Table 1. Likelihood Ratio Tests of Selective Pressures on cocoonase in Lepidoptera.

Models	ω(dN/ds)	lnL	np	Models compared	P values
A. All branches share same ω	ω = 0.16308	-22225.452	123	A vs. B	0.06688
B. Moths and butterflies with uncovered pupae have ω1, moths spinning enclosed cocoons have ω2	ω0 = 0.16603 ω1 = 0.13840 ω2 = 0.04881	-22222.748	125

lnL: Natural logarithm of the likelihood value; np: Number of parameters.

The one-ratio model (Model A) and two-ratio model (Model B) were used to estimate the selective pressures using Maximum-likelihood method. The ratio of non-synonymous to synonymous substitution rates-ω, was used to estimate the mean selection pressures on different branches of the phylogenetic tree.