Courtship Behavior in Drosophila melanogaster

Essay by budgerigar February 2004

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In every organism, genes for behaviors including innate ones require an environment or a physical body to be expressed. The major significance of an innate behavior is that differences of environments or physical bodies do not affect the behavior. In behavioral biology, innate behavior is a behavior that is developmentally fixed. Although there are environmental differences within and outside organisms' bodies during their development and throughout their life, they all exhibit the same behavior. Maximization of fitness, to the point that genes for variant behavior were lost, was a result of evolution of innate behaviors from the automatic exhibition of certain behaviors without having any specific reason.

In male fruit flies, all of their behaviors including wing vibration, waving, tapping, licking, circling, and stamping may be considered to be innate behaviors since they exhibit these behaviors immediately after they are put in vials with female flies in it.

Specific innate behaviors may include decamping and depressing performed by the female fruit flies. Decamping is when a nonreceptive female runs, jumps, or flies away from the courting male. Depressing is when a nonreceptive female prevents access to her genitalia by depressing her wings and curling the tip of her abdomen down.

A hypothesis for a lab testing if male fruit flies placed in a vial with only males will demonstrate courtship behaviors is: Male fruit flies do not demonstrate courtship behaviors when placed in a vial with only males. To test this hypothesis, one should obtain two vials each with male fruit flies. Carefully transport one male fruit fly from one of the two vials to another vial with one male fruit fly in it. Observe first with the naked eye, and once flies have encountered each other, use the stereoscopic microscope to make observations. Look for any...