TY - JOUR T1 - Why insects swarm: testing the models for lek mating systems on swarming Empis borealis females JF - Behav. Ecol. Sociobiol. Y1 - 1992 A1 - Svensson, B. G. A1 - Petersson, E. SP - 253 EP - 261 VL - 31 ER -