Insects and Spiders

This is one suggestion for a one-hour program. Docents are free to present the program in any way they think is effective.

(This file is a little different; following the program suggestions, there is a long section with more detail on insects and spiders, to use or just to be more prepared for questions.) Take: Portfolio,

Arthropod case from Marty’s room, puppets (if desired) from Marty’s room. Live animals: tarantula, black widow, cockroach; live crickets &/or mealworms (in plastic viewers near Polly’s desk); walkingsticks Insect/spider sorting game; large plastic insects

Program goal: By the end of the program, the children should know: 1. That insects and spiders are very important in our world. Insects pollinate and recycle (among other things); spiders control the insect population. 2. The difference between insects and spiders. 3. How we can be helpful to insects and spiders 4. A few cool facts Possible ways to open the program: 90% of the animals in the world are smaller than your fingernail; 95% are smaller than your finger. Who are they? Insects and spiders. For every person in the world there are 1,000,000 insects. 50% of species of all living things, plants & animals, are insects. We are outnumbered, but that’s a good thing. “Are insects and spiders good or bad?” Insects are important. They

-pollinate fruit and crops, -eat other insect pests, -provide food for other insects, birds, fish, humans, others. -Produce honey, silk, and wax. -Indicate water pollution -Are used to treat diseases in people -Break down, or recycle, dead animal and plant material; help the quality of the soil by aereating it and recycling organic material back to the soil and the ecosystem.

Without insects, we would be up to our knees in dead animals and plants. And spiders? Spiders make sure we have the right number of insects. Without spiders, we would be up to our knees in insects! And that’s all good! Brief intro to arthropods (have exoskeleton, jointed legs (like hinges in armor). Especially for younger kids, the word “arthropod” does not need to be emphasized. More detailed information on arthropods is at the end of the outline. INSECTS have four characteristics: 1) exoskeleton; 2) 3 body parts, 3) 6 legs, 4) 2 antennae. Most also have 2-4 wings (though not all) Use puppets here if you like. Or give a child one of the large plastic insects and ask them to share ONE thing that they notice: six legs, antennae, body parts, eyes, whatever. Give children different animals and see which one thing each notices. Which ones are true of all the plastic animals? Six legs for sure; three body parts are not always apparent (as in lady bugs) The head is used mainly for eating and sensing. The thorax supports legs and wings The abdomen contains organs for digestion and reproduction Discuss metamorphosis: complete, incomplete, lacking. Use butterfly/caterpillar puppet, charts, or plastic models [Quick metamorphosis discussion further down this file] Pollination: This is a good place to use the puppets. Put flour or corn flour (if they are in the portfolio) in a fake flower (also in the portfolio). Have the bee fly from that flower to another, dipping its legs in the flour. Show how the flour shows up in the second flower. Depending on the number of insect puppets, you can have several children “pollinating.” Bees pollinate apples, peaches, apricots and many more. Pull plastic foods from the small bag in the portfolio and as you hold each one up to show the class, ask who likes to eat them. At the end, emphasize that these foods are only available to us because insects pollinate the plants they grow from. From here on, there are many aspects of insects to talk about, more than a program’s worth. Pick the elements below that interest you and that seem appropriate for the age and interest of the children. Use your models or pictures when you talk about each thing. Show pie chart of percentage of insects in animal world (50% of species of all living things, plants & animals, are insects)

The exoskeleton has many sense organs to sense light, pressure, sound, temperature, wind, and odors.

Cool fact: Sense organs may be located almost anywhere on the insect body, not just on the head. You can have a lot of fun talking about some of these, such as “ears” on a grasshopper’s knees. Lift up your knee and yell into it. Or for a moth, where the receptor is under the wing, lift your arm as you ask, “What? Speak up!” Stuff like that. Details about these senses are at the end of this program description.

