Yan Shi

Neuropeptide CCHamide-1 (abbreviated as CCHa1) is a recently discovered peptide that is present in many arthropods and is the ligand of the CCHa1R, a member of the G protein-coupled receptors (GPCRs) superfamily, which plays a regulatory role in diverse physiological processes such as feeding, circadian rhythm, insulin production, lipid metabolism, growth, and reproduction. However, the function of this gene in aphids is still unknown. Here, we characterized and determined the potential role of CCHa1/CCHa1R signaling in the pea aphid, Acyrthosiphon pisum, which is a notorious pest in agriculture. The docking analysis revealed that the CCHa1 peptide binds to its receptor CCHa1R through specific amino acid residues, which are critical for maintaining the structural and functional integrity of the peptide–receptor complex. Quantitative real-time reverse transcription-PCR (qRT-PCR) revealed the expression levels of CCHa1/CCHa1R transcripts in different development stages and different tissues, indicating that the CCHa1 expression was high in the first nymphal instar compared to the upcoming nymphal instars and adults, and was predominantly high in the brain. The CCHa1/CCHa1R transcript levels were significantly upregulated in starved aphids compared to fed aphids. Moreover, RNAi knockdown by the injection of dsRNA-CCHa1 and dsRNA-CCHa1R significantly reduced the corresponding expression of the target gene and reduced their food intake in adult aphids, as revealed by the electrical penetration graph results. CCHa1/CCHa1R-silencing also reduced the reproduction, but not the survival, in A. pisum. Our data demonstrated that CCHa1/CCHa1R play a role in the regulation of feeding in A. pisum, suggesting a role of the CCHa1 signaling pathway in the aphids relating to their nutritional status.

Insect short neuropeptide F (sNPF), an ortholog of prolactin-releasing peptide of invertebrates, regulates diverse biological processes, including feeding, olfaction, locomotion, and sleep homeostasis in insects. However, its function is still unclear in an important model insect and agricultural pest, the pea aphid (Acyrthosiphon pisum). Here, we investigated short neuropeptide F (ApsNPF) and its receptor (ApsNPFR) in A. pisum. The sNPF gene contains three exons and two long introns. In addition, the genome contains a single sNPF receptor with seven transmembrane domains. Stage- and tissue-specific transcript profiling by qRT-PCR revealed that ApsNPF and ApsNPFR were mainly expressed in the central nervous system. The receptor was also detected in antennae, midgut, and integument. The highest expression levels were found in first instar nymphs compared to other developmental stages. Besides, the starvation-induced pattern indicated that the sNPF network depends on the nutritional state of the insect. An electrical penetration graph showed that probing time and phloem duration of A. pisum on broad bean plants decreased in response to dssNPF and dssNPFR in RNAi assays. sNPF silencing reduced the number of nymphs per female but not aphid survival. We believe that our results advance in-depth knowledge of the sNPF/sNPFR signaling cascade and its place in regulating feeding behavior in insects. In turn, it may contribute to the potential design of new strategies to control aphids, with a focus on the sNPF system.

The oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), is one of the most important economic pests in tropical and subtropical areas of the world, where it causes serious damage to fruit production. This study aimed to investigate the criteria for dividing the instars of B. dorsalis, which will be fundamental for the control and forecasting of development rates, as well as the development of efficient control measures for B. dorsalis. Five morphological variables, including the body length, the length and width of mouth hooks, and the length and width of the pharyngeal sclerite of the larvae, were measured. The Crosby growth rule was used in determining that B. dorsalis has 3 instars. The length of the pharyngeal sclerite is the best morphological variable for distinguishing the instars of B. dorsalis, whereas the length and the width of mouth hooks and the width of the pharyngeal sclerite can be used as additional characteristics. There was an overlap in the body length bet... Resumen La mosca de la fruta oriental, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), es considerada una de las plagas más importantes desde el punto de vista económico en las zonas tropicales y subtropicales del mundo, donde causa daños serios a la producción de frutas. El objetivo de este estudio fue investigar el criterio para dividir los instares de B. dorsalis, que serán fundamentales para el control y pronóstico de la tasa de desarrollo, así como el desarrollo de medidas de control eficaces contra B. dorsalis. Se midieron cinco variables morfológicas, incluyendo la longitud corporal, la longitud y el ancho de los ganchos bucales y la longitud y el ancho de las escleritas faríngeas de las larvas. Se utilizó La regla de crecimiento de Crosby para determinar que B. dorsalis tiene 3 estadios. La longitud de las escleritas faríngeas es la mejor variable morfológica para distinguir los instares de B. dorsalis, mientras que la longitud y el ancho de los ganchos bucales y el ancho de las escleritas fa...