Yes, butterflies primarily feed on nectar as adults. Nectar is a sugary liquid produced by flowers to attract pollinators, and it is the main source of energy for adult butterflies. Some species of butterflies also feed on other liquids such as tree sap, rotting fruit, and animal dung, but nectar is their main food source.
It's worth noting that while adult butterflies feed on nectar, their larvae (caterpillars) feed on the leaves of specific host plants. The type of host plant varies depending on the species of butterfly, but it is necessary for the survival and development of the larvae. The adult butterflies lay their eggs on or near the host plants, and when the eggs hatch, the larvae begin to feed on the leaves. As they grow, the larvae shed their skin several times, and eventually, they form a chrysalis and undergo metamorphosis into an adult butterfly.