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Simple Summary: The European corn borer (Ostrinia nubilalis) is a major pest of corn, managed successfully in North America since 1996 with transgenic Bt-corn. However, practical field resistance and early-warning increases in frequency of resistance genes for all available insecticidal Bt proteins expressed in corn were detected recently at several locations in Canada. Given the high mobility of moths, design of containment and mitigation measures would have to be implemented at large spatial scales around a resistance hotspot to be successful. Effective strategies must account for high gene flow consistent with improved understandings of this species' complex movement ecology, including migratory behavior. The European corn borer (Ostrinia nubilalis, Hübner) has been managed successfully in North America since 1996 with transgenic Bt-corn. However, field-evolved resistance to all four available insecticidal Bt proteins has been detected in four provinces of Canada since 2018. Evidence suggests resistance may be spreading and evolving independently in scattered hotspots. Evolution and spread of resistance are functions of gene flow, and therefore dispersal, so design of effective resistance management and mitigation plans must take insect movement into account. Recent advances in characterizing European corn borer movement ecology have revealed a number of surprises, chief among them that a large percentage of adults disperse from the natal field via true migratory behavior, most before mating. This undermines a number of common key assumptions about adult behavior, patterns of movement, and gene flow, and stresses the need to reassess how ecological data are interpreted and how movement in models should be parameterized. While many questions remain concerning adult European corn borer movement ecology, the information currently available is coherent enough to construct a generalized framework useful for estimating the spatial scale required to implement possible Bt-resistance prevention, remediation, and mitigation strategies, and to assess their realistic chances of success. [ABSTRACT FROM AUTHOR]

Simple Summary: The European corn borer, Ostrinia nubilalis Hbn., is an annual pest of the Romanian corn crop. The research followed the development of the European corn borer in the context of the climate warming recorded in recent years in Eastern Romania. We monitored the development of the egg, larva, pupa, and moth stages using cage studies and observations in an experimental cornfield. We also analyzed the impact of climatic conditions on developmental time. Our data show that the increase in winter temperatures ensures the survival of a higher percentage of mature larvae, which leads to intense moth flight at the end of June and the beginning of July. However, the high summer temperatures caused an increasing percentage of the larvae to transform into pupae, which led to the recording of a secondary flight in August. Although the insect is known to have one generation per year, it is apparent that a multivoltine ecotype is also present. We conclude that the climate warming we are witnessing affects the species' development and that higher larval infestations could occur. Between 2020 and 2021, we conducted research in eastern Romania to monitor the bioecology of the European corn borer (Ostrinia nubilalis Hbn.), an important pest of corn. The bioecology research established the pest stage duration (egg, larva, pupa, and moth), the flight curve, and the flight peak. The bioecological study occurred in the experimental corn field and a field cage. According to our findings, the insect has one generation per year. The European corn borer hibernates as a mature larva in corn residues and continues developing in the spring, when the weather warms. It pupates from May to July over 37 days. Analyzing the data recorded during the winters of 2020 and 2021, we observed that the warming trend favored the high survival of hibernating larvae (60.7%). Due to the large number of mature larvae that had favorable conditions during the winter, there is an intense flight, starting in June and ending in September. When the first moth was caught in the light trap, the ∑(tn-10) °C (sum of degree days) was 245.6 °C. In 2020, the flight was recorded for 94 days. In 2021, the European corn borer flight lasted 104 days. The initial egg masses were detected when the total of ∑(tn-10) °C reached 351.5 °C. Moths laid the eggs for 25 days, mostly during peak flight in late June and early July. The first larvae hatched when ∑(tn-10) °C totaled 438.4 °C, and stages III–V were recorded in the harvested crop. Understanding the bioecology of the European corn borer can offer valuable insights into managing population levels and identifying optimal timing for addressing infestations in corn crops. [ABSTRACT FROM AUTHOR]

