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Insect identification by example

Insect identification by example


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Upstate NY USA here.

I am trying to identify the type of insect that this is:

Top-side:

Bottom-side:

Is this a cockroach? If so what type/sub-species might it be? If not, what other type of bug have I stumbled across here?


This is some species of Ground Beetle (family Carabidae); the trochanter of the hind leg (just before and somewhat overlapping the femur) and the threadlike antennae helps point to that group. The book The beetles of northeastern North America by N. M. Downie and Ross H. Arnett (Sandhill Crane Press 1996; now out of print but in at least some libraries) may help with a species identification (fair warning: the keys are not profusely illustrated).


Nomenclature and classification of insects

Insect classification, and thereby entomological nomenclature and more particularly insect scientific names have undergone many reorganisations and modifications over the last decades. The general public is not familiar with scientific nomenclature, whether zoological or botanical. Moreover, their notion of what a species is or represents is quite vague. o name an animal or a plant species, people generally use the words « a kind of », a sort of », « a variety », « a race ».
Such approximate and therefore imprecise language highlights how difficult it is for the public to name or apprehend some “thing”, whether animal or plant, that more or less looks like some “thing” else. For scientists, the word “species” has a well-defined meaning: it is the basic unit (also called taxon) of systematic classification.Although the concept of “species” is currently interpreted in different ways by the scientific community, its main feature is inter-fecundity, i.e. the capacity for individuals belonging to a same population to interbreed and give birth to viable, fecund offspring in natural conditions.
Accuracy and rigour are needed more than ever. They allow traceability, language uniformity and universal accessibility when family, genus, species and sub-species names are expressed in scientific terms. Besides, scientific terms give access to targeted, accurate bibliographical research data that would not be accessible with only vague species indications. Naming organisms accurately (and only scientific names are accurate) even in the agricultural sector, is an indispensable and unavoidable prerequisite of any research, any experimentation and any study, in laboratory or on site.
For a better reading of this text, we thought it would be useful to give a reminder of some essential rules that apply to insect nomenclature and classification. The rules also apply to other organisms than insects.
What is classification?
The classification of organisms relies on a hierarchical, pyramid-structured system that consists in creating groups and sub-groups that constitute taxonomical categories: classes, orders, families, genera, species, sub-species. (Table 1).
Each group or sub-group gathers together animals or plants (insects in our case) that possess common, usually morphological, features. If we move toward the top of the pyramid, the degree of resemblance between groups decreases (for example, in the Arthropod branch, animals that do not display much resemblance with one another are found, such as crabs, spiders, insects and centipedes). Conversely, if we move toward the base of the pyramid, resemblance increases (for example, within the Hexapod (insect) class, the Diptera (flies) and Hymenoptera (bees) orders display higher resemblance with each other). Table 1 :


Insect Order Ephemeroptera (Mayflies)

Mayflies may be the most important insects for trout anglers to understand. They are an ancient order of insects, famous outside the fly-fishing world for their fragile beauty and short adult lifespan, often a single day to mate and die. The mayfly's poignant drama attracts poets and anglers alike, but anglers make the most of it.

Mayflies live more than 99% of their lives as nymphs on the river or lake bottom, filling many crucial roles in freshwater ecosystems as they feed and grow. They eventually emerge from the water as winged sub-adults called "subimagos" by scientists and "duns" by anglers. Duns evolved to be good at escaping the water, with a hydrophobic surface and hardy build, but they are clumsy fliers. Within a day or two they molt one last time into "imagos" or "spinners," the mature adults, a transformation captured in this photo series of a dun molting into a spinner. They have longer legs and tails, and sleeker, more lightweight bodies, giving them the airborne speed, agility, and long grasp they need for their midair mating rituals. They are usually darker than the duns and have shinier, more transparent wings. They die within minutes or hours after mating.

The importance of mayflies comes largely from their emergence and mating behavior. While many organisms assure the survival of their species using individualistic tools like stealth, speed, venom, or parental care, mayflies are famous instead for their "strength in numbers" approach. They coordinate their emergence and mating times (both time of year and time of day) so that they leave their safe habitats and emerge together in large numbers in a very short period of time. This can trigger feeding frenzies in every nearby insect-eater, from trout to birds to dragonflies, but there are simply so many mayflies at once that many luck out and survive to reproduce. These trout feeding frenzies are the stuff of legend among fly anglers, and they also pose one of our greatest challenges, because trout feeding feverishly on a thick hatch are often unwilling to strike any fly that doesn't properly imitate the mayfly of the hour.

The duns of each species typically emerge during an hour or two each day for a couple of weeks in the spring or summer, though there are some important fall hatching species. Some species follow more sporadic emergence strategies, and many of these combine to create a sort of "background noise" of miscellaneous mayfly activity on many trout streams throughout much of the summer. This mixed bag of mayflies provides good opportunities for anglers to catch rising trout that aren't too picky.

Mayfly nymphs emerge into duns in several different ways. Most often, the nymph swims to the water's surface and splits open its exoskeleton above the thorax ( Thorax: The thorax is the middle part of an insect's body, in between the abdomen and the head, and to which the legs and wings are attached. ) . The dun wriggles out onto the surface, where its wings fill with fluid hydraulically and allow it to take flight. (In contrast to the common myth of mayflies needing time to "dry their wings," this process is more like inflating a raft.) Different species may be quick or slow at each stage of this process. Some take a long time to escape their nymphal shuck (

Shuck: The shed exoskeleton left over when an insect molts into its next stage or instar. Most often it describes the last nymphal or pupal skin exited during emergence into a winged adult. ) , making flies that imitate these "emergers" especially effective. Some species very quickly take flight when they hit the surface, while others ride the surface for some minutes like little sailboats, a prime target for hungry trout and a welcome sight for the dry fly angler. Cool or windy weather may prolong these struggles and increase the availability of mayflies to trout.

Many important species follow completely different emergence patterns. In some, full winged duns emerge on the bottom of the stream and float to the surface. Others swim to shore and crawl out on land before emerging. Learning to identify mayflies and associate them with the right behaviors gives an angler an advantage: the ability to make a good guess about which style and stage of emergence to imitate, simply from seeing and recognizing some duns or mature nymphs.

Once mayflies have molted into spinners (imagos), they usually gather in swarms to mate, usually over riffles. When they're done they fall dead, or spent ( Spent: The wing position of many aquatic insects when they fall on the water after mating. The wings of both sides lay flat on the water. The word may be used to describe insects with their wings in that position, as well as the position itself. ) , on the water in an event anglers call a spinner fall. Spinner falls are usually better coordinated than emergences, because spinners gather in swarms for mating. This means some species with sporadic, unnoticed dun emergences become far more concentrated and important to anglers as spinners.

