A pictorial key for identification of the hoverflies (Diptera: Syrphidae) of the Madeira Archipelago

BACKGROUND: Syrphid flies are important ecological indicators and provide crucial ecosystem services, being important pollinators and biological control agents of insect pests. These charismatic insects are conspicuous and, due to their size and colourful patterns, are relatively easy to identify. However, the lack of user-friendly literature (e.g. photographic guides) for most areas may hamper its wider selection as a study group in biodiversity and ecological studies. The syrphid fauna of Madeira Archipelago comprises 26 species, including four endemics (Eumerus hispidus Smit, Aguiar & Wakeham-Dawson, 2004; Melanostoma wollastoni Wakeham-Dawson, Aguiar, Smit, McCullough & Wyatt, 2004; Myathropa usta, Wollaston, 1858 and Xanthandrus babyssa, Walker, 1849), but, despite the current good taxonomic knowledge on this group, information on species distribution, ecology and conservation is still lacking. Here, we provide a pictorial key to the adult hoverflies of Madeira Archipelago highlighting diagnostic characteristics and present photographs of both males and females (in dorsal and lateral views) in colour plates. The key and plates will help researchers to differentiate these species, thus encouraging the use of this insect group in future bioindication studies. In addition, this study also aims to engage a broader audience of non-experts in improving the knowledge on the distribution and ecology of Madeira syrphids. NEW INFORMATION: We provide a checklist for the hoverflies of Madeira Archipelago and a pictorial key to help on species identification.We acknowledge the financial support from Fundação para a Ciência e a Tecnologia (FCT, Portugal) through project PTDC/BIA-BIC/1013/2014, UIDB/00329/2020-2024 and contract DL57/2016/CP1375/CT0001 to MB. We also thank Instituto das Florestas e da Conservação da Natureza (IFCN) for allowing the collection of specimens in Madeira Archipelago.