Transcript Entomology/Insect Biology

Insect Biology
Topic 2042
Aaron Gearhart
Biology of Insects
This lecture will go over the following topics
• Insect Body
– Head
– Thorax
– abdomen
• Insect Life Cycles
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No metamorphosis
Gradual metamorphosis
Incomplete metamorphosis
Complete metamorphosis
http://www.ent.iastate.edu/list/images.html
Body of an Insect
• Divided into three parts
– Head
– Thorax
– Abdomen
Segmentation allows for
efficiency since each
segment is specialized
for a different function
The Head
• Contains the following
parts
– Eyes – Simple or Compound
– Anennae – used for smelling
or feeling
– Mouthparts – for sucking or
chewing
www.earthlife.net/insects/six.html
Mouthparts
• Almost infinite variations
• Mouthparts are often used to determine type of
control that will be most effective for a specific
insect
• Examples:
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Fly: has a sponge type mouth
Assasin bug: Has a spear or needle type mouth
Grasshopper: Has a chewing mouth
Some butterflys: Have a long “hose” for sucking nectar
Thorax
• The locomotive segment of an
insect
• Contains wings and legs
• Of course insects have three
pairs of legs for a total of….6
• Insects may have
– 0 wings: ants, lice, mites
– 1 pair of wings: flys, true bugs
– 2 pairs of wings: wasps, bees
http://www.ent.iastate.edu/list/images.html
Abdomen
• Contains the following
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Digestive organs
Reproductive organs
Respiratory organs
Excretory organs
Abdomen can change
shape depending on how
much it ate or if it has
eggs.
http://www.denniskunkel.com/PublicHtml/WANTED/BODIES/IndexBodies.html
Lifecycles of the Insect
No metamorphosis
Gradual metamorphosis
Incomplete metamorphosis
Complete metamorphosis
No Metamorphosis
• These insects emerge
from the eggs looking
exactly like the adult
but smaller
• Primitive insects like
the silverfish are
examples of this
• Also known as
ametabolous
http://www.life.uiuc.edu/Entomology/insectgifs/thysanura.gif
Gradual Metamorphosis
• Similar to no
metamorphosis but the
youngster coming out
of the egg is slightly
different from the
adult
• Examples are
grasshoppers and
crickets
http://www.ent.iastate.edu/
Incomplete metamorphosis
• These insects change from
egg -> nymph -> adult
• After their last molt these
insects rapidly change to
adult
• Some examples would be
dragonflies
• Also termed
hemimetabolous
http://stephenville.tamu.edu/~fmitchel/dragonfly/photo/cw_aes1.htm
Complete metamorphosis
• Goes through four
distinct stages
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Egg
Larvae
Pupa
Adult
http://www.geocities.com/pchew_brisbane/wanderer.htm
Questions or Comments?
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