Figure 1

The specific activity of ALP in the midgut of 5th instar Lymantria dispar larvae exposed to different temperature treatments from unpolluted (UP) and polluted forest (PP) (A); UP 23 and PP23—larvae reared on 23 °C from hatching to sacrification; UP 23In and PP 23In-larvae reared on 23 °C from hatching until the first day of 4th instar, and then exposed to temperature of 28 °C for 24 h (induced thermotolerance). Afterwards they were returned to 23 °C until the third day of 5th larval instar; UP 28 and PP23—larvae reared on 23 °C from hatching until the first day of 5th larval instar, and then exposed to temperature of 28 °C for 72 h; UP 28 In and PP 28 In-larvae reared on 23 °C from hatching until the first day of 4th instar, and then exposed to temperature of 28 °C for 24 h (induced thermotolerance). Afterwards they were returned to 23 °C until the first day of 5th larval instar, and then exposed to temperature of 28 °C for 72 h. Error bars indicate the standard error of the mean (SEM) for (n = 8–11). Significance of the effects of the thermal treatments, population origin, and their interaction on the variance of ALP activity with thermal treatments as fixed factor (two-way ANOVA, p ≤ 0.05). Native PAGE gels stained for ALP with enzyme isoforms (B), and densitometric analysis of the bands using Image J program (C). Gel is cropped, and original gels are presented in Supplementary information, Figs. 1 and 2.