Insects

The health, behavior, and physiology of honeybees and other pollinators are critical areas of research with profound implications for biodiversity, agriculture, and ecosystem stability [...]

The variegated cutworm Peridroma saucia Hübner, a recently emerged polyphagous pest in China’s Huang-Huai River Basin, uses sex pheromones (Z)-11-hexadecenyl acetate (Z11-16: Ac) and (Z)-9-tetradecenyl acetate (Z9-14: Ac) for mate finding. Insect pheromone-binding proteins (PBPs) serve as the primary filter for detecting specific sex pheromones. Although comprehensive functional analyses of PBPs exist, their binding mechanisms remain poorly characterized. In this study, we elucidated the binding properties and mechanisms of PsauPBP3 in sex pheromone recognition by computational and experimental approaches. PsauPBP3, predominantly expressed in male P. saucia antennae, showed high binding affinity for both Z11-16: Ac and Z9-14: Ac, as demonstrated by binding-free-energy calculations and fluorescence binding assays. Molecular dynamics simulations and docking studies identified five key residues (Thr-10, Phe-13, Ile-53, Ile-95, and Phe-119) that consistently interact with these pheromones, indicating their critical role in ligand binding. Computational alanine scanning further demonstrated that all five residues act as binding determinants, with Phe-13 and Ile-95 making particularly significant contributions to ligand affinity. The results were further validated by site-directed mutagenesis and fluorescence binding assays. This work provides insights into the function and binding mechanisms of PBPs in sex pheromone recognition and supports the development of targeted mating disruption strategies for P. saucia control.

Synchronous emergence is a widespread adaptive strategy in cicadas, yet the proximate cues governing its timing in urban environments remain poorly understood. We examined the emergence phenology of three common urban cicada species (Cryptotympana atrata, Hyalessa maculaticollis, Graptopsaltria nigrofuscata) across two urban parks with contrasting habitat structure (a closed-canopy urban forest park vs. an open urban park) in Seoul, South Korea, over three summers (2015–2017). Despite interannual variation in rainfall amount and timing, peak emergence consistently occurred about two weeks after the monsoon rainfall peak. Poisson generalized estimating equation (GEE) analyses confirmed that antecedent precipitation at a 2–3-week lag significantly increased emergence counts across all three species, while precipitation one week prior had no significant effect. Emergence synchrony varied among species and habitat conditions, but the rainfall–emergence lag relationship was robust across years and sites. These findings demonstrate that precipitation timing is a key driver of peak cicada emergence in urban habitats. As East Asia experiences increasingly variable monsoon rainfall under climate change, understanding precipitation-based phenological cues will be essential for predicting the dynamics of urban insect populations.