Fraction of planetesimals captured by the planet versus their source semi-major axis for the reference case. Green, white, and turquoise areas correspond to the first, second, and third regions, respectively, denoted in Sect. 3.2. The difference between these regions is due to the different nature of the dominant shepherding process. Gray area shows the initial planetary feeding zone for planetesimals in circular orbits (e = 0). Dotted lines indicate the positions of the 2:1, 5:3, and 3:2 MMRwith the planet at the beginning of the simulation. The bin width of the histogram is 1∕3 AU.