Drosophila suzukii wing spot size is robust to developmental temperature

Thermal plasticity of wing size and wing spot size in Drosophila guttifera

Thermal plasticity of melanin pigmentation patterns in Drosophila species has been studied as a model to investigate developmental mechanisms of phenotypic plasticity. The developmental process of melanin pigmentation patterns on wings of Drosophila is divided into two parts, prepattern specification during the pupal period and wing vein-dependent transportation of melanin precursors after eclosion. Which part can be affected by thermal changes? To address this question, we used polka-dotted melanin spots on wings of Drosophila guttifera, whose spot areas are specified by wingless morphogen. In this research, we reared D. guttifera at different temperatures to test whether wing spots show thermal plasticity. We found that wing size becomes larger at lower temperature and that different spots have different reaction norms. Furthermore, we changed the rearing temperature in the middle of the pupal period and found that the most sensitive developmental periods for wing size and spot size are different. The results suggest that the size control mechanisms for the thermal plasticity of wing size and spot size are independent. We also found that the most sensitive stage for spot size was part of the pupal period including stages at which wingless is expressed in the polka-dotted pattern. Therefore, it is suggested that temperature change might affect the prepattern specification process and might not affect transportation through wing veins.

Phylogenetic analysis and designing new primers for molecular identification of Drosophila suzukii

The family Drosophilidae includes over 3750 species worldwide and over 2000 of these are species of Drosophila. Spotted wing drosophila (SWD), Drosophila suzukii is one of the most dangerous species in this family. The insects live on undamaged ripening fruits, using its peculiar serrated ovipositor to break the skin of fresh ripening fruits and lay eggs in it. Drosophila species are very difficult and practically impossible to detect at larval stages. The present investigation was conducted at the All-Russian Plant Quarantine Center and Agrarian and Technological Institute of RUDN University, Moscow, Russia in 20182020. The aim of this study was to investigate the method of accurate and rapid identification of D. suzukii, and to design specific primer pairs for pest identification by Real-Time PCR method. The real-time quantitative PCR is a fast, sensitive, repeatable and accurate method for quantifying gene transcript levels. In this study, we designed specific primers (4.Dsuz.FRP) for Real-Time PCR to identify D. suzukii from other relative species. Although D. suzukii is absent in the Russian Federation and has not been reported so far, the project could be a precautionary measure.

Genome-wide gene expression profiles of the pea aphid (Acyrthosiphon pisum) under cold temperatures provide insights into body color variation

Cold temperatures are one of the factors influencing color polymorphisms in Acyrthosiphon pisum, resulting in a change from a red to greenish color. Here we characterized gene expression profiles of A. pisum under different low temperatures (1°C, 4°C, 8°C, and 14°C) and durations (3, 6, 12, and 24 h). The number of differentially expressed genes (DEGs) increased as temperatures decreased and time increased, but only a small number of significant DEGs were identified. Genes involved in pigment metabolism were downregulated. An interaction network analysis for 506 common DEGs in comparisons among aphids exposed to 1°C for four durations indicated that a cytochrome P450 gene (CYP, LOC112935894) significantly downregulated may interact with a carotenoid metabolism gene (LOC100574964), similar to other genes encoding CYP, lycopene dehydrogenase and fatty acid synthase. We proposed that the body color shift in A. pisum responding to low temperatures may be regulated by CYPs.

Plasticity Is Key to Success of Drosophila suzukii (Diptera: Drosophilidae) Invasion

After its initial discovery in California in 2008, Drosophila suzukii Matsumura has become one of the most important invasive agricultural pest insects across climate zones in much of Asia, Europe, North America, and South America. Populations of D. suzukii have demonstrated notable behavioral and physiological plasticity, adapting to diverse environmental and climatic conditions, interspecific competition, novel food sources, and potential predators. This adaptability and plasticity have enabled rapid range expansion and diversified niche use by D. suzukii, making it a species particularly suited to changing habitats and conditions. This article reviews factors and evidence that influence plasticity in D. suzukii and promotes this species' invasiveness.