A week or two ago, Dan discovered a large, shiny blue beetle crawling through the grass on our lawn and called me out to see it. Even before investigating I had a fair idea of what it was: a blister beetle, of the genus Meloe. This isn’t the first one I’ve seen, and it isn’t even the first one Dan’s found for me – last fall he brought me a male one. The one above is a female; you can tell the difference by the antennae, since the males have a U-shaped kink in theirs, which they use for grasping the female during mating, and those of the female are straight. Females also have larger abdomens. Blister beetles are so named for the liquid they exude from their joints when startled or threatened, which contains a chemical called cantharidin. There are some third-party beetle species which will collect the cantharidin from blister beetles and use it as a sperm additive (putting it into the sperm packet they transfer to the female); when she lays her eggs, the eggs are coated in this protective chemical. Humans use the chemical too, but for less honest purposes – it’s used in making the aphrodisiac/date-rape drug “Spanish Fly”. I wrote more about blister beetles when I found my first one; you can read a bit more here.