Lepidopteran Larvae Research Articles

Reared specimens of western Palaearctic Ophion Fabricius (Hymenoptera: Ichneumonidae: Ophioninae) in the National Museums of Scotland

Following recent changes to the taxonomy of north-western European Ophion Fabricius, 1798, species, host records are updated and new records presented for these nocturnal, koinobiont endoparasitoids of Lepidoptera larvae. Rearing data are presented for 22 species with two species re-described. Five species are recorded as new to Britain and Ireland.

Can low concentration flufenoxuron treatment increase the pathogenicity or production of nucleopolyhedrovirus occlusion bodies in Spodoptera exigua (Hübner) or Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae)?

Nucleopolyhedroviruses (Baculoviridae) are lethal pathogens that naturally infect lepidopteran larvae. The chitin synthesis inhibitor flufenoxuron has been reported to potentiate the insecticidal properties of nucleopolyhedrovirus occlusion bodies (OBs) by degrading the integrity of the peritrophic matrix in lepidopteran larvae. In the present study we examined the effect of flufenoxuron treatment on susceptibility of Spodoptera exigua (Hübner) and Spodoptera frugiperda (JE Smith) fifth instars to their homologous nucleopolyhedroviruses, SeMNPV and SfMNPV, respectively. Preliminary bioassays indicated that a 1 mg/l concentration of flufenoxuron resulted in 6.6 - 13.3% mortality of larvae, which could be used in combination with OB inoculum concentrations of 1.5 × 104 OBs/ml of SeMNPV OBs or 1.3 × 10⁶ OBs/ml of SfMNPV OBs. Treatment of larvae with flufenoxuron did not significantly affect virus-induced mortality of either S. exigua (16.7 - 17.2%) or S. frugiperda (28.9 - 34.4%) and had no significant effect on the mean yield of OBs from virus-killed insects of either species. The identity of both SeMNPV and SfMNPV in experimental insects was confirmed by examination of the restriction endonuclease profiles of each virus. These findings contrast with the results of previous studies in which high concentrations of flufenoxuron (100 mg/l) greatly potentiated virus-induced mortality in the silkworm Bombyx mori L., although insect mortality due to flufenoxuron treatment alone was not reported, for reasons that are unclear. We conclude that flufenoxuron (1 mg/l) failed to potentiate the insecticidal activity of SeMNPV or SfMNPV in their respective hosts.

Novel insecticidal proteins from ferns resemble insecticidal proteins from Bacillus thuringiensis.

Lepidopterans affect crop production worldwide. The use of transgenes encoding insecticidal proteins from Bacillus thuringiensis (Bt) in crop plants is a well-established technology that enhances protection against lepidopteran larvae. Concern about widespread field-evolved resistance to Bt proteins has highlighted an urgent need for new insecticidal proteins with different modes or sites of action. We discovered a new family of insecticidal proteins from ferns. The prototype protein from Pteris species (Order Polypodiales) and variants from two other orders of ferns, Schizaeales and Ophioglossales, were effective against important lepidopteran pests of maize and soybean in diet-based assays. Transgenic maize and soybean plants producing these proteins were more resistant to insect damage than controls. We report here the crystal structure of a variant of the prototype protein to 1.98 Å resolution. Remarkably, despite being derived from plants, the structure resembles the 3-domain Cry proteins from Bt but has only two out of three of their characteristic domains, lacking the C-terminal domain which is typically required for their activities. Two of the fern proteins were effective against strains of fall armyworm that were resistant to Bt 3-domain Cry proteins Cry1Fa or Cry2A.127. This therefore represents a novel family of insecticidal proteins that have the potential to provide future tools for pest control.

Lepidopteran prolegs are novel traits, not leg homologs.

Lepidopteran larvae have both thoracic legs and abdominal prolegs, yet it is unclear whether these are serial homologs. A RNA-seq analysis with various appendages of Bicyclus anynana butterfly larvae indicated that the proleg transcriptome resembles the head-horn transcriptome, a novel trait in the lepidoptera, but not a thoracic leg. Under a partial segment abdominal-A (abd-A) knockout, both thoracic leg homologs (pleuropodia) and prolegs developed in the same segment, arguing that both traits are not serial homologs. Further, three of the four coxal marker genes, Sp5, Sp6-9, and araucan, were absent from prolegs, but two endite marker genes, gooseberry and Distal-less, were expressed in prolegs, suggesting that prolegs may be using a modular endite gene-regulatory network (GRN) for their development. We propose that larval prolegs are novel traits derived from the activation of a pre-existing modular endite GRN in the abdomen using abd-A, the same Hox gene that still represses legs in more lateral positions.