Most have wings, but don’t have to have them to be an insect. Mouths: variety of eating styles: piercing, sucking, sponging, cutting, or chewing Bees taste with their legs and antennae. Flies have their taste buds on the bottom of their feet. Hearing: Moths: hear with simple receptor cells on chest, below wings. Better hearing when wings are extended. Can pick up ultrasound, inc. bats’ output for echolocation. Moths then do loops or drop to the ground. Flies: some have vibration sensor hair on their legs; some have eardrums on their chest. Mosquitoes: no ears; have thread-like filaments on antennae. To hear bats and—more important—to listen for a potential mate. (The low-pitched beating of a female mosquito’s wings is irresistible to a male.) If their antennae get covered in something, no hearing. Crickets & grasshoppers: simple eardrums on front legs. Male “sing” (with their leg barbs) to attract females. One species can’t understand the song of another. Cockroaches: hear through hairs on body, especially the knee joints, and cerci (rear “antennae”) Beetles: sound vibrations through membrane behind the head The praying mantis has sensitive hairs on its neck for feeling. Smell: Moths, ants, and other insects can pick up odors with their antennae. Muscles: more than we have, and small body means strong muscles (which attach to exoskeleton). Grasshoppers have 900 muscles in their body; people have 792 Circulation: heart with open system: fluids just flow around; very few vessels.

Breathing: Air enters through openings in exoskeleton (spiracles) and into breathing tubes; no lungs. Defenses: Camouflage, bad taste, exuding bad smell, flying, jumping Helpful predation: dragonflies eat many mosquitoes Many insects are decomposers. For any of the above, use puppets Activities: pass around compound-eye tubes; plastic magnifier cups that contain crickets Some people like to spend awhile on community insects, especially bees or ants (details at end of file) SPIDERS 2 body parts, 8 legs (2 pedipalps aren’t legs, help with eating & moving things around), exoskeleton no antennae Carnivorous; use venom to liquefy their prey and suck their meal into their stomach Spin silk but not all use it to make webs; it can also help them transport themselves, make shelter, or provide egg sacs Two types: 1) web spinners (uneven leg lengths) and 2) hunters/ambushers/jumpers (even leg lengths). (Hunting styles and web styles are discussed below) Have leg “hair” (often microscopic) that provides an excellent sense of touch; they also use pits on leg cuticle, and can sense vibrations through air, water, or surfaces they are touching. Smell is also through leg hair. Most spiders have 8 simple eyes (some have fewer). Discuss tarantulas (there is no record of anyone ever dying from a tarantula bite)

[ Story you might want to share, depending on audience: Pepsis wasp: bites tarantula (which it has found by smell) to paralyze (if tarantula doesn’t get him first); lays eggs on tarantula, who is eaten by the wasp larva] Discuss Black Widows (.5% bite fatalities, in very young or infirm) retiring, like dark or hidden places; not aggressive to people Reproduction trivia: though most insects & spiders lay eggs and leave, some take more care: A true bug stands watch until its eggs are hatched. A web-spinning spider weaves its own legs into a cocoon and, thus ensnared, stands ready to defend her brood. In some species, the mothers care for the young well after they have hatched. How we can help: Use fewer pesticides; let the spiders get rid of the insects. Take spiders outside when we find them in our house; demonstrate with cup and card how to do it. How these insects and spiders help us; if you have time, do the following play: Kids line up, holding pictures of: flower – spider – ladybug – frog – hawk (which you have brought along) Story: Mrs. Pennybottom loves her roses, even talks to them (presenter plays Mrs. P). She sees an aphid and screams and sprays everything with pesticide (use water spray bottle; spray everyone, including audience). Then the drama plays out as aphid eats the poison leaf and is eaten by the ladybug, etc., until all have kicked the bucket. Discuss how pesticides hurt or kill more than what they are sprayed on; the value of ladybugs, spiders, and all others, and effectiveness of a vinegar spray or other non-toxic remedies. ( Show how to catch household spiders and get them outside.) Kids come see live animals, mounts, play sorting game (for younger ones) Children pick a plastic critter from the box and put it into the “insects” cup, the “spiders” cup, or the “neither one” cup. Ask why they made their choice.

