Do female black widow spiders kill and eat their mates after sex? July 7, 2020February 8, 2012 by Pamela Landy Sometimes. What makes them decide to do so is uncertain. Related Answers Who played The Merry Widow (1925) and whose widow was she? Who has been killing spiders since he was thirty? Who were Adlai Stevenson’s running mates in the 1952 and 1956 elections? Who are Captain Ahab’s mates in Melville’s MobyDick (1851)? Did the Pilgrims eat Turkey at the first Thanksgiving celebration at Plymouth Rock? How fast do piranhas eat?