Arthropods/insects

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Arthropods/insects

• Phylum Arthropoda -Most successful phylum of
  animals due to diversity and numbers.
• Five classes of Arthropods in Illinois
• Class Chilopoda - millipedes
• Class Dilopoda - centipedes
• Class Crustacea - crustaceans
• Class Arachnid - spiders, mites, ticks and
  scorpions
• Class Insecta - insects (Use text chapter
  28-sect 3 as a supplement)
• Insects have
• segmented body
• jointed appendages
• exoskeleton
• three body parts- head, thorax, abdomen
• one pair of antennae on head
• one pair of legs per segment
• some have wings

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What do insects do?

• 1. What problems do we have with insects?
• 2. Do insects help us? How?
• Where do they live?
• 4. How are insects classified? Mouthparts,
  wings
• 5. What are two diseases which are spread by
  insects?
• Facts 17, 000 species of insects in Illinois
• Biomass of humans is equal to the biomass of
  insects.
• Why are insects successful?????

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Insects Success

• Three types of variations
• A. Structural - These are changes in body parts
  to help insects adapt or have an advantage.
• Types of Movement
• 6. Find an example (photo) of each movement type
  online.
• a. Cursorial - walk/run
• b. Saltatorial - jump/hop
• c. fossorial - dig/burrow
• d. Aerial - fly
• e. Natatorial -swim

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• B. Physiological (inside) - These are
  differences in the way their bodies work
  internally. These include enzymes that help them
  digest special foods such as grass, wood or
  blood. This also includes any immune responses
  to chemicals or toxins they produce.
• List three insects and discuss their special
  physiology.

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• C. Behavioral - These are differences in the
  ways that insects respond to stimulus. These
  include being active at night or day, living
  alone or in groups, and being aggressive or not.
• 8. Pick one insect species and discuss how they
  have a special behavior which helps them be
  successful.

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Social insects Leaf cutter ants
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Termites
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External Structure of insects

• 1. Head - brain, mouthparts, antenna an compound
  eyes, three simple eyes
• 2.Thorax - legs and wings attached
• 3 parts - prothorax, mesothorax, metathorax
• Wings - two pair - forewings to protect
• - hindwings used to fly
• Where do the wings come from? exoskeleton
• 3. Abdomen - reproduction, digestion, excretion
• 9. Find an insect diagram online with labels of
  the body segments. Place it in the next slide
  with a heading.

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Internal Structure

• 1. Complete digestive system
• 2. Circulatory system- Aorta - is a large blood
  vessel that pumps blood at muscular regions. No
  true heart.
• 3. Respiratory System- use spiracles and trachea
  to move oxygen and gases in and out of body.
• 4. Nervous system- three simple eyes detect
  light, two compound eyes help it to see in all
  directions (detects movement).
• Tympanum- sound sensor membrane Brain with
  ganglia.
• 5. Reproduction - sexes separate, internal
  fertilization.
• Ovipositor of female is used to lay eggs.
• Development- Two types
• 1. Complete - egg?larva?pupa?adult
• 2. Incomplete - egg?nymph?adult
• Complete metamorphosis- caterpillar changes to an
• adult after going through a pupa stage.
• Chrysalis vs. Cocoon? Chrysalis- butterfly
  cocoon- moth

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9. Find an example of a female insect and put
the photo below. How do you know?
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Arthropods
Complete Metamorphosis

• Most insects develop through the four stages of
  complete metamorphosisegg, larva, pupa, and
  adult.
• Competition reduced within a species by
  metamorphosis. Complete metamorphosis has a
  larval stage that is very different from the
  adult and eats different food.
• metamorphosis

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Arthropods
Incomplete Metamorphosis dragonfly

• Insects that undergo incomplete metamorphosis
  hatch from eggs as nymphs.

• After several molts, young nymphs become winged
  adults.