Spinner falls are also usually more predictable than emergences, because so many of them (although not all) take place at dusk, and they are preceded by visible aerial spinner swarms, which may start hours earlier at treetop level and descend gradually toward the water as night falls. Dusk spinner falls often mark the angler's best chance to see a good rise of trout each day. However, like most things in nature, mayfly spinners aren't as predictable as we'd like. Sometimes clouds of thousands of spinners will gather over a riffle in the evening and fly back into the woods as quickly as they came, never falling spent ( Spent: The wing position of many aquatic insects when they fall on the water after mating. The wings of both sides lay flat on the water. The word may be used to describe insects with their wings in that position, as well as the position itself. ) . When that happens, anglers must swallow their disappointment and look for them to finish the job in the morning.

Mayfly females face the extra duty of laying their eggs after mating. Many species release their eggs as they fall spent ( Spent: The wing position of many aquatic insects when they fall on the water after mating. The wings of both sides lay flat on the water. The word may be used to describe insects with their wings in that position, as well as the position itself. ) on the water near the males after mating. Some land on the water, release a few eggs and take off again. Others fly low over the water and dip the tips of their abdomens below the surface for just a moment to release eggs. Still others drop their eggs from high in the air. In one very common genus, Baetis, the females land near shore and crawl underwater to lay their eggs in neat little rows on rocks and logs.

Mayfly nymphs or " naiads ( Naiad: Naiad is the technical term for nymph used by modern entomologists. ) " grow underwater for a period ranging from 3 months to 2 years, depending on the species. Like the stoneflies of Plecoptera, their development follows "incomplete" metamorphosis, meaning they do not undergo a dramatic transformation to adulthood via a pupal stage like butterflies and caddisflies (Trichoptera) do. Their changes are more gradual, at least internally. As the nymphs grow they proceed through numerous slightly different developmental stages called instars ( Instar: Many invertebrates molt through dozens of progressively larger and better-developed stages as they grow. Each of these stages is known as an instar. Hard-bodied nymphs typically molt through more instars than soft-bodied larvae. ) , between which they molt out of their old exoskeletons and expose new ones.


  • Some streamlined swimmers move like little bullets, faster then fish of the same size, and they swim upstream against strong current without a problem. Others inhabit slow water and use their speed to dart between leaves in the weed beds.

  • Clingers of the family Heptageniidae are typically flat nymphs with strong legs and claws for holding on to rocks. Some have evolved further adaptations for clinging in fast water for example, the genus Rhithrogena has gills resembling suction cups. There is great variation among the clingers and some species have adapted to slow water.

  • Crawlers come in the most varied forms they are a catch-all group for "average" families that usually excel at neither swimming nor clinging. The Hendricksons and Sulphurs of the Ephemerella genus are typical crawlers. There are tiny crawlers like Tricorythodes, and there are oddballs like Baetisca. The crawlers in Leptophlebiidae are quite good at swimming, and those in Drunella (especially Drunella doddsii) are quite good at clinging.

  • The distinctive burrowers of Ephemeridae (and the less important Polymitarcyidae) are pale nocturnal creatures which use tusks to carve U-shaped burrows into the river bottom, where they live most of the time. Their long yellow bodies and feathery gray gills make them unmistakable. Their hatches are some of the angler's favorites, especially the giant Hexagenia limbata flies of the Midwest and West or the Eastern Green Drakes, Ephemera guttulata.

Entomologists have a similar system, but even their line between categories is a blurry one. Some burrowers swim well, some crawlers cling well, and some families like Leptophlebiidae and Potamanthidae straddle the boundary between categories.

If you fish a fertile stream, watch the bottom ahead of you as you walk. Sometimes, especially in April and May, you'll see lots of mayfly nymphs in front of you swimming out of your way or scurrying to the undersides of rocks. You don't need to be down on all fours with a magnifying glass to see mayfly life underwater.


Insect identification by example - Biology

University of Kentucky Department of Entomology - KENTUCKY BUG CONNECTION
Youth Entomology Resources | MIDDLE - HIGH SCHOOL
>PRESCHOOL - ELEMENTARY >4H RESOURCES

Using Insects in the Classroom
By Stephanie Bailey. Adapted from "Six-Legged Science: Insects in the Classroom," by G.A. Dunn.
Updated 10/04 by Blake Newton, Extension Specialist

Insects are an excellent resource for science education. Many insects are easily maintained in the classroom and can happily thrive despite being handled and kept in captivity. The remarkable diversity in form and function of commonly found insects promotes interest and enthusiasm in observing the natural world. Insects can also be used to model a variety of scientific principles.

The objectives of this page are to give educators basic information about insects and ideas on how to use insects in the classroom.

Collecting Insects

There are two types of insect nets: sweep nets (used for tall grass and shrubs) and aerial nets (for flying insects) the latter are sometimes called "butterfly nets." These can be purchased from mail-order companies or made at home very cheaply. Materials needed are an old broom handle or large dowel, wire coat hanger (unwound, then shaped into a"hoop"), duct tape, and either a pillowcase (for a sweep net) or netting remnant. Many crawling insects can be captured without a net by using a small jar.

Once caught, insects need to be placed in a killing jar or an observing container. In either case, a clean, large mason jar or peanut-butter jar works well. If you want to kill the insects and make a collection, use nail polish remover or rubbing alcohol to wet down cotton balls, and put them and some tissues into the jar. The tissues give insects places to "hide," so they don't damage their wings when trying to escape. Insects can also be killed by placing them in a freezer for 24 hours. Collected and killed insects need to be pinned through their thorax, a little to the right of the midline. High grade insect pins can be purchased from mail order companies or hobby stores. Insects should then be placed in a sealed box, such as a cigar box or tight-fitting shoe box. Serious enthusiasts may want to purchase professional boxes - either glass cases or a Schmidt box from a hobby store or mail order catalog. Moth balls will protect specimens from scavengers.

If you want to rear, maintain, or observe live insects, read our page on Classroom Mascots.

Aquatic insect tanks are also easy to make and fun to observe. Use a strainer or colander to collect aquatic insects. Insects you might catch include: dragonfly immatures, mayfly immatures, whirlygig beetles, water striders, giant water bugs, diving beetles, water boatmen, and caddisfly immatures. Many of these are predaceous, so supply some small feeder guppies or fairy shrimp, or else the tank will turn into a REAL test of survival of the fittest! For more details on maintaining an aquatic insect habitat, read our page on Pet Bugs: Aquatic Insects.

The best place to start catching insects is the school yard. Insects are found around trees and shrubs, leaf litter, grass, and flowers. You can also look under rocks and logs. Some insects (flies and wasps especially) can be attracted with sugary or fruity liquids that are left outside in the sunshine. Butterflies will form "puddle clubs" when tempted with small pools of sugary or salty water. If you bury a bucket to the rim and fill it with gravel, then pour sweet and salty liquids over the gravel, you can have a permanent puddle for butterflies to use. The foundation along the perimeter of the building, as well as bathrooms and supply rooms are suitable habitats for crickets, spiders, ants, and possibly cockroaches. Field trips to a lake, forest, or park will offer even more opportunities for collecting insects.