Simple Summary: Delaying or preventing the evolution of resistance to Bacillus thuringiensis (Bt) toxins produced by transgenic crops in insect pests is a major challenge for agriculture. A simulation model suggested that the rotation of different single-gene crops planted in subsequent seasons has the potential to delay resistance. To test this prediction, we set out laboratory selection experiments under the alternation of multi-toxins by mixing individual toxins (Cry1Ab, Cry1F, and Cry1Ie) in an artificial diet to emulate single-gene Bt maize plants. Two (Cry1Ab-Cry1F, Cry1Ab-Cry1Ie) or three (Cry1Ab–Cry1F–Cry1Ie) toxin alternation regimes were tested to imitate two or three single-gene crops in a rotation fashion. The species tested was the Asian corn borer, Ostrinia furnacalis (Guenée), the most economically important species of maize pest in Asia. The present study suggested that rotation of multiple toxins did not slow the evolution of resistance to Cry1F or Cry1Ie. Data generated from the study will assist in the development of sustainable resistance-management strategies. A common strategy for delaying the evolution of resistance to transgenic crops that produce insecticidal proteins from Bacillus thuringiensis is to ensure that insect pests are exposed to multiple toxins with different mechanisms of action (MoAs). This can take the form of planting crops in a rotation pattern when different crops expressing single toxins are available on the market. The efficacy of a rotation strategy is reliant on mathematical models based on biological assumptions. Here, we designed laboratory evolution experiments to test whether Bt-based insecticidal proteins with different MoAs used in rotation could delay resistance from developing in Asian corn borer (ACB), Ostrinia furnacalis. We investigated the proteins Cry1Ab, Cry1F, and Cry1Ie, which are widely utilized for commercial insect control. We found that rotation of multiple toxins did not slow the evolution of resistance to Cry1F or Cry1Ie. Furthermore, the evolution of ACB to the Cry1Ab toxin develops faster when Cry1F or Cry1Ie is present, as compared to Cry1Ab exposure only. Our results suggest that toxins used in a rotation fashion do not work as an effective strategy in delaying ACB resistance evolution to Cry toxins over one-toxin exposure. Our result highlights the need to better understand the biological factors leading to insecticidal protein resistance and to develop IRM strategies against target insects. [ABSTRACT FROM AUTHOR]

Biochemical studies provided convincing evidence that an antennae-specific CYP from the pale brown chafer I Phyllopertha diversa i can rapidly degrade the sex pheromone [[23]], and inhibition of the CYP activity led to pheromone anosmia in this insect species [[24]]. In addition, several I OfurCCE i s were expressed in both antennae and non-olfactory tissues, e.g., I OfurCCE1 i in male and female antennae as well as in abdomen; I OfurCCE3 i in male antennae, female antennae, head, and abdomen (Figure 7). 4. In I A. polyphemus i and I B. mori i , antennae-specific AOXs were involved in the degradation of aldehydic sex pheromones [[32]]; in the navel orange worm I Amyelois transitella i , AOXs from antennae degraded both sex pheromones and plant volatile aldehydes [[33]]. Keywords: Ostrinia furnacalis; antennal transcriptome; odorant degradation; expression profiles EN Ostrinia furnacalis antennal transcriptome odorant degradation expression profiles 1027 18 11/17/22 20221101 NES 221101 1. This number is less than that in I Ectropis obliqua i (35 genes) [[53]] and I D. melanogaster i (25 in male antennae and 26 in female antennae) [[9]], but is comparable to those in I A. lepigone i (20 genes) [[42]], I S. littoralis i (19 genes) [[43]], I C. suppressalis i (19 genes) [[41]], I C. medinalis i (18 genes) [[35]], and I C. pomonella i (12 genes) [[40]]. [Extracted from the article]

