Fig. 2: Calculation of the day length.
From: Spatiotemporal computations in the insect celestial compass
a The expression of type 1 cryptochromes (Cry1) is proportional to the skylight irradiance (Isky). On the left, we show the highest skylight irradiance for each day in a year. On the right, we show the actual irradiance in each hour on April 7 (highlighted on the left). The letters on the horizontal axis indicate the month. b Our estimates of the day length are updated using the Cry1 mRNA levels, resulting in an annual oscillation (black line) that follows the specific day’s actual length (orange line). c Day length estimation is still possible (although with decreasing accuracy) as the average daily light exposure of the insect decreases to as little as one hour. This assumes the parameters for estimation can be adjusted, for example, by evolving to match a specific foraging pattern. Each box shows the quartiles of the data (n = 8 784 samples span over the year 2024; 366 × 24). The whiskers extend to show the rest of the distribution except for points that exceed 1.5 × the inter-quartile range, which are marked as outliers.
