Videorecordings as an innovative method to investigate the behaviour of arthropods on high altitude plants : The case study of Androsace brevis (Hegetschw.) Cesati (Primulaceae)

Androsace brevis is a narrow endemic plant that grows on siliceous peaks and ridges above 2000 m asl in the western Alps of Lombardy and neighbouring Switzerland. This species is representative of mountain species threatened by the ongoing climate warming. In particular, A. brevis is characterized by a very early flowering, occurring immediately after snowmelt (May-June),and lasting few weeks. Therefore, a key risk for this plant could be represented by climate change-driven mismatches between its flowering and pollinator presence and activity. Recent studies have found that A. brevis needs pollinators to ensure its reproduction; a pollinator network has also been identified through the capture of the arthropods visiting the flowers. To evaluate the occurrence and ethology of A. brevis flower-visiting arthropods in-field video recording sessions were conducted. Environmental parameters were also monitored to investigate their influence on recorded arthropods activity. We recorded 165 videos for a total of about 42 hours and analysed them with a behavioural observation software (BORIS). Our results allowed the identification of taxa involved in A. brevis pollination, but also revealed the existence of a great variability in the activity and behaviour among flower-visiting arthropods, suggesting that this plant can represent an essential resource for high-altitude arthropod community. This innovative approach, less invasive than human direct observation and sampling, is expected to represent a powerful instrument to finely define the relationship between plants and associated fauna in this particularly vulnerable environment, providing crucial knowledge for their conservation.