The Relationship Between Female Mate Choice and Male Calling Songs in the Chinese Cricket Is Modulated by the Intra-Sexual Competition Among Females

Abstract

Although researchers have widely considered male song to influence female mate choice, it is less clear whether male song affects the likelihood of female encounters with males or their evaluation of potential mates. It is also unclear whether intra-sexual competition alters female reliance on male acoustic signals during mate selection. To investigate these questions, we conducted experimental studies on female mate choice in the Chinese cricket (Gryllus chinensis). We first demonstrated a significant correlation between the frequency of male courtship songs and calling songs and male body length. We then designed three experiments to manipulate males' ability to chirp. In each experiment, a group of female crickets (n = 2, 4, 6, and 8) chose between two males with known body and forewing lengths: in the first, one male could chirp while the other could not due to forewing removal; in the second, both males could chirp; and in the third, only the larger-bodied male had its forewings removed. In the first experiment, most females chose the male that could chirp. In the second, females preferred the larger-bodied male when competition was low, but selected the male with larger forewings when competition intensified. In the third experiment, significantly fewer females chose the larger-bodied male when we removed its forewings. These findings suggest that male acoustic behavior is used by females in choosing which males to approach and that intra-sexual competition among females modulates the influence of male calling song characteristics on female mate choice.