Bees get depressed when shaken, not stirred: We humans can be a pessimistic lot, seeing the worst in things whenever we get depressed. But it turns out this behavior isn't limited to humans; mammals and birds also demonstrate negative biases in their cognitive processes when they're subject to long-term stress. Now we can lump the birds and the bees together, according to a team from Newcastle University. How do you depress a bee? Shake vigorously! "We show for the first time that agitated bees are more likely to classify ambiguous stimuli as predicting punishment," according to the authors. Levels of various neurotransmitters were also lowered in the bees. The authors might be overreaching a bit when they claim that the results suggest "that honeybees could be regarded as exhibiting emotions," though.
Male flies know if they're mating with a virgin, and adjust their ejaculate accordingly: Female flies are promiscuous, and males compensate by loading their ejaculate with proteins that manipulate the females' reproductive behavior. The scary part: the males can tell whether the female had mated before, and adjust their ejaculate accordingly. If the female is a virgin, the male pumps her full of a protein that significantly increases her egg production. If she has already mated, the male doesn't bother.