Sharp-tailed bees, sometimes called "cuckoo leafcutter bees," are sleek, all-business bees with lines as dark and mysterious as a stealth fighter. For good measure, as they have a secret mission to perform: quietly slip into a leafcutter bee's nest and drop an egg. An egg that when hatches, will outcompete the nest builder's own eggs for the pollen resources she provides. Yes, this is a parasitoid bee, and its striking looks and intriguing behavior typically demand a strong emotion from one who sees it. Sometimes this is admiration and astonishment at its stately beauty, but more often the emotion is fear. This bee looks positively venomous. No bee looks more venomous.