Lesson 03: Characteristics of Adults in the Insect Orders (Printer Friendly Format)

The order Collembola contains individuals commonly called springtails. They are very primitive and we find them in a diversity of habitats. They may be as small as 0.25 mm, and sometimes may be close to 10 mm long. Most species are one to three mm in total length.

Springtails demonstrate ametabolous metamorphosis because they don't really change when they molt. Springtails develop from egg to young to an adult. They have no wings and are described as having chewing mouthparts. Springtails derive their name from a structure (you can see on the line illustration connected to this order) that extends from the tip of their abdomen. This structure is called the furcula. It folds up underneath the body, and when the insect wants to move forward, the furcula is released and the springtail is propelled forward.

We know that there are about 6,000 different species in the world. In North America north of Mexico, there is just slightly fewer than 700 different species. This rather primitive group of organisms may be quite abundant when soils are rich in organic material. In forest soils, springtails have been reported to be as abundant as 10,000/m². You may have witnessed snow becoming blackened on the surface, usually during a January thaw event. The tiny black insects that congregate on the soil surface are a species of springtail commonly referred to as snowfleas. Obviously this is not a true flea but a member of the order Collembola.

Springtail

Order: Collembola

Family: Sminthuridae

Cricket

Order: Orthoptera

Family: Gryllidae

Katydid

Order: Orthoptera

Family: Tettigoniidae

Examine the two illustrations. You can see in the top view of the cricket the tegmina or the leathery front wing that is folded over the top of the body.

In the lateral view of the katydid, you can see the leathery wing just slightly covering most of the membranous wing beneath.

There are about 12,500 different species worldwide in this order. In North America north of Mexico there's about 1,080 species. Common members of this order associated with turfgrass include species called mole crickets.

Members in the order Dermaptera are commonly referred to as earwigs. Worldwide there are about 1,100 different species, and in North America north of Mexico, there's about 20 different species of earwigs.

They demonstrate paurometabolous metamorphosis. They're described as having wings that are short and hard. Earwigs are described as having front wings called tegmina that are leathery. And they have membranous hind wings.

Both nymphs and adults have chewing mouthparts. One of the distinctive features that you can see on the illustration associated with this insect order is the presence of forceps at the end of the abdomen. These structures are not used aggressively, but are used to defend territory.

It's thought that the common name "earwig" is given to this group as a result of their association with wigs worn by humans. Perhaps these insects crawled under the wig overnight. Wearers of these wigs thought that the insects were attempting to crawl into their ears. That's not an accurate account, although we do know that earwigs are nocturnal and they usually seek out dark, damp places to rest during daytime hours.

Earwig

Order: Dermaptera

Family: Forficulidae

The order Hemiptera contains individuals we commonly refer to as "true bugs." This order contains individuals known as plant bugs, stink bugs, ambush bugs, or assassin bugs. True bugs develop from an egg to nymph, molting several times, until they reach the adult stage.

Metamorphosis is described as paurometabolous. True bugs have two pairs of wings. The front pair is referred to as the hemelytron, and is leathery at the base and membranous at the tip.

Members of the order Hemiptera have piercing-sucking mouthparts. They can be differentiated from a closely related group of organisms that we will discuss next by the fact that the beak or their piercing-sucking mouthparts arise from the front of their head.

If you examine the line illustration connected with this particular insect order, you can see at the tip of the head, the mouthparts fold back under the head, but they essentially arise from the front of the head.

There are many beneficial species within this particular order, but as you might conclude there are also some pest species. An example of a pest species would be the hairy chinch bug. And a beneficial would be the big-eyed bugthat is a predator. Stink bugs have various food habits. Some are plant feeders while others are excellent predators on such things as leaf-eating caterpillars.

With regard to their importance worldwide, we know of about 50,000 different species of true bugs in the world. In North America north of Mexico there are about 3,600 difference species.

Wheel Bug

Order: Hemiptera

Family: Reduviidae

The order Homoptera contains many different individuals such as aphids, scale insects, cicadas, whiteflies, and leafhoppers. They demonstrate gradual metamorphosis. Adults usually have two pairs of wings. In some cases, individuals such as female scale insects never develop wings.

