The Formal Model for the hoverfly Sphaerophoria scripta (Diptera, Syrphidae) agent-based model in the Animal Landscape and Man Simulation System (ALMaSS)

We present a formal model for the aphidophagous hoverfly Sphaerophoria scripta , a species widely used for biological control of Myzus persicae and other aphids, as well as for pollination services. The model is structured for integration within the Animal Landscape and Man Simulation System (ALMaSS) to investigate population dynamics under variable field conditions, with the overarching aim of improving regulatory risk assessments of pesticide impacts on hoverflies. Our approach is individual-based, spatially explicit, and operates on a daily time step. The principal model drivers include temperature, the spatial and temporal distribution of aphid prey for larvae, and the availability of nectar and pollen resources for adult females. Dispersal functions are designed to interact dynamically with foraging and oviposition behaviours, with daily activity patterns governed by the interplay between reproductive objectives and foraging requirements. Key life-history parameters, including egg incubation duration, larval instar development, pupariation, adult longevity, and fecundity, were derived from available laboratory and field studies. The prototype model defines state transitions, developmental thresholds, mortality functions, and foraging-oviposition behaviours, and is prepared for calibration and scenario-based application.