Use of Selected Chemical and Biological Insecticides to Control Lepidopteran Pests of Maize Fields in Central Côte d'Ivoire

Control of lepidopteran larvae, the main pests in maize fields, has become necessary since the appearance and spread of Spodoptera frugiperda. The study was carried out at the Institut National Polytechnique Houphouët-Boigny in Yamoussoukro (Central Côte d’Ivoire). The study aimed to determine the effectiveness of three chemical - Viper 46 EC (Acetamiprid 16 g/l and Indoxacarb 30 g/l), K-Optimal 35 EC (Lambdacyhalothrin 15 g/l and Acetamiprid 20 g/l) and Ampligo 150 ZC (Chlorantanlipol 100 g/l and Lambdacyhalothrin 50 g/l) - and one biological insecticide Bio-Elit (Azadirachtin, Salanin, Nimbin and Melandriol) on lepidopteran larvae in maize fields using a randomized complete block design with five treatments and three repetitions. Data on insect identification, plant infestation, damage, and yield were collected. Insects’ identification was based on morphology using identification keys. Plant damage was assessed by visually estimating the plant health status (unattacked and attacked plants). Grain dry weight was used to estimate field yield. The encountered maize field insects belonged to 10 orders: Heteroptera, Hymenoptera, Homoptera, Coleoptera, Diptera, Dictyoptera, Odonata, Orthoptera, Dermaptera, and Lepidoptera. Five lepidopteran pest larvae have been recorded. Three of them were classified as minor pests (Eldana saccharina, Ostrinia nubilalis, and Helicoverpa zea), one as important (Sesamia calamistis), and one as a major pest (Spodoptera frugiperda). On untreated plots, more than 76% of plants were moderately to heavily attacked. However, on treated plots, plants showed isolated to moderate attacks. Insecticide sprayings controlled pest populations, reduced damage, and increased yield. The yields obtained on untreated plots (2.26±0.21 t/ha) were lower than those on treated plots (3.29±0.11 to 3.60±0.09 t/ha). The yield increase rate ranged from 45.74 to 59.63%. The best control was recorded with Ampligo (59.63%) and Bio-Elit (50.83%) compared to Viper (49.41%) and K-Optimal (45.74%). Therefore, the alternating use of synthetic or biological insecticides, which are not very toxic for humans and the environment but are effective on insect pests, increases the effectiveness of the control and provides a positive response to the problem of pest resistance while protecting the environment.

Estimation of the extent of defoliation in Avicennia L. (Acanthaceae) caused by caterpillars of Hyblaea puera (Cramer, 1777) in a tropical mangrove

The record of severe defoliation caused by lepidopteran larvae in mangrove forests has increased in recent decades and has caused concern because the mangrove is an ecosystem already threatened by several stressors. In this study, we used Sentinel-2 spatial data to quantify the extent and assess the health of the mangrove forest of the Mamanguape River estuary, Paraiba State, Brazil, in response to severe defoliation of Avicennia germinans and Avicennia schaueriana caused by caterpillars of the invasive exotic moth Hyblaea puera. The caterpillar outbreak was recorded in the period from May to July 2020 and satellite images referring to the years 2019–2021 were evaluated. Mangrove mapping was performed using supervised classification and forest health was assessed using the Normalized Difference Vegetation Index (NDVI). Supervised classification indicated that about 10% of the total mangrove area was intensely affected by defoliation caused by H. puera caterpillar infestation. Proportionally, the area of the A. schaueriana stand was more affected by defoliation than the A. germinans stand. NDVI indicated degraded health of the A. germinans and A. schaueriana stands in October 2020 while an improvement in biomass production was observed in June 2021. The results showed that the A. germinans stand is more resilient than the A. schaueriana stand. The consequences of severe defoliation, caterpillar characteristics, mangrove species details, and methodological issues are discussed.

