Cannibalism May Be Key for These Cockroach Couples
Wood-eating cockroaches are not the only creatures that make food from their companions, but their inspiration may be unique.
“Spiders often have cannibalism,” said Maria Jose Albo, an evolutionary biologist at Republic University in Uruguay. Between sexually cannibal spiders and praying mantes such as insects, it is usually a large female who eats her mate. Although on the surface this seems like a bad outcome for the male, he may benefit by transferring more sperm while the female dines, Drs. Barbo said.
On a less grueling note, Drs. Albo said, some male insects and spiders give their companions a so-called secret gift: food that is sometimes made from the male’s own body. The gift may buy him more time to orgasm or to escape.
All of these cases involve feeding only one partner, Drs. Said Albo, which is what makes cockroaches so unusual. “If both sexes have fitness benefits by eating mutual sex, this will be the first case of mutual gift-eating,” he said.
Those benefits are probably not nurturing, Ms. Osaki and Drs. Kasuya wrote, because cockroach wings are not fleshy. But Roshe probably benefits from losing her wings, as wings are cumbersome when staying in tight quarters. Writers may also write that mold or mite may occur.
“It makes sense that getting rid of your wings is an advantage if you’re not going to fly again,” said evolutionary biologist Ellen J. Moore of the University of Georgia. Some other pests that live underground or inside the wood also shed their feathers after mating, such as termites, close relatives whom Dr. Moore called “just fancy cockroaches”.
But these insects have to lose their wings on their own. “This mutual help is truly unique,” he said.