Fig. 3

Evolutionary conservation of hsp40 copy number and cis-regulatory HSEs. Relationships of homologous hsp40 were reconstructed with PhyML for 17 insect species (rooted on A. pisum) using a JTT substitution model with 1000 bootstrap replicates (>90 support indicated). The outgroup and Hymenopteran branches are indicated in blue and red, respectively. Statistically significant episodes of positive selection using Branch-Rel are indicated along the branch (+ corresponds to p < 0.05; * = p < 0.01; ** = p < 0.001). Cis-regulatory HSE elements in the promoter region spanning 370 bps from the transcription start site (TSS; right side) are mapped onto the phylogeny and are annotated by their length and motif type. S. invicta did not provide enough sequence information for the identification of cis-regulatory HSEs