Long-term changes as oil palm plantation age simplify the structure of host-parasitoid food webs.

Understanding host-parasitoid food webs, as well as the factors affecting species interactions, is important for developing pest management strategies in an agroecosystem. This research aimed to study how the long-term change in oil palm plantations, specifically the tree age, affect the structure of host-parasitoid food webs. The field research was conducted on an oil palm plantation located in Central Kalimantan and Jambi Province, Indonesia. In Central Kalimantan, we conducted observations of lepidopteran larvae and parasitoid wasps at different tree ages, ranging from 3 to 18 years old. For tree ages from 3 to 10 years, observations of host-parasitoid food webs were conducted by collecting the lepidopteran larvae using a hand-collection method in each oil palm tree within a hundred trees and they were later reared in the laboratory for observing the emerging parasitoids. The fogging method was applied for trees aged 12 to 18 years because the tree height was too high, and hand-collection was difficult to perform. To compare host-parasitoid food webs between different regions, we also conducted a hand-collection method in Jambi, but only for trees aged 3 years old. The food-web structure that was analyzed included the species number of lepidopteran larvae and parasitoid wasps, linkage density, and interaction diversity. We found 32 species of lepidopteran pests and 16 species of associated parasitoids in Central Kalimantan and 12 species of lepidopteran pests, and 11 species of parasitoids in Jambi. Based on the GLM analysis, tree age had a negative relationship with the species number of lepidopteran larvae and parasitoids as well as linkage density and interaction diversity. Different geographical regions showed different host-parasitoid food web structures, especially the species number of lepidopteran larvae and interaction diversity, which were higher in Central Kalimantan than in Jambi. However, some parasitoids can be found across different tree ages. For example, Fornicia sp (Hymenoptera: Braconidae) was recorded in all ages of oil palm sampled. Results of the GLM analysis showed that the abundance of Fornicia sp and its host (lepidopteran larvae abundance) were not affected by the tree age of the oil palm. In conclusion, the long-term change in oil palm plantations simplifies the structure of host-parasitoid food webs. This highlights the importance of long-term studies across geographical regions for a better understanding of the consequences that wide monoculture oil palm plantations have on biological control services.

New Decision-Making Control System for Caterpillars on Soybean Fields

Decision-making systems are essential to integrated pest management (IPM) programs, particularly in the context of soybean (Glycine max), the world’s most cultivated legume. As agricultural practices change, including adopting new cultivars, planting seasons, and planting regions, the challenges in pest management, mainly caterpillars (Lepidoptera larvae), also change. To address this, this study aimed to devise an updated decision-making approach tailored to the current soybean field conditions. Over two years, caterpillar densities were evaluated in 38 commercial soybean fields. The beating tray sampling technique was superior in precision and efficiency compared to the direct counting and beating cloth techniques. This technique involved assessing 61 plants per field to determine caterpillar density. Economic thresholds were determined at 7.11 caterpillars per beating tray for vegetative stages and 3.60 for reproductive stages. The new proposed sampling system was validated and demonstrated more precise and representative caterpillar density determination than the standard beating cloth system. Both methods exhibited similar costs and execution times. Therefore, this refined decision-making system has the potential for incorporation into soybean IPM programs due to its accuracy, representativeness, feasibility, speed, and cost-effectiveness. This study underscores the viability of integrating the newly developed decision-making system to enhance soybean pest management strategies.

Day-flying lepidoptera larvae have a poorer ability to thermoregulate than adults.

Changes to ambient temperatures under climate change may detrimentally impact small ectotherms that rely on their environment for thermoregulation; however, there is currently a limited understanding of insect larval thermoregulation. As holometabolous insects, Lepidoptera differ in morphology, ecology and behaviour across the life cycle, and so it is likely that adults and larvae differ in their capacity to thermoregulate. In this study, we investigated the thermoregulatory capacity (buffering ability) of 14 species of day-flying Lepidoptera, whether this is influenced by body length or gregariousness, and whether it differs between adult and larval life stages. We also investigated what thermoregulation mechanisms are used: microclimate selection (choosing locations with a particular temperature) or behavioural thermoregulation (controlling temperature through other means, such as basking). We found that Lepidoptera larvae differ in their buffering ability between species and body lengths, but gregariousness did not influence buffering ability. Larvae are worse at buffering themselves against changes in air temperature than adults. Therefore Lepidoptera may be more vulnerable to adverse temperature conditions during their larval life stage. Adults and larvae rely on different thermoregulatory mechanisms; adults primarily use behavioural thermoregulation, whereas larvae use microclimate selection. This implies that larvae are highly dependent on the area around their foodplant for effective thermoregulation. These findings have implications for the management of land and species, for example, highlighting the importance of creating and preserving microclimates and vegetation complexity surrounding Lepidoptera foodplants for larval thermoregulation under future climate change.