Activity: "Show and Tell" with Insects. Have each student capture, identify, and look up information about an insect. The students may want to develop an insect zoo and invite neighboring classes to attend.

Insect Diversity and Success

There are well over 1 million species of insects. They outnumber all other animals combined by more than 4 to 1. There are more species of beetles than species of flowers. Insects range in size from larger than the smallest mammals to small enough to crawl through the eye of a needle. They have been around since before dinosaurs.

Secrets for insect success include:

Small size: insects can exploit many more niches (places in food webs) in a given area compared to larger animals
Short life cycle: insects can develop in temporary habitats such as water puddles and decaying organic matter, and adapt to changing conditions much more rapidly than other animals.
High reproductive capacity: as an example, an aphid has 50 offspring within its three week lifespan.
Complete metamorphosis: insects with complete metamorphosis, such as beetles and butterflies, can exploit two separate niches in one lifetime.
Exoskeleton: an exoskeleton protects insects from dehydration and damage.
Flight: wings allow rapid movement to new habitats and food sources, and to escape from predation.
Diversification: although insects all have the same basic structure, each insect species has adapted to its own particular environment.

Insects have diversified in two ways:

1) Insects are present in every type of habitat except the middle of the ocean. They are found on the tops of mountains and underground caves. They thrive in deserts, rivers, fields and forests. They have even been in space: Biosatellite II orbited the earth with fungus gnats, roaches, and wasps. Insects are probably crawling through your house right now. Some of the more highly specialized insects even build homes for themselves. Caddisflies, as larvae, make cases in which they live. A few species of wasps, aphids, midges, and psyllids can make galls (special swellings of plants due to feeding by the insect), which they feed on and receive protection from. Many wasps, bees, and ants (order Hymenoptera) create nests, burrows, or social colonies. Termites, which belong to a different order (Isoptera), also build large colonies and live socially. Parasitoids live inside another insect until becoming adults. Other insects live in or on the leaves, stems, or roots of plants.

2) Although they each have the same general body plan, different species of insects have developed changes in appearance and function of their body parts to adapt and survive in different niches.

Camouflage allows some insects to blend into surroundings. Certain butterflies, treehoppers, and caterpillars blend with their surroundings to hide from predators. However, some predators, like assassin bugs and praying mantids use camouflage for surprise attacks.

ACTIVITY: CAMOUFLAGE EFFECTIVENESS. Materials needed: several colors of construction paper or pipe cleaners, at least 1 of which blends with grass (if outside) or with posterboard (inside). Cut these into small pieces. Spread the pieces randomly inside a marked area, either on grass or a sheet of posterboard, then have students pick up as many as possible within 10 seconds. See how many and which colors are picked up.

Other mechanisms used for protection include:

Hairs and spines: Many caterpillars have hairs and spines. Some are "urticating" hairs, which sting, others prevent parasitoids from laying eggs in the caterpillars.
Stingers: Wasps can sting repeatedly while honeybees only sting once. Some wasps use their stingers to paralyze prey, then lay eggs and let their larva feed on the prey.
Poison: Some insects feed on poisonous plants and accumulate the plant's poison (e. g. monarch gets its poison from milkweed). Other insects have a mechanism to produce their own poisons (e. g. ladybug).
Mimicry: Some unrelated poisonous insects share color patterns. For instance, milkweed beetles and ladybugs are both red and black. Both of these insects produce poison. It is believed that a predator will learn to avoid all red-and-black insects if it feeds on one that makes it sick. Sometimes, non-poisonous insects will mimic these color patterns as well, even though they are not poisonous. An example: the non-poisonous Viceroy butterfly which mimics the poisonous Monarch butterfly.

Insect Form, Function, and Development

External Body Plan

The integument or body wall of an insect is used for muscle attachment and protection from damage and desiccation. The integument is made up of two layers: the epidermis, which consists of living cells. These cells secrete the outer layer, the cuticle, which is composed of protein and chitin. Caterpillars and soft-bodied insects have cuticles that are mostly endocuticle, which remains flexible. Hard-bodied insects have a harder exocuticle, with the endocuticle underneath.

An insect's body is made of three main body parts: a head, thorax, and abdomen.

The head is the center of coordination and feeding, with antennae, eyes, and mouthparts

Form and Function of Insect Mouthparts - Different insects possess different types of mouthparts. These mouthpart types can be compared with the functions of common objects:
chewing mouthparts (grasshoppers) - scissors
sucking mouthparts (stinkbugs) - turkey baster
stabbing mouthparts (deer fly, mosquito) - boxed drink straws
coiled mouthparts (butterfly) - party favor
sponging mouthparts (housefly) - dishwashing wand-sponge

Some insects with stabbing mouthparts can transfer diseases. This can be shown by first uptaking colored water with a turkey baster, let it out, then uptake clear water with the baster. The clear water will become slightly colored.

The thorax is the center of locomotion, containing legs (1 pair per segment) and wings, if present (on the last two thoracic segments). Front wings may be modified to very hard (beetles) or leathery (grasshoppers), and function as armor. True flies (order Diptera) have a special adaptation to their second pair of wings, which have evolved into knob-like structures called halteres, which are used for balance.

Observation: The Movement of Wings in Flight. Materials: strobe light and large butterfly, moth, or roach. Tether a large insect by gluing a thick string to its thorax, then lift the insect off the ground and allow it to flap its wings. Adjust the strobe light until the movement can be easily seen and stopped. Note the curve of the forward line of wings in downstroke and upstroke. A note of caution: use of the strobe light with this experiment may bring on epileptic seizures so check with students or parents first!

The abdomen contains reproductive structures, most of the spiracles (openings for breathing, also present on the thorax), and cerci, which are sensory structures, much like antennae. All of these external structures can easily be shown with large grasshoppers.

Internal Systems

Insects have open circulation. The only artery is the dorsal aorta, which pumps blood from the back of the insect up to the head.

Respiration is not through the bloodstream. Oxygen enters insects through their spiracles (holes on the side of the body) and branches out through a network of tubes into every cell in the body.

Digestion proceeds from the insect's mouth through the esophagus, and into the crop, which is a storage site. A valve called the proventriculus separates the crop from the midgut. In some chewing insects, the proventriculus has hardened "teeth" which help to break up food stored in the crop. In the midgut, an envelope called the peritrophic membrane protects the walls of the midgut while allowing digestive enzymes to enter and digested products to filter out and pass through the midgut membrane into the hemolymph. The gastric caeca are large pockets on the anterior side of the midgut that allow adsorption of digested materials. Malphigian tubules, located at the posterior end of the midgut, have a function similar to our kidneys, namely filtering water and wastes out of the bloodstream. Fingerlike projections absorb waste particles and excrete them into the hindgut, which like our large intestines regulates osmotic (water) pressure as waste passes from the insect.

