<p>The African tsetse fly does not need a -brain, everything- it has to do in life is programmed into its nervous system.</p>
<p>Why is the -brain, everything- part wrong?</p>
<p>A semicolon should be used instead of a comma.</p>
<p>It's a Run-on sentence;
they are two independant clauses that need to be combined using a conjunction or separated by something.
you could put a semi colon or add the word 'because'.</p>