Study of Ecological Diversity of Predatory Asopinae Bugs in the Agro-ecosystem of the Mid-Western Plains

The aim of the present study was to investigate the seasonal abundance of Asopinae predatory stink bugs within an agro-ecosystem. This research was carried out by utilizing sweep nets to collect these insects during the period spanning from May to August in the year 2022. The survey yielded two prominent species of predaceous bugs, specifically Andrallus spinidens and Eocanthecona furcellata. Interestingly, E. furcellata emerged as the dominant species within the field conditions. A noteworthy phenomenon occurred in June when a sudden surge in the population of both species was observed. This population increase was attributed to the presence of lepidopteran larvae in the field, which likely served as a rich food source for these predatory stink bugs. The ecological analysis revealed some important findings regarding the diversity and distribution of these insects in the agro-ecosystem. Specifically, the Shannon Diversity Index was notably low, registering at less than 1.99, indicating a limited variety of species within the sampled population. Similarly, the Simpson Index indicated a low degree of diversity or heterogeneity, falling within the range of 0.01 to 0.04, which further supports the notion of a relatively homogeneous population. Additionally, the Margalef Richness Index signalled a level of disturbance, measuring less than 2.05. This disturbance could be linked to various factors affecting the ecosystem, including changes in agricultural practices or environmental conditions. Lastly, the Dominance Index was relatively high, ranging between 0.5 and 1.0, signifying that a few dominant species, particularly E. furcellata, exerted a significant influence within the ecosystem. In summary, the ecological indices suggested limited diversity, low heterogeneity, disturbance, and dominance within the stink bug population, shedding light on the dynamics of these beneficial insects in the agro-ecosystem.

Pathogenecity testing of indigenous Bacillus thuringiensis isolates against chickpea pod borer, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) in Ethiopia

Helicoverpa armigera (Hübner) is the most significant insect pest of chickpea in Ethiopia. Sole reliance on insecticide causes both human and environmental health problems. A common soil bacterium, Bacillus thuringiensis used as a bioinsecticide to control numerous Lepidopteran larvae. Therefore, indigenous isolates were collected, screened, tested for pathogenicity against H. armigera with a reference Bacillus. var. thuringiensis. From 121 soil samples collected, 23 Bacillus species were isolated and purified. Bt index ranged from 0.33 to 1.00 and the mean was 0.73 average Bt index. Absorbance values ranged from 0.46 to 0.98. Screening biotoxicity assay was conducted at the rate of 1 mL against 3rd instar larvae of H. armigera. Experiments were replicated three times; ten larvae were used per replicate and reputed thrice. Ten indigenous Bt isolates were screened based on larval mortality which ranged between 27.78% and 75.83% and LT50 values of 45.71–143.9 h. The highest mortality of 75.83% and LT50 of 45.71 h was recorded from reference Bt followed by indigenous Bt isolate KDL with mortality percentage of 69.16% and LT50 of 48.49 h. Statistically no significant difference was observed among the tested bacterial isolates. Biotoxicity assay was conducted at five concentrations ranging from 0.25 to 2 mL. The LD50 and LD 90 values were 0.84–1.24 mL and 1.54–1.98 mL, respectively. The lowest LD50, 90 of 0.84 mL and 1.54 mL were recorded from KDL Bt isolate compared to reference Bt whose LD50 and LD90 were 0.84 mL and 1.66 mL. Results of Bt growth under varied values of temperature ranged from 15oC to 40 °C. All the Bt isolates showed growth at all the values of the tested temperatures with steady growth from 15 °C to 20 °C and uniform growth observed from 20 °C to 30 °C. After 35 °C, the growth of all the Bt isolates declined indicating that 30 °C–35 °C is the optimum growth temperature range. Protein content ranged from 0.43 to 0.97 (mg/mL). However, protein content and larval mortality was not linearly correlated. It was concluded that all the tested indigenous Bacillus isolates were virulent enough and identified as a promising candidate bioinsecticide against H. armigera. Hence, recommended for further intensive evaluations under greenhouse and field trails.