Simple Summary: While chemical insecticides are conventionally effective for pest control, they also cause severe problems, such as insect resistance and environmental pollution. Alternative insecticides with distinct mechanisms are needed. Cyclosporin A (CsA), a polypeptide produced by fungi, is widely used as an immunosuppressant in organ transplantation. This study used Ostrinia furnacalis, a major pest of maize in Asia, as a model to investigate the insecticidal activity of CsA. CsA had marked insecticide activity against O. furnacalis larvae. Furthermore, sublethal doses of CsA caused negative effects on larval, pupal and adult development. CsA treatments suppressed reproduction, significantly decreasing the mating rate, ovary size, and numbers and hatchability of eggs. CsA showed excellent combined toxicities when mixed with five common insecticides, respectively. Importantly, CsA acts by suppressing calcineurin, which represents a novel insecticidal target. Thus, CsA has potential as a new insecticide for sustainable pest management. The long-term use of chemical insecticides has caused serious problems of insect resistance and environmental pollution; new insecticides are needed to solve this problem. Cyclosporin A (CsA) is a polypeptide produced by many fungi, which is used to prevent or treat immune rejection during organ transplantation. However, little is known about the utility of CsA as an insecticide. Therefore, this study evaluated the insecticidal activity of CsA using Ostrinia furnacalis as a model. The results demonstrated that CsA was toxic to O. furnacalis with LC50 values of 113.02 μg/g and 198.70 μg/g for newly hatched neonates and newly molted third-instar larvae, respectively. Furthermore, CsA treatment had sublethal effects on the development of O. furnacalis, and significantly reduced the fecundity of adults; this suggests that CsA has great potential to suppress O. furnacalis populations. Further analysis revealed that CsA suppressed calcineurin activity in larvae. CsA had independent or synergistic toxic effects on O. furnacalis when combined with β-cypermethrin, indoxacarb, emamectin benzoate, azadirachtin, and the Bacillus thuringiensis toxin Cry1Ac, which suggests that CsA can help prevent or manage resistance. Our study provides detailed information on the potential of CsA as an insecticide for controlling lepidopterans. [ABSTRACT FROM AUTHOR]

Simple Summary: The Asian corn borer, Ostrinia furnacalis (Guenée), is the most destructive lepidopteran insect pest of corn (Zea mays L.) in China. Pathogenic microorganisms play an important role in the population control of the Asian corn borer. Although microorganisms can cause the death of O. furnacalis, an immune response also occurs as an attempt to fight off and eliminate invading pathogens. If the molecular mechanism of interaction between O. furnacalis and pathogenic bacteria is clarified, the lethal effect of pathogenic microorganisms can be better exerted by inhibiting the natural immune response of O. furnacalis. As an important member of the pattern-recognition receptor family, peptidoglycan recognition protein (PGRP) plays a key role in the insect innate immune response. In this study, we cloned two PGRP genes from O. furnacalis and analyzed their spatiotemporal expression. In combination with bacterial induction experiments, we revealed the immune signal recognition pathway involved in the two proteins. The results of this study deepen the understanding of the natural immune response of O. furnacalis and provide new ideas for better utilization of pathogenic microorganisms in biological control of the Asian corn borer. Peptidoglycan recognition proteins (PGRPs) are important components of insect immune systems, in which they play key roles. We cloned and sequenced two full-length PGRP, named OfPGRP-A and OfPGRP-B, from the Asian corn borer, Ostrinia furnacalis. These two genes comprise open reading frames of 658 and 759 bp, encoding proteins of 192 and 218 amino acids, respectively. qPCR showed that OfPGRP-A and OfPGRP-B are prominently expressed in the midgut of O. furnacalis fourth instar larvae. After inoculation with Staphylococcus aureus and Bacillus thuringiensis, the expression of OfPGRP-A was significantly upregulated, whereas the expression of OfPGRP-B was enhanced after inoculation with Escherichia coli. This suggests that OfPGRP-A mainly recognizes Gram-positive bacteria and may participate in the Toll signaling pathways, while OfPGRP-B identifies Gram-negative bacteria and may participate in Imd signaling pathways. Our results provide insights into the roles of PGRPs in O. furnacalis immune function and a foundation for using pathogens for the biological control of O. furnacalis. [ABSTRACT FROM AUTHOR]

