Male bedbugs will schtup anything, and when they do, their stabby little penises can do great damage to one another. Female bedbugs have some "down there" armor that absorbs the punishing blows of the bedbug's love-spear, but males lack this protection. A pheromone discovered by a Swedish researcher can cause male bedbugs to kill each other with their penises through uncontrolled shagging:
According to lead researcher Camilla Ryne, bedbugs are notoriously undiscerning about who they mount, and are accustomed to stab their penis straight into another male's abdomen...

Males with blocked glands were mounted as often as other males, but for longer and suffered more wounds.

"This is the first time I've seen an alarm pheromone used as a sexual one," New Scientist quoted Ryne as saying.

New discovery may help deal with bedbug infestation (Thanks, Steve)

(Image: 98221_hires.jpg, a Creative Commons Attribution photo from liz.novack's photostream)