How does Curley react to Lennie's silence when Curley comes into the bunkhouse looking for his father?

Curley believes Lennie is mocking him. A joke is made about Curley's relationship with his wife. Of course Curley sizes up Lennie and picks him out as someone he can beat up. Curley has a major case of small guy complex. Lennie does not speak to Curley, which he takes as a further sign that Lennie is vulnerable.