Average proportion (± s.e.) of larvae of An. gambiae s.s. surviving on damp soil after exposure to different periods of drought. The lines show the models after back-transformation of the linear model (arcsine(√ p) = a * time + b) obtained after arcsine square root transformation of the original data. Model descriptions are given in Table 2. A: first-instar larvae, B: second-instar larvae.