In memoriam: Dr. J. (Hans) van den Assem

On 11 April 2014 behavioral biologist Hans van den Assem passed away. As member of the Ethology group at the University of Leiden he has contributed significantly to the blossoming of the field of behavioral biology. Hans was a pioneer in the study of mating behavior of parasitoid wasps, contributed to the development of Nasonia as a hymenopteran model organism, and was among the first to show that parasitoids can adaptively adjust their progeny sex ratios. He has been an inspiring mentor and is best remembered as a "scholar and gentleman".