Swarming in the storm: Collembola aggregations on sub-Antarctic Marion Island

Abstract The intensity and frequency of extreme weather events in rapidly changing environments continue to increase, driving unusual behaviours and posing significant threats to terrestrial ecosystems. In this study, we describe the co-occurrence of 1) Collembola swarming, 2) vegetation die-off and 3) extreme weather events, particularly heavy rainfall and high temperatures, over a 5 day period on sub-Antarctic Marion Island. Taxonomic and molecular evidence confirmed that the Collembola species displaying swarming behaviour was Ceratophysella denticulata , an invasive hypogastrurid. Our observations suggest that environmental stressors may have induced vegetation die-off, which, in turn, may have directly or indirectly driven Collembola aggregation. The association of these factors highlights the potential role of Collembola as bioindicators of soil ecosystem responses to climatic extremes, and that the recognition of these interactions can be critical in the prediction and management of ecological responses to changing environments.