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 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: 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 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 Egg Larvae Pupa Adult http://www.geocities.com/pchew_brisbane/wanderer.htm

Questions or Comments? http://www.ent.iastate.edu/list/images.html