A species of cockroach eats a few of its partner’s wings after they breed, a new study reveals.
Japanese scientists who studied the wood-feeding cockroach (Salganea taiwanensis) found that males and females ate the wings of the other man.
The species enjoy a post-coral process that involves several stages, starting with a bit of courtship decoration, before moving on to feeding.
The then-eaten cockroach can violently shake his body to throw the other off once he has had enough of ejaculating, researchers said.
Over time, cockroaches S. taiwanensis can weld their companion’s wings to a stub, becoming smaller and smaller as they grow older.
The ‘other-spouse’ predation is very unusual and is different from the most common case of sexual cannibalism in insects, where the main female kills and eats the male after they breed. .
This sex may be ‘really monogamous’ – meaning it has a sexual relationship with just one partner for the rest of its life, researchers say.
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Adult Salganea taiwanensis before (right) and after (left) wing-eating behavior. The right person has long full wings. The left person has short wings. Most of its wings are eaten by a companion
True monogamy is ‘complete and longevity’ and is the only condition in which yoke is freed from sexual conflict, but may be compromised by betrayal behavior.
Pressing each other’s wings could help hold them down and ‘reduce flight maintenance costs’, the researchers suggest.
This can somehow allow them to invest more in reproduction or caring for children.
The behavior could also serve as a hygiene control against mites or mold, which was seen on their wings in the laboratory.
‘Within pairs of wood-feeding roosters, both males and females feed on each other’s wings, which is the first “mutual” issue in these behaviors,’ says Haruka Osaki and Eiiti Kasuya from the Department of Biology of Kyushu University.
‘Winged eating’ can be an example of real collaboration and may help to explain some female-male interactions from a new perspective.
‘If eating the wings increases the mate’s ability to raise the children, this behavior is flexible for the eater as well as his companion.’
Researchers said that since wings do not contain meat, the value of wings as a food source appears to be ‘very small’.
For the S. taiwanensis species, new adults fly away from their natal colony, a rotten log in a forest, to find a mate.
Osaki told the New York Times that she had been collecting insects from the forest as a hobby since she became a biology student at Kyushu University.
‘When I caught the wood-feeding cockroaches in the desert, I noticed that their wings were chewed by something,’ she said.
Photograph of a pair of courtship during a wing eating behavior by study author Haruka Osaki. The individual in the face, who already has wings eaten, eats the wings of his companion
For their experiments, Osaki and Kasuya collected 24 young adult pairs of the genus from Yona Field, Okinawa, Japan, which were returned to the laboratory, put them together in containers and recorded video for three days.
In total, 12 of the pairs engaged in wing eating until the wings of each species grew as short as the wings of wild parents.
Overall, the wingspan consumed was approximately 66.7 percent of the total wing area in males and 68.3 percent in females in these 12 pairs.
Of the remaining pairs, nine ate some wings and three pairs did not eat wings at all.
The team has also broken down the ‘normal series’ of cannibalism that includes the ‘actor’, the one actively eating the wings, and the ‘recipient’, the actor’s companion which is being spit.
Both male and female can be actors, meaning the roles are reversed after a single beat (which includes wedding grooming, nibbling and wagging).
In 12 of the 12 pairs, the actor approached his partner first and grabbed the antennae to the other insect and kicked the body parts, including the head, wings and the legs, as a kind of decoration.
The actor then climbed onto the recipient’s back and ate the recipient’s wings, while the stopper stopped, while the supported person approached. the actor.
When the actor stopped eating, in 61.7 percent of times the recipient remained motionless, and in the remaining 38.3 percent of times, the recipient shook his body to the left and to the south (known as ‘wagging’), researchers looked.
After the recipients stopped, the actor stopped eating more often.
A typical set of winged eating behaviors. Both male and female can be actors in each bout
Once a bout stopped, the pair usually would not breed and eat wings until the next bout.
In the times between strokes, both species were motionless, walking or digging – scraping the ground using their woods.
This new study, published in Ethnology, reveals that the wood-feeding cockroach benefits from a more peaceful and consistent form of insect cannibalism than others found in the country.
‘Complementary wing eating is similar to sexual cannibalism, but it’s different because no single friend is killed,’ they say.
Sexual cannibalism in insects is well documented and tends to be the main female killing and eating of the male after breeding.
In general, the benefits of sexual cannibalism may include nutrition for reproduction or encouraging men to avoid breeding with inferior women, previous studies show.
From the man’s point of view, it is beneficial for himself to sacrifice for the good of his companion and offspring, who benefit from his vital nutrients.
In some cases, such as the prayer mantis, the females eat the males before they get a mate, especially if they are perceived as unfit or inappropriate, and thus as seen they have more nutritional benefit than reproductive benefit.
The male has come forward to set up a fight, often leading to a violent feud between the two, to increase his chances of breeding successfully.
‘Sexual cannibalism usually involves the woman who eats the male – the back type is rare,’ says Osaki and Kasuya.
Another type of sexual cannibalism is called nuptial feeding, where the male gives the woman a small ‘gift’ from a part of her body to eat.
In nuptial feeding, males are usually given substances in addition to sperm to improve the number of offspring, as described in a 2014 study in Letters of Biology.