Dataset Information

Host strain specific sex pheromone variation in Spodoptera frugiperda.

ABSTRACT:

Background

The fall armyworm Spodoptera frugiperda (Lepidoptera; Noctuidae) consists of two distinct strains with different host plant preferences for corn and rice. To assess whether pheromonal-mediated behavioral isolation accompanies the habitat isolation on different host plants, we compared the sex pheromone composition among females of the two strains. Pheromone glands were extracted with or without injection of pheromone biosynthesis activating neuropeptide (PBAN). To assess the mode of inheritance of this variation, we also analyzed the pheromone composition of F1 hybrid females.

Results

Relative to intra-strain variation, the pheromone composition of the two strains differed significantly. Corn strain females contained significantly more of the second most abundant pheromone compound Z11-16:Ac (m), and significantly less of most other compounds, than rice strain females. When females were injected with PBAN before their glands were extracted, the differences between the strains were less pronounced but still statistically significant. The pheromone composition of hybrid females showed a maternal inheritance of the major component Z9-14:Ac (M) as well as of Z11-16:Ac (m). Most other compounds showed an inheritance indicating genetic dominance of the corn strain. The within-strain phenotypic correlations among the various components were consistent with their hypothesized biosynthetic pathway, and between-strain differences in the correlation structure suggested candidate genes that may explain the pheromone differences between the two strains. These include Delta9- and Delta11 desaturases, and possibly also a Delta7-desaturase, although the latter has not been identified in insects so far.

Conclusion

The two host strains of S. frugiperda produce systematically differing female sex pheromone blends. Previously-documented geographic variation in the sexual communication of this species did not take strain identity into account, and thus may be partly explained by different strain occurrence in different regions. The finding of pheromone differences reinforces the possibility of incipient reproductive isolation among these strains, previously shown to differ in the timing of nocturnal mating activity and host plant use. Finding the genetic basis of the pheromone differences, as well as these other biological traits, will help to elucidate the role of premating isolation in the continuing differentiation of these two strains that may eventually lead to speciation.

SUBMITTER: Groot AT

PROVIDER: S-EPMC2628650 | biostudies-literature | 2008 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Host strain specific sex pheromone variation in Spodoptera frugiperda.

Groot Astrid T AT Marr Melanie M Schöfl Gerhard G Lorenz Sybille S Svatos Ales A Heckel David G DG

Frontiers in zoology 20081225

<h4>Background</h4>The fall armyworm Spodoptera frugiperda (Lepidoptera; Noctuidae) consists of two distinct strains with different host plant preferences for corn and rice. To assess whether pheromonal-mediated behavioral isolation accompanies the habitat isolation on different host plants, we compared the sex pheromone composition among females of the two strains. Pheromone glands were extracted with or without injection of pheromone biosynthesis activating neuropeptide (PBAN). To assess the m ...[more]

PMID: 19109878

Similar Datasets

Project description:The corn- and rice-strains of Spodoptera frugiperda exhibit several genetic and behavioral differences and appear to be undergoing ecological speciation in sympatry. Previous studies reported conflicting results when investigating male attraction to pheromone lures in different regions, but this could have been due to inter-strain and/or geographic differences. Therefore, we investigated whether corn- and rice-strain males differed in their response to different synthetic pheromone blends in different regions in North America, the Caribbean and South America. All trapped males were strain-typed by two strain-specific mitochondrial DNA markers. In the first experiment, we found a nearly similar response of corn- and rice-strain males to two different 4-component blends, resembling the corn- and rice-strain female blend we previously described from females in Florida. This response showed some geographic variation in fields in Canada, North Carolina, Florida, Puerto Rico, and South America (Peru, Argentina). In dose-response experiments with the critical secondary sex pheromone component (Z)-7-dodecenyl acetate (Z7-12:OAc), we found some strain-specific differences in male attraction. While the response to Z7-12:OAc varied geographically in the corn-strain, rice-strain males showed almost no variation. We also found that the minor compound (Z)-11-hexadecenyl acetate (Z11-16:OAc) did not increase attraction of both strains in Florida and of corn-strain males in Peru. In a fourth experiment, where we added the stereo-isomer of the critical sex pheromone component, (E)-7-dodecenyl acetate, to the major pheromone component (Z)-9-tetradecenyl acetate (Z9-14:OAc), we found that this compound was attractive to males in North Carolina, but not to males in Peru. Overall, our results suggest that both strains show rather geographic than strain-specific differences in their response to pheromone lures, and that regional sexual communication differences might cause geographic differentiation between populations.

