Religiosity as a significant cultural aspect can impact an array of reproductive behaviors. In particular, religiosity can influence intrasexual rivalry as a competitive strategy and content of mate retention behaviors among men and women. However, a few studies have examined the relationship between religiosity, intrasexual rivalry, and mate retention behaviors in non-Western cultures. In Study 1, we examine the province-level relationship between religiosity and reproductive outcomes (i.e., fertility, divorce, family values, and sex ratio) in Iran, a nonWestern understudied culture. In Study 2, we use a multi-item measure of religiosity, a new multi-dimensional measure to assess intrasexual rivalry (Intrasexual Rivalry Scale; two components of rival-derogation and selfpromotion), and Mate Retention Inventory-Short Form (MRI-SF) in a community sample (N = 211). Results suggested that province-level religiosity in Iran is associated with male-biased sex ratio, lower degrees of divorce, and higher levels of fertility. Study 2’s findings showed that religiosity is inversely associated with selfpromoting intrasexual traits. We demonstrated that self-promotion is related to benefit-provisioning and rivalderogation attitudes in a same-sex individual or is associated with cost-inflicting mate retention behaviors. We demonstrated that religiosity can predict important mating outcomes in both province- and individual-levels in Iran.

Across cultures, men and women engage in a variety of behaviors to maintain their romantic relationships and to prevent defection from the relationship. Individuals engage in a large variety of behaviors meant to prevent their partner’s infidelity and/or to prevent same-sex rivals from successfully mating (either short-term or long-term) with their partner (Buss, 1988). Humans have evolved specific psychological mechanisms to guard their partners against infidelity and defection. These tactics are often referred to as mate retention strategies (see Buss, 1988; Salkicevic, Stanic, & Grabovac, 2014). Although these tactics are universal across human societies, their manifestation is dependent upon cultural contexts (Lopes, Shackelford, Santos, Farias, & Segundo, 2016), attachment orientation (Barbaro, Sela, Atari, Shackelford, & ZeiglerHill, 2019), personality traits (Atari, Barbaro, Sela, Shackelford, & Chegeni, 2017), and various hormones (Arnocky, Albert, Carré, & Ortiz, 2018). Recent factor-analytic studies have found that mate retention behaviors come in two distinct, but related components: benefit provisioning and cost inflicting (e.g., Atari, Barbaro, Shackelford, & Chegeni, 2017; Lopes et al., 2016; Miner, Starratt, & Shackelford, 2009). Thornhill and Alcock (1983) suggested that mate retention behaviors serve as intrasexually-competitive strategies.