Insects

The Greek translation of insect means cut into segments or segmented which is a good description of an insect’s body. All insects have three body segments the head, thorax, and abdomen. Insects also have three pairs of legs, six in total. Spiders, tics, and mites on the other hand have 4 pairs of legs or eight in total. These members of the arachnid family are often confused as insects but they are not true insects.

Besides the 3 pairs of jointed legs, all insects have compound eyes, a pair of antennae, and a ridged exoskeleton made of chitin, a relatively hard substance similar to the material that makes up our finger nails. There are over 1 million species of insects found throughout the globe and nearly 80,000 species of insects have been identified in our region. It is estimated that insects make up nearly 90% of the known living creatures on the planet when you count sheer numbers.

Most insects hatch from eggs and exhibit either incomplete or complete metamorphosis. Incomplete metamorphosis means that the juvenile often known as a nymph looks a lot like the adult. This juvenile goes through a series of molts where they cast of their old exoskeleton then develop a new one as they grow a bit larger. The various stages that an insect goes through before they become an adult is called an instar. Insects that display complete metamorphosis arise as a grub like larvae from the egg, they go into an inactive pupal state then they emerge as an adult looking much different than the larvae. Moths, butterflies, and beetles exhibit complete metamorphism.

Some insects can reproduce asexually without an egg. An example of this are aphids. During the summer adult female aphids can give rise to all female aphids. In the fall aphids mate and both male and female aphids are produced. Insects are found in all environments and they walk, fly or swim to get around. Most insects live solitary lives but some like, bees, ants, and terminates live in large well organized colonies. Insects come in all shapes and sizes and some are native to this region having evolved in our area for thousands of years while others are recently introduced from far off lands. These exotics normally enter this country from sea ports as a result of global trade. Many of these new arrivals become serious pests because there are no native controls to keep their populations in check. Insects can be harmful or beneficial to humans with some having both qualities.

Beneficial insects produce useful products such as honey, beeswax, and silk, they pollinate crops, trees, and other plants, eat harmful insects, help decompose organic material, beautify the landscape, and preform a number of other beneficial tasks that are not fully understood. Harmful insects can spread disease, inflict painful or venomous bites, destroy crops, harm plant life, rot wood, and be a general nuisance. The study of insects is called Entomology and it is a challenging pursuit based on the sheer numbers of species present and the continual introduction of new species. Having a working knowledge of insects is an important part of being a successful gardener, forester, arborist, horticulturist, nurseryman, orchardist etc.

Insects can have a profound effect on the health and vigor of individual trees and forests. Oftentimes insects are characterized by their method of feeding when describing the damage they inflict on trees and shrubs. Insects can damage trees by piercing and sucking plant fluids, chewing up the leaf or other plant part, or boring into the plant. There are a number of insects that damage trees by one of these three methods found in this region. Future columns will focus on some of the insects that impact our local trees and shrubs.

Article be Mike Kay, Frederick County Forestry Board

Nature note for 2/26/22