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Friday, 17 August 2018

14-8-2018 - LAGUNA DE CANIZAR, TERUEL - GATEKEEPER BUTTERFLY (Pyronia tithonus)


The gatekeeper or hedge brown (Pyronia tithonus) is a species of butterfly found across Europe. Given its preference for warmer weather, the restriction of range expansion can be assumed to be due to climate.[clarification needed] Colonies vary in size depending on the available habitat, and can range from a few dozen to several thousand butterflies. Named for its rigorous patrol of hedges and woodland rides, the gatekeeper butterfly is a prime pollinator. The caterpillars primarily feed on fine grasses such as fescues (Festuca) and bents (Agrostis), which are common in meadows and roadside verges.

It is a member of the subfamily Satyrinae in the family Nymphalidae. A similar species is the meadow brown; the two species can be difficult to distinguish with closed wings, since the underwing markings are very similar. However, the gatekeeper tends to rest with its wings open, whereas the meadow brown usually rests with its wings closed. The gatekeeper is also smaller and more orange than the meadow brown and has double pupils on its eyespots.


Two other similar species of Pyronia are found in southern Europe, the southern gatekeeper (P. cecilia) and the Spanish gatekeeper (P. bathsheba).

P. tithonus has two known subspecies. P. t. ssp. britanniae, defined by Ruggero Verity in 1915, is represented in the British Isles. P. t. ssp. tithonus, defined by Carl Linnaeus in 1771, is not found in the British Isles. Instead, this subspecies is seen in central and southern Europe except southern Italy and in the Mediterranean islands except for southern Corsica and Sardinia.

The gatekeeper is orange with two large brown spots on its wings and a brown pattern on the edge of its wings. The eyespots on the fore wings most likely reduce or deflect bird attacks, which would explain why the gatekeeper is often seen resting with its wings open. A large number of aberrant forms are known, such as excessa, where specimens have two to four extra spots on the fore wing upperside. The number of spots on the hind wing underside also varies.