From around 130 million years ago flowering plants and insects have evolved together in something called co-evolution. This has resulted in a number of different ways of attracting insects to the plants. Entomophilous plant species have frequently evolved mechanisms to make themselves more appealing to insects, e.g. brightly coloured or scented flowers, nectar, or appealing shapes and patterns. Pollen grains of entomophilous plants are generally larger than the fine pollens or anemophilous (wind-pollinated) plants, which has to be produced in much larger quantities because such a high proportion is wasted. This is energetically costly, but in contrast, entomophilous plants have to bear the energetic costs of producing nectar.  Butterflies and moths have hairy bodies and long proboscides which can probe deep into tubular flowers. Butterflies mostly fly by day and are particularly attracted to pink, mauve and purple flowers. The flowers are often large and scented, and the stamens a