Pesticide use, arthropod fauna and fruit damage in apple orchards in a Nordic climate Pesticides and arthropods in Nordic apple orchards.

Integrated pest management (IPM) has a long history in fruit production and has become even more important with the implementation of the EU directive 2009/128/EC making IPM mandatory. In this study, we surveyed 30 apple orchards in Norway for three years (2016-2018) monitoring pest- and beneficial arthropods as well as evaluating fruit damage. We obtained growers' diaries of pest management and used these data to study positive and negative correlations of pesticides with the different arthropod groups and damage due to pests. IPM level had no significant effects on damage of harvested apples by arthropod pests. Furthermore, damage by arthropods was mainly caused by lepidopteran larvae, tortricids being especially important. The number of insecticide applications varied between 0 and 3 per year (mean 0.8), while acaricide applications varied between 0 and 1 per year (mean 0.06). Applications were often based on forecasts of important pest species such as the apple fruit moth (Argyresthia conjugella). Narrow-spectrum insecticides were commonly used against aphids and lepidopteran larvae, although broad-spectrum neonicotinoid (thiacloprid) insecticides were also applied. Anthocorid bugs and phytoseiid mites were the most abundant natural enemies in the studied orchards. However, we found large differences in abundance of various "beneficials" (e.g. lacewings, anthocorids, parasitic wasps) between eastern and western Norway. A low level of IPM negatively affected the abundance of spiders. Lepidoptera was found to be the most important pest group in apple orchards. Insecticide use was overall low, but number of spray applications and use of broad-spectrum insecticides varied between growers and regions. IPM level did not predict the level of fruit damage by insects nor the abundance of important pests or most beneficial groups in an apple orchard. This article is protected by copyright. All rights reserved.

Morphology and Distribution of Antennal Sensilla on Spodoptera frugiperda (Lepidoptera: Noctuidae) Larvae and Adults

The invasive pest, Spodoptera frugiperda, commonly known as the fall armyworm (FAW), is a serious threat to food security in multiple countries worldwide. Insects’ antennal sensilla play a crucial role in perceiving plant odors and communication between male and female insects. This study aimed to examine the antennal morphology and sensilla variations on the antennae of FAW larvae and adults through scanning electron microscope analysis. The results revealed that third and fifth instar larval antennae possessed smell pores, sensilla pegs, and five types of antennal sensilla, namely sensilla trichodea, sensilla basiconica, sensilla chaetica, sensilla campaniform, and sensilla styloconicum, and the smell pores were first observed in Lepidoptera larvae. Furthermore, the size of sensilla in fifth instar larvae was significantly greater than those in third instar. On the adult antennae, there were smell pores and 12 types of sensilla identified: sensilla trichodea, sensilla basicaonica, sensilla auricillica, sensilla cavity, sensilla placodea, sensilla ligulate, Böhm’s bristles, sensilla chaetica, sensilla squamous, sensilla coeloconica, sensilla styloconicum, and sensilla uniporous peg. Notably, the sensilla cavity, sensilla placodea, sensilla ligulate, sensilla uniporous peg, and smell pores were first discovered in FAW adults. Compared with larvae, FAW adults have more types and amounts of sensilla. Additionally, we also discussed the possible functions of these antennal sensilla. This study provides valuable information for a comprehensive understanding of the type and function of antennal sensilla in FAW and assists in the development of novel pest control strategies, such as pest behavior control technology, for the prevention of this invasive pest.

