Fig. 1.

Nutrient balancing towards an intake target depends on the dietary source of EAAs. (A) Bees fed a choice of diets containing caseinate and 0.5 mol l⁻¹ sucrose and 0.5 mol l⁻¹ sucrose alone balanced their intake of protein and carbohydrate to an intake target of 1:149 w/w (P:C). (B) Bees fed with diets containing free EAAs and 0.5 mol l⁻¹ sucrose and 0.5 mol l⁻¹ sucrose alone achieved an intake target of 1:255 mol/mol (1:560 w/w). The dotted line in both panels illustrates the putative intake target. (C) The proportion of caseinate-sucrose diet to sucrose-only diet depended on the diet pair. (D) Bees fed the EAA-sucrose to sucrose-only diet consistently ate more of the sucrose-only diet than the diets containing free EAAs. (E) Bees fed with diets high in caseinate had a lower risk of mortality than bees fed diets high in free EAA (F). The data are for the same individuals in all panels. Error bars indicate s.e.m. N=20 bees per diet pair per panel.