Because of exhaust gases, insects can no longer find their way to the flower - but you can still attract butterflies. Grow plants in your garden that provide food for nocturnal insects and thus increase the supply for the animals.
Many moths feed on rotting fruit, but there are also plants that only open their flowers to insects at dusk and exude a tempting scent. A bait attracts the butterflies so that you can observe them well: you make a puree from pears or apples, honey or sugar and beer, to which you add a little yeast, fruit schnapps or red wine.