Project description:Pheromone cues released from hosts or prey are of crucial importance to natural enemies for prey and habitat location. The use of herbivorous insect sex pheromones has long been considered as a potential pest control alternative that is non-toxic and harmless to beneficials. We hypothesized that Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), a major predatory coccinellid beetle of the devastating migratory pest Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae), could perceive and use the sex pheromone of S. frugiperda to locate its habitat. Here we tested the electrophysiological and behavioral responses of H. axyridis to the two components Z7-12:Ac and Z9-14:Ac of S. frugiperda sex pheromone by using electroantennography (EAG) and Y-tube bioassay. The 3D modeling of H. axyridis odorant-binding proteins (HaxyOBPs) and molecular docking were also performed. The results showed that both female and male H. axyridis exhibited significantly higher electrophysiological and behavioral responses to Z9-14:Ac at the concentrations of 0.001, 0.01, and 0.1 μg/μL, while no significant electrophysiological and behavioral responses of H. axyridis were observed to Z7-12:Ac. The blend of Z7-12:Ac and Z9-14:Ac at the ratio of 1:100 had a significant attraction to both male and female H. axyridis at the concentrations of 0.01 and 0.1 μg/μL based on electrophysiological and behavioral assays, but no significant behavioral responses were observed at the ratios of 1:9. According to the 3D modeling of HaxyOBPs and molecular docking, HaxyOBP12 has a good affinity with Z9-14:Ac. Z9-14:Ac is bound to the HaxyOBP12 by hydrogen bonding and hydrophobic interactions. However, there were no credible docking results between HaxyOBPs and Z7-12:Ac. Our findings revealed that H. axyridis can perceive Z9-14:Ac and could use it as a chemical cue to locate prey habitat. We speculated that Z7-12:Ac, which showed some antagonistic effect toward the response of H. axyridis to Z9-14:Ac, could improve the adaptability of S. frugiperda in the presence of predators. This study provides new insights into the application of pheromones to manipulate natural enemy behavior for pest control.

Project description:The Sf9 and Sf21 cell lines derived from ovarian tissues of the wide-host-range phytophagous lepidopteran Spodoptera frugiperda are widely used for research and commercial-scale production of recombinant proteins. These cell lines are chronically infected with a rhabdovirus (Sf-RV) that does not cause any overt cytopathic effects. We demonstrate that wild populations of S. frugiperda in the eastern United States and Caribbean are infected with genetically diverse strains of Sf-RV and that this virus is also capable of infecting cells of Spodoptera exigua, Heliothis subflexa, and Bombyx mori Feeding studies demonstrated the ability of S. frugiperda larvae to deposit Sf-RV onto human-consumed vegetables during feeding. Although no evidence for replication in two species of plant cells was detected, subcellular localization studies demonstrated that the Sf-RV nucleocapsid was targeted to plasmodesmata, while two forms of the accessory protein were differentiated on the basis of their ability to localize to nuclei. Collectively, the results from this study suggest that environmental exposure of humans to Sf-RV is likely to be commonplace and frequent, but its inability to replicate in plant or human cells suggests that there is no substantial risk to human health.IMPORTANCE Insect-derived cell lines are widely used commercially for the production of vaccines and protein-based pharmaceuticals. After decades of safe and beneficial use, it was a surprise to the biotechnology industry to discover an endemic rhabdovirus in Sf9 cells. This discovery was made possible only by the substantial advancements in DNA sequencing technologies. Given the public health concerns associated with many rhabdovirus species, several initiatives were undertaken to establish that Spodoptera frugiperda rhabdovirus (Sf-RV) does not pose a threat to humans. Such actions include the generation of cell lines that have been cleared of Sf-RV. Given that Sf9 is derived from a moth whose larvae feed on human-edible foods, we explored the prevalence of Sf-RV in its wild and lab-grown populations, as well as its ability to be deposited on food items during feeding. Collectively, our data suggest that there is no overt risk from exposure to Sf-RV.