The ventral nerve cord, like our dorsal nerve cord, brings messages to and from the brain.

Reproductive structures in insects include ovaries, bursa copulatrix and uterus in females, testes, aedeagus in males. Interesting mating habits include those of bedbugs (the male 'stabs' sperm into the female through her body wall) and dragonflies (males transfer sperm to secondary structures located on the second abdominal segment to mate, males hook their cerci behind the female's head, then the female must curve her body underneath to collect sperm. This forms a "wheel").

Insects are cold-blooded. Any activity depends on a certain amount of body heat. Often, flying insects must "warm up" their bodies by flapping their wings before being able to take off. In very hot temperatures, insects must find shade so as not to overheat. Many insects, including moths, butterflies, and bees can funnel heat produced from flying into the abdomen, where abdominal spiracles and body wall allow heat to escape. Dragonflies at rest modify their posture depending on whether they're hot or cold. If hot, they position themselves upright to make as little surface area as possible exposed to direct sun. If they are seeking warmth, they rest flat on a surface perpendicular to the sun's rays to get maximum exposure.

Experiment: Cricket Thermometers. Materials: Male tree cricket, thermometer, ice in a bucket, hot or warm water in a bowl. Count chirps per 15 seconds at several different temperatures (at least 3, preferably 5). Use the ice to cool, then hot water to increase temperature. Determine the lowest temperature that crickets chirp, and then graph chirps vs. temperature. Later on, without using a thermometer, see what room temperature is by the number of chirps. (The sum of tree cricket chirps in 15 seconds plus 40 approximates the air temperature in degrees fahrenheit around the cricket.)

Insect Development

Insects grow by molting, as opposed to gradual development of humans. Whenever an insect grows slightly larger, it must shed its skin. Once insects become adults, they are unable to molt any further, and will not grow any larger.

Metamorphosis: Insects have either Simple or Complete Metamorphosis.

Simple Metamorphosis: Development proceeds from an egg to nymphs (which usually look like the adult, except for underdeveloped wings) to an adult. Examples include grasshoppers and milkweed bugs. Also called "incomplete metamorphosis."

Complete Metamorphosis: Development proceeds from the egg to a larva, which is usually wormlike and does not resemble the adult insect. When full-grown, the larva transforms into a pupa, then finally the adult. The pupal stage is needed to develop the wings and other appendages such as antennae. Examples of this type of development are butterflies and moths, beetles, wasps and flies.

Observation: Insect Development. Materials: Insects (milkweed bugs or hissing cockroaches will show simple metamorphosis, butterfly or moth caterpillars or mealworms will have complete metamorphosis), food, water, container. Get eggs from a mail order catalog, then 1) count the number of molts and/or days till they become adults, or 2) measure head capsule and/or body length each day to see WHEN they molt, how much bigger they get as they molt, and how long in between molts.

Observation: Butterfly or Moth Emergence. Collect several cocoons or chrysalis in spring or fall (if fall, pupae need to be kept cold to complete development). Hopefully at least one will emerge during class in the spring.

Insect Classification or Taxonomy

All organisms are classified according to a hierarchy:

Kingdom
Phylum
Class
Order
Family
Genus
Species

This can be compared with the division of land in the United States. The largest grouping is a country, which is divided into states, then counties, towns, streets, and individual houses.

Insects all belong to the Class Insecta. These are further grouped into orders. 90% of insects belong to a few very common orders. Common adult insects can be distinguished by looking at characteristics of their wings, mouthparts, and legs:

Odonata: dragonflies and damselflies. These insects have large, clear wings and chewing mouthparts.
Orthoptera: grasshoppers and crickets. The front wings of crickets and grasshoppers are leathery and these insects have chewing mouthparts and back legs which are large and adapted for jumping.
Hemiptera: true bugs. True bugs have sucking mouthparts, and the front pair of wings are half leathery, half membranous.
Homoptera: aphids, cicadas, leafhoppers. Homopterans have sucking mouthparts, and the front wings are either leathery or membranous (but not half and half, as with true bugs).
Coleoptera: beetles. Beetles have very hard or leathery front wings with no veins showing and chewing mouthparts.
Lepidoptera: butterflies and moths. These insects have coiled sucking mouthparts and scale-covered wings.
Diptera: flies, including house flies, mosquitoes, and horse flies. True flies have only one pair of functional wings, with the back pair modified into balancing organs called "halteres." True flies have and piercing, sucking, or sponging mouthparts.
Hymenoptera: bees, wasps, and ants. These insects have two pairs of clear wings and chewing mouthparts.

Observation: Comparative Study of Butterfly and Moth. Capture a butterfly and moth, and put each in a separate jar. Compare similarities (number of legs, wings, mouthparts, etc.) and differences (colors, antennae, body, how wings are held at rest, etc.).

Have students collect lots of insects (maybe working in groups) with the goal of getting representatives from several orders. Ask students to try to classify each insect into the correct order by their own methods, giving their reasons for putting the insects in certain groups.

Older students may be able to appreciate learning where words originate (e. g. "diptera" means two-wings, "lepidoptera" means scale-wings). Much of the vocabulary in insect taxonomy can easily be explained based on characteristics of insects having a particular taxonomic name.

Other Classroom Uses of Insects

1) Name "good" and "bad" insects and things they do (remember, in the natural world, there is no such thing as "good" and "bad." Insects are only good or bad when humans label them as such!).

Good insects: honey, wax and pollination from bees, silk from silkworms, pollination from many insects for fruit and alfalfa production, scent from flowers due to luring insects, beneficial insects which eat pests (ladybugs, praying mantids), medical cures and research (e. g. movie "Medicine Man"), fly maggots can be used to clean infected wounds.

Bad insects: Less than 1% of insects are considered "bad." Examples of pest insects include those that damage food (e. g. worms in apples, others feed on various crops) roaches, termites, houseflies and other household pests those which sting or bite (wasps, bees, mosquitoes, ticks, fleas) insects that transmit diseases, especially mosquitoes, which transmit malaria and dengue fever.

2) Alphabug: Go around the room, with each person naming an insect or insect "part" that starts with each letter of the alphabet.

1) Do honeybees prefer sugar to nutrasweet?

Fill small, open containers with either sugar water or water mixed with nutrasweet (or any artificial sweetener). Place the containers near a bee hive or in a field where bees are foraging. Have the students record the number of bees that visit each type of liquid. Older students may want to do a statistical test like the t-test or chi square.

2) Can honeybees see & learn colors?

Use a few colors of construction paper to represent "flowers." Place a clear container in the center of each flower. Fill one container with sugar water but use plain water for the rest. After a few minutes, the bees will probably start flying straight to the flower with the sugar water. If so, rearrange the flowers, to see if they still go to the right color. Hint: bees can't see red!

