Female signals enhance the efficiency of mate assessment in satin bowerbirds (Ptilonorhynchus violaceus)

Recent evidence suggests that males adjust their sexually selected display traits in response to female behaviors during courtships. Little is known, however, about whether females signal to influence male displays and whether females benefit from this interaction. Male courtship displays in the satin bowerbird (Ptilonorhynchus violaceus) are highly intense and aggressive. Females may use these displays as indicators of mating benefits, but these displays often startle females and disrupt courtship. Previous studies have shown that successful males decrease female startling by adjusting their display intensity according to female crouching behaviors, suggesting that crouching behaviors function as signals. Here we address whether female crouching is a signal by using observations of natural courtship behaviors. In addition, we examine why females differ in signaling and whether females benefit from signaling. First, we find that female crouching is related to the likelihood that females will be startled by male displays, suggesting that crouching signals the degree of display intensity that females will tolerate from a male without being startled. Second, we find that female tolerance for intense display increases during successive courtships as females assess potential mates, and that female tolerance may also be affected by age and condition. Third, we find evidence that females that reduce startling by signaling their intensity tolerance are more efficient in mate searching. These results suggest that females signal to influence how males display their sexually selected traits, and by doing so, females may increase their benefits in mate choice. Copyright 2004.