x1 = species_0
x2 = species_1
x3 = species_2
x4 = species_3
x5 = species_4
x6 = species_5
x7 = species_6
x8 = species_7
x9 = species_8
x10 = species_9
x11 = species_10
x12 = species_11
x13 = species_12
x14 = species_13
x15 = species_14
x16 = species_15