Yes, butterflies actually sleep. Rather rest. The period of sleep in a butterfly is not such a period of sleep as we humans have. This is a state in which butterflies can not fly almost. They become lethargic and their metabolic processes decrease.
Sleeping butterflies, usually hanging on something upside down or clinging to land on flowers, stems of plants, leaves folded wings. Larger species of butterflies sleep on tree trunks or bushes.
The monarch butterfly eats plants that excrete that milky juice. Caterpillars consume exclusively milky juice. In the diet of adult monarchs, the nectar of flowers and plants: lilacs, carrots, aster, clover, goldenrod and others.
The most abundant delicacy for a monarch is a cotton wool. The last years the cotton wool is grown in gardens between trees, on city beds, in front gardens of private housing complexes.