Size-temperature plots of a sample CNR.

The black arrows in the IR images (“nest 02”) on the right side show the CNR selected; white text gives the relative time in min in decimal format from emerging (at 15:30 h) until fading off. (A) Close-up view with a fanning bee (fb, marked by lila arrow) positioned in the centre of the selected CNR. (B) Activity plot of fanning: lila: active fanning; black: “non-fanning” or “fanning bee is not visible”. (C) Time course of the CNR size (ACNR) in cm2. (D) Time course of differential CNR temperature (ΔT̃CNR, see Eq 4). (E) Sketch for the definition of the CNR parameters (Tmax, T̃sink, Tmin, ACNR ≈ Amid) displaying 16 temperature partitions (ordinate) between 26° and 40°C. (F) Correlation between ΔT̃CNR and ACNR regarding six intervals of relative time: (a) blue, from 1.00 to 3.53 min (decimal format) after the start of observation; (b) green, 3.53–10.58 min; (c) yellow, 10.58–14.10 min; (d) orange, 14.10–16.22 min; (e) red, 16.22–16.91 min. The nonlinear display of the data (see black regression line for the time intervals blue to orange with R2 = 0.735) let assume that funnel control varies in several states: initially ACNR grows larger while ΔT̃CNR turns cooler (blue coded state), followed by a series of permutations (green and yellow coded state); before the CNR disappeared (red coded state) ACNR varied around a constant magnitude of ΔT̃CNR.