Demonstrations with Spiders. Even though spiders aren't insects, they are closely related and make great subjects for classroom demonstrations.

1) How do spiders know when they've caught something in their web?

This demonstration can show that spiders are able to determine when an insect gets captured in their web, and how large the prey is. Tie a string taught between two fixed objects. Have a student on one end not look but touch the string to feel vibrations (this is the "spider"). Have another student twang the string at the other end with different forces, and see if student #1 can tell the difference.

2) Do all spiders' webs have the same pattern?

Visit and observe spider webs or collect several webs by first coating with talcum powder or spray gently with white spray paint, then attach the webs to black construction paper that has been sprayed with hair spray to make it sticky. Compare to see if all spiders make webs with the same geometry. Students may fins that spiders that are of the same species build similar webs, but unrelated spiders may make very different webs

References and other good books:

Berenbaum, M. Ninety-nine Gnats, Nits and Nibblers.
Dunn, G. A. Six-Legged Science: Insects in the Classroom. Young Entomologists Society.
Eyewitness Books: Butterfly & Moth (1988), Insect (1990), Amazing Beetles (1991).
Hickman, P. M. Bugwise.
Klots, A. B. & E. B. 1001 Questions Answered About Insects.
Milord, S. The Kids' Nature Book.
Russo, M. The Insect Almanac.
Turpin, F. T. The Insect Appreciation Digest. The Entomological Foundation.
Van Cleave, J. Biology for Every Kid.

Other Entomology Resources

Kentucky 4-H has detailed guides for insect collecting, identification, and pinning. These should be readily available from county 4-H offices.

County 4H agents may also be able to visit classrooms with activities and live insects borrowed from the University of Kentucky. Owners of local pest control companies may also be interested in coming to a classroom and talking to students. Pest control professionals are usually knowledgeable about insects, and they can also discuss the pest control business, which is unusual and interesting.

OTHER TOPICS
Classroom Mascots - how to keep insects and their relatives in the classroom.
Starting an Observation Honey-Bee Hive

Youth Entomology Resources | PRESCHOOL - ELEMENTARY
For preschool and elementary educational materials, please visit our adjacent site, KATERPILLARS.

Photos courtesy B. Newton and R. Bessin, University of Kentucky Department of Entomology.
Except "american cockroach" and "mealworm," courtesy USDA.


Level of Identification

Macroinvertebrate identification is a key component of the benthic index of biological integrity (B-IBI) calculation. Identification may be completed to the taxonomic level of family or may be taken further to the genus or even species level for many aquatic insects. Volunteers may complete identification to family using pictorial keys. More specific identification to genus or species is completed by professionals using dichotomous keys. Dichotomous keys have not been created for all aquatic organisms to the species level because scientists are still learning how to distinguish among those that are very similar. The phrase "lowest practical taxonomic level" is typically used to indicate that organisms have been keyed as specifically as possible, given the present body of knowledge. Nearly all insects can be keyed down to at least the genus level, and most can be keyed to species. However, some non-insect macroinvertebrates, such as roundworms, leeches, and freshwater sponges, are typically keyed only to phylum, order, class, or sub-class level.

A B-IBI can be calculated whether aquatic insects are identified to the family, genus, or lowest practical taxonomic level. Decisions about the appropriate level of macroinvertebrate identification typically depend on the purpose of the study, other potential uses for the data, the expertise of the taxonomist, and the funding available for the study. When samples are identified to genus or the lowest practical taxonomic level, a ten metric scoring system is used. When samples are identified to the family level, a five metric scoring system is used.

B-IBI scores calculated from samples identified to the genus or lowest practical taxonomic level will reflect the ecological condition of a site with more statistical precision than samples identified to the family level only. In other words, smaller differences in site condition will be detected with genus or species level scoring than with family level scoring. The statistical precision improves because more metrics are included in the final scoring calculation and because more information is obtained for each metric at more specific levels of identification. Family level scoring is a useful tool for a "first cut" at site condition. Scientists completing research or resource managers who need to make land-use decisions often identify samples to genus or lowest practical taxonomic level. It has not yet been determined whether B-IBI scores calculated from lowest practical taxonomic level data are more statistically precise than B-IBI scores calculated from genus-level information.

One group of aquatic insects that is particularly difficult to identify is Chironomidae, or midges, a family of the true flies. These flies have tiny heads and few easily identifiable characteristics, making their identification to lowest practical taxonomic level rather time consuming, even for professionals. Therefore some organizations may choose to have most of the organisms in their samples keyed to the genus level or lowest practical taxonomic level, but will leave Chironomidae only identified to family.

B-IBI metric scores can be entered into the Salmonweb website at three taxonomic levels:

These three methods all use the same ten metrics. The values assigned to the metrics are adjusted for each taxonomic level so that the final scores will still fall within the same ranges identifying the relative health of the stream. Scoring criteria for family-level identification, which uses five metrics, has different scoring ranges identifying the relative health of the stream. Family-level metric scoring cannot be entered onto the website at this time.


Insect identification by example - Biology

KINGDOM: Animalia | PHYLUM: Arthropoda | CLASS: Insecta | ORDER :Diptera
FAMILIES: Muscidae (house flies), Calliphoridae (blow flies), Sarcophagidae (flesh flies), Tachinidae (tachinid flies)

Although it can be difficult to determine the family to which any one of these flies belongs, there are common characteristics exhibited by each family which are highlighted in the Common Types section below. These characteristics can aid in identification, but a microscope is essential for accurate identification. For technical details on identifying these flies, consult an accurate guide to insect taxonomy, such as:
Peterson Field Guide to Insects: Borror and White
Introduction To The Study of Insects: Borror, Triplehorn, and Johnson

Like all true flies (order Diptera), house flies and their relatives do not have chewing mouthparts. Instead, most flies in these 4 families have sponging mouthparts which are used to absorb liquids, such as nectar. Others, like stable flies, have piercing mouthparts used to suck blood. Like all insects, flies have 6 legs, 3 body regions (head, thorax, and abdomen) and 2 antennae.

Except for a few species whose larvae are parasitic on other insects, larvae from the "house fly" families are legless, soft-bodied maggots. Maggots are most commonly found in carrion or in animal waste.


Blow fly larva: a typical maggot (R. Bessin, 2000)

Their are many important pests in the families Muscidae, Calliphoridae, and Sarcophagidae. Flies in all of these families are a nuisance when they get into homes and when they occasionally spread diseases to humans. Read about the control of home-invading flies in our ENTFact:
www.uky.edu/Agriculture/Entomology/entfacts/struct/ef624.htm

The family Muscidae also contains Face Flies, Horn Flies, and Stable Flies. These flies harm livestock by causing irritation and spreading disease. Read about these livestock pests in the following ENTFacts:
Face Flies and Pink Eye
Horn Flies and Cattle

Some flies in the families Calliphoridae and Sarcophagidae are capable of infecting open wounds on humans and animals, a condition known as myiasis. Myiasis in humans is rare in the United States, but commonly occurs in tropical regions.

