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Antenna (zoology)

life science Maturity 9-11 Next article →

Antennae are special body parts used for sensing the world.

Rosalia alpina side
Rosalia alpina side

Most arthropods have them in pairs on their heads. These structures are often called feelers. They help animals sense things like touch or heat. They can also detect air motion and vibrations. For many, they are used to smell or taste.

Insect antennae
Insect antennae

This sensing is vital for staying alive and finding food.

How an antenna works depends on its shape. In many insects, the antenna has three main parts. First is the scape, which is the base. It sits in a socket on the head. Next is the pedicel, or the stem. This part contains a special sensory organ called Johnston's organ.

Vespula germanica SEM Antenna 03
Vespula germanica SEM Antenna 03

Finally, there is the flagellum. This is a long part made of many segments called flagellomeres. Some insects can even move these parts using blood pressure.

Scientists have studied how these parts change over time. All arthropods likely had one pair of simple, unbranched antennae. This is called a uniramous structure. Later, some groups developed two branches on their limbs. This is called a biramous structure.

Barnacle anatomy - antenna highlighted
Barnacle anatomy - antenna highlighted

You can see this in modern crustaceans and fossil trilobites. While most insects have one pair, crustaceans have two pairs. These are called the primary and secondary antennae.

Different creatures use their antennae for very different jobs.

antennae ctb
antennae ctb

A monarch butterfly uses its antennae like a sun compass. This helps the butterfly know which way to fly during migration. Some larvae, like the nauplius, use antennae just to swim. Barnacles use theirs to stay attached to rocks. In certain beetles, the antennae can even fold like a knee. This shape is called geniculate, and it helps them stay safe.

Antennae connect living things to their environment in amazing ways.

Tykadlo
Tykadlo

An ant uses its feelers to find other members of its group. A moth uses them to stay steady while flying through the air. Female moths also use them to find the right plants for their eggs. Some insects even use them to find a mate. Without these important tools, many small creatures could not find food or stay safe.

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🖼️ Images & Media (19)
File:Rosalia alpina side.JPG
Rosalia alpina side.JPG
File:Barnacle anatomy - antenna highlighted.svg
Barnacle anatomy - antenna highlighted.svg
File:Crustacean antenna - Copepoda Cyclops 1st-antenna.svg
Crustacean antenna - Copepoda Cyclops...
File:Crustacean antenna - Isopoda Austroarcturus africanus 1st-antenna.svg
Crustacean antenna - Isopoda...
File:Crustacean antenna - Amphipoda Gammarus locusta 1st-antenna.svg
Crustacean antenna - Amphipoda Gammarus...
File:Crustacean antenna - Decapoda Paguroidea 1st-antenna.svg
Crustacean antenna - Decapoda Paguroidea...
File:Crustacean antenna - Decapoda Megalopa 1st-antenna.svg
Crustacean antenna - Decapoda Megalopa...
File:Crustacean antenna - Remipedia Speleonectes tanumekes 1st-antenna.svg
Crustacean antenna - Remipedia...
File:Crustacean antenna - Thecostraca Cirrepedia 1st-antenna.svg
Crustacean antenna - Thecostraca...
File:Crustacean antenna - Copepoda Cyclops 2nd-antenna.svg
Crustacean antenna - Copepoda Cyclops...
File:Crustacean antenna - Isopoda Austroarcturus africanus 2nd-antenna.svg
Crustacean antenna - Isopoda...
File:Crustacean antenna - Amphipoda Gammarus locusta 2nd-antenna.svg
Crustacean antenna - Amphipoda Gammarus...

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