More than 75 percent decline over 27 years in total flying insect biomass in protected areas Hallmann, Caspar A. ; Sorg, Martin ; Jongejans, Eelke ; Siepel, Henk ; Hofland, Nick ; Schwan, Heinz ; Stenmans, Werner ; Müller, Andreas ; Sumser, Hubert ; Hörren, Thomas ; Goulson, Dave ; de Kroon, Hans Abstract Publication: PLoS ONE Pub Date: October 2017 DOI: 10.1371/journal.pone.0185809 Bibcode: 2017PLoSO..1285809H