A general payoff matrix for male relatives (<i>M1</i>, <i>M2</i>) for either inbreeding or avoiding inbreeding with a female (<i>F1</i>) of equally close relatedness (<i>r</i>).

Unless both M1 and M2 avoid inbreeding, inbreeding depression (δ) will reduce the fitness of F1’s offspring. If both males avoid inbreeding, for simplicity, F1 is assumed to mate with an unrelated male. F1 is assumed to produce 2 offspring. A general payoff matrix for male relatives (M1, M2) for either inbreeding or avoiding inbreeding with a female (F1) of equally close relatedness (r).