@article {3544,
	title = {Why insects swarm: testing the models for lek mating systems on swarming Empis borealis females},
	journal = {Behav. Ecol. Sociobiol.},
	volume = {31},
	year = {1992},
	pages = {253-261},
	author = {Svensson, B. G. and Petersson, E.}
}
@article {3521,
	title = {The evolution of empty nuptial gifts in a dance fly Empis snoddyi (Diptera: Empididae): bigger isn{\textquoteright}t always better},
	journal = {Behav. Ecol. Sociobiol.},
	volume = {45},
	year = {1999},
	pages = {161-166},
	author = {Sadowski, J. A. and Moore, A. J. and Brodie, E. D.}
}