More information follows…..

INSECTS SPIDERS

What  is  the  same?  

.Are  arthropods:  have  an  exoskeleton         .Are  arthropods:  have     &  jointed  legs                       exoskeleton  &  jointed  legs                                        

.Hatch  from  tiny  eggs             .Hatch  from  tiny  eggs  

.Are  essential  for  a  healthy  environment       .Are  essential  for  a  healthy  (they  pollinate  and  recycle  dead  matter)                                     environment      (they  

eat  insects)    

What  is  different?  

.Have  THREE  body  parts    (head,         .Have  TWO  body  parts  (combined    

                 thorax,  &  abdomen)                      head/thorax  and  abdomen)  

 .Have  SIX  legs               .Have  EIGHT  legs  

.Have  two  antennae             .Have  no  antennae  

.Have  compound  eyes.                                                                                                                      .Have  single  eyes  (typically  6  or  8)                       with  lenses      .Many  have  wings  &  can  fly           .None  have  wings  or  can  fly  

.Most  go  through  metamorphosis.                                                                                      .Hatch  in  adult  shape;              (change  body  shape)  after  hatching                                  no  metamorphosis    .Eat  plant  &  animal  material   .Eat  animals  only;  most  eat  insects;  

some  eat  spiders  or  very  small  animals  

 .Many  live  in  groups  (ants,  bees,  wasps)       .Very  few  live  in  groups  or              &  communicate  through  chemicals                                  communicate            or  body  movement    

Complete Metamorphosis

Most insects undergo complete metamorphosis. Each stage of the life cycle—egg, larva, pupa, and adult—looks different from the others. The larvae bear no resemblance to their adult parents and their habitats and food sources may be entirely different from the adults as well. Larvae grow and molt, usually multiple times. Some insect orders have a unique name for their larval forms: butterfly and moth larvae are caterpillars; fly larvae are maggots; and beetle larvae are grubs. When the larva molts for the final time, it transforms itself into a pupa. The pupal stage is usually considered a resting stage, although much activity occurs internally, hidden from view. The larval tissues and organs break down entirely, then reorganize into the adult form. After the reorganization is complete, the pupa molts to reveal the mature adult with functional wings. Most of the world's insect species undergo complete metamorphosis, including: butterflies, moths, flies, ants, bees, and beetles.

Incomplete metamorphosis

Insects with incomplete metamorphosis have three different life stages. Egg, larva (or nymph), and adult. Nymphs are just baby insects and usually look similar to the adult, but smaller, perhaps a different color, and does not have wings. As the nymph grows, it sheds its 'skin' (epicuticle—outer portion of the exoskeleton). Examples: cricket, dragonfly, cockroach.

(FYI--The most primitive insects, such as springtails, undergo little or no true metamorphosis during their life cycles.)

Two groups of community insects: 1)Termites and 2) Bees, Wasps, Ants. The order called Hymenoptera, the "membrane-winged" insects, include bees, ants, and wasps. The Hymenoptera include famous examples of social insects, such as honeybees and true ants; these insects have developed regimented social systems in which members are divided into worker, drone, and queen castes. Such social hymenoptera may live together in nests or hives of many thousands of individuals, all descended form a single queen. Not all hymenoptera are social, however; many live a solitary life, coming together only for a brief mating. This group is very beneficial to humans. Many are important pollinators (bees), recyclers (ants), and eaters of plant-eating insects (wasps). Hymenoptera usually have two pairs of wings. Their mouthparts are created for chewing, with well-developed mandibles. Many species have further developed the mouthparts into a lengthy proboscis, with which they can drink liquids, such as nectar. They have large compound eyes, and typically three simple eyes that serve as light sensors.

The only other social order is the one that includes termites, who build colonies above ground (as in Africa) or underground (in the U.S.).

