Fig. 1. Myostimulatory activity of Aedes aegypti allatotropin (AT) on the hindgut (HG) of Triatoma infestans 4th-instar larvae. (A) Changes in the frequency of contraction induced by A. aegypti allatotropin. ^*Significant difference between pure AT applied at 10^–18 mol l^–1 and the other groups analysed (P0.05). Each bar represents the mean ± s.e.m. of the number of contractions m^–1 in one of three experiments performed showing similar results (N=3–5 samples per treatment). (B) Image obtained from a hindgut preparation maintained in saline (Control). (C) The same preparation after treatment with pharmacological concentrations of pure A. aegytpi AT, showing a full and long-term contraction of the HG.