Trade-offs among developing structures are widespread in insects, and they constitute a dramatic cost of growing elaborate weapons. But this particular cost—stunted growth of other structures—applies primarily to insects such as beetles, flies, ants, and bees. It does not apply to any animals that I am aware of outside of insects. The reason almost certainly has to do with the way these particular insects develop. Specifically, it has to do with when, during development, all of the various adult structures are formed. Exaggerated weapons of sexual selection always grow at the end of development, around the time when males reach sexual maturity. Deer, elk, and moose all begin antler growth only after males are young adults. Elephants and boars grow their tusks after they are adults. Even shrimp and crabs begin the process of enlargement of their fighting claws around the time that their gonads mature. In all of these animals, bodies have already grown and organs, tissues, and appendages are already at or near their adult proportions, long before the weapons begin to grow. Weapons cannot stunt the growth of other traits in these animals because all of the other structures are produced first. In contrast, beetles, bees, flies, and ants all undergo metamorphosis as they develop, and this means that they grow their adult body parts at the same time as their weapons. Simultaneous growth exposes these structures to the insidious effects of resource limitation and allocation trade-offs.

Emlen, Douglas J, Animal Weapons_ The Evoluti…, loc. 758