Fly story: This is for the right audience (old enough so that they won’t panic the next time a fly lands on their food). Probably not for the young ones. Flies lay eggs on food (garbage, feces, dead animals) so their larva can eat that. They taste with their feet, so they also walk on sweet things, which are a favorite. They might easily go from garbage (or worse) to your birthday cake. They have no jaws, but just a sponge; the fly throws up on its food so its stomach juices can digest the cake (or whatever) and the fly can sponge it up. So, first they walk on it with their grimy feet; then they throw up on it.

More spider info, as time or opportunity allows:

Web Builders

Many spiders use webbing to ensnare their prey. Their web designs vary and may or may not be elaborate. Web-builder spiders include cobweb spiders, orb weaver spiders, cellar spiders, and funnel web spiders.

Cobweb Spiders (including black widows) are inconspicuous, although their web is not. The outer sticky threads of the web entangle insect prey. Some species construct a retreat within the web and hide there during the day, and the spider hangs upside down in the center of the web at night. They typically construct an irregular web in sheltered sites indoors or outdoors. One member of this family, the common house spider, is about 1/3 inch long. This species frequently abandons webs that do not yield prey, and then constructs new ones until it finds a productive site. Webs become dust covered (cobwebs) when abandoned.

Orb Weaver Spiders construct the familiar circular, flat, elaborate web in which flying insects are trapped. Each species typically constructs a distinctive web. Webs usually occur outdoors. These spiders have poor vision and locate their prey by feeling the vibration and tension of the threads in their web. They use silk to wrap the victim. Despite their formidable appearance, orb weaver spiders are not considered dangerous to humans.

Cellar Spiders are frequently found in dark, damp places such as basements, crawlspaces, and outbuildings. They typically construct a loose, irregular-shaped web in a dark corner. They continually add to their web, which can result in extensive webbing. The male and female live together in a web and can be found hanging upside down in it. They shake the web violently when alarmed. Cellar

spiders can quickly establish large populations in a structure.

Funnel Web Spiders construct large, flat, horizontal webs of nonsticky silk. The web contains a funnel at one end that serves as the spider’s retreat. The funnel is open at both ends so the spider can readily escape. The spider hides at the narrow end of the funnel; when it feels the vibration of an insect crossing the web, it dashes out, bites the insect, then carries it back to the funnel. The silk of funnel web spiders was used at one time to cover wounds to stop bleeding.

Hunting styles:

Active Hunters. Some spiders actively search for their prey. Any webs that they construct are used as resting areas. These spiders are commonly encountered when they venture from their retreat to search for prey.

Wolf Spiders are fast runners that will chase their prey. Wolf spiders are hairy and often large, up to 1-3/8 inches long, sometimes confused with tarantulas. Their legs are long and spiny. Many are dark brown. Wolf spiders may hunt day and night. They usually occur outdoors, but may wander indoors in search of prey. They tend to stay at or near floor level. They typically construct web retreats in sheltered sites. Wolf spiders are not aggressive, but may bite if handled. Females carry their large, globular egg sac attached to spinnerets under the abdomen. Upon hatching, the spiderlings climb onto their mother’s back and stay there several days or more before dispersing.

Jumping Spiders can jump many times their own length. They make quick, sudden jumps to capture prey or avoid a threat. They also can walk backward. These common spiders are about 1/8 – 3/4 inches long, very hairy, stocky build, and short-legged. Two of their eight eyes are very large. They have the keenest vision of all spiders. Many species have patches of brightly colored or iridescent scales. Some are black with spots of orange or red on the upper surface of the abdomen, at times confused with black widow spiders.

Jumping spiders are active during the day and prefer sunshine. They normally live outdoors, but can become established indoors and their hunting activities often center about windows and entry doors where their prey is most common

Nursery Web Spiders attract much attention due to their large size as they can have a leg span of 3 inches. Many are earth tone colored. They live near lakes and streams, but occasionally are found indoors in moist areas. Many can run over the surface of water and, if chased, dive and stay submerged for some time. They hunt day and night for aquatic insects and even small fish. They are sometimes commonly called fishing spiders.

