Animal weapons such as antlers, tusks and limbs specialized for fighting require a large energy expenditure to produce and may cost even more to maintain. Because the leaf-footed bug sheds its large hind limbs, used as weapons in male-male battles, scientists working at the Smithsonian Tropical Research Institute (STRI) in Panama could measure energy use of live bugs with and without hind legs to calculate the hidden energetic cost of weapons’ maintenance.