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Nutrition

• What do insects eat?
• A. Predation - hunting/killing other organisms.
  99 of all prey is eaten alive.
• 1. Common in all habitats Dragonfly link
• 2. Broad range of prey
• 3. Large eyes
• B. Herbivory - eat plants Locusts honey bee
• 1. Monophagous- eat only one thing
• 2. Oligophagous - eat few different things
• 3. Polyphagous - eat many different things
• Saprophytes/detritovores- eat decaying matter
• D. Sanguinivore - blood eating fly
• E. Parasitism - eat on other organisms normally
  without killing
• 1. Unkown of species (1 million )
• 2. Every insect has a parasite(s) which attacks
  certain stages
• Parasitoid species link

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10. Name and show an example photo of an insect
for each feeding category.
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Why do insects go through metamorphosis?

• Hormones regulate metamorphosis.
• Caterpillars are specialized for growth
• Adults with wings are specialized for
  reproduction and growing.
• Both stages need large amounts of energy.
• Metamorphosis reduces competition between larva
  and adults. How?
• Hint What do they eat?
• Where do they live? How does it help them
  survive better?
• different places (some have aquatic stages)
• How do insects survive in cold weather? Eggs/
  dormant stages

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11. Label how each of these are a mode of
defense.
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Viceroy vs Monarch
12. Why do they mimic?
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Defense

• 1. Apatetic coloration (Camouflage) blending in
  to background
• 2. Warning coloration (aposematic)- insects
  advertise their danger of chemicals, stings and
  bad taste with bright and bold colors.
• 3. Intimidation- look like a large item or scary
  eyes/face
• 4. Mimicry - advertisement of poison or bad
  taste.
• Mullerian mimicry - Some types of insects have
  very similar colorings to warn that all are
  harmful.
• Batesian mimicry- this is a fake warning
  coloration that fools predators that the insect
  is harmful (some flies look like bees)
• Facts In some species, females have the mimic
  coloration for protection. Males tend to not
  have mimic coloration. Females dont respond to
  males with changes in coloration. Ex Tiger
  Swallowtail females take on dark color of
  Pipevine Swallowtail to look poisonous. Males
  are yellow and do not mimic pipevine or
  red-spotted purple.

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black swallowtail
Pipevine swallowtail
Tiger swallowtails
red-spotted purple
male
female
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Class Insect - common Orders to
know!Ephemeroptera - Mayflies Phthriaptera
sucking, chewing liceOrthoptera- grasshoppers,
crickets Archaeognatha- bristletailsIsoptera-
termitesDermaptera- earwigs Thysanoptera -
thirpsHomoptera- leafhoppers, aphids,
cicadasHemiptera- true bugs Siphonaptera -
fleasNeuroptera- nerve-wingedColeoptera-
beetles Trichoptera caddisflies Thysanura-
silverfishLepidoptera-butterflies and
mothsMecoptera-scorpionfliesDiptera- flies and
kin Collembola -springtailsHymenoptera- bees,
wasps and antsMantodea Mantids Protura-
proturansPhasmida walking sticks Blattaria-
Cockroaches Diplura- DipluransOdonata
dragonflies, damselflies
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• Ants, Bees Wasps (12 records) Hymenoptera
  membranous wing Hymen membrane, ptera wings.
  Winged forms of ants, bees and wasps possess 2
  pair of membranous wings. Butterflies Moths
  (67 records) Lepidoptera means scale wings
  lepido scale, ptera wings. Wings of
  butterflies and moths are often covered with a
  colorful mosaic of minute scales. Flies (7
  records) Diptera means two wings di two,
  ptera wings. Flies do very well with their
  single pair of fore wings. The hind pair are
  often reduced to a couple of knob-like balance
  organs. Beetles (16 records) Coleoptera means
  sheath wings coleo - sheath, ptera wings.
  Beetles front pair of wings are modified to
  hardened casings, known as elytra, to protect the
  hind wings and body below. Lacewings Antlions
  (1 record) Neuroptera means nerve wings neuro
  nerve, ptera wings. Wings of these insects
  are constructed with an elaborate network of
  supporting veins. Cicada, Hoppers Aphids (7
  records) Homoptera means uniform wings homo
  alike, ptera wings. The front wings of these
  insects have a uniform textured appearance in
  contrast to their Hemiptera relatives. True
  Bugs (12 records) Hemiptera means half wings
  hemi half, ptera wings. The front wings of
  these insects are divided between a thickened
  basal region and a membranous tip. Cockroaches
  (1 record) Cockroaches are fast-running insects
  often with wings. A few well know species have
  successfully evolved to exploit human dwellings
  and food supplies. Mantids (1 record)
  Mantodea means soothsayer a person claiming to
  be able to predict the future. These insects have
  highly modified front legs often held in a
  position suggestive of prayer. Grasshoppers
  Crickets (9 records) Orthoptera means straight
  wings ortho straight, ptera wings. These
  insects often have a pair of elongated and
  thickened forewings and a membranous hind pair.
  Walking Sticks (3 records) Stick insects are
  usually extremely elongated and twig-like in
  appearance. Sometimes this camouflage is taken a
  step further with the addition of leaf-like
  structures. Dragonflies Damselflies (7
  records) Odonata means tooth. Apart from jet
  propulsion, the aquatic nymph often possess an
  extendable jaw capable of catching prey some
  distance away from the rest of the head.
  Mayflies (1 record) Ephemeroptera means
  short-lived wings emphemera one day, ptera
  wings. After a year or more as an aquatic nymph,
  adults emerge in swarming nuptial flights and
  live for only a day or so. Some Are Not Insects
  (6 records) Arthropod means segmented feet
  arthro joint, poda foot. Including insects,
  this huge group contain animals often mistaken
  for insects such as spiders and centipedes.

