Fruit flies use wings and legs to warn rivals
AIP neurons（AIP neurons）
A small group of fly brain cells that can start the threat display.
descending neurons（descending neurons）
Brain cells that send movement signals toward the body.
exaptation（exaptation）
Using an old body system for a new job.
What happened
Researchers at the California Institute of Technology (Caltech, a research university) studied male fruit flies. Their paper appeared in Current Biology, a biology journal. It explains how two brain modules coordinate wing and leg movements during a threat display.
A male fly shows four actions during this display. It makes short, stuttering charges. It raises its wings into a V shape at about 45 degrees. It repeatedly turns toward the other fly. It also pumps its wings forward too quickly for human eyes to follow. The fly does not perform this full display without another male nearby.
From movement to message
Wings and legs first help animals move through the world. They help animals find food, find mates, and escape predators. Many animals also reuse these body parts as signals. Birds can spread their wings during courtship. Crabs can wave their claws. Humans use gestures and posture too.
The fruit fly uses movement for a social purpose. Its display can make the fly appear threatening. The important question is how the brain combines separate body movements. Wings and legs need different muscles. They still have to work together at the right time.
How the two circuits work
Earlier work found a tiny group called AIP neurons. Each half of the fly brain has only five to seven of them. Activating these cells with light can trigger the threat display, even without another fly. Silencing them stops the display before a fight, although the fly can still attack.
The new study traced signals from the AIP group. Researchers identified four major cells downstream from it. Two were descending neurons, which send signals from the brain toward the body. Activating either one alone caused only weak wing movements. Activating both together produced the V-shaped lift and the rapid wing pump.
The other two cells connected with many movement neurons. One made the fly walk continuously. The other made it stand still. Activating both together created the short, stuttering charges of the threat display. The wing-control cells were different from the cells used for flight. The charging cells reused part of a larger walking system.
Why it matters
The study shows that one social action can come from several cooperating brain systems. The brain does not need one simple command for every complete behavior. It can combine timing, posture, and movement into one message.
The finding also illustrates exaptation. This means using an old body system for a new job. Wings and legs evolved for movement. The fly can also use them to look threatening. Evolution can reuse existing parts instead of building a new body part for every signal.
What is confirmed, and what is not
The study connects two brain systems with the coordinated wing and leg movements. It also shows that different cells can control flight movements and threat movements. The experiments reveal which cells can produce parts of the display when activated together.
They do not yet show which circuit starts first. They also do not show whether the two circuits connect directly. Researchers still need to learn how sight or smell shifts the fly into threat mode. Similar wiring in other fruit fly species remains unknown.
What to watch next
Future studies can test the timing of each circuit. They can change one group and measure the whole display. Researchers also plan to examine other fruit fly species. They may ask whether similar circuits support courtship or escape.
The small fly offers a useful lesson. Animals can communicate without sounds or words. Their brains can turn several ordinary movements into one clear social message.
Source: Phys.org report
Fruit flies use wings and legs to warn rivals
📰 Full story: Fruit flies use wings and legs to warn rivals
Scientists found two brain circuits behind a fruit fly’s threat display. The circuits help its wings and legs move together.
brain circuit（brain circuit）
A connected path of nerve cells that carries messages.
threat display（threat display）
Body movements that warn another animal to stay away.
💡 The gist
- One brain circuit helps control the wings.
- Another brain circuit helps control the legs.
- Together, they create a warning display.
Fruit flies sometimes face other males. During a conflict, they use several quick movements. These include short charges and turns toward the other fly. The fly also raises its wings. It can pump them too fast for human eyes to follow.
A brain circuit is a connected path of nerve cells. Nerve cells carry messages through the brain and body. One circuit helps guide the wings. Another helps guide the legs. Both circuits can work at the same time. Their timing creates one clear warning display.
Earlier research found a tiny group of brain cells. Turning those cells on can trigger the display without another fly. Turning them off stops the display before a fight. The fly can still attack. It simply loses the warning movements.
Researchers then traced signals from those cells. They found two paths linked with wing movements. Each path alone caused only weak movement. Both paths together created the special wing display.
They also found two other cells linked with charging. One cell made the fly keep walking. The other made it stop. Both together created the short charges used in the warning display.
Some wing-control cells were different from flight-control cells. That suggests the brain can use different cells for different situations. It can also reuse ordinary walking systems for a special social action.
This matters because body parts can have more than one job. Wings and legs help animals travel. They can also send messages. Evolution can give an old body system a new purpose.
Scientists still have questions. Which circuit starts first? Do the circuits connect directly? Do other fruit fly species use similar wiring? Do the same cells help courtship or escape?
Next, researchers can test sight and smell signals. They can also change one circuit and watch the whole display. These tests may show how a small brain builds a message from many movements.
A fruit fly warns with wings and legs
📰 Full story: Fruit flies use wings and legs to warn rivals
A fruit fly meets another fly. Its brain makes wings and legs move together.
The simple idea
- One little brain path helps the wings.
- Another little brain path helps the legs.
- Together, they make a warning pose.
A fruit fly is a very small fly.
Sometimes, one fly meets another fly.
The first fly lifts its wings.
Its legs make quick little moves.
The fly is making a warning.
The warning says, “Please stay back.”
The fly’s brain has two tiny paths.
One path helps the wings move.
The other path helps the legs move.
Both paths work together.
So the wings and legs move as one.
Wings help the fly move through the air.
Legs help the fly walk.
They can also send a message.
Scientists know the two paths work together.
They do not know which path starts first.
They will keep watching the fly’s brain.
The little fly shows that bodies can talk.