Simple Summary: Homeotic genes encode transcription factors that coordinated the anatomical structure formation during the early embryonic development of organisms. In this study, we functionally characterized two homeotic genes, Abdominal-A (Abd-A) and Ultrabithorax (Ubx), in the Asian corn borer, Ostrinia furnacalis (a maize pest that has devastated the Asia-Pacific region) by using a CRISPR/Cas9 genome editing system. Our results show that the mutagenesis of OfAbd-A and OfUbx led to severe morphological defects in O. furnacalis, which included fused segments and segmental twist during the larval stage, and hollowed and incision-like segments during the pupal stage in OfAbd-A mutants, as well as defects in the wing-pad development in pupal and adult OfUbx mutants. Overall, knocking out Abd-A and Ubx in O. furnacalis resulted in the embryonic lethality to, and pleiotropic impact on, other homeotic genes. This study not only confirms the conserved body planning functions in OfAbd-A and OfUbx, but it also strengthens the control implications of these homeotic genes for lepidopteran pests. (1) Background: Abdominal-A (Abd-A) and Ultrabithorax (Ubx) are homeotic genes that determine the identity and morphology of the thorax and abdomen in insects. The Asian corn borer, Ostrinia furnacalis (Guenée) (Lepidoptera: Pyralidae), is a devastating maize pest throughout Asia, the Western Pacific, and Australia. Building on previous knowledge, we hypothesized that the knockout of Abd-A and Ubx would disrupt the abdominal body planning in O. furnacalis. (2) Methods: CRISPR/Cas9-targeted mutagenesis was employed to decipher the functions of these homeotic genes. (3) Results: Knockout insects demonstrated classical homeotic transformations. Specifically, the mutagenesis of OfAbd-A resulted in: (1) Fused segments and segmental twist during the larval stage; (2) Embryonic lethality; and (3) The pleiotropic upregulation of other homeotic genes, including Lab, Pd, Dfd, Antp, and Abd-B. The mutagenesis of OfUbx led to: (1) Severe defects in the wing pads, which limited the ability of the adults to fly and mate; (2) Female sterility; and (3) The pleiotropic upregulation of other homeotic genes, including Dfd, Abd-B, and Wnt1. (4) Conclusions: These combined results not only support our hypothesis, but they also strengthen the potential of using homeotic genes as molecular targets for the genetic control of this global insect pest. [ABSTRACT FROM AUTHOR]

Simple Summary: RNA interference (RNAi) has shown great potentials as a novel technology for insect pest management. However, numerous studies have shown that the efficiency of RNAi varies substantially among different insect species. For example, as a major insect pest of corn, the Asian corn borer (Ostrinia furnacalis) showed very low RNAi efficiency. Therefore, it is necessary to develop new strategies for enhancing RNAi efficiency in insects with low RNAi efficiency. In this study, six core RNAi pathway genes were identified and characterized from O. furnacalis transcriptome database. After dsEGFP was injected into O. furnacalis, the expression of the core RNAi pathway genes (OfDicer2 and OfAgo2) was significantly up-regulated in response to the exposure of dsEGFP. As a result, the RNAi efficiency against the target genes in certain tissues of O. furnacalis was significantly improved. These results suggest that RNAi efficiency can be improved by inducing the expression of key RNAi pathway genes in O. furnacalis. RNA interference (RNAi) is a sequence-specific gene silencing mechanism that holds great promise for effective management of agricultural pests. Previous studies have shown that the efficacy of RNAi varies among different insect species, which limits its wide spread application in the field of crop protection. In this study, we identified and characterized six core RNAi pathway genes including OfDicer1, OfDicer2, OfR2D2, OfAgo1, OfAgo2, and OfAgo3 from the transcriptomic database of the Asian corn borer (Ostrinia furnacalis). Domain analysis showed that the six deduced proteins contained the necessary functional domains. Insect developmental stage- and tissue-specific expression analysis showed that five genes were expressed in all the stages and tissues examined except OfAgo3, which showed low expression in larvae, and high expression in pupae and adults and in the midgut. RT-qPCR was performed to examine the response of these six genes to exogenous double-stranded RNA (dsRNA). Interestingly, the transcript levels of OfDicer2 and OfAgo2 were significantly enhanced after the injection of dsEGFP at different time points and tissues investigated. Consequently, the RNAi efficiency in targeting the insect endogenous genes can be greatly enhanced in the hemolymph or midgut. Taken together, our investigations suggest that RNAi efficiency can be enhanced by pre-injection of dsRNA to induce the RNAi core machinery genes, which could be a useful strategy to improving RNAi efficiency for studying gene functions under laboratory conditions. [ABSTRACT FROM AUTHOR]

