Animal stories: Beetles
Beetles are small oval-shaped insects. The common name ‘beetle’ comes from older English words for a ‘little biter’.
Most beetles are dark brown or black, but many are red, blue, green, purple or a combination of colours. There are about 350,000 different species of beetles. They usually have hard bodies, but sometimes they are leathery or even have soft bodies. These bodies may be very smooth or very hairy.
They have a hard exoskeleton, a three-part body (head, thorax, and abdomen), two compound eyes, three pairs of jointed legs, and two antennae. They breathe through holes called spiracles.
The most important features of the beetles is their elytra, the hard exoskeletal covering over their wings that protects them. Some species are able to trap moisture on their wings and keep it because the elytra protects it from the heat and wind. Other species can live under
water because they are able to trap air in their wings and keep it under the elytra.
One of the well known beetles are ladybugs. Children love them because they are colourful and easy to catch. They are usually red with black spots on the wing covers. The number of spots identifies the type of ladybug. As ladybugs age, the spots fade. They are helpful for farmers because they eat many pest insects. Birds are the major predator of the ladybug. Ladybugs will play dead when threatened.
Beetles have an incredible ability to adapt to any environment so they will exist, probably long after humans have disappeared from earth. Most beetles live deep in the soil or in decaying leaf litter on the ground. Other beetles live under rocks or in caves. They can also be found in decaying plant, in mud, in fungi, in water, in stored food and in bird and mammal nests. Some species live in ant nests and feed on ant larvae.
Beetles are either plant feeding or hunters. Many species feed as scavengers on dead plants and animals. Some species feed on fungi and a few are parasitic on other insects. Among the insects, beetles are the most important group of ground-dwelling predators. Some predators can be omnivorous, with the larva or adult feeding on both plants and animals. Many adult beetles can be found in flowers where they may feed on the petals, nectar, or pollen. Most of the beetles eat many kinds of fungi. Some eat bracket fungi that grow on trees, and others prefer mushrooms.
Beetles have complete metamorphosis with egg, larva, pupa, and adult. Female beetles keep the eggs inside their bodies and give birth to live larvae. As the larva molts and becomes larger, it changes into C-shaped bodies and are usually soft. Some larvae looks like worms and some are like caterpillars. All larvae have three pairs of legs on the thorax. Most beetle larvae pass through 3-5 stages. At the end larvae changes into pupae. The pupae are usually encased in a thin, light-coloured skin. In some species the pupa is surrounded by a silk cocoon. After the pupal stage, the adult beetle will emerge.
Most beetles require a year to complete one generation. Some long-horned beetles have been known to take 30 years to complete their life cycle.