Manual identification and quantitative analysis of trap catches are necessary in classical collection methods. Machine learning, image recognition, and artificial intelligence are useful methods for the identification of food-contaminating beetle species (Wu et al., 2019). Batz et al. proved that such methods could be used for small insect pests: specifically, for systematic monitoring of aphids, automated identification, and intelligent forecasting.

Climate change impacts crop production and the interaction of biotic and abiotic stresses, posing considerable threats to sustainable food security (Wang et al., 2022; Robles-Zazueta et al., 2023). Warming of the climate affects biological invasions by shifting interactions between plants and herbivores (Lu et al., 2013); this highlights the importance of assessments of the effects of climate warming on the population distributions of pests and their natural enemies. Lian et al. analyzed key environmental factors affecting both the survival and the potential distribution of Lipaphis erysimi, an important vegetable aphid, and its dominant predatory natural enemy, the hoverfly Eupeodes corollae, based on the MaxEnt model and using data on the geographical distribution of historical occurrences. Their data will be beneficial for pest-monitoring and for early warning and biological control systems.

A suction trap is useful method of surveying migration in small insect pests, such as aphids. Wheat aphids, in particular, are migrant pests. Using data from suction traps, Li et al. analyzed the migration patterns of the wheat aphid species Sitobion miscanthi, Rhopalosiphum padi, and Schizaphis graminum in the northern plains of the wheat-growing region of China during the period 2018 to 2020. Aphid migration trajectories changed over the years, as simulated by the NOAA HYSPLIT model. The facultative bacterial symbionts of migrant wheat aphids were investigated with specific PCR and amplicon sequencing. The dominant infection strains (Serratia symbiotica, Hamiltonella defensa, and Regiella insercticola) were identified from S.miscanthi, R. padi, and the diversity of the bacterial community varied across wheat aphid species and migrant populations.

Omics approaches, i.e., transcriptomes, proteomes, secretomes, and so on, are useful methods of understanding insect development, metabolism, and host adaptation.

Taking the horned gall aphid Schlechtendalia chinensis as a test target, Wei et al. combined data from morphological observations of male aphids using SEM, high-throughput transcriptome sequencing, and weighted gene co-expression network analysis; they identified gene co-expression modules and hub genes correlated with body size traits and speculated that the male aphid degrades its own substances via autophagy and apoptosis in order to sustain life activities, resulting in body size reduction after molting.

In aphids with piercing–sucking mouth parts, salivary glands and their secretions play an important role in the feeding process. The identification of saliva proteins is an important step in understanding the adaptation of aphids to host plants (Zhang et al., 2017; Zhang et al., 2022; Zhang et al., 2023). Zhang et al. selected Pseudoregma bambucicola, a severe bamboo pest, as the target of their analysis; this aphid species feeds on stalks of bamboos by degrading hard bamboo cell walls. Using salivary transcriptome, secretome, and proteome analyses, they detected some secretory proteins homologous to known aphid effectors in P. bambucicola. Although plant cell wall-degrading enzymes were identified, most of them were expressed at low levels in the aphid salivary glands. These results imply that symbiotic bacteria of P. bambucicola may help the aphid adapt to a specific habitat.

Aphids and their primary symbiont, Buchnera aphidicola, form a stable and mutually beneficial relationship that plays an important role in providing the necessary nutrients to the host aphid (Li et al., 2023). Based on the genome sequence of the wheat aphid Siotobion miscanthi and its primary symbiont Buchnera, which the authors had previously studied, Li et al. identified a metabolic relay gene, ilvA, linking the aphid and Buchnera in the isoleucine synthesis pathway, with higher levels of expression observed in the aphid bacteriocytes. This gene is also conserved in different aphid genomes. The function of ilvA is important in aphid development and reproduction, as evaluated through RNAi.

JC: Writing – original draft, Writing – review & editing.