Bugs 101: Getting to Know Another World OSU Master Gardener Training Designed by Patricia Patterson Lane County Extension Service Insect Diversity Diversity by Insect Order What is our hope for you here? You will learn to recognize the most common orders Using these orders will help you find the arthropod You will learn the value of arthropods You will learn how many odd things Arthropods offer as life styles and behaviors This is not especially a class in control, that comes later We hope that you may appreciate this alien empire for its own value and be led to want to observe and learn much more. An Introduction to Another Life Form Basic arthropod & insect structure Insect development The most common insect orders Insect reproduction & communication Non-insect invertebrates often encountered The uses of insects 1
Arthropod Structure Arthropoda means jointed legs and is the family which contains the classes: Crustacea (sowbugs & lobsters/crabs), Arachnida (spiders & mites), Chilopoda (centipedes), Diplopoda (millepedes) Insecta (insects) and many more. We shall be concentrating on the Insecta, the largest group. Breathing Mouthparts Wings Insect Structure Breathing through Spiracles Mouthparts Chewing Piercing/stabbing Sucking Siphoning Lapping/sponging Rasping/lapping The Miracle of Metamorphosis What, No Metamorphosis? Ametabolous Yes, there are a few primitive insects who do not undergo any metamorphosis. Apterygota: springtails, proturans, diplurans, and bristletails. Of these, we see silverfish, firebrats, springtails mostly. The proturans and diplurans mostly show up in soil. 2
Ametabolous Development Juveniles resemble adults, except that they are smaller With each molt, abdominal segments are added Gradual Metamorphosis (Parametabolous) These insects hatch from an egg and look much like miniature adults. Nymphs. Lack wings and sexual organs until the final molt. Eat the same food as adults Examples are grasshoppers, thrips, termites, lice, true bugs and aphids. Aphids usually skip the egg stage producing live young. Incomplete Metamorphosis (Hemimetabolus) This term refers to insects who spend part of their life cycle in water. Naiads. Naiads eat a different food than the adults. Mayflies, stoneflies, damselflies and dragonflies are good examples. The final change to an adult occurs not in a pupa, but inside the last naiad stage. 3
Incomplete Metamorphosis Complete Metamorphosis (Holometabolous) One of Nature s best tricks. This growth form is representative of the majority of insects by numbers. Ones we see most are the beetles, wasps, butterflies and moths, flies, and fleas. The process involves 4 totally different life stages: egg, larva, pupa and adult. Naiads are water dwelling One of Nature s Wonders Some Important Orders There are 31 insect orders, but we shall concentrate on just 9: Coleoptera, Diptera, Hemiptera ( suborders: Homoptera, Heteroptera) Hymenoptera, Lepidoptera, Orthoptera, Odonata, Mantodea & Blattodea. There are more in the MG manual. Ptera means wing, so we define by the wings for most insects. Wings Most insect orders are classified by wings 4
This image cannot currently be displayed. Coleoptera Coleoptera: Beetles & Weevils 2 Underwings are soft and do the flying, 2 overwings are armored and meet in a straight line down the back. Chewing mouthparts Young are called larvae or grubs Cucumber beetle, Black Vine Weevil, Ladybird (ladybug) Over 300,000 kinds God must have loved beetles, he made so many of them Diptera (2 wings) The only insects with just 2 wings. The other pair are gone or, in flies halteres. The eyes are very prominent and faceted. They may even nearly meet. Young are larvae or maggots. Flies, gnats, mosquitoes Piercing/sucking, chewing or sponging mouthparts. Diptera 5
Mosquito Blow fly A flea and a fly in a flue Fly factoids Mimicry Dangers Prowess Robber fly Hemiptera (1/2 Wings) Heteroptera, Suborder 2 pair of wings, the hind pair like membrane, the front pair partly hardened. All have a triangular shield on their back. X Easily confused with beetles Gradual metamorphosis from egg to nymph to adult Nymphs and adults usually feed on the same food All true bugs: stinkbug, Lygus bug etc. Piercing, sucking mouthparts. Hemiptera, Suborder Heteroptera Not All True Bugs Are Bad Heteroptera, Suborder Homoptera (Same Wings) 2 pair of equal membranous wings. Wings held in tent over body when resting Wings may be missing (aphid, scale) Nymphs and adults have the same diet Piercing, sucking mouthparts Aphid, whitefly, scale, mealybug, cicada 6
Homoptera: Those Little Suckers Aphids rule Parasitoid wasp laying eggs in aphid Aphid mummies Hymenoptera (membrane wings) 2 pair of clear, thin, membranous wings Smaller hindwings hook to forewings Have a stinger and/or protruding ovipositor Most are beneficial Mostly chewing mouthparts Young are larvae Wasps, hornets, bees, ants, sawflies Hymenoptera 7
Mostly the Gardener s Friends Carpenter Bees Termites (Isoptera) versus Ants Sawfly or Caterpillar? Lepidoptera (Scaly Wings) 2 pair of often showy wings, covered with small scales that can easily be rubbed off. Adult mouthparts coiled, sucking. Many do not eat as adults. Young are larvae or caterpillar or worm & have chewing mouthparts. Pupa stage is a cocoon (moth) or chrysalis (butterfly) Codling moth Lepidoptera 8
