Figure 2.

(a–c) Predicted profiles of insect numbers within 10 m height intervals in a stably stratified nocturnal boundary layer, (a) 2 hours, (b) 4 hours and (c) 8 hours after climbing to z₀=150 m, and thereafter behaving as neutrally buoyant massive particles with response time τ=15 s. (d–f) The results of a simulation where the insects are assumed to actively respond to any substantial gusts (with vertical speeds exceeding w_c=0.1 m s⁻¹) by regulating their aerodynamic lift to maintain zero vertical airspeed so that they are ‘passively’ advected either upwards or downwards by the gust until the gust speed w falls back below the threshold w_c: (d) 2 hours, (e) 4 hours and (f) 8 hours.