NPR shares romance among the insects with research that shows at least one species of cockroach, Salganea taiwanensis, forms long-term pair-bonds. And, poetically, these cockroach couples do it by eating each other’s wings:
That “just means that two individual organisms will spend an extended period of time with each other and will exclude other individuals from the bond,” says Nate Lo, an evolutionary biologist at the University of Sydney and an author of the new study. “The two individuals know that the other member has their back.”
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Now, Lo and his colleagues believe they’ve found some of the first indications of pair bonding in an invertebrate. This means that these roaches, and perhaps other insects, may have more sophisticated cognition and social behavior than researchers once thought.
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“The male and the female will burrow into the rotting wood and form a little gallery,” he says.
And then they do something… unique. Over a period of hours, the two roaches chew off each other’s wings — and eat them.
The “female eat[s] the male’s wings and the male eats [the] female’s wings,” says Haruka Osaki, a behavioral ecologist at the Museum of Nature and Human Activities in Hyogo, Japan. And when this one-time meal is complete, “it means they formed a pair.”
This is when the couple starts making a nest out of their little patch of rotting paradise where they then mate and care for their young. “The wings, they’re a protein source,” explains Lo, “and this seems to set them up for some kind of romance into the future.”
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The experiment was simple. The team put pairs of roaches in artificial nest boxes. Some of those pairs had eaten each other’s wings and some had not. The researchers then introduced a single intruder to the pairs.
Lo calls up a video to show what happened. A pair of roaches that both still have their wings appears on the screen. When the intruder enters the nest, there’s no aggression or fuss. The interloper — whether male or female — is allowed to stay.
“You see, they’re just very relaxed about it,” says Lo.
But when he calls up a roach pair that had eaten one another’s wings, “both the male and the female attack,” he observes, by ramming the intruder. “They also wiggle their butts and hit them with their butts. They’re quite aggressive little creatures.”
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There’s another takeaway. “Invertebrates probably are more complex and have some form of cognition, more than we might expect,” says Lo. “Even though they’ve got tiny brains, they can develop quite human-like characteristics.”