Simple Summary: The performance of two egg parasitoids T. dendrolimi and T. ostriniae were compared on Asian corn borer (ACB) Ostrinia furnacalis eggs of different ages under choice and no-choice conditions. Both parasitoid species showed significant preferences in parasitizing ACB eggs of different ages. Younger ACB eggs (0–8-h-old) showed high suitability while eggs older than 8 h were not suitable for T. dendrolimi. The age of ACB eggs did not affect the biological parameters of T. ostriniae. Overall, our results highlighted the T. ostriniae species as the best candidate biocontrol agent for managing ACB populations. The Asian corn borer (ACB), Ostrinia furnicalis, is a serious corn pest in south-east Asia, causing huge economic losses every year. Trichogramma dendrolimi and Trichogramma ostriniae, two egg parasitoids, have previously been identified as key biological control agents. To determine the age impact of ACB eggs on their effective biocontrol potential, herein we compared the biological parameters (i.e., number of parasitized eggs, emergence, developmental time, and sex ratio) of both parasitoids on ACB eggs of various ages (i.e., 0–4, 4–8, 8–12, 12–16, 16–24, 24–36, and 36–48 h old), respectively. Our results showed that the age of ACB eggs had a significant impact on the parasitization activity of T. dendrolimi in both choice and no-choice conditions. Trichogramma dendrolimi preferred to parasitize 0–8-h-old ACB eggs, and its parasitization dramatically declined on ACB eggs older than 8 h under choice and no-choice conditions. On the other hand, T. ostriniae showed high preference to parasitize all tested ACB egg ages. The age of ACB eggs had no significant impact on the parasitization of T. ostriniae under choice and no-choice conditions. Furthermore, the female progeny of T. dendrolimi decreased as the age of ACB increased, while no differences were found in female progeny of T. ostriniae. Trichogramma ostriniae also developed faster on each ACB egg age group in comparison with T. dendrolimi. Overall, the age of ACB eggs had a significant impact on T. dendrolimi performance, leading us to conclude that T. ostriniae is more effective than T. dendrolimi as a biocontrol agent of the ACB. [ABSTRACT FROM AUTHOR]

Simple Summary: Moths typically rely on sex pheromone communication to find a mate. This involves the production of species-specific sex pheromones by females (the signaller) and the corresponding selective detection by conspecific males (the receiver). A key question in the evolution of the pheromone communication system is how the female signals can diversify and still be tracked by the receivers over the process of speciation. The genus Ostrinia, which comprises 20 species worldwide including several well-recognised agricultural pests, is an attractive model in the study of the evolution of sex pheromone communication, as the closely related species and strains provide an ideal example of ongoing speciation. This review presents a comprehensive overview of the research on pheromone communication in different Ostrinia species over the past four decades, from the identity and biosynthesis of pheromones in the females to the molecular and neuronal basis of the pheromone perception in males. The evolutionary insights from these studies are discussed and the directions for future research are outlined. It remains a conundrum in the evolution of sexual communication how the signals and responses can co-ordinate the changes during speciation. The genus Ostrinia contains several closely related species as well as distinctive strains with pheromone polymorphism and represents an example of ongoing speciation. Extensive studies in the genus, especially in the species the European corn borer O. nubilalis (ECB), the Asian corn borer O. furnacalis (ACB) and the adzuki bean borer O. scapulalis (ABB), have provided valuable insights into the evolution of sex pheromone communication. This review presents a comprehensive overview of the research on pheromone communication in different Ostrinia species over the past four decades, including pheromone identification and biosynthesis, the ligand profiles of pheromone receptor (PR) genes, the physiology of peripheral olfactory sensory neurons (OSNs) and the projection pattern to the antennal lobe. By integrating and comparing the closely related Ostrinia species and strains, it provides an evolutionary perspective on the sex pheromone communication in moths in general and also outlines the outstanding questions that await to be elucidated by future studies. [ABSTRACT FROM AUTHOR]