Moths and Butterflies What About Butterfly Gardens? Moths usually fly at night, butterflies by day. Butterflies fold their wings at rest. Moths rest with wings outstretched. 20,000 species. Major pollinators Odonata Odonata Not defined by their wings. Odonata means toothed. It may refer to the formidable mandibles. Incomplete metamorphosis with Naiads which are ferocious hunters. Representatives are dragonflies and damselflies. Chewing mouthparts Acrobats of the Insect World Dragonfly nymph 9
Orthoptera Straight wings is the meaning The hindwings are folded like a fan and stored under the forewings. Grasshoppers, crickets, katydids. Chewing mouthparts. Mantids and cockroaches used to be in this order, but now each have their own: Mantodea & Blattodea. Orthoptera A Plague of Locusts Upon You Crickets Grasshoppers Locusts Mantodea Praying Mantis 10
Blattodea Insect Reproduction Reproductive Techniques Insects have a wide range of reproductive behaviors from direct contact to drop & run. Behaviors include gift-giving, displays, perfumes, and sacrifice. Sperm storage is a common tactic. Reproductive Tricks Parthenogenesis: no males needed, thank you. Chastity belts Guarding Mimicry for nefarious reasons Insect Communication 11
Communication Insects communicate by chemical signals They may also use light signals Vibration and touch are important Major organs of communication are antennae, setae and tympani. Some insects have good sight and color perception & use that also. Constant Chatter Bug friend to bug friend Predator/prey Plant and insect Long range versus close Insect Galls Insect Galls Insect galls tend to be chambered, disease galls are solid. Well known galls are Oak apples, jumping oak gall, and petiole gall from aphids. Some galls are just deformed leaf parts and these are usually due to mites or aphids. OtherArthropods Arachnida: all our spider friends, mites, ticks, scorpion etc. Crustacea: sow bugs, pill bugs, lobster Myriapoda: centipedes, millipedes, symphylans All the above are by CLASS, not ORDER Arachnida This class breaks down into the true spiders and the mites for our usage. There are others. Araneida is the order of true spiders Acari is the mites 12
Araneida Commonest spiders here are the Golden Argiope, Wolf Spiders, Funnel Web spiders, Flower spiders, Cellar spiders and Trapdoor spiders. Our only spider here dangerous to humans is the the Black Widow. The jury is still out on the Hobo Spider. Serious bites are rare. 2 body parts, 8 legs, no wings or antennae Class Arachnida: Order Araneida 2 distinct body divisions, 4 pair legs All have venom glands and spinnerets The pedipalps in males are enlarged (boxing gloves) and modified for sperm transfer Most spiders put sperm on a piece of webbing and soak it up onto the pedipalps. Female Hobo Golden Argiope Orb Weaver Wolf Spider Black Widow Den-note egg sack. Black widow & male 13
Jumping Spider & Trapdoor Spider Acari Mites are another varied group. In the garden we note mostly the plant feeding mites, such as spider mites & gall mites, then the predacious mites, then the soil mites. Clover mites may invade our homes, but cause no damage. Dust mites are difficult to manage. 2 body parts, 8 legs, no wings or antennae Appears to be one body part as head minuscule Spruce spider mite Acari Mollusca Mollusca: slugs, snails, clams are not Arthropods We are interested in the class Gastropoda--terrestrial slugs and snails. Gastropoda means belly foot. Gastropoda Slugs & Snails Limax maximus--spotted Garden Slug 14
Slug-a-Bilia Slug Rapture Slug factoids about slime and extraordinary abilities. The Many Values of Insects Beneficials: pollinate plants, feed on things we consider pests. Aesthetics: beauty, jewelry, art Soil builders, decomposers and farmers Food: for arthropods, other animals & humans Weapons Forensic entomology Beneficials Beneficials may be predators (ground beetle), parasites, or parasitoids (wasps & flies mostly) They will be normally present in a well-diversified yard and garden which is not sprayed a lot. Art Jewelry Intrinsic beauty Aesthetics 15
Soil Helpers Food Source Insects are a crucial part of the world food chain for man & beast. Many cultures use insects as a food and medicine source Insects are an outstanding source of protein and fats Weapons Humans have used arthropods as effective weapons. Stinging insects Disease carrying insects 16
Forensic Entomology This is a field which is understaffed By the progression of insect types and life stages, cause of death, time of death, even manner of death may be discovered. If there is no other witness, a fly is the first arrival at the death scene. Marketing In case you had not noticed, insects are in! Movies such as Bugs Life and Microcosmos. TV specials. Books, coloring books, jewelry, cards, lollipops, T-shirts: you name it, someone has put insects in or on it. Learn to Be Humble Insects outweigh us, outnumber us, outperform us in most natural fields. If insects should all disappear, life would become impossible for us. Should we disappear, they would scarcely notice. 17
18
19
20
Sources for More Info CD of bug pix Field Guide to Insects and Spiders of NA, National Wildlife Fed. Bugs of Washington and Oregon Garden Insects Many reference books in MG library 21