APPLIED ENTOMOLOGY STUDY NOTES

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1 APPLIED ENTOMOLOGY STUDY NOTES INTRODUCTION TO THE SYSTEMATICS OF INSECTS AND MITES 0 OBJECTIVES At the end of the unit, you should be able to: o o o o define and explain systematics discuss the objectives of classification state the elements of classification give an outline of the general classification of insects and mites 0 Introduction to Systematics The naming and ordering of objects into groups is probably the most fundamental step in the development of scientific principles. For instance, in chemistry the discovery and naming of elements and organizing them into the periodic table became the basis for the development of the science.. In biology, the naming of organisms is referred to as nomenclature, and ordering them into a hierarchy of categories is known as classification. A related science, taxonomy, involves the theoretical basis for classification and the study of classification schemes. Specialists working in these areas usually are referred to as Systematists; their overall activity, systematics, is the study of the diversity and classification of organisms. Because of the tremendous size of the class Insecta, the naming and classification of all insects would seem to be a difficult, if not impossible achievement. However, hundreds of insect systematists around the world work daily on this task, and great strides have been made in understanding insect diversity. Indeed, some experts estimate that nearly 7,000 species new to science are discovered, named, and classified each year! However, there is still much systematics work to be done before insects will be as well known as birds, mammals, and other animals. Page 1

2 The study of the classification or taxonomy of any insect is called systematic entomology. If one works with a more specific order or even a family, the term may also be made specific to that order or family, for example systematic dipterology. 0 Objectives of Classification Like the periodic table of chemistry, classification allows us to order what we know about insects and to compare and contrast characteristics. From these comparisons, we formulate predictions about relationships, including those with both evolutionary and ecological meaning. For instance, members of the same species are expected to behave similarly in their food habits, tolerances to environmental extremes, developmental patterns, and other ways. A group of similar species, put together in a higher category called a genus, also could be predicted to share somewhat similar ecologies and to have evolved from the same ancestor. Moving to higher and higher groupings in classification, we expect more and more diversity within the grouping. A major application of classifications is in identification of insect specimens. Identifications of major groups such as insect orders can usually be made at a glance; however, finer identifications often require the use of keys. Most keys comprise a sequence of paired statements and questions that allow the user to eliminate alternative options and eventually associate the unknown specimen with a name. Many keys exist for orders and families of insects. Some of the most useful are those written by D. J. Borrer, C. A. Triplehorn, and N. F. Johnson (An Introduction to the Study of Insects) for the insects of North America, and by C. T. Brues, A. L. Melander, and F. M. Carpenter (Classification of Insects) for the insects of the world. Correct identification is the first step and probably the most important one in dealing with a Pest. It allows us to retrieve the information required for insect pest management. Without identification, we have no basis for predicting injury and advising action. 0 Elements of Classification Page 2

3 The classification of organisms is based on a hierarchy of categories, with the most inclusive occurring at the top and the least inclusive at the bottom. The major categories used in animal classification are phylum, class, order, family, genus, and species. But for added distinction in large, diverse groups, many other categories fall between these major ones. For example, a subclass category is commonly present below the class category and a superfamily category above the family category. An example of the major categories for the European corn borer shows the following classification: Phylum-Arthropoda Class-Insecta Order-Lepidoptera Family-Pyralidae Genus-Ostrinia Species-Ostrinia nubilalis Note that each category consists of only one word except the species category. The scientific name of a species is binomial; it is composed of two names, a genus name and a specific name, also called a specific epithet. Unlike all the higher categories, the specific name cannot stand alone; it must be used with the genus name. In zoology, it is conventional, but not required, for the species name to have the name of the person who first described the species as a suffix. Therefore, we might see the species name written as Ostrinia nubilalis (Hubner). The parentheses around the author name indicates that when Hubner originally described the species, he placed it in another genus. An author name without parentheses means that the species remains in the genus originally used by the describing author. Author names; are used often in technical systematic literature; they are omitted in this book. The system of binomial nomenclature we use today for classification was advanced by Swedish naturalist Carolus Linnaeus, who first used it consistently in Strict rules and conventions apply few name assignment, and these are stated for zoology in the International Code of Page 3

