Opportunistic citizen science data could be a faster and more efficient way to detect and monitor the spread of invasive species especially in developing countries: The case of harlequin ladybird Harmonia axyridis in Algeria.

Abstract Accelerated spread of the non-native species Harmonia axyridis in Algeria may pose problem to local biodiversity, and new challenges to natural resource management, and economies. Three new records of this species have been detected in different part of the country via an investigation on social media platforms and, in a citizen science database. Our findings indicate the presence of the species in at least three localities, more than 400 km away for the most distant of them, and highlighted the important role of citizen science in developing countries where the funding of doing research in that field almost non-existent.