Biologic evolution

It is work today. Swallowtail butterfly's larva has died. It is not a leaf of the mandarin orange that catches the larva, and it has died without eating at all though the leaf of other mandarin oranges was given to food. It was disappointed.
The salinity measurement numerical value of swallowtail butterfly's Fn was 0.6g/100g. It eats the salinity of the leaf and no tile even if excreted.