THE HOUSE FLY
FAMILY: Muscidae | GENUS and SPECIES: Musca domestica
The House Fly, Musca domestica, pictured below, is one of the most common members of the family Muscidae, and one of the most common flies found in homes. It is about 1/4" long, and gray with 4 black stripes on the thorax. The house fly doesn't bite, unlike face flies, stable flies, and horn flies, which are also in the family Muscidae. Muscid flies and their maggots breed most commonly in manure.


The Easy Guide to Making a Dichotomous Key with Editable Examples

In the field of biology, classification plays a major role. With new species being discovered every day, it’s important to have techniques in place to identify and classify them. One such tool is the dichotomous key. It helps identify organisms by directing the user to look at the known organisms.

In this simple guide, we will explain what is a dichotomous key and how to create one. Some examples are provided in the dichotomous key examples section you can use any template to start your project right away. Download them as PNGs, JPEGs, SVGs or PDFs for publishing, printing, and sharing.

What is a Dichotomous Key

Students and professionals use the dichotomous key to identify and classify objects (i.e. people, animals, plants, bacteria, etc.) into specific categories based on their characteristics. It’s the most commonly used form of classification or type of identification key used in biology as it simplifies identifying unknown organisms.

Simply put, it is a method used to identify a species by answering a series of questions based on contrasting features (eg: physical characteristics) that have two possible outcomes.

“Dichotomous” means divided into two parts, hence the dichotomous keys always present two choices based on the key characteristics of the organism in each step. By correctly selecting the right choice at each stage, the user will be able to identify the name of the organism at the end. The further you divide the key, the more you learn about the specimen you are trying to identify.

When creating a dichotomous key, both qualitative (i.e. physical attributes such as how the organism looks, what color it is, etc.) and quantitative (i.e. the number of legs, weight, height, etc.) factors are considered.

It can be done in both a graphical (as a branching flowchart) or written format (series of paired statements organized sequentially). Most often, they are used to identify plant and animal species, although it can be used to classify any object that can be identified by a set of observable characteristics.

What is the dichotomous key used for

A dichotomous key is usually used for

  • Identifying and categorizing organisms
  • Helping students easily understand harder scientific concepts
  • Organizing large amounts of information to make identification of an organism much easier

How to Make a Dichotomous Key

Below we have listed the steps you need to follow when creating a dichotomous key.

Step 1: List down the characteristics

Pay attention to the specimens you are trying to identify with your dichotomous key. List down the characteristics that you can notice. For example, say you are trying to classify a group of animals. You may notice that some have feathers whereas others have legs, or some have long tails and others don’t.

Step 2: Organize the characteristics in order

When creating your dichotomous key, you need to start with the most general characteristics first, before moving to the more specific ones. So it helps to have identified the more obvious and less obvious contrasting characteristics among the specimen before creating your dichotomous key.

Step 3: Divide the specimens

You can use statements (i.e. has feathers and no feathers) or questions (does it have feathers?) to divide your specimens into two groups. The first differentiation should be made on the most general characteristic.

Step 4: Divide the specimen even further

Based on the next contrasting characteristic, divide the specimen further. For example, first, you may have grouped your animals as have feathers and have no feathers, in which case the ones with feathers can be categorized as birds while you can further subdivide the ones that have no feathers as having fur and having no fur. Continue to subdivide your specimen by asking enough questions until you have identified and named all of them.

Step 5: Draw a dichotomous key diagram

You can either create a text-based dichotomous key or a graphical one where you can even use images of the specimen you are trying to identify. Here you can use a tree diagram or a flowchart as in the examples below.

Step 6: Test it out

Once you have completed your dichotomous key, test it out to see if it works. Focus on the specimen you are trying to identify and go through the questions in your dichotomous tree to see if you get it identified at the end. If you think the questions in your dichotomous key needs to be rearranged, make the necessary adjustments.

Best practices to keep in mind

  • Consider only one characteristic at a time
  • Use morphological or observable characteristics as much as you can
  • Use major characteristics when dividing the organisms in the beginning and use lesser or less obvious characteristics to divide them into smaller groups
  • When writing contrasting statements, rely on similar word formats (i.e. have feathers and don’t have feathers)
  • Be specific in your statements and avoid repeating the same characteristics
  • Use questions that lead to yes or no answers rather than statements

Dichotomous Key Examples

Let’s look at some examples to make more sense of what is a dichotomous key.

Dichotomous key for animals

Dichotomous Key for Animals (Click on the template to edit it online)

Dichotomous key for insects

Dichotomous Key for Insects (Click on the template to edit it online)

Dichotomous key for plants

Dichotomous Key for Plants (Click on the template to edit it online)

Dichotomous key for leaves

Dichotomous Key for Leaves (Click on the template to edit it online)

Any More Tips on Making a Dichotomous Key?

We hope that this guide will help you familiarize yourself with the dichotomous key method. Make use of the editable templates to get a headstart in class. Invite your friends/ students to edit them online, and make a fun group activity out of it.

Any more useful tips on creating a dichotomous key that our readers can rely on? Do share them in the comments section below.


All About Insects

There are more insects on Earth than all other kinds of creatures combined &ndash over 900,000 known species. They are animals in the big group (or Phylum) Arthropoda , which includes crabs, spiders, scorpions and centipedes. Their group (or Class) is called Insecta has many smaller groups (Orders) that break insects down into like insects, like: beetles (Coleoptera), butterflies and moths (Lepidoptera) and grasshoppers (Orthoptera). for a list of insect orders: LINK

Classification of Insects:
Kingdom: Animals
Phylum: Arthropda
Class: Insecta
Orders: Orthoptera (Grasshoppers and Kaydids)

The study of insects is called entomology.

Insect Pests: Insects can hurt people by damaging food crops and forest trees, spreading diseases like malaria and yellow fever, or just biting and stinging painfully. Examples of insect pests are mosquitoes, caterpillars and fire ants.

Insect Helpers: Insects can also help people by pollinating food crops, making products like honey, supplying animals with food (like song birds, turtles, frogs and bats) and ridding us of other pests like aphids and such. Examples of helpful or beneficial insects are honey bees, praying mantis, and predatory ladybugs.

Looking at Insects: It is fun to collect insects that you find (that are already dead) and study them. Or just see insects outside and watch what they do. To understand insects and make watching them more interesting, there are some things you should know about them.

What Makes a Bug an Insect?

  • 3 body parts a head, thorax and abdomen
  • 1-2 pairs of wings attached to the thorax
  • 3 pairs of legs attached to the thorax
  • 1 pair of antennae attached to the head
  • Mouth parts that bite, suck, pierce, lap, sip or rasp.

