bite the hand that feeds you, to

To show ingratitude; to turn against those who have helped you. The metaphor of a dog biting the master or mistress who fills its bowl is very old. It was especially popular in the eigh- teenth century; for example, the Irish statesman Edmund Burke wrote, “And having looked to Government for bread, on the very first scarcity they will turn and bite the hand that fed them” (1790). Two centuries later, a physicist who insisted on anonymity said, “Nobel laureates don’t want to bite the hand that feeds them” and hence are reluctant to criticize the award system (NewYork Times, Oct. 17, 1989).