Hygrobia facts for kids
Quick facts for kids Hygrobia |
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| Hygrobia hermanni | |
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Hygrobiidae
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Hygrobia
Latreille, 1804
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Hygrobia is a group of special water beetles. They are found in different parts of the world, including Europe, North Africa, China, and Australia. These beetles are the only members of their family, called Hygrobiidae. People often call them squeak beetles or screech-beetles because of a unique sound they can make.
There are six types of Hygrobia beetles alive today. They live in very spread-out places across the globe. There was also one type that is now extinct, named Hygrobia cretzschmari.
Contents
What are Squeak Beetles Like?
Where Squeak Beetles Live
All Hygrobia beetles live in low-lying areas. They prefer still water, like ponds. You can often find them in the mud, dirt, and plant bits at the bottom of these ponds.
Usually, different types of Hygrobia beetles live in separate places. However, two species, H. nigra and H. australasiae, can be found together in southeastern Australia.
What Squeak Beetles Eat
Both adult and young Hygrobia beetles are predators. This means they hunt and eat other small creatures. They mainly specialize in eating oligochaete worms, which are a type of segmented worm.
Adult beetles can spend up to 30 minutes eating underwater. They only come to the surface for a very short time to get more air.
Why They are Called Squeak Beetles
Adult Hygrobia beetles can make a sound. This is called stridulation. They rub parts of their bodies together to create a noise that you can hear. This is why they earned their common names: squeak beetles or screech-beetles!
How Squeak Beetles Look
Hygrobia beetles are usually between 8.0 and 11.0 millimeters long. That's about the size of a small fingernail.
They have large compound eyes. These eyes stick out a lot and are not split into top and bottom parts. Their mouth has a short, wide part called a labrum. They also have antennae with 11 segments. These antennae are thin and mostly smooth.
Family Tree and History
Scientists are sure that all Hygrobia beetles belong to the same family. This means they all came from a common ancestor.
The Hygrobia family is closely related to other groups of water beetles. These include Dytiscidae (diving beetles), Amphizoidae (trout stream beetles), and Aspidytidae (cliff beetles). Scientists figured this out by studying their DNA.
When we look at the different types of Hygrobia beetles, H. hermanni is like a cousin to the Australian species. Among the Australian species, H. nigra is closely related to H. australasiae.
The Hygrobia family likely started to become different from other water beetles a long time ago. This was around the time the supercontinent Pangea began to break apart. Later, the beetles in today's Europe and Asia and those in Australia split up. This might have happened in the middle of the Mesozoic Era, possibly by spreading to new places.
Where Different Species Live
Here are the six living species of Hygrobia and where they are found:
- Hygrobia australasiae (Clark, 1862) - Lives in Australia.
- Hygrobia davidi Bedel, 1883 - Found in Jiangxi, southeastern China.
- Hygrobia hermanni (Fabricius, 1775) - Lives in Europe, northern Africa (Morocco, Algeria, and Tunisia), and Israel.
- Hygrobia maculata Britton, 1981 - Lives in Australia.
- Hygrobia nigra (Clark, 1862) - Lives in Australia.
- Hygrobia wattsi Hendrich, 2001 - Lives in Australia.
About the Family Name
There has been some discussion about the correct family name for squeak beetles. The names are Hygrobiidae and Paelobiidae. Paelobiidae was technically named first. However, Hygrobiidae has been used much more widely until recently.