All members of this order have piercing-sucking mouthparts and they can be differentiated from true bugs by the fact that the beak arises from the underside of the head. This may be apparent in the illustration of the leafhopper associated with our discussion of this order.

One of the key features associated with aphids is the presence of projections that arise from the side near the posterior end of the abdomen. These structures are called cornicles. Cornicles are usually located on the top side of the fifth or sixth abdominal segment on aphids. They secrete a defensive material that warns members of the same species of the possible presence of a predator. In the line illustration of the winged aphid you can see the cornicles sticking out along the side of the tip of the abdomen.

Worldwide there are about 32,000 different species in this order with just slightly under 6,400 different species in North America north of Mexico.

Winged aphid

Order: Homoptera

Family: Aphididae

Leafhopper

Order: Homoptera

Family: Cicadellidae

The next order, Thysanoptera, includes individuals commonly referred to as "thrips." The term "thrips" is both singular and plural. In other words, there is no insect called a "thrip." In terms of important species, the western flower thrips, gladiolus thrips, and pear thrips are three species that may be encountered in landscapes.

These individuals are examples of a transitional condition between gradual and complete metamorphosis. Thrips develop from an egg, to larval stage, and molt into prepupal and a pupal stage prior to becoming an adult.

Thrips are somewhat unique developmentally, and thus, we describe them as being indicative of having both complete and gradual types of metamorphosis. They have two pairs of fringed wings (check the illustration associated with this order). Thrips are not known to be strong fliers.

If you check older entomological references you may find that thrips are described as having rasping-sucking mouthparts, but we now know them to have piercing-sucking mouthparts.

One of the key features of members in this order is that their tarsi are bladder-like at the tip. That is, thrips have swollen areas associated with the very end of their legs.

We know that there are about 4,000 different species worldwide with about 700 species of thrips known to occur in North America north of Mexico.

Thrips

Order: Thysanoptera

Family: Thripidae

The order Neuroptera is made up of individuals commonly called lacewings, fishflies, alderflies, and antlions. Sometimes aquatic members of this order are placed in the order Megaloptera, but for the purposes of this course, we'll use the order Neuroptera.

These individuals have holometabolous or complete metamorphosis in that they develop from an egg to a larva that molts several times. Next is the pupal stage followed by as adults. They have two pairs of wings and chewing mouthparts. A distinctive feature is that their wings are described as net-veined, and when folded they are held roof-like over their body.

The illustration for this order shows a lacewing adult female resting on foliage. You can see the net veins and the roof-like disposition of the wings over its body. This particular order is comprised of beneficial individuals and species that inhabit aquatic environments. One example would be the dobsonfly whose immature stage is referred to as the hellgrammite.

There are additional illustrations for this order. One shows a male dobsonfly with its characteristic tusks. Additionally, the darker individual associated with this order is an alderfly whose immature stage develops in rivers and streams.

There are about 4,700 species in this order worldwide with about 350 different species known to occur in North America north of Mexico.

Goldeneye Lacewing

Order: Neuroptera

Family: Chrysopidae

Dobsonfly

Order: Neuroptera

Family: Corydalidae

Alderfly

Order: Neuroptera

Family: Sialidae

Coleoptera contains the most abundant group of animals on planet Earth. Entomologists have described more than 300,000 different species of beetles and weevils worldwide. In North America north of Mexico there are about 24,000 different species.

These individuals undergo holometabolous or complete metamorphosis. They have two pairs of wings, the front wings being described as the elytron. The front wings may be either hard or leathery, and the elytron protects the membranous wings folded beneath.

Both the adult and larval stages have chewing mouthparts. One of the key characteristics for members of this order is that their front wings are hard and veinless. Knowing the characteristic shape and color pattern on the elytron will help you identify many beneficial species in this order such as ground beetles or tiger beetles. Additionally, knowing patterns on the elytron will allow you to identify pests such as certain species of weevils and scarab beetles whose larval stages may feed on turfgrass.