Simple Summary: The Asian corn borer (ACB), Ostrinia furnacalis, is an important economic pest of corn and other crops, and is widely distributed in China. Depending on the climate, ACB may have one or up to seven generations each year, from north to south, respectively. The degree of crop damage is closely related to its phenology and number of generations per year (voltinism). Climate warming may result in an alternation of voltinism in the ACB. In the present study, we investigated the voltinism of different populations under different simulated environments. From the diapause response, both the uni- and multivoltine ecotypes were coexisting in the Harbin (H) population collected from action sites of ACB moths in Harbin, Heilongjiang Province, China. Diapause incidence declined given the climate-warming scenario, which was temporally specific and could be overridden by significantly low daily average temperatures. Elevated CO2 did not directly impact voltinism. On the basis of voltinism, the H population reflected sympatric uni- and multivoltine ecotypes, with multivoltinism being dominant. The univoltinism trait was recessive. Climate warming could significantly override photoperiod effects. Warmer temperatures and declining latitude (reduced daylength), and their interaction, are estimated to drive ACB evolution to increased homogeneity and multivoltinism. In the Asian corn borer (ACB), Ostrinia furnacalis (Guenée), diapause is governed by a multigenetic constitution that responds to daylength and temperature with seasonality. The ACB displays uni- or multivoltinism, depending on its geographic specificity. Hence, warmer temperatures may result in alternation of voltinism in the ACB, which will help in understanding the ecological consequences of climate warming on insects. In the present study, we investigated the voltinism in two natural populations from Harbin (H) and Gongzhuling (G) as well as a laboratory (L) population (established from the H population in 2017) of the ACB, at ambient and elevated atmospheric CO2 (aCO2 390 μL/L and eCO2 750 μL/L) and temperature (aT and Et = At + 2 °C). From the diapause response, both the uni- and multivoltine ecotypes were coexisting in the H population. The neonate occurrence date of 50% individuals that induced diapause was ca. 10 days later in the G population than in the H population, but it was about 10 days earlier than in the L population. Comparing to the dates of onset and the peak of diapause induction, the G and L populations were less variable than the H population in response to a short and/or shortening daylength in the field. The univoltine individuals could not be eliminated completely after 19 generations of selection. Diapause incidence decreased with a climate-warming scenario, which was temporally specific and could be overridden by significantly low daily average temperatures. The eCO2 did not directly impact the voltinism. On the basis of voltinism, the H population was sympatric for uni- and multivoltine ecotypes, with multivoltinism being dominant. The univoltinism trait was recessive. Climate warming could significantly override the effect of photoperiod, which was yearly dependent. Warmer temperatures and a decreased latitude (shortened daylength), and their interaction, would drive ACB evolution toward diapause homogeneity for multivoltinism. [ABSTRACT FROM AUTHOR]