The sole use of their silk webbing is for the egg sac. The female uses her mouthparts to carry the egg sac under her body until the spiderlings are ready to emerge. She then fastens the egg sac to some leaves and encloses it within a “nursery” web, where the spiderlings remain until they are ready to disperse. The female stands guard near the nursery web to protect her young.

Passive hunters are spiders that lay in wait for their prey rather than searching for it. When their prey approaches, they may jump or pounce to seize it. Example: tarantulas, crab spiders

Crab Spiders have a flattened body and hold their legs at right angles to their sides, presenting a crablike appearance. They can walk forward, backward, or sideways. Many have horns or ornaments, and some mimic bird droppings. Those that inhabit trees or the ground are usually gray, brown, or black; those that frequent flowers are bright red, yellow, orange, white, and/or green

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Book Lungs. !Arachnids have two pairs of lungs, called booklungs because they are made up of many fine layers, like sheets of paper in a book.! These layers are held apart by supports so that air can circulate freely between them. Arachnids take in air though the “pages” in their booklungs.

Spiders’ jaws:

The chelicerae (pronounced kell-ISS-er-ee) are mouth parts, pointed appendages, with fangs at the end, that are used to grasp food. They are hollow and contain, or are connected to, venom glands, and are used to inject venom into prey or a perceived threat.

Primitive spiders, who have been around the longest--250 million years, are heavy-bodied, burrowing spiders such as tarantulas, trap-door spiders, and funnel-web spiders. They have forwardly pointing jaws that move up and down. In contrast, the jaws of a modern spider (youngsters only 200 M years old) work like pincers, or back and forth. In primitive spiders, the chelicerae point downwards, which mean the spiders must rear up to strike down on their prey. Therefore they cannot crunch their prey. They wait until the prey contents are dissolved before they can suck it empty.

The jaws of modern spider species work like a pair of pincers coming together across their mouth parts. Modern spiders, are far more adaptable and can capture prey from a web, wander around to ambush or run down, so they don't need to lie in wait down a hole.

The poison of a spider contains different agents that cause paralysis and the death of cells. After the prey is killed, the spider spits enzymes from its mouth

into the victim. Enzymes dissolve the contents of the prey. The spider digests the proteins in the prey itself and sucks it empty. (It is not the venom that has the enzymes; venom plays a very small role in digestion.)

The mouth of a spider is located between the palps, which are connected to the stomach muscles that perform the sucking. A series of muscles circle the sucking stomach and serve like rubber bands, contracting to shrink the size of the stomach. Dilator muscles contract to expand the stomach’s volume. When acting in coordinated unison, the structure becomes an efficient pump. Food is also pulled through the stomach into a fingerlike cavity called the caeca, where they can store enough food to go for long periods of time, over a year in some cases, without eating.

Because the food that is taken up can be large in comparison to its own body volume, the abdomen of many spiders can swell enormously-- because the abdominal covering contains only pliable endocuticle, not the hardened exocuticle typical of the cephalothorax. With most other arthropods, at least as adults, the abdomen contains the hard exocuticle and is not potentially able to shrink or expand. If they stumble on a windfall of food, they can’t take advantage of it as

Spider pedipalps

Pedipalps are a pair of appendages that look like small legs, one attached to each side of the spider's mouth, forming the sides of the mouth. Each pedipalp has six segments. In most kinds of spiders, the segment closest to the body bears a sharp plate with jagged edges. The spider uses this plate to cut and crush its food. In adult male spiders, the last (end) segment of each pedipalp bears an enlarged part that is used to transfer sperm from an opening under his abdomen into the equivalent opening in the female.

Spider legs

A spider has 4 pairs of legs, which are attached to its cephalothorax. Each leg has 7 segments. In most kinds of spiders, the tip of the last segment has 2 or 3 claws. A pad of hairs may surround the claws. This sticks to smooth surfaces and helps the spider walk on ceilings and walls. Each leg is also covered with sensitive bristles that serve as organs of touch and perhaps organs of smell. Some bristles pick up vibrations from the ground or air, or the spider's leg. Others detect chemicals in the environment.

