Tracking the Asian tiger mosquito (Aedes albopictus) in Austria: benefits of combining expert-based monitoring with citizen science data

Background The Asian tiger mosquito ( Aedes albopictus ) is an invasive species and a competent vector of numerous pathogens. Its establishment in Austria represents a growing public health concern, underscoring the need for effective surveillance strategies. In Austria, two complementary monitoring systems are implemented, an expert-based ovitrap monitoring programme and a citizen science-based monitoring approach. This study investigates whether combining structured expert monitoring with citizen science reporting provides measurable benefits and identifies which advantages are most relevant. Methods We analysed data from Austria’s nationwide ovitrap monitoring programme (following AIM-SURV protocol) and the citizen science project “Mosquito Alert” between 2020 and 2024. Both systems were evaluated at two spatial resolutions (5 × 5 km 2 and 20 × 20 km 2 grids) to quantify detection coverage, timing, and contribution to tracking spatial spread. Results Combining ovitrap monitoring with the citizen science-based approach significantly improved detection coverage and spatiotemporal resolution. At fine scale (5 × 5 km 2 ), the integrated approach increased positive grid cells by up to 70% compared to ovitraps alone, particularly in later years when citizen science reports dominated new detections. On the coarse scale (20 × 20 km 2 ), ovitraps remained the primary source of early detections, while Mosquito Alert provided complementary signals in certain regions. Citizen science data were especially valuable for documenting local clustering, whereas ovitraps were more effective for identifying isolated new detections. Conclusions Integrating structured expert surveillance with validated citizen science creates a more comprehensive and responsive monitoring framework for Ae. albopictus . This multi-source approach enhances early warning, spatial coverage, and operational decision-making, offering a scalable model for invasive vector surveillance in Europe.