Simple Summary: RNA interference is a gene suppression tool that uses double-stranded RNA to prevent specific genes from producing proteins. By targeting essential genes RNA interference can be developed for control of insect pests. Unfortunately, RNA interference is not equally effective for all insects. Previous investigation suggested that RNA is rapidly digested by unidentified components of body fluids in the European corn borer caterpillar. We characterized genes encoding proteins from European corn borer that are associated with RNA digestion in other insects. Our results suggest that two proteins (RNA interference efficiency-related nuclease and double-stranded RNA-degrading endonuclease 2) may be responsible for digesting RNAs in the European corn borer gut, whereas two other proteins (double-stranded RNA-degrading endonuclease 1 and double-stranded RNA-degrading endonuclease 4) may be responsible for digesting RNA in European corn borer body fluid. These findings suggest digestion of RNA in the European corn borer is likely due to the activity of these proteins. These findings provide information about the mechanism(s) influencing RNA stability in insects. The knowledge generated by this study will facilitate the development of strategies for enhancing RNA interference in insects. Variable RNA interference (RNAi) efficiencies limit RNAi-based pest management strategies for many pests. Previous efforts to understand mechanisms contributing to low RNAi efficiency indicate that double-stranded RNA (dsRNA) is degraded in the European corn borer (ECB), Ostrinia nubilalis, due to nuclease activity. To investigate the contribution of dsRNA-degrading endonucleases (dsRNases) and lepidopteran-specific RNAi efficiency-related nucleases (REases) to dsRNA instability and low RNAi efficiency in ECB, five complementary DNAs putatively encoding four dsRNases (OndsRNase1, 2, 3, and 4) and one REase (OnREase) were sequenced. Characterization of these transcripts revealed that substrate specificity might vary among the four dsRNases due to different amino acid combinations in the substrate-binding sites. Gene expression analysis indicated that OndsRNase2 and OnREase were highly expressed in the larval gut, and OndsRNase1 showed the highest expression in hemolymph, especially in older developmental stages. Transcript level analysis after dsRNA exposure revealed that expression of OnREase rapidly increased upon dsRNA ingestion or injection, whereas OndsRNase4 expression only increased after long-term ingestion of dsRNA. While the biological function of these nucleases remains to be verified, our results suggest that OnREase and OndsRNase2, and OndsRNase1 and OndsRNase4 may be responsible for degradation of dsRNAs in the ECB gut and hemolymph, respectively, thereby contributing to low RNAi efficiency. [ABSTRACT FROM AUTHOR]

To understand mitogenome characteristics and reveal phylogenetic relationships of the genus Ostrinia, including several notorious pests of great importance for crops, we sequenced the complete mitogenomes of four species: Ostrinia furnacalis (Guenée, 1854), Ostrinia nubilalis (Hübner, 1796), Ostrinia scapulalis (Walker, 1859) and Ostrinia zealis (Guenée, 1854). Results indicate that the four mitogenomes—O. furnacalis, O. nubilalis, O. scapulalis, and O. zealis—are 15,245, 15,248, 15,311, and 15,208 bp in size, respectively. All four mitogenomes are comprised of 37 encoded genes and a control region. All 13 protein-coding genes (PCGs) initiate with ATN and terminate with TAN, with the exception of cox1 that starts with CGA, and cox1, cox2, and nad5 that terminate with an incomplete codon T. All transfer RNA genes (tRNAs) present the typical clover-leaf secondary structure except for the trnS1 (AGN) gene. There are some conserved structural elements in the control region. Our analyses indicate that nad6 and atp6 exhibit higher evolution rates compared to other PCGs. Phylogenetic analyses based on mitogenomes using both maximum likelihood (ML) and Bayesian inference (BI) methods revealed the relationship (O. palustralis + (O. penitalis + (O. zealis + (O. furnacalis + (O. nubilalis + O. scapulalis))))) within Ostrinia. [ABSTRACT FROM AUTHOR]

Heavy metal pollution is becoming an increasingly serious problem in agricultural ecosystems. Heavy metals such as cadmium (Cd) accumulate in the food chain and may lead to detrimental effects on the physiological functions of living organisms, including herbivorous insects. One such example is the Asian Corn Borer, Ostrinia furnacalis (Lepidoptera: Pyralidae). However, how Cd can affect the development and reproduction of O. furnacalis is largely unknown. In this study, we exposed larvae of O. furnacalis to a diet containing Cd and investigated the effects of Cd on the development, mating behavior, and fecundity of the insect. We showed that Cd accumulates in the larvae and inhibits development by extending larval and pupal duration and decreasing the survival rate. The excretion of Cd through multiple routes during the larval and pupal stages resulted in low levels of residual Cd in the adult insects, which were not fed with Cd. However, the mating behavior and fecundity of these insects were significantly affected, compared to control insects. This suggests that the bioaccumulation of heavy metals such as Cd has long lasting and detrimental effects on O. furnacalis over the entire life cycle, affecting fecundity, even when specimens are only exposed at an early life stage. [ABSTRACT FROM AUTHOR]