4 Zoological Nomenclature. Although they may be based in any language, scientific names are Latinized and usually refer to some characteristic of the animal or group named. The binomial of a species is always printed in italics or, if handwritten, is underlined to indicate italics. The names of genera and higher categories begin with a capital letter, but the specific name of the species and subspecific names always begin with a lowercase letter, as in the subspecies Diabrotica undecimpunctata undecimpunctata Mannerheim. In this example, the third name indicates a subspecies, a group of individuals of the same species that have differences in body form or color and geographical distribution.. A frequently used name for the species, the common name, is not covered by the formal rules of nomenclature. The name "European com borer" is a common name, somewhat similar to a nickname. Such names are often used in insect pest management because they are easily pronounced compared with the Latin name. However, because no formal rules govern these names, we may find different names or versions used in different localities for the same species, and confusion may arise. Because there is only one scientific name, it is always the safest name to use to avoid problems of semantics. In the United States, a list of common names approved by the Entomological Society of America is presented in Common Names of Insects and Related Organisms. These names are merely recommended and are not necessarily followed by the international scientific community. The species category plays the central role in systems of classification. It is the only category that is real; in other words, it is the only natural group. The species is a complex unit that is sometimes difficult to define, but a widely used definition applied to the species concept is as follows: a group of interbreeding individuals that are similar in body structure and that produce fertile offspring; moreover, these groups are reproductively isolated from other such groups. This is the biological species definition. All other categories of the hierarchy are based on the species category but are abstractions. Even though they are derived from suspected pathways of insect evolution, these other categories are human contrivances used for convenience. Because this is so, we find many differences of Page 4

5 opinion as to where to "lump" and where to "split" categories; therefore, many different schemes of insect classification result. 0 General Classification of Insects Insects are the most successful group of animals. They are a large and varied group. Of the 1 million or so known species of animals, over 850,000 or 76% are insects. Thousands of species remain to be discovered. Insects live in almost every type of environment; land, sea and fresh water. The distribution of insects extend from the poles to the tropics. The extensive distribution of insects is probably as a result of; 0 Their ability to fly 1 Their small size 2 The production of resistant eggs that can be carried by air, water currents, animals, etc 3 Their resistance to desiccation 4 Their adaptability 5 In general, this list proceeds from the most primitive insects to the most highly evolved. 6 7 Kingdom: Phylum: Class: Animalia Arthropoda Insecta Subclass: Apterygota primitively winged insects Order: Protura - proturans Order: Collembola - springtails Order: Diplura two-pronged bristletails Order: Thysanura silverfish (the three pronged bristletails) Order: Microcoryphia jumping bristletails Page 5

6 Subclass: Pterygota winged and secondarily wingless insects Superorder: Exopterygota simple body change during growth Order: Ephemeroptera - mayflies Order: Odonata dragonflies and damselflies *Order: Orthoptera grasshoppers, crickets Acrididae grasshoppers / locusts Tettigoniidae - longhorn grasshoppers and katydids Gryllidae crickets Order: Dermaptera - earwigs *Order: Isoptera - termites Kalotermitidae drywood termites Rhinotermitidae subterranean termites Order: Embioptera - web spinners Order: Plecoptera - stoneflies Order: Zoraptera Order: Psocoptera - bark and book lice *Order: Mallophaga - biting lice *Order: Thysanoptera - thrips *Order: Hemiptera bugs Suborder: Heteroptera true bugs Pentatomidae stink bugs Family Coreidae leaffooted bugs Lydaeidae seed bugs Nabidae damsel bugs Anthocoridae minute pirate bugs Miridae plant bugs Suborder: Homoptera aphids, scale insects, cicadas, whiteflies, psyllids and hoppers Cicadidae cicadas Page 6

7 Cicadellidae leafhoppers Psyllidae jumping plantlice Aleyrodidae whiteflies Aphididae aphids Order: Dictyoptera - cockroaches and mantids *Order: Siphunculata / Anoplura - sucking lice Pediculidae head and body lice Pthiridae crab lice Order: Grylloblatodea Order: Phasmida - stick-insects 8 9 Superorder: *Order: *Order: Order: Endopterygota complex body change during growth Neuroptera lace-wings, antlion flies, alderflies, snakeflies fishflies, owlflies Coleoptera beetles, weevils, fireflies Carabidae ground beetle Staphylinidae rove beetles Scarabaeidae scrab beetle Buprestidae metallic wood borers Elateridae click beetles Dermestidae dermestids Coccinellidae ladybird beetles Meloidae blister beetles Cerambycidae longhorned beetles Chrysomelidae leaf beetles Curculionidae weevils Scolytidae bark beetles Strepsiptera twisted-winged parasites, stylops Order: Mecoptera scorpion flies Order: *Order: Trichoptera - caddis flies Lepidoptera - butterflies and moths Page 7

8 Tineidae clothes moths and others Psychidae bagworm moths Tortricidae totricid moths Pyralidae snout and grass moths Papilionidae swallowtail butterflies Nymphalidae brushfooted butterflies Lasiocampidae tent caterpillars and lappet moths Sphingidae sphinx moths Noctuidae noctuid moths *Order: Diptera true flies (houseflies, mosquitoes, midges, sandflies) Culicidae mosquitoes Cecidomyiidae gall midges Tabanidae horse flies and deer flies This is a SAMPLE (Few pages have been extracted from the complete notes:-it s meant to show you the topics covered in the full notes and as per the course outline. Page 8

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Unit 3 Insect Orders

Unit 3 Insect Orders General Directions: 1. To complete this study guide, please read the assigned readings for Unit 3 and watch the lecture. If you need additional information to complete this study guide,