Platypus apicalis facts for kids
Quick facts for kids Platypus apicalis |
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P. apicalis
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| Platypus apicalis White, 1846
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The Platypus apicalis, also known as the New Zealand pinhole boring beetle, is a type of beetle that lives only in New Zealand. You can find it on both the North and South Islands in many different places. This beetle is famous for boring tiny "pinholes" into wood.
Contents
What Does the Pinhole Borer Look Like?
Like all arthropods, the Platypus apicalis is an invertebrate. This means it doesn't have a backbone. Instead, it has a hard outer shell called an exoskeleton, a body made of different parts (segmented), and jointed legs.
The beetle is mostly dark brown. Its antennae (feelers) have yellow parts at the base, and its middle body section (metathorax) and upper legs (femora) are also yellow. Its body is long and round, like a cylinder. It's very small, less than 2 millimeters (0.08 inches) wide and about 5.8 millimeters (0.23 inches) long.
The beetle's mouthparts, called mandibles, point downwards. Its antennae have a flat, large end segment. The hard wing covers, called elytra, have parallel grooves. They are mostly smooth but have tiny hairs at the back and sides, and they slope downwards at the end.
Differences Between Male and Female Beetles
Male and female Platypus apicalis beetles look a bit different. This is called sexual dimorphism.
- Male beetles have small, tooth-like bumps at the back of their wing covers. They also release a strong smell to attract females when they start digging a breeding tunnel.
- Female beetles have more hair on their bodies and don't have the tooth-like bumps on their wing covers. Their bodies are also more rounded. Females don't release the special scent.
Baby Beetles: Eggs and Larvae
The eggs of the Platypus apicalis are round and creamy white, less than 1 millimeter across. When they first hatch, the young larvae (baby beetles) are flat and have fleshy bumps on their sides. As they grow, they become white, round, and lose their legs. Their heads turn yellow, and their mandibles start to point downwards. Ridges also begin to appear on the top of their first body section (prothorax).
Where Do Pinhole Borers Live?
Natural Home in New Zealand
The Platypus apicalis beetle is endemic to New Zealand. This means it's found nowhere else in the world! You can find it on the West Coast of the South Island and in the middle of the North Island. It lives in natural beech forests and sometimes in planted forests of trees like Eucalyptus.
Favorite Places to Live
These beetles mostly prefer to live in dead beech wood forests, including Red Beech, Silver Beech, and Black Beech trees. They live inside the dead parts of trees.
The beetles work closely with certain fungi. Some fungi, called Ambrosia fungi, provide food for the beetles. Other fungi can infect or even kill live trees, and the beetles can carry these fungi.
While they usually live in dead wood, if there are too many beetles, they can start to threaten healthy trees. They are sometimes seen as pests in native forests when they attack healthy trees. They are a bigger problem in tree plantations, where they can damage valuable timber. Their tunnels and the fungi they carry can make the wood less useful.
You can find these beetles all over the North Island, South Island, and Chatham Island. However, they haven't been seen in some eastern forests like Balmoral and Eyrewell State forests in Canterbury.
Economic Impact of the Beetle
The Platypus apicalis can cause problems for timber companies.
- It carries fungi that change the color of the wood.
- Its tunnels go deep into the wood, creating flaws and making the timber weaker. This means less high-quality wood is available for building or other uses.
Life Cycle of the Pinhole Borer
The life cycle of the Platypus apicalis beetle is quite interesting.
Starting a New Home
It all begins in early summer, usually November and December. A male beetle bores a tunnel into a host tree. As it digs, it releases tiny spores of Ambrosia fungi. These fungi are the main food source for the beetle, which is why they are sometimes called "Ambrosia Beetles."
Once the tunnel is a few centimeters long, the male beetle releases a special smell. This smell attracts female beetles. If many male beetles do this at once, it can lead to "mass attacks" where many beetles attack one tree.
Mating and Nest Building
Mating happens at the entrance of the tunnel. After mating, the female goes into the tunnel to start building a nest. The male continues to make the tunnel bigger and removes waste material, called frass. The tunnel first goes straight into the tree, then turns sharply towards the center of the tree (heartwood).
The female lays her first batch of eggs, usually four to seven eggs. Then, the male starts another branch of the tunnel, and the female lays a second batch of eggs. Both parents feed the larvae using special structures on their heads called mycangia. About 8 to 10 months after mating, the larvae are ready for the next stage.
Growing Up: Larvae to Adults
The exact time when the eggs hatch isn't fully known. However, it takes about two years from when the eggs are laid until fully grown adult beetles emerge from the tree.
During this time, the larvae go through several stages:
- At first, the larvae simply extend the tunnels made by their parents. Their tunnels are curved, unlike the parents' flat tunnels.
- The larvae grow larger and start to look more like adult beetles.
- After several months, the larvae dig small rooms inside the tree called pupal chambers.
- The larvae then enter these chambers and change into pupas. A pupa is an intermediate stage between a larva and an adult insect.
- Finally, after two years, adult beetles emerge from the chambers and leave the tree. This usually happens in the summer, from January to March.
On average, about 115 beetles emerge from one tree. The adult beetles then fly off to find a new host tree, and the life cycle starts all over again. An adult pinhole beetle usually lives for about 3 to 4 years.
What Do Pinhole Borers Eat?
The Platypus apicalis is known as an ambrosia wood boring beetle. These beetles survive by digging tunnels into the xylem (which carries water) and phloem (which carries food) of a host tree.
Ambrosia beetles have a special partnership, called a symbiotic relationship, with a type of fungus called Ambrosia. The beetles carry the fungal spores inside their bodies. As they bore into a tree, they release these spores. The fungus then grows inside the tree, and the beetles eat the fungus as their food.
The beetles do not eat the wood of the tree itself. The wood is just a place for the fungus to grow. Instead, both adult and larval beetles eat the yeast that grows in their tunnels. This yeast provides a steady food source for them.
Who Are the Pinhole Borer's Enemies?
Besides the helpful Ambrosia fungi, there are also harmful fungi that can infect and kill trees attacked by adult beetles.
Currently, human agricultural practices help control the beetle population. There aren't many known natural predators that effectively hunt these beetles. There is a type of parasitic worm that lives with the beetle, but scientists aren't sure how much it helps control the beetle numbers.
Scientists have tested different types of fungi, like B. bassiana, B. brongniartii, and Metarhizium anisopliae, which are found in southern beech forests. They tested 10 different types on both adult and larval beetles. They found that all of them killed the adult beetles. This shows a promising natural way to help control the Platypus apicalis population in the future.
Pinhole Borer's Special Scents
Even though the New Zealand Pinhole Borer beetle is a wood-boring beetle, its special scents, called pheromones, are more like those of bark beetles. This is because it produces an "aggression pheromone." This chemical, made in its hind gut, allows Platypus apicalis to cause many trees to die when they attack together.
