All About Beetles
What Are Beetles?
Beetles are truly fascinating creatures, no other insect group can boast more species than beetles do. There are believed to be in excess of 300,000 different species existing around the world. To put this into context, Beetles account for 20 percent of all living organisms.
Beetles can range in size from as small as 1mm to as large as 15cm. When we first think of beetles, we usually think of an entirely black insect. However beetles are found that are very colourful and quite beautiful.
Even today, new species of beetles are still being found. Biologists have a name for all beetles, they call them Coleoptera.
Did you know that Beetles account for about 40% of all insects?
Do Beetles Fly?
Yes, the majority of beetles can fly. Most beetles have two pairs of wings. The front pair of wings are tougher than than the back pair and are often called shields. These "shields" are made from a material called "Chitin" which makes them tougher and more rigid. Consequently, these "shields" are not really effective as wings, but protect the "real" more delicate wings underneath them.
There are a few species of ground beetles that have lost the ability to fly having become more accustomed to running. Some have even fused their wing cases, or shields, together to make stronger "armour" and offer them greater protection.
- Mayflies have a single pair of direct flight wings
- Dragonflies have two pairs of direct flight wings
- wing muscles insert directly at wing bases
- gives a greater degree of flexibility in flight(easier to change direction)
- all other insects have adopted this mode of flight
- muscles attach to the thorax rather than to the wings
- the thorax deforms in shape, moving the wings
Beetle Flight Mechanisms
Dung Beetle Taking Flight - Slow Motion Video
Where Do Beetles Live?
Beetles are very adaptive insects and different species of beetles make their home in quite varied places. For example some water beetles live in ponds, some live on the ground and some in bushes and trees. In fact almost anywhere you can think of that has water, vegetative foliage, roots, or decaying plant matter is a likely home to one type of beetle or another.
Did you know that Beetles are found almost everywhere except near the Poles and in the oceans?
How Long Do Beetles Live?
A beetles lifespan includes 4 stages. From an egg to larva to pupa to adult. However, when trying to determine how long a beetle lives, it is generally accepted that the time spent in an egg does not count. Just as with chickens, we only start counting an insects age from the moment it emerges from its egg.
In reality, the lifespan of any individual beetle will depend on the environment surrounding it. If all conditions are perfect, then it may only spend a couple of years developing as a larva. Different species of beetle also have different lifespans as adults, some of only a few weeks some of several years.
Japanese Beetle Life Cycle
Did you know that all beetles start life as grubs?
What Do Beetles Eat?
Each species of beetle will have its own particular food sources and dietary needs. However many eat plant material. Some species specialize and will only certain leaves or seeds. Some beetles, such as the Bark beetle feed on the starches and sugars found in the bark and sapwood of trees. Other beetles such as the Ambrosia beetle, cultivate fungal gardens.
There are beetles that prey on other insects and others that will eat just about any form of meat that they can find.
Did you know that all beetles have chewing mouthparts?
Beetle Body Structure
Did you know that an insects skeleton is on the outside of its body? - it is called an exoskeleton?
Can Beetles See?
The fact is that Beetles cannot see very well - at least not in the same way as we can. They have compound eyes, which means that they have eyes that are actually made up of smaller parts. It is believed, that this allows beetles to see flowers differently than us.
Beetles probably see less of the colour that we see, but instead see flowers as being much more patterned which is understood to lead the beetle more easily to the centre of the flower.
Beetle Compound Eyes
Are Beetles Harmful?
Most beetles are harmless to people. However, they are some species that can inflict harm on a person, or on a persons belongings or on their food. An example of a beetle that can cause physical harm to a person is a Bombardier Beetle. This beetle can eject an extremely hot spray that can burn a persons skin. The Bombardier Beetle uses this as a defence mechanism against predators such as ants, spiders and even frogs.
Bombardier Beetle Attack - Video
Blister Beetle - A Harmful Beetle
Another beetle that can cause harm is the Blister Beetle. These little beetle's are about 2.5cm in length. Their bodies contain a substance called cantharidine which causes blistering of the skin. Some say that it feels like receiving a nettle sting.
Blister Beetle Facts:
- larvae undergo 6 stages of development
- the larvae are carnivorous (feeding on other insects including bees)
- vary in size from 1 cm to 2.5 cm in length
Different Varieties of Blister Beetles
Did you know that insects blood is normally green? Because insect blood doesn't need to transport oxygen around its body, it contains no haemoglobin - which is what gives blood a red colour in people.
Japanese Beetles - A Harmful Beetle
A small beetle at about 15 millimetres in length and 10 millimetres wide.
In its native Japan, this beetle is of little harm as it is controlled by natural predators. However, in America it is considered a huge pest to many plants such as roses, hops and grapes. It is believed that the Japanese Beetle appeared in America around 1916 when accidentally imported with a shipment of Iris bulbs.
Boll Weavil Beetle - A Harmful Beetle
The Boll Weevil is a beetle that feeds on cotton buds and flowers.
This small insect measures about 6 millimetres, but was responsible for devastating the cotton industry in the American South during the 1920's. The Boll Weavil lays its eggs inside cotton bolls and the larvae eat there way out.
There are many varieties of Weavi, most are small and considered to be pests as they can damage and kill crops.
Whiplash Rove Beetle - A Potentially Harmful Beetle
This is an interesting Beetle in that it is known to cause skin rashes and even severe dermatitis in some people.
The Rove Beetle is from a large family of beetles and are known to have existed in the Triassic period some 200 million years ago.
How Do Beetles Defend Themselves?
Beetles have developed a number of ways to try to defend themselves from predators. These include such things as camouflage, toxicity and mimicry.
Some types of Longhorn Beetles have developed to look like wasps. While other beetles have developed hair or scales to make them look like inedible things such as bird dung.
Giant Longhorn Beetle - A Fearsome Bite
The Longhorn Beetle can bite through a pencil with one snap of its powerful jaws - this might hurt if you let your finger get in the way.
But generally, provided that you are careful around them, beetles are harmless to people.
When threatened this beetle produces a loud hissing noise.
The Giant Longhorn beetle is quite rare living in quite a limited habitat.