Mass–radius (top panel) and Hertzsprung–Russell (bottom panel) evolutionary diagrams. In both diagrams, the black symbols denote the δ Scuti members of oEA stars that belong either to spectroscopic single- or double-lined (SB1 or SB2) and eclipsing (EB) or ellipsoidal (el) systems (dots) or only to eclipsing systems (squares). The sample was mainly gathered from Liakos & Niarchos (2017). Magenta and cyan symbols refer to the primary (filled) and secondary (open) components of RR Lep and BF Vel, respectively. Solid black lines indicate the ZAMS and TAMS limits and the coloured solid lines (B = blue, R = red) the boundaries of the instability strip (IS; Soydugan et al. 2006b).