All About Beetles

## **What Are Beetles?**

Beetles are genuinely fascinating creatures; no other insect group can boast more species than beetles do.

There are believed to be more than 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 1 mm to as large as 15 cm.

When we first think of beetles, we usually think of an entirely black insect.

However, beetles are often very colorful and quite beautiful.

Even today, we occasionally find new species of beetles.

Biologists have a name for all beetles, and they call them ***Coleoptera.***

## **Beetle Fact:**

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 more robust than the two back wings.

The front wings and are often called shields.

These "***shields***," are made from a material called "**c*hitin*"**which makes them sturdier and more rigid.

Consequently, these "***shields***" are not that 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 as they have become more accustomed to running.

Some have even fused their wing cases, or shields, together to make stronger "***armor***" and offer them better protection.

**Direct Flight:**

* Mayflies have a single pair of direct flight wings.
* Dragonflies have two pairs of direct flight wings.
* The wing muscles insert directly at wing bases.
* Gives a higher degree of flexibility in flight (*making it easier to change direction*).

**Indirect Flight:**

* 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.

## **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.

Almost anywhere you can think of that has water, vegetative foliage, roots, or decaying plant matter is likely home to one type of beetle or another.

## **Beetle Fact:**

Did you know that beetles are found almost everywhere except near the Poles and in the oceans?

## **How Long Do Beetles Live?**

A beetle's lifespan includes four 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 insect's 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.

## **Beetle Fact:**

Did you know that all beetles start life as grubs?

## **What Do Beetles Eat?**

Each species of beetle will have its particular food sources and dietary needs.

However, many eat plant material.

Some species specialize and will only eat specific leaves or seeds.

Beetles, like 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.

Some beetles prey on other insects and others that will eat just about any form of meat that they can find.

## **Beetle Fact:**

Did you know that all beetles have chewing mouthparts?

## **Beetle Fact:**

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 made up of smaller parts.

It’s thought that this allows beetles to see flowers differently than us.

Beetles probably see less of the color that we see, but instead, see flowers as being much more patterned, which is understood to lead the beetle more readily to the center of the flower.

## **Are Beetles Harmful?**

Most beetles are harmless to people.

However, they are some species that can inflict harm on a person or a person's belongings or their food.

An example of a beetle that can cause physical damage to a person is a Bombardier Beetle.

This beetle can eject a scalding spray that can burn a person's skin.

Bombardier Beetles use this as a defence mechanism against predators such as ants, spiders, and even frogs.

## **Blister Beetle - A Harmful Beetle:**

Another insect that can cause harm is a Blister Beetle.

These little beetles are about 2.5 cm 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 six 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.

## **Beetle Fact:**

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:**

### ***Popillia japonica.***

A small beetle at about 15 millimeters in length and 10 millimeters wide.

In its native Japan, this beetle is of little harm, being controlled by natural predators.

However, in America, it is considered a massive pest to many plants such as roses, hops, and grapes.

It’s thought 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 millimeters but was responsible for devastating the cotton industry in the American South during the 1920s.

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:**

An exotic 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 is known to have existed in the Triassic period some 200 million years ago.

## **How Do Beetles Defend Themselves?**

Beetles have developed several 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 appear unpalatable and something to avoid.

## **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.

**Gallery Slide-Show Of Images For This Article:**

*** A Jewel Beetle
* Beetle Flight Mechanisms, Direct flight: muscles attached to wings. Large insects only
* Beetle Flight Mechanisms, Indirect flight: muscles make thorax oscillate in most insects.
* Life-cycle of the Japanese beetle. Larvae feed on roots underground, while adults feed on leaves and stems.
* Beetle body structure, using cockchafer. A: head, B: thorax, C: abdomen. 1: antenna, 2: compound eye, 3: femur, 4: elytron (wing cover), 5: tibia, 6: tarsus, 7: claws, 8: mouthparts, 9: prothorax, 10: mesothorax, 11: metathorax, 12: abdominal sternit
* Beetle Compound Eyes, A diagram describing a beetles compound eyes.
* Bombardier Beetle.
* Different Varieties of Blister Beetles, Various types of Blister beetles
* A variety of Weavils.
* Rove Beetles.
* Top Left: Longhorn Beetle looking like a wasp. Bottom: Giant Longhorn Beetle.
1/11**