I was having a conversation with my bestie, Paul, about praying mantises. I was telling him a couple of cool things I recently learned about them, including that the female only needs to mate one time and can lay up to 6 egg sacs throughout the warm months as long as she gets enough to eat. Fascinating! I still, by the way, keep going out to the front porch to see if Beauty has returned... I'll check again in the morning.
Anyway, Paul asked whether they can fly, and I told him that the females can't because they have wings that are less than half the length of their large abdomen, so they can't. The male mantis, however, can and does fly (probably to find as many females to mate with as they can before one of them literally bites his head off after mating... another reason to have the means for a quick getaway).
So, we started talking about cool evolutionary changes, such as female mantids (another word for mantis is mantid) probably having once had wings that were long enough to carry their weight, but because they really do stay put once they find a small territory with a plentiful food supply, over time the wings started shrinking. This led to the conclusion that if you don't use your wings, you lose them.
That was the long story as to the impetus for this phrase. Thank you, Paul Sabuco!