The genomic consequences and persistence of sociality in spiders

Illustration for calculating the social period length for current social species as an instant process. t₂ denotes the length of the social period. T₁ denotes the divergence time between social species and its sister subsocial species. ω_sub denotes the d_N/d_S estimated from the subsocial species branch in branch-wise PAML estimations. ω_sub–social denotes the d_N/d_S estimated from the social species branch in branch-wise PAML estimations. ω_social denotes the d_N/d_S (in practice, pi_N/pi_S) estimated from the pairwise PAML estimations of two separate social species populations. The red shadow region represents the scenario in which the d_N/d_S may increase as a continuous process.