Insect Mortality Caused by Baculovirus: a Model of Second-Order Phase Transitions

Baculoviruses, especially prevalent in Lepidoptera, have attracted the most attention as biological insect control agents. Infection with baculoviruses is usually fatal and therefore can affect host population density, especially if virus transmission increases with host density. Lepidoptera larvae show a strong dose-dependent response to pathogens such as baculoviruses, so their response to various pathogen exposures was studied in the present work. Models of virus exposure to insect hosts are usually judged by whether or not they generate cyclical population dynamics of multiple host generations. However, the existing theoretical models based on systems of differential equations are of little use for practical application due to the large number of variables and free parameters. In this regard, the possibility of using a mathematical model for describing the epizootic Malacosoma neustria L. and Lymantria dispar L. under the influence of nuclear polyhedrosis virus is considered. To assess the sensitivity of insects to the effects of baculoviruses, laboratory experiments were carried out on the mortality of caterpillars under various infectious loads. In this paper, we consider the possibility of constructing a model for the lifetime of insects after exposure to baculoviruses as an analogue of a second-order phase transition in physical systems and give estimates of the model parameters for two insect species at different titers of baculoviruses and at different ages of caterpillars. The dependence of the parameters of the proposed model on nuclear polyhedrosis virus strains is shown. The importance of the applied parameters for the organization of forest protection measures is substantiated.

Field evaluation of Bt 127SC formulation for efficacy against lepidopteran larvae infesting soybean under Manipur conditions

Bt 127SC formulation supplied by the ICAR-Indian Institute of Oilseeds Research, Hyderabad was field tested atImphal (Manipur) during kharif 2016-2018 against lepidopteran larvae infesting soybean. Two spray application of Bt 127 SC formulation @ 3 ml/litre of water was observed to be less superior to commercial synthetic insecticides but at par with Bt commercial Delfin in reducing Bihar hairy caterpillar and bean leaf webber and comparatively similar in efficacy with the synthetic insecticides in reducing tobacco caterpillar.

Complete genome sequences of two Bacillus thuringiensis serovar kurstaki strains isolated from Lebanon and Tunisia, highly toxic against lepidopteran larvae.

Bacillus thuringiensis-based products are key in the biopesticides market. Bacillus thuringiensis kurstaki strains Lip and BLB1 were isolated from Lebanese and Tunisian soils, respectively. These strains are highly toxic against lepidopteran larvae, Ephestia kuehniella. Here, we report Lip and BLB1 complete genomes, including their plasmid and toxin contents.

Damage Caused by Lepidopteran Pests on Maize Fields in Yamoussoukro, Central Côte d’Ivoire

Various larvae of Lepidoptera cause severe damage to maize crops. The dynamics of these maize larvae pests have been studied during all stages of plant development. The trial was carried out on the Institut National Polytechnique Houphouët-Boigny farm plots in Yamoussoukro (central Cote d’Ivoire). The study aims were to monitor the dynamics, determine the importance (frequency and abundance), and assess the damage of Lepidopteran pests on the maize variety EV8728 SR using a randomized complete block design with four replicates. The variety was sown on 05 September 2020. Insects were characterized with keys following on-site observation and capture of larvae on the plants. Five Lepidopteran species, grouped into three families, were counted on the plots. Spodoptera frugiperda was the most frequent (Occurrence C = 20.9%) and highly abundant (Relative Abundance Ar = 65.79%). The other Lepidoptera species were rare (C < 5%). However, Sesamia calamistis was very abundant (Ar=15.22%), while Eldana saccharina (Ar = 9.44%) and Ostrinia nubilalis (Ar = 5.25%) were abundant. Helicoverpa zea is scarcely abundant (Ar=4.3%). Furthermore, three Lepidoptera species (E. saccharina, O. nubilalis, and H. zea) were as minor pests (Damage Index I < 10%), while S. calamistis was important pest (I < 25%) and S. frugiperda was major pest (I< 75%). The populations of the insects fluctuated during crop development. The mean dried grain yield varied from 2.4±0.42 to 2.61±0.71 t/ha. Populations of S. frugiperda larvae and their damage appeared more important than those of other Lepidoptera. Knowledge of maize lepidopteran larvae is essential for effectively and efficiently controlling these pests and improving the quality and quantity of maize production.

Systematic analyses with genomic and metabolomic insights reveal a new species, Ophiocordyceps indica sp. nov. from treeline area of Indian Western Himalayan region.