Ground beetle

Order: Coleoptera

Family: Carabidae

Ladybeetle

Order: Coleoptera

Family: Coccinellidae

Longhorned beetle

Order: Coleoptera

Family: Cerambycidae

The insect order Diptera contains the true flies, including species known as gnats, mosquitoes, horse flies, and black flies. Members of this order demonstrate holometabolous development or complete metamorphosis.

As adults, true flies have one pair of wings, although there are some parasitic species that may lose their wings once they find a host. Flies are described as having mouthparts that may be piercing-sucking as in mosquitoes. Sponging mouthparts are found in the more advanced flies such as the house fly.

A distinctive feature is that members of this order will only have one pair of wings. The hind wings are modified into structures called halteres. Halteres are modifications of the hind wings that are small knobbed structures. They function as organs of equilibrium, essentially acting like gyroscopes during flight.

With regard to this order, there are about 120,000 different species worldwide with about 18,200 species known to occur in North America north of Mexico. Members in one particular beneficial family, the Tachinidae, lay their eggs on pest species and are known to be beneficial in managing pest species in landscapes.

I'm sure many of you are familiar with the order Lepidoptera that includes butterflies, moths, and skippers. Butterflies have clubbed antennae, moths are usually described as having feathery antennae, and skippers have clubbed antennae with a tiny hook at the tip. By examining antennae of adults in this order, we can differentiate these three common groups.

The Lepidoptera go through holometabolous or complete metamorphosis. Most of them have two pairs of wings as adults, although there are certain members whose females are wingless, such as some species in the family Geometridae. The larval stages or caterpillars in this family are sometimes called inchworms or loopers. Adults are described as having siphoning mouthparts. Their mouthparts are distinctive and referred to as a proboscis that is long and coiled.

The larval stage of many species in this order feed on turfgrass as well as the foliage of woody ornamental plants. Individuals such as armyworms, cutworms, and species called sod webworms may be economically important to turfgrass managers.

Worldwide there are about 112,000 different species of butterflies, moths, and skippers. In North America north of Mexico there are about 11,300 different species that have been identified.

Butterfly

Order: Lepidoptera

Family: Papilionidae

Moth

Order: Lepidoptera

Family: Sphingidae

Skipper

Order: Lepidoptera

Family: Hesperiidae

Lastly, the order Hymenoptera is a large order containing individuals such as ants, bees, wasps, and a group of plant feeders commonly called sawflies. We write "sawflies" as one word to indicate that they are not true flies. We write the common name of "true flies" as two words such as black fly, horse fly, or deer fly to indicate that they are members of the order Diptera. Sawfly larvae are plant feeders on the foliage of conifers or deciduous plant material. Some are even known to bore into plant tissue.

Worldwide there are 108,000 different species. In North America north of Mexico there are 17,200 different species in the order Hymenoptera. Members of this order have holometabolous or complete metamorphosis. They have two pairs of wings. Mouthparts of adults in this order are described as being chewing or chewing-lapping.

One of the distinctive features of members of this order is that their membranous wings have few veins. Additionally, the base of the abdomen is often constricted. You can see these characteristics in the two illustrations associated with this order of insects.

As a side note, landscape managers are often asked questions by folks playing a round of golf or looking at something they may have collected at their own homes. These clients often ask, "Is this a winged ant or is this a termite?"

Examine the two illustrations provided. You can first note with a winged termite that the antennae are straight; whereas, if you look at a winged ant, the antennae are described as being elbowed.

Additionally, when you look at the wing veins in a winged ant, there are very few veins apparent when compared to the presence of many veins in the wings of an eastern subterranean termite.

Another characteristic to look for when identifying a winged ant is that you can see three distinct body regions. The head, thorax, and abdomen are apparent on the ant. When you look at the illustration of the winged termite, you can see the head, but the juncture of the thorax and the abdomena isn't as easily seen.

I hope you'll find the characteristics listed above useful to you when answering this common question posed to golf course superintendents and turfgrass or landscape managers.

Ant

Order: Hymenoptera

Family: Formicidae

Wasp

Order: Hymenoptera

Family: Sphecidae

Eastern Subterranean termite

Order: Hymenoptera

Family: Rhinotermitidae

Typical Winged Caste Ant

Order: Hymenoptera

Family: Formicidae