Responses of tree defoliators to traffic-derived particulate matter along a roadside pollution gradient. Dataset

The dataset quantifies how real-world roadside particulate pollution affects host plants and a specialist herbivore. It includes: (i) physicochemical leaf traits of Crataegus monogyna and Prunus cerasifera (specific leaf area, leaf toughness); (ii) particulate matter (PM) loads on leaves measured as surface PM and in-wax PM across size fractions (PM₁₀–₁₀₀, PM₂.₅–₁₀, PM₀.₂–₂.₅); (iii) foliar trace elements (Ba, Cu, Fe, Mn, Mo, Pt, Rb, Sr, Zn), with elements excluded from analyses when values were at or below the XRF detection limit; and (iv) biological responses of Yponomeuta padella larvae and adults, including 3-choice feeding outcomes, emergence dynamics from logistic fits (growth rate, inflection point), eclosion success, and adult body mass (sex-specific). Sampling was done along a traffic pollution gradient at three site categories—Roadside, Sidewalk, Control—near an expressway in Poznań, Poland (10 replicates per category),, and larvae reared on foliage from the same site–plant combinations under controlled lab conditions. The data are structured to test whether increasing PM/TE loads correspond to altered food preference, delayed development, reduced survival, and lower adult mass in a monophagous/oligophagous moth system.