Understanding this startup circuit
Q1 is a depletion mode device, therefore it is ON with zero Vgs.  When Vin is applied, Q2 is off, Vgs of Q1 is held to zero by R12, and Zener D6 clamps the voltage to the controller to ~33V.  



The controller starts switching, causing the bias winding to deliver energy to the Vdd input of the controller through D4, and to the gate of Q2 through D6.

Q2 pulls the gate of Q1 below the source, turning Q1 off, and therefore eliminating the power dissipation in the startup circuit.

The 200K voltage divider on the gate of Q1 prevents damage from exceeding the +/-20V max Vgs rating of the device.