Creatures that are NOT Insects: Some things may be "bugs," but are not true insects. These include spiders, millipedes and centipedes &ndash who are in a bigger group (called a Phylum) with insects called Arthropoda . Other animal groups in Arthropoda are crabs, lobsters, scorpions, and barnacles.

Look for the insect traits you have learned to decide whether or not a bug is really an insect:

Other Important Insect Traits
A good sample insect is the grasshopper. It has all the traits of a typical insect plus some other interesting features.

  • They listen with a type of eardrum on its sides.
  • They have grinding mouthparts for eating grass and a grinding gizzard to further breakdown its food.
  • They have small openings all over the body called spiracles through which they breathe.
  • They go through what is called " Incomplete Metamorphosis &rdquo which means that they hatch out looking somewhat like an adult but smaller (this is called an instar) and gradually shed their hard outer layer (exoskeleton) as they grow (several times) into the adult size and form.

Other Insects, like butterflies and moths, go though " Complete Metamorphosis &rdquo where they go through a complete change from birth to adulthood.

  • A butterfly hatches as a caterpillar (wormlike larvae) with mouthparts for eating.
  • Then it cocoons themself up to form a pupa, where it goes through a complete physical change.
  • Then it emerges from the cocoon or chrysalis as an adult insect.

One purpose of this change allows the insect to use several food sources. Early on as a caterpillar, it can eat leaves. Then by the time the adult butterfly emerges, the plants have flowered and they can collect nectar. They can also survive the winter in their pupal phase and try again next summer, though Monarch butterflies will actually migrate, flying all the way to Mexico for the winter months.

Assess Insect Parts - Fill in the Blanks.

Assess Insect Traits Multiple Choice Test for content comprehension: Mutiple Choice Test.

Assess Insect Traits True False Quiz for content comprehension: Quiz


Plummeting insect numbers 'threaten collapse of nature'

The world’s insects are hurtling down the path to extinction, threatening a “catastrophic collapse of nature’s ecosystems”, according to the first global scientific review.

More than 40% of insect species are declining and a third are endangered, the analysis found. The rate of extinction is eight times faster than that of mammals, birds and reptiles. The total mass of insects is falling by a precipitous 2.5% a year, according to the best data available, suggesting they could vanish within a century.

The planet is at the start of a sixth mass extinction in its history, with huge losses already reported in larger animals that are easier to study. But insects are by far the most varied and abundant animals, outweighing humanity by 17 times. They are “essential” for the proper functioning of all ecosystems, the researchers say, as food for other creatures, pollinators and recyclers of nutrients.

Insect population collapses have recently been reported in Germany and Puerto Rico, but the review strongly indicates the crisis is global. The researchers set out their conclusions in unusually forceful terms for a peer-reviewed scientific paper: “The [insect] trends confirm that the sixth major extinction event is profoundly impacting [on] life forms on our planet.

“Unless we change our ways of producing food, insects as a whole will go down the path of extinction in a few decades,” they write. “The repercussions this will have for the planet’s ecosystems are catastrophic to say the least.”

Scarce copper butterflies. Photograph: Marlene Finlayson/Alamy Stock Photo/Alamy

Insect collapse: the red flags

Butterflies and moths
There has been a “severe reduction” in butterflies and moths in the Kullaberg nature reserve in Sweden compared with 50 years ago. Scientists found more than a quarter of the 600 species once found had been lost. Butterflies were hardest hit, losing almost a half of species, including the large tortoiseshell and scarce copper. In England, two-thirds of 340 moth species declined from 1968-2003.

Bumblebees
Museum records enabled scientists to assess the fate of 16 species of bumblebees in the US midwest from 1900 to 2007. They found four had completely died out, while eight were declining in number, and blamed intensive agriculture and pesticides.

Dragonflies
Red dragonfly populations have fallen sharply in Japan since the mid-1990s, which scientists link to insecticides in rice paddies that stop the water-living nymphs emerging into adults. In the US, recent surveys across California and Nevada found 65% of dragonflies and damselflies had declined in the 100 years since 1914.

Leafhoppers
Leafhoppers and planthoppers often make up a large proportion of the flying insects in European grasslands. But scientists found their abundance in Germany plunged by 66% in the 50 years to 2010. Soil acidification, partly due to heavy fertiliser use, was the main cause.

Ground beetles
In the UK, dramatic declines in ground beetles have been seen in almost three-quarters of the 68 carabid species studied from 1994-2008. A few species increased, but overall one in six of all the beetles was lost in that time.

The analysis, published in the journal Biological Conservation, says intensive agriculture is the main driver of the declines, particularly the heavy use of pesticides. Urbanisation and climate change are also significant factors.

“If insect species losses cannot be halted, this will have catastrophic consequences for both the planet’s ecosystems and for the survival of mankind,” said Francisco Sánchez-Bayo, at the University of Sydney, Australia, who wrote the review with Kris Wyckhuys at the China Academy of Agricultural Sciences in Beijing.

The 2.5% rate of annual loss over the last 25-30 years is “shocking”, Sánchez-Bayo told the Guardian: “It is very rapid. In 10 years you will have a quarter less, in 50 years only half left and in 100 years you will have none.”

One of the biggest impacts of insect loss is on the many birds, reptiles, amphibians and fish that eat insects. “If this food source is taken away, all these animals starve to death,” he said. Such cascading effects have already been seen in Puerto Rico, where a recent study revealed a 98% fall in ground insects over 35 years.

The new analysis selected the 73 best studies done to date to assess the insect decline. Butterflies and moths are among the worst hit. For example, the number of widespread butterfly species fell by 58% on farmed land in England between 2000 and 2009. The UK has suffered the biggest recorded insect falls overall, though that is probably a result of being more intensely studied than most places.

Surveying butterflies in Maine, US. Photograph: Shawn Patrick Ouellette/Getty Images

Bees have also been seriously affected, with only half of the bumblebee species found in Oklahoma in the US in 1949 being present in 2013. The number of honeybee colonies in the US was 6 million in 1947, but 3.5 million have been lost since.

There are more than 350,000 species of beetle and many are thought to have declined, especially dung beetles. But there are also big gaps in knowledge, with very little known about many flies, ants, aphids, shield bugs and crickets. Experts say there is no reason to think they are faring any better than the studied species.

A small number of adaptable species are increasing in number, but not nearly enough to outweigh the big losses. “There are always some species that take advantage of vacuum left by the extinction of other species,” said Sanchez-Bayo. In the US, the common eastern bumblebee is increasing due to its tolerance of pesticides.

Most of the studies analysed were done in western Europe and the US, with a few ranging from Australia to China and Brazil to South Africa, but very few exist elsewhere.

“The main cause of the decline is agricultural intensification,” Sánchez-Bayo said. “That means the elimination of all trees and shrubs that normally surround the fields, so there are plain, bare fields that are treated with synthetic fertilisers and pesticides.” He said the demise of insects appears to have started at the dawn of the 20th century, accelerated during the 1950s and 1960s and reached “alarming proportions” over the last two decades.