Project description:Mounting evidence indicates that the gut microbiota influences the neurodevelopment and behavior of insects through the gut-brain axis. However, it is currently unclear whether the gut microbiota affect the head profiles and immune pathway in pests. Here, we find that gut bacteria is essential for the immune and neural development of adult Spodoptera frugiperda, which is an extremely destructive agricultural pest worldwide. 16 S rRNA sequencing analysis showed that antibiotics exposure significantly disturbed the composition and diversity of gut bacteria. Further transcriptomic analysis revealed that the adult head transcripts were greatly affected by gut dysbacteriosis, and differently expression genes critical for brain and neural development including A4galt, Tret1, nsun4, Galt, Mitofilin, SLC2A3, snk, GABRB3, Oamb and SLC6A1 were substantially repressed. Interestingly, the dysbacteriosis caused sex-specific differences in immune response. The mRNA levels of pll (serine/threonine protein kinase Pelle), PGRP (peptidoglycan-sensing receptor), CECA (cecropin A) and CECB (cecropin B) involved in Toll and Imd signaling pathway were drastically decreased in treated male adults' heads but not in female adults; however, genes of HIVEP2, ZNF131, inducible zinc finger protein 1-like and zinc finger protein 99-like encoding zinc-finger antiviral protein (ZAP) involved in the interferon (IFNα/β) pathway were significantly inhibited in treated female adults' heads. Collectively, these results demonstrate that gut microbiota may regulate head transcription and impact the S. frugiperda adults' heads through the immune pathway in a sex-specific manner. Our finding highlights the relationship between the gut microbiota and head immune systems of S. frugiperda adults, which is an astonishing similarity with the discoveries of other animals. Therefore, this is the basis for further research to understand the interactions between hosts and microorganisms via the gut-brain axis in S. frugiperda and other insects.

Project description:In the Americas, the fall armyworm (Spodoptera frugiperda) exists in two genetically distinct strains, the corn (C) and rice (R) strains. Despite their names, these strains are not associated with host plant preferences but have been shown to vary in pheromone composition and male responses. Recently, S. frugiperda was detected in Africa as an invasive species, but knowledge about variation in strain types, pheromone composition and inter-strain mating of populations of the pest in the continent has not been fully examined. Therefore, this study aimed to investigate variations, if any in the pheromone composition of female moths, male moth responses, and mating between C and R mitotypes of S. frugiperda populations in Kenya, as well as their geographic distribution. Strains (mitotypes) of S. frugiperda were identified using mitochondrial DNA (mtDNA) markers, and their pheromonal composition determined by coupled gas chromatography-mass spectrometric (GC-MS) analysis. Male moth responses to these compounds were evaluated using GC-electroantennographic detection (EAD), electroantennogram (EAG), and wind tunnel assays. Oviposition assays were used to determine whether R and C mitotype moths could mate and produce eggs. The results showed that both the R and C mitotypes were present, and there were no statistically significant differences in their distribution across all sampled locations. Five pheromone compounds including (Z)-7-dodecenyl acetate (Z7-12:OAc), (Z)-7-tetradecenyl acetate (Z7-14:OAc), (Z)-9-tetradecenyl acetate (Z9-14:OAc), (Z)-11-tetradecenyl acetate (Z11-14:OAc) and (Z)-11-hexadecenyl acetate (Z11-16:OAc), were detected in the pheromone glands of female moths of both mitotypes, with Z9-14:OAc being the most abundant. The relative percentage composition of Z9-14:OAc was similar in both mitotypes. However, the R mitotype had a 2.7 times higher relative percentage composition of Z7-12:OAc compared to the C mitotype moth, while the C mitotype moth had a 2.4 times higher relative percentage composition of Z11-16:OAc than the R mitotype moth. Male moths of both mitotypes exhibited similar responses to the pheromone compounds, showing the strongest responses to Z9-14:OAc and Z7-12:OAc in electrophysiological and behavioural assays. There was mating between R and C mitotypes with egg production comparable to mating within the same mitotype. Our results revealed that differences between the two S. frugiperda mitotypes are characterized by female moth pheromone composition rather than male moth responses to the pheromones, and that this does not prevent hybridisation between the mitotypes, which may have implications for their management.

Dataset Information

Host strain specific sex pheromone variation in Spodoptera frugiperda.

Background

Results

Conclusion

Publications

Host strain specific sex pheromone variation in Spodoptera frugiperda.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets