Butterflies and moths

Northern Brown Argus

Small Pearl-bordered Fritillary

Butterflies and moths form a group of winged insects called the Lepidoptera. Characteristically their wings are covered with minute overlapping scales. One of many differences between butterflies and moths is that as a general rule butterflies fly during the day and moths fly during the night. However there are exceptions to this rule. Worldwide there are thought to be about 150,000 named species of butterflies and moths, with a further 150,000-350,000 species as yet unnamed or undiscovered.

Butterflies

In Britain there are 56 species of resident butterfly, with around 36 species recorded in Yorkshire. Although there are a variety of different habitats in the Yorkshire Dales the relatively cool upland climate means that only about 25 species are regularly recorded in the area.

The most widespread butterfly species in the Dales is the green-veined white which can be found in a wide range of habitats from the river valleys to some of the highest fell tops. As would be expected, a number of other butterfly species such as small tortoiseshell and peacock are also widespread in the Dales. Several species are common in areas of suitable habitat: the green hairstreak on heather moorland where bilberry is present, the common blue on damp and limestone grassland and the orange-tip in damp sheltered areas along woodland edges and road verges.

There are a number of species including the ringlet, speckled wood and small skipper that have until relatively recently been very scarce in the Dales, that are increasing and appear to be colonising new areas of suitable habitat. Another potential coloniser, the gatekeeper, remains a rare visitor and has not yet been recorded breeding. Some species are rare in the Dales because of a lack of suitable habitat and include the white-letter hairstreak which is associated with elms, and the brimstone which only lays eggs on buckthorn.

There are two priority butterfly species in the Yorkshire Dales National Park. The northern brown argus is a localised species restricted to limestone grassland where where common rock rose is present and the much rarer small pearl-bordered fritillary, found at only eight mires and rushy meadow sites in the Dales. A further species, the dark green fritillary, is a scarce species in the National Park but encouragingly, recent records indicate that the number of sites where this species is found is increasing.

Moths

For convenience entomologists have divided moth species into two subgroups based on their size. Micro-moths (micros) are in general smaller in size with a forewing length of 1cm or less and macro-moths (macros) are generally larger in size with a forewing greater than 1cm in length. These two subgroups often have separate field guides. In the United Kingdom there are almost 1500 species of micros (c.930 species in Yorkshire), and more than 800 species of macros (c.550 species in Yorkshire). Scarce moths found in the Yorkshire Dales National Park include the triple spotted pug (Eupithecia trisignaria), the cistus forester (Adscita geryon), and the barred tooth stripe (Trichopteryx polycommata).

Links:

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Northern Brown Argus Species Action Plan (opens in new window)

Small Pearl-Bordered Fritillary Species Action Plan (opens in new window)

Websites:

Butterfly Conservation (opens in new window)

Other sources of information:

Lewington, R & Bebbington, J (2002) Caterpillars of the butterflies of Britain and Ireland Field Studies Council/ Butterfly Conservation. Fold-out chart available from the Field Studies Council or Tel: 01743 852140.

Yorkshire Dales National Park Authority/ English Nature/ Butterfly Conservation (2004) Butterflies of the Yorkshire Dales National Park Gateshead: Cameron Publishing. Fold-out chart available from Yorkshire Dales National Park Centres.