He thinks new classes of insecticides introduced in the last 20 years, including neonicotinoids and fipronil, have been particularly damaging as they are used routinely and persist in the environment: “They sterilise the soil, killing all the grubs.” This has effects even in nature reserves nearby the 75% insect losses recorded in Germany were in protected areas.

German conservation workers inspect an urban garden for insects. Photograph: Sean Gallup/Getty Images

The world must change the way it produces food, Sánchez-Bayo said, noting that organic farms had more insects and that occasional pesticide use in the past did not cause the level of decline seen in recent decades. “Industrial-scale, intensive agriculture is the one that is killing the ecosystems,” he said.

In the tropics, where industrial agriculture is often not yet present, the rising temperatures due to climate change are thought to be a significant factor in the decline. The species there have adapted to very stable conditions and have little ability to change, as seen in Puerto Rico.

Sánchez-Bayo said the unusually strong language used in the review was not alarmist. “We wanted to really wake people up” and the reviewers and editor agreed, he said. “When you consider 80% of biomass of insects has disappeared in 25-30 years, it is a big concern.”

Other scientists agree that it is becoming clear that insect losses are now a serious global problem. “The evidence all points in the same direction,” said Prof Dave Goulson at the University of Sussex in the UK. “It should be of huge concern to all of us, for insects are at the heart of every food web, they pollinate the large majority of plant species, keep the soil healthy, recycle nutrients, control pests, and much more. Love them or loathe them, we humans cannot survive without insects.”

Matt Shardlow, at the conservation charity Buglife, said: “It is gravely sobering to see this collation of evidence that demonstrates the pitiful state of the world’s insect populations. It is increasingly obvious that the planet’s ecology is breaking and there is a need for an intense and global effort to halt and reverse these dreadful trends.” In his opinion, the review slightly overemphasises the role of pesticides and underplays global warming, though other unstudied factors such as light pollution might prove to be significant.

Volunteers look for the wormwood moonshiner beetle in Suffolk, UK. Photograph: Sean Smith/The Guardian

Prof Paul Ehrlich, at Stanford Universityin the US, has seen insects vanish first-hand, through his work on checkerspot butterflies on Stanford’s Jasper Ridge reserve. He first studied them in 1960 but they had all gone by 2000, largely due to climate change.

Ehrlich praised the review, saying: “It is extraordinary to have gone through all those studies and analysed them as well as they have.” He said the particularly large declines in aquatic insects were striking. “But they don’t mention that it is human overpopulation and overconsumption that is driving all the things [eradicating insects], including climate change,” he said.

Sánchez-Bayo said he had recently witnessed an insect crash himself. A recent family holiday involved a 400-mile (700km) drive across rural Australia, but he had not once had to clean the windscreen, he said. “Years ago you had to do this constantly.”


Contents

The order has a worldwide distribution, but most species are found in the tropics. These tropic species vary from stick-like species to those resembling bark, leaves and even moss or lichen. The stick insect can sometimes reach over 13 inches (33 cm) long. [3] The longest is Chan's megastick.

A few species, such as Carausius morosus, are even able to change their pigmentation to match their surroundings. Many species are wingless, or have reduced wings. [4]

Phasmids are herbivorous, feeding mostly on the leaves of trees and shrubs. Their eggs are usually camouflaged, look like plant seeds, and may remain dormant for a full season or more before hatching. The nymphs are born already closely resembling the adults. [4]

Stick insects make rhythmic, repetitive side-to-side movements. This is like vegetation moving in the wind. This is used to stick bug people.

Also, the swaying movements may help the insects see objects against the background. Rocking movements by these sedentary (sitting) insects may replace flying or running as way to define objects in the visual field. [5]

Some species of phasmid are able to produce a defensive spray when threatened. The spray contains pungent-smelling volatile molecules which the insect gets from its food plant. The spray from one species, Megacrania nigrosulfurea, is even used as a treatment for skin infections by a tribe in Papua New Guinea by virtue of its antibacterial constituents. [6]

Mating involves long pairings. A record among insects, the Indian stick insect Necroscia sparaxes was seen coupled for 79 days at a time. It is not uncommon for this species to assume the mating posture for days or weeks on end, and among some species (Diapheromera veliei Walsh and D. Covilleae), pairing has been seen to last three to 136 hours in captivity. [7] Explanations for this behaviour range from males guarding their mates against other males, to the view that the pairings are a defensive alliance against predators.

They are unusual in that the whole order is camouflaged. They are all mimics of their natural background. Some species (such as O. macklotti and Palophus centaurus) are covered in mossy or lichenous outgrowths that supplement their disguise. Some species can change color as their surroundings shift (B. scabrinota, T. californica). Many species have a rocking motion, where the body sways from side to side, like leaves or twigs swaying in the breeze. The nocturnal feeding habits of adults also helps them to hide from predators.

Secondary defences Edit

Once found, they make use of secondary defences.

  1. They may play dead. That is called "thanatosis".
  2. They often use "startle displays" for defence if discovered and threatened. As a predator approaches, they flash bright colors and make a loud noise. Some species, drop to the undergrowth to escape, and open their wings momentarily during free fall to show bright colors that disappear when the insect lands. Others will maintain their display for up to 20 minutes, hoping to frighten the predator and convey the appearance of a larger size. Some accompany the visual display with noise made by rubbing together parts of the wings or antennae. Some species, such as the young nymphs of E. tiaratum, have been observed to curl the abdomen upwards over the body and head to resemble ants or scorpions in an act of mimicry, another defence mechanism by which the insects avoid becoming prey.
  3. When threatened, some phasmids have femoral spines on the front legs (O. martini, Eurycantha calcarata, Eurycantha horrida, D. veiliei, D. covilleae). They curl the abdomen upward and repeatedly swinging the legs together, grasping at the threat. If the menace is caught, the spines can draw blood and inflict considerable pain. [8] chemicals may be used. A number of species have glands at the front which release chemical compounds. These chemicals may give off unpleasant smells or cause a stinging, burning sensation in the eyes and mouth of a predator. [9] Recent research suggests they manufacture their own chemical defense substances. [10] Some species employ a shorter-range defensive secretion, where individuals bleed reflexively through the joints of their legs and the seams of the exoskeleton when bothered. The blood contains distasteful additives. Stick insects, like their distant relation the grasshopper, can also discharge the contents of their stomachs through vomiting when harassed, a fluid considered uneatable by some predators.

Their natural camouflage can make them extremely difficult to spot. Phasmatodea can be found all over the world in warmer zones, especially the tropics and subtropics. The greatest diversity is found in Southeast Asia and South America, followed by Australia. Phasmids also have a considerable presence in the continental United States, mainly in the Southeast.


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