Methods, apparatus, systems and articles of manufacture are disclosed to throttle resource access by web crawlers. An example apparatus disclosed herein includes memory including computer readable instructions. The example apparatus also includes a processor to execute the computer readable instructions to generate a media request message to obtain media hosted by a server, insert, into the media request message, a source indicator of the media requesting source, the source indicator indicating whether the media requesting source is associated with a media provider to provide audience measurement information associated with the media provided by the media provider, transmit the media request message to the server, and execute a delay tag in a media response message received from the server, the delay tag to cause a delay time period based on the source indicator.