Figure 3

Mortality risk curve for α = 5, and corresponding conditions favouring not fighting by Q2. Effect of relative fighting ability of Q1 (f) on diminishing the probability that overt fighting leads to the death of both contestants following d = m e^-αf². The inset graph shows the distribution of the probability of both queens dying for m = 1 and α = 5. The risk of mortality of both queens is restricted to a smaller range of f values, and is close to zero for extremely biased fighting ability. The main figure shows that when the risk to inclusive fitness decreases with increasing asymmetry in fighting ability, Q2 is more likely to fight, particularly when it is a relatively strong fighter. Not fighting remains the preferred strategy when fighting represents a risk to inclusive fitness.