• The two-horned beetle (Dicheros bicornis) is a species of a scarab beetle (family Scarabaeidae) that is found in Malaysia, the Philippines, and Indonesia. There are a number of subspecies that range in color from brown to red to yellow to white.

    Beetles (order Coleoptera) are the largest group of animals on Earth, with over 350,000 distinct species, and scientists believe there may still be thousands of species of beetles that haven’t yet been discovered. Like all insects, beetles have three main body segments–the head, the thorax, and the abdomen. Like many other insects, beetles have two pairs of wings. This very diverse group of insects is characterized primarily by their hard front wings, called elytra, which protect their soft abdomen and their more frail back wings. Most beetles can fly using their back wings.

    Scarab beetles are a family of beetles whose bodies are compact and oval in shape. They can be as small as 1 millimeter (0.04 inches) or as large as 12 centimeters (4.7 inches). The characteristic that best distinguishes scarab beetles from other families of beetles is their unusual antennae. In scarab beetles, the last few segments of their antennae form lamellae or plates. These lamellae can be folded to form a club or fanned open to sense odors. Many scarab beetles also have toothed front legs that they use to dig. Scarabs include some of the most well-known of all beetles, such as the rhinoceros beetle, the dung beetle, the invasive Japanese beetle, and the large Goliath beetle. Some species of scarab beetles, like the metallic jewel scarabs, are brightly colored, making them a favorite of insect collectors.

     

    1. Beetles are the largest group of animals on Earth. What can you infer from this about their habitat and range?

      Answers will vary, but students should be able to infer that the range and habitats of beetles are highly variable, allowing them to thrive in most locations around the world.

    2. As with beetles, biologists classify other plants and animals using a hierarchy based on increasingly specific criteria. What is the value of classifying or organizing living things in this way? What are some possible drawbacks?

      Classifying living things helps biologists to study and discuss them more easily. It can show the relationship between things that might not otherwise be evident. It can also make identifying specimens easier. On the other hand, having rigid categories can result in some living things being forced into groups where they do not really fit, which can affect the way scientists think about those organisms.

    3. Scientists think that there may be thousands of unidentified species of beetles. How is this possible? Where might some of these beetles be found?

      Beetles are highly diverse and are adapted to live in many different habitats around the world. They can also be very small, which would make it easy to miss them. In addition, as new information comes in, some current species might be split into new subspecies. New species of beetles could be found almost anywhere, but remote locations and areas of dense growth, such as a rain forest, would be good places to start.

  • Term Part of Speech Definition Encyclopedic Entry
    abdomen Noun

    belly, or the part of an animal containing its stomach, intestines, and liver.

    elytra Plural Noun

    hardened front wings that protect the anterior wings of beetles and some other insects.

    lamellae Plural Noun

    thin, relatively rigid, plate-like anatomical structure.

    thorax Noun

    part of a body between the neck and abdomen in animals or the part fused with the head in crustaceans and arachnids.