis, a species whose colonies simultaneously produce reproductive queens and completely sterile workers. In total, M. pharaonis embryonic, larval, and pupal development lasts 45 days. During embryogenesis, the majority of developmental events are conserved between M. pharaonis and the fruit fly Drosophila melanogaster. We discovered, however, two types of same-stage embryos before gastrulation: (1) embryos with internalized germ cells; and (2) embryos with germ cells outside of the blastoderm at the posterior pole. Moreover, we also found two-types of embryos following germ band extension: (1) embryos with primordial germ cells that will develop into reproductive queens; and (2) embryos with no germ cells that will develop into completely sterile workers. Together, these data show that queen and worker castes are already determined and differentiated by early embryogenesis. During larval development, we confirmed that reproductive and worker larvae proceed through three larval instars. Using anatomical and developmental markers, we can further discern the development of gyne (unmated queen) larvae, male larvae, and worker larvae as early as the 1st instar. Overall, we hope that the ontogenetic series we present here will serve as a blueprint for the generation of future ant developmental tables.

Suppression of Cadra cautella (Lepidoptera: Pyralidae) development by phytosanitary irradiation doses and their impacts on physiochemical and microbiological quality of dates.

Cadra cautella is a serious insect pest of stored figs and dates. The irradiation sensitivity of different development stages of C. cautella and large-scale testing of the proposed irradiation quarantine doses (50-500 Gy), were investigated. The impact of a PI dose of 400 Gy on the physiochemical and microbiological quality of dry dates (Bartamoda cv.) stored at room temperature was also investigated. An irradiation dose of 100 Gy prevented egg hatching in the F1 generation when 1-3 days old eggs were irradiated. Irradiation doses of 200 and 300 Gy prevented adult emergence when 2nd and 4th instar larvae were irradiated. When the pupae stage was irradiated, an irradiation dose of 400 Gy prevented the hatchability of F1 generation, indicating that this stage was the most radio-tolerant. The results of large-scale testing of the proposed phytosanitary irradiation dose (400 Gy) applied to 18, 0000 pupae resulted in no reproduction (zero hatching of F1 generation). There were no significant differences in the physiochemical properties of stored dates during the storage period at room temperature. Stable ESR signal intensity was recorded for 6 months in all parts of the irradiated fruits, and the intensity was highest in the kernel. The PI dose of 400 Gy also slightly reduced all microorganisms' counts. In conclusion, the dose level of 400 Gy stopped the reproduction potential of C. cautella. and they maintained the quality characteristics of dry date Bartamoda fruits during storage at room temperature for 6 months in tightly closed packages.

Revealing the larval anatomy of the hoverfly Sphaerophoria rueppellii (Wiedemann, 1820) (Diptera, Syrphidae) using micro-computed tomography

Micro-computed tomography (micro-CT) is an X-ray-based technique that allows visualisation of the internal anatomy of insects in situ and does not require dissections. Traditionally, the study of insect anatomy has been mainly based on dissection techniques and microtome sections. However, micro-CT is becoming an increasingly widespread study technique. We report the use of micro-CT scans to study, in detail, the external and internal structures and organs of the third instar larva of the dipteran Syrphidae Sphaerophoria rueppellii, a Palaearctic species included in the list of effective agents used in European biocontrol programmes against aphids. Detailed images and videos provided evidence of the external morphological characteristics and an overview of the internal anatomy (musculature, digestive tube, salivary glands, Malpighian tubules, fat body, circulatory system, nervous system, cephalopharyngeal complex, tentorium, and mouth parts). The study evidenced the following: an external lateroventral complex of muscles that form muscular rings that allow the compression of the body segments in a similar functional way as occurs in annelid worms; the existence of mandibles with prosthecae; the nervous system present a conspicuous distinguishable suboesophageal ganglion; the so-called antennomaxillary organs are the antennae; the maxillae are separate structures, with an articulated maxillary palpus; S. rueppellii has only one pair of Malpighian tubules instead of the two pairs that were thought to be the general rule for Syrphid larvae; and the evidence of an imaginal disc of genitalia in the posterior part of the body, below the rectum, which in male larvae has a clear correspondence with the morphology of the external male genitalia, which allows to differentiate the sexes in the larval stage. This study constitutes a true anatomical atlas of the third instar larvae of S. rueppellii. High-quality rendered images and additional supplementary videos together with a 3D model, suitable for use with mobile devices, are useful tools for future research and teaching aids.