RESUMEN
Mating has profound physiological and behavioural consequences for female insects. During copulation, female insects typically receive not only sperm, but a complex ejaculate containing hundreds of proteins and other molecules from male reproductive tissues, primarily the reproductive accessory glands. The post-mating phenotypes affected by male accessory gland (MAG) proteins include egg development, attraction to oviposition hosts, mating, attractiveness, sperm storage, feeding and lifespan. In the Mexican fruit fly, Anastrepha ludens, mating increases egg production and the latency to remating. However, previous studies have not found a clear relationship between injection of MAG products and oviposition or remating inhibition in this species. We used RNA-seq to study gene expression in mated, unmated and MAG-injected females to understand the potential mating- and MAG-regulated genes and pathways in A. ludens. Both mating and MAG-injection regulated transcripts and pathways related to egg development. Other transcripts regulated by mating included those with orthologs predicted to be involved in immune response, musculature and chemosensory perception, whereas those regulated by MAG-injection were predicted to be involved in translational control, sugar regulation, diet detoxification and lifespan determination. These results suggest new phenotypes that may be influenced by seminal fluid molecules in A. ludens. Understanding these influences is critical for developing novel tools to manage A. ludens.
Asunto(s)
Expresión Génica , Conducta Sexual Animal , Tephritidae , Animales , Copulación , Femenino , Masculino , Oviposición , Reproducción , Tephritidae/genéticaRESUMEN
The genus Helicoverpa (Lepidoptera: Noctuidae) includes phytophagous and polyphagous agricultural insect pests. In the Americas, a native pest, Helicoverpa zea (Boddie), and an invasive pest, Helicoverpa armigera (Hübner), are causing severe damage in vegetable and agronomic crops. The population structure of both species in South America is poorly understood, and the phylogenetic relatedness of H. armigera and H. zea suggests natural interspecific gene flow between these species. Using microsatellite loci, we investigated: 1) the genetic diversity and gene flow of H. armigera specimens from Brazil; 2) the genetic diversity and gene flow between H. zea specimens from Brazil and the United States; and 3) the possibility of interspecific gene flow and the frequency of putative hybrids in Brazil. We detected high intraspecific gene flow among populations collected in the same country. However, there is a geographic limit to gene flow among H. zea individuals from South and North America. Pairwise Fst and private alleles showed that H. armigera is more similar to H. zea from Brazil than H. zea from the United States. A comparative STRUCTURE analysis suggests natural hybridization between H. armigera and H. zea in Brazil. High gene flow and natural hybridization are key traits to population adaptation in new and disturbed environments, which can influence the management of these pests in the American continent.
Asunto(s)
Flujo Génico , Variación Genética , Hibridación Genética , Mariposas Nocturnas/genética , Animales , Brasil , Genes de Insecto , Larva/genética , Repeticiones de Microsatélite , Mariposas Nocturnas/crecimiento & desarrollo , Filogenia , Estados UnidosRESUMEN
We present the development of a genomic library using RADseq (restriction site associated DNA sequencing) protocol for marker discovery that can be applied on evolutionary studies of the sugarcane borer Diatraea saccharalis, an important South American insect pest. A RADtag protocol combined with Illumina paired-end sequencing allowed de novo discovery of 12 811 SNPs and a high-quality assembly of 122.8M paired-end reads from six individuals, representing 40 Gb of sequencing data. Approximately 1.7 Mb of the sugarcane borer genome distributed over 5289 minicontigs were obtained upon assembly of second reads from first reads RADtag loci where at least one SNP was discovered and genotyped. Minicontig lengths ranged from 200 to 611 bp and were used for functional annotation and microsatellite discovery. These markers will be used in future studies to understand gene flow and adaptation to host plants and control tactics.
Asunto(s)
Genoma de los Insectos , Lepidópteros/genética , Análisis de Secuencia de ADN , Animales , ADN , Marcadores Genéticos , Repeticiones de Microsatélite , Polimorfismo de Nucleótido Simple , SaccharumRESUMEN
We present polymorphic microsatellite markers isolated for genetic studies of the sugarcane borer, Diatraea saccharalis (Fabricius). We isolated 16 microsatellite loci through an enriched genomic library protocol. After characterization, 12 markers showed polymorphic information expressed in the observed number of alleles (ranging from 2 to 7; 5 on average) and in the polymorphism information content (ranging from 0.292 to 0.771; 0.535 on average). These markers can be used in further studies to understand the basic ecological characteristics of the sugarcane borer, e.g., dispersion patterns and population genetic differentiation, associated with distinct geographic scales and host plants.
Asunto(s)
Sitios Genéticos/genética , Lepidópteros/genética , Repeticiones de Microsatélite/genética , Saccharum/parasitología , Animales , Datos de Secuencia MolecularRESUMEN
We developed six microsatellite markers for the fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae). The SSR loci were isolated with enriched genomic library protocol by using native individuals as a genome source for markers. These loci were characterized in 48 individuals and they were tested for the ability to identify candidate migrants exchanged among the samples. The number of alleles per locus ranged from 5 to 18 (10.8 on average). The observed polymorphism information content ranged from 0.172 to 0.891. Beside the lower efficiency to obtain SSR loci, the six microsatellites were polymorphic and sufficiently discriminant for the genetic studies of S. frugiperda; it allowed us to identify migrants with both NJ clustering and the Bayesian methods. These markers will be useful for molecular ecology studies of this highly polyphagous species in order to understand the processes that determine genetic differentiation in the complex agro-ecosystems that it infests and improve local integrated pest management practices.