3.2: INSECT MORPHOLOGY 2020-08-04 14:30:47

Insect Morphology

Distinguishing harmful insects from benefcial or benign insects is important. Proper identifcation is a key step towards making future management decisions. Insects are typically identifed based on wing and mouthpart types, however there are many other distinguishing characteristics that can help with identifcation.

The insect body can be divided into three main regions—the head, which contains the antennae, eyes, and mouthparts; the thorax, which has the legs and wings; and fnally the abdomen, which contains a large portion of the digestive system and the reproductive parts.

Morphology of the northern corn rootworm beetle.

Morphology of the green cloverworm larva. Wings are one of the main features that allow us to categorize different types of insects. Most adult insects have wings, while larvae and nymphs do not. Wings provide both a great deal of mobility to insects and a useful key for feld scouts to distinguish species. The adult stage of caterpillars (moths) that injure corn and soybean can be identifed by wing patterns and colors. Many beetles can also be identifed by distinctive markings on their forewings.

Wings

Insect mouthparts are important for two main reasons. First, they may be used to identify the insect species. Second, mouthparts provide information on how insects feed and what sort of damage they cause. For instance, insects with sucking mouthparts use them like a straw or hypodermic needle. All fies have sucking mouthparts, and mosquitoes are a great example of insects that use sucking mouthparts like a straw to ‘suck up’ blood. Aphids also use sucking mouthparts to withdraw fuid from plants. Other insects, such as the spined soldier bug, are predatory insects that use these mouthparts when feeding on prey.

Other groups of insects, such as wasps and bees, beetles, praying mantises, and grasshoppers have chewing mouthparts. These insects chew on their food in a similar manner as humans. Honey bees have a lapping, tongue-like mouthpart used to collect nectar.

Chewing Mouthparts Sucking Mouthparts

Antennae are important sensory organs for insects. The antennae of insects are used as “feelers” that have a role in everything from sensing movement or vibration to smell and taste. Antennae come in a wide variety of shapes and sizes that are specially adapted to help insects survive.

Antenna

Insect legs are important for mobility and other tasks such as feeding or digging. Legs can also help to identify insects.

Insect legs are also very diverse and can be used to help determine a specifc insect.