Muscles in the legs make the legs bend at the joints. But spiders have no muscles to extend their legs. The pressure of the blood in their bodies makes their legs extend. If a spider's body does not contain enough fluids, its blood pressure drops. The legs draw up under the body, and the animal cannot walk.

Spinnerets

are short, fingerlike organs with which the spider spins silk, attached to the rear of the abdomen. Most spiders have 6 spinnerets, but some have 4 or 2. The tip of a spinneret is called the spinning field. The surface of each spinning field is covered by as many as 100 spinning tubes. Through these tubes, liquid silk flows from silk glands (of up to 8 different kinds) in the spider's abdomen to the outside of its body. The silk then hardens into a thread.

Eggs and spiderlings

Once a spider's eggs are fertilized, they have to stay safe from predators until the spiderlings can hatch out. Egg sacs come in all shapes, sizes and colors. They may be built inside a burrow, under bark, in the web, in a curled leaf, suspended on a long line, or hidden among foliage. Some spiders stay with the egg sac, guarding it until the spiderlings emerge or carry the egg sac about with them sometimes in their jaws. Wolf Spiders carry their spherical egg sacs slung from the spinnerets. When the young hatch they climb onto the mother's back, clinging to special knob-shaped hairs. The mother carries them about until they moult and disperse.

After hatching from the eggs, the spiderlings stay in the egg sac until they undergo their first moult - their small cast skins can be seen inside the old egg sac. Then they emerge, having cut a hole in the sac with the fangs (perhaps aided by a silk-digesting fluid and sometimes helped by the female from outside). The spiderlings cluster together initially, still living largely upon the remnants of yolk sac in their abdomens.

After several days (or weeks in the case of tarantulas and other large, primitive spiders), and sometimes another moult, the spiderlings begin to disperse gradually away. This is necessary to avoid competition for food and prevent cannibalism among the hungry siblings. They disperse by walking or by bridging and ballooning. Bridging is repeated climbing up through foliage and then dropping down on a silk line to cross to adjacent branches, often with some breeze-assisted swinging. Ballooning involves ascending to a high point on foliage and letting out fine silk lines that catch the breeze and eventually gain enough lift to waft the spider up and away.

Spiders have blue blood that doesn’t flow through blood vessels but washes through their body Spider hair? The “hair” on spiders’ legs, is not really hair. It is not made of keratin and doesn’t grow from follicles. Spider “hair” is really a long, drawn-out extension of their exoskeleton, which is made of chitin, not keratin (a type of cellulose, not protein). It’s like pulling a long, thin extension from the surface of clay. If lost, these “hairs” can’t grow back. They reappear with the next full molt of the exoskeleton.

Sometimes our museum tarantulas scrape hairs off their abdomen. You’ll note that that patch stays bare for a long time, until a molt.

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Arthropods. The most successful animals on the planet are the arthropods. They have conquered land, sea and air, and make up over three-fourths of all currently known living and fossil organisms, or over one million species in all. Arthropods have an exoskeleton of a tough compound called chitin. This outer shell provides the structure against which arthropod muscles pull (muscles more powerful for size), reduces water loss, and protects them from environmental dangers. So that arthropods can move inside such a rigid armor, the chitin is laid down in plates, with joints between them. This gives the arthropods their name, meaning "jointed feet." Arthropods also have an open body cavity in which blood flows and bathes the tissues and organs. The gut is complete. Respiration takes place through the body surface, and/or by means of gills, tracheae, or book lungs. The nervous system has a brain (cerebral ganglion) and a nerve ring that connects the brain with a pair of nerve cords that contain many ganglia. Most arthropods have paired reproductive organs (ovaries, testes). Fertilization is internal in most, but not all, groups. Most lay eggs, and development often includes some form of metamorphosis.

Arthropods include: insects, spiders, centipedes & millipedes, shrimps, lobsters, crabs, & others. Below: pix of colonies of bees (2), ants, termites