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Monarchs -Adults (butterflies) lay eggs under
leaves on milkweed plants. (April -August) They
usually only lay one egg per plant unless few
plants are found.-Monarch females lay about 400
eggs. Butterflies have tasters on their front
legs to test plants.-Life cycle from egg to
adult 30 days (this can vary during
seasons)-Eggs can be harvested from plants by
taking plant or leaf. They will only eat
milkweed so have plenty on hand. -Eggs hatch in
about 3 days after laying. Faceplate of
caterpillar can be seen in egg when ready to
hatch. It is also shed with moltings, but not
eaten by growing caterpillar.-5 Instars or
stages are named for the 5 moltings of
exoskeleton (skin). --They grow and shed five
times as caterpillars. They should be 2-2 1/2
inches long at last instar.Metamorphosis is
complete egg--gt larva--gtpupa-gtadult
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Steps in change1. Larva attached itself to
high point (top of cage or underside of leaf)2.
Thread mat is made of silk and a silk button is
made where prolegs (last two) are anchored with
hooks. 3. Caterpillar hangs like a J shape.
Changes start taking place internally. Body will
straighten and skin will be shed in about 1
hour. The skin comes up and is dropped. Green
body is different and visible. Chremaster (looks
like a stinger) comes out of chrysalis to find
silk button and attach. Prolegs are knocked
off.Metallic gold spots - affect color and
density of scales on wings. Egg to chrysalis in
18 days hangs as chrysalis for about 10-14 days.
Total time from egg to adult 30 days.4.
Chrysalis cuticle is clear. Color changes due to
changes inside. 5. Adult emerges- blood must
be pumped into wings. Proboscis is zipped
together. Frass comes out. Hangs for 1 hour .
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Adults Males - have 2 scent glands on their
back. (large black increase in vein). Spiracles
are also visible on the chrysalis. As a pupa -
males have dimples in chrysalis under spiracles
Adults live about 4 weeks on average. They
mate, lay eggs and die. Those that emerge after
Aug. 15th go into sexual diapause. They do not
mature --They migrate to mountains of Mexico and
California for the winter (cool and moist). They
have antifreeze in their bodies and cluster for
warmth. Illinois is along the migration route.
They have fat cells to help them on their trip
and through the winter. Return late
spring/summer to lay eggs and die. This is main
food of monarchs - various types exist.Milkweed
is pollinated by insects and is vital for seed
production. Legs pull out the pollen. Of all
the flower heads, only one pod develops, even if
all flowers are fertilized. Milkweed can be dug
up in the fall and planted in various areas-
perennial and will come back each year.