Ophiocordyceps is a species-rich genus in the order Hypocreales (Sordariomycetes, Ascomycota) depicting a fascinating relationship between microbes and insects. In the present study, a new species, Ophiocordyceps indica sp. nov., is discovered infecting lepidopteran larvae from tree line locations (2,202-2,653 m AMSL) of the Kullu District, Himachal Pradesh, Indian Western Himalayan region, using combinations of morphological and molecular phylogenetic analyses. A phylogeny for Ophiocordyceps based on a combined multigene (nrSSU, nrLSU, tef-1α, and RPB1) dataset is provided, and its taxonomic status within Ophiocordycipitaceae is briefly discussed. Its genome size (~59 Mb) revealed 94% genetic similarity with O. sinensis; however, it differs from other extant Ophiocordyceps species based on morphological characteristics, molecular phylogenetic relationships, and genetic distance. O. indica is identified as the second homothallic species in the family Ophiocordycipitaceae, after O. sinensis. The presence of targeted marker components, viz. nucleosides (2,303.25 μg/g), amino acids (6.15%), mannitol (10.13%), and biological activity data, suggests it to be a new potential source of nutraceutical importance. Data generated around this economically important species will expand our understanding regarding the diversity of Ophiocordyceps-like taxa from new locations, thus providing new research avenues.

Genetics and Environmental Factors Associated with Resistance to Fusarium graminearum, the Causal Agent of Gibberella Ear Rot in Maize

Maize is one of the most important food and feed sources at the worldwide level. Due to this importance, all the pathogens that can infect this crop can harm both food safety and security. Fungi are the most important pathogens in cultivated maize, and Fusarium spp. are one of the most important families. Reduction in yield and production of dangerous mycotoxins are the main effects of Fusarium spp. infection. Fusarium graminearum (part of the Fusarium graminearum species complex) is one the most important fungi that infect maize, and it is the causative agent of Gibberella ear rot (GER). The main characteristics of this species include its ability to infect various species and its varying infection pressures across different years. This fungus produces various harmful mycotoxins, such as deoxynivalenol, zearalenone, butanolide, and culmorin. Infection can start from silk channels or from ear wounds. In the first case, the environmental conditions are the most important factors, but in the second, a key role is played by the feeding action of lepidopteran larvae (in Europe, Ostrinia nubilalis). All these factors need to be taken into account to develop a successful management strategy, starting from cropping methods that can reduce the source of inoculum to the direct control of the fungus with fungicide, as well as insect control to reduce ear wounds. But, the most important factor that can reduce the effects of this fungus is the use of resistant hybrids. Different studies have highlighted different defensive methods developed by the plant to reduce fungal infections, like fast drying of silk and kernels, chemical compounds produced by the plant after infection, and mechanical protection from insects’ wounds. The aim of this paper is to review the scientific evidence of the most important management strategies against GER in maize and to highlight the genetic basis which is behind hybrid resistance to this disease, with a focus on genes and QTLs found in studies conducted across the world and with different types of maize from tropical cultivars to European flint.

Multiple interaction networks reveal that Lepidoptera larvae and adults prefer various host plants for diet and pollination.

Plant-Lepidoptera interactions are often studied using the pollination or herbivore networks only. Lepidoptera species are involved in two types of plant-insect interactions because they are herbivores as larvae and pollinators as adults. The study of entangled networks is critical, since the interaction of different networks can affect the overall network and community stability. Here, we studied the interaction of plants and Lepidoptera on the Yongxing Island, South China Sea. A plant-lepidopteran pollination network and a plant-lepidopteran herbivore network were built by using data from flower-pollinator and leaf-herbivore interactions. We then combined the two networks into a single network. We measured plant composition similarity within each sub-network and across sub-networks for Lepidoptera species. Our findings indicate that the plant-Lepidoptera pollination network and the herbivory network share significant proportions of Lepidoptera but small proportions of plant assemblages. The pollination network had higher nestedness and connectance than the herbivore network. Agrius convolvuli was the most specialized species, while Zizina otis had the highest species strength in the pollination network. Most Lepidoptera species were highly specialized in the herbivore network and their importance positively correlated across the two networks. Furthermore, there was no dietary composition similarity between the two networks for most Lepidoptera species. Our findings highlight the visible structural difference between the pollination and the herbivore networks. Adult Lepidoptera selects different plants for oviposition and feeding, a strategy that may benefit their reproduction and survival by sustaining adequate resources for their two life stages and the diversity of both plants and insects in oceanic island communities.