Why moths are important? (In The UK)

Aesthetic value

Butterflies and moths are part of our natural heritage and have been studied for over 300 years.
Butterflies and moths are beautiful, with many being iconic and popular.
There are many references to butterflies and moths in literature, from the Bible through Shakespeare to modern day literature, and from poetry to musical lyrics.

Butterflies and moths are indicators of a healthy environment and healthy ecosystems
They indicate a wide range of other invertebrates, which comprise over two-thirds of all species.  Areas rich in butterflies and moths are rich in other invertebrates. These collectively provide a wide range of environmental benefits, including pollination and natural pest control.
Moths and butterflies are an important element of the food chain and are prey for birds, bats and other insectivorous animals (for example, in Britain and Ireland, Blue Tits eat an estimated 50 billion moth caterpillars each year).
Butterflies and moths support a range of other predators and parasites, many of which are specific to individual species, or groups of species.

Butterflies and moths have fascinating life-cycles that are used in many countries to teach children about the natural world. The transformation from egg to caterpillar to chrysalis is one of the wonders of nature.
Other educational aspects include the intricate wing patterns and iridescence, and as examples of insect migration.

People enjoy seeing butterflies both around their homes and in the countryside.
Over 10,000 people record butterflies and moths in the UK alone, involving getting outside and walking considerable distances. Over 850 sites are monitored each week in the UK and collectively volunteers have walked the equivalent of the distance to the moon counting butterflies. 
Several hundreds of thousands of people garden for wildlife in the UK, many of them specifically for butterflies and moths.

Thousands of people travel abroad each year looking for butterflies and moths. Eco-tours bring income to many European countries and developing countries around the world (e.g. the valley of the butterflies in Rhodes and the Monarch roost in Mexico).
Every butterfly and moth has developed its own suite of chemicals to deter predators and parasites, find a mate, and overcome the chemical defenses of its host plant. Each of these chemicals has a potential value and could be exploited economically. For example, powerful antibiotics have been found in the Meadow Brown, one of our commonest and most widespread species.

Butterflies and moths have a right to exist, as much as any other species on the planet.
Butterflies and moths have been around for at least 50 million years and probably evolved some 150 million years ago.
They are part of Life on Earth and an important component of its rich biodiversity.
Butterflies and moths are a highly diverse group comprising over 250,000 species and make up around one quarter of all named species.

Butterflies (and moths to a lesser extent) are an extremely important group of ‘model’ organisms used, for centuries, to investigate many areas of biological research, including such diverse fields as navigation, pest control, embryology, mimicry, evolution, genetics, population dynamics and biodiversity conservation.
The long history and popularity of butterfly study have provided a unique data resource on an insect group unmatched in geographical scale and timescale anywhere in the world. This has proved extremely important for scientific research on climate change.

Moths are important pollinators.While some moths, particularly caterpillars such as the corn earworm, are major agricultural pests, many others are important pollinators.
In some parts of the world, moths are a major food source for people, too. More than 90 percent of people in some African countries eat moth and butterfly caterpillars, according to a 2004 survey by the Food and Agriculture Organization of the United Nations. Caterpillars are packed with protein and healthy fats, and research shows that 100 grams of these insects provides more than 100 percent of the daily requirement of some vital minerals, such as potassium, calcium, zinc and iron.