http://therationalmale.com/2014/11/11/beta-tells/

One of the best Beta tells is how defensive a guy gets about the subject of mate guarding.

An Alpha has little preoccupation with mate guarding because subconsciously he knows he has sexual options. That applies both within and without monogamy. I’m presenting this here because the majority of what motivates Beta tells (and really a Beta mindset) is rooted in how men deal with a scarcity mentality. Beta tells are almost always indicators that a man believes he needs to guard his paired woman and thus telegraphs a Beta status to that woman as well as other women in her peer clutch.

Mate guarding, and its intrinsic set of subconscious suspicions and behaviors, is an evolved adaptation of ensuring paternity for a Beta-provider. These men must rely upon exchanging resources and external benefits for women’s sexual fidelity. In essence, it’s an unspoken awareness that Beta men must negotiate for what they hope will be a woman’s genuine desire in exchange for his provisioning, parental investment support and emotional involvement.

Beta men are aware on on a limbic level that Hypergamy dictates an Alpha Fucks / Beta Bucks trade-off in women’s sexual strategy – thus a subconscious ‘mate guarding’ mindset evolved from Beta men’s heightened awareness of women’s preference for Alpha Fucks particularly around the proliferative phase time of women’s ovulation.