Abstract
Abstract How to identify ecological systems at risk of failure is a central question of modern biology and agriculture. Due to human impacts and global change, there is a growing need for early warning signals that identify when an ecological system is at risk of a state change before those changes become irreversible or extremely complex and costly to remediate. Honeybees (Apis mellifera) are an urgent case because our food crops heavily rely on them for pollination and annual bee colony losses reported by beekeepers across the globe are unsustainable. Given enough warning, beekeepers can rescue dying colonies, but early warning signals of death for individual bee colonies are lacking. Here we used early warning signals to investigate whether fluctuations and dynamical patterns in internal hive temperature can be used as an early indicator of impending colony failure. Across three distinct datasets we found that temperature regulation of failing colonies was different enough to distinguish them from healthy colonies weeks before they died. This signal comes early enough to intervene and assist colonies with standard beekeeping practices. Our study shows that early warning theory can help to identify practical signals of risk of state change even in systems that change state relatively rapidly, such as a dying bee colony, early enough to intervene and prevent losses.