Mate Quality and Novelty Influence Post-Copulatory Female Choice in Decorated Crickets, Gryllodes sigillatus

Females of numerous animal taxa can secure important indirect genetic benefits by mating multiply, either by increasing the genetic diversity of their offspring, acquiring ‘good genes’, avoiding genetic incompatibility, or diluting inbreeding effects (Jennions & Petrie 2000; Kokko et al. 2002; Zeh & Zeh 2003). Only by mating with different partners, however, can females secure the diverse ejaculates needed to maximize these kinds of indirect genetic benefits. Selection for indirect benefits can, therefore, favor female preferences for novel males. Indeed, evidence that females prefer novel males to previous mating partners has been documented in a wide array of taxa (Bateman 1998; Zeh et al. 1998; Archer & Elgar 1999; Hughes et al. 1999; Eakley & Houde 2004; Ivy et al. 2005; LaDage & Ferkin 2007; Gershman 2009). All of these studies, with one exception (Gershman 2009), have focused on females’ pre-copulatory mating preferences. However, it well known that females can select the sire(s) of their offspring even after copulation has commenced, by prematurely terminating copulations, failing to store transferred sperm, removing or ejecting stored sperm, or delaying oviposition until after mating with desirable males (Eberhard 1996). In crickets, a male’s spermatophore remains secured outside the female’s body to her genital opening after mating, and thus females can exert post-copulatory choice by removing the male’s spermatophore before complete sperm transfer has occurred (Sakaluk 1984; Simmons 1986; Ivy & Sakaluk 2007). Premature removal of a male’s spermatophore reduces his fertilization success relative to those males transferring complete ejaculates to the same female (Sakaluk & Eggert 1996; Calos & Sakaluk 1998; Eggert et al. 2003; Bussière et al. 2006). The timing of spermatophore removal can be influenced by various male traits, such as the size of food gifts offered by males (Fedorka & Mousseau 2002), body size (Sakaluk 1985; Simmons 1986; Correspondence Scott K. Sakaluk, Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL 61790-4120, USA. E-mail: [email protected]