Gatekeeper

Gatekeeper Pyronia tithonus (Linnaeus 1771)

Family: Nymphalidae, sub-group Satyrinae (the Browns)

Description

Left: Female Gatekeeper, without the dark sex brand of the male. Centre: Gatekeeper underside. Right: Male Gatekeeper showing sex brands.

Header photo by Chris Weston

Other photos by Paul Simmons

Gatekeepers are similar to Meadow Browns (which share the same habitats) but are smaller and brighter, with the central parts of their upperwings strongly orange. The male is slightly smaller than the female, with broad, dark sex brands across the centre of its upper forewings. Note the two white dots in black eyespots (upperwings and underwings) compared to Meadow Brown’s one (usually - although two are sometimes seen in Scottish Meadow Brown specimens). Also look for a pattern of white dots on the lower wing in closed-wing view. The Meadow Brown is generally darker and more drab.

Habitat

Gatekeepers are found in rough grassy areas in sunny spots, especially in the shelter of hedges and scrub, or along woodland edges, including wide rides and sunny clearings. They are also found in unimproved pastures and meadows as well as sand dunes (as at Spurn) and on heathland. They are quite common along the uncut parts of suitable roadside verges and disused railway tracks, and are often seen nectaring on bramble flowers in sheltered but sunny corners. Gatekeepers have very short probosces so they can only feed on flowers where nectar is readily accessible.

Distribution

The northern limit of the Gatekeeper’s British range lies across central Yorkshire, roughly from Flamborough Head to the southern lake District, but with a scatter of records to the north of this line. Despite the promise of a northward expansion, their distribution has changed little in the last 15 years, and the main trend seems to have been a move away from the east coast. The centre of the county has by far the greatest numbers, especially in the eastern halves of West and South Yorkshire, with very few in the north-west and the east of the county.

This is a species which can produce very large numbers in quite small areas, therefore counts in the multiple hundreds are not uncommon, but they may vary widely from year to year.

Life Cycle

Pale eggs, which become mottled and darker with time, are laid singly on tallish grasses sheltered by hedges and shrubs in sunny places. Quite a wide range of grasses are used. Eggs are also sometimes ejected in flight or attached to the bark of nearby shrubs.

They hatch after about 3 weeks and hibernate as larvae, usually in October after their first moult. Night feeding recommences around March or April. The larvae have two colour forms in their final stage - greenish-grey, or dingy grey-brown, both with darker stripes and fine spotting. Pupation usually takes place in early June, the pupa being a rather striking brown with cream streaks when seen in isolation, but is well disguised when suspended in the vegetation.

Adults emerge after about 3 weeks in early July and the timing of this is synchronised across the county and even the country. Peak numbers are seen in the first week in August, and the butterflies are usually gone by the end of the month.

Gatekeepers live in clearly-defined colonies with virtually no migration between sites. Colony sizes vary considerably, depending on habitat – the smallest are along hedgerows, the largest are in open scrubby woodland. Males often spend several days in one small area, frequently perching and keeping a lookout for females and rival males.

Photo above right of Gatekeepers mating by Paul Simmons

Status

The species is not under threat.

Aberrations

A very variable species with over 60 described aberrations, many of which involve variations in the style and number of eyespots eg ab excessa Tutt which has 1 to 5 extra spots on upper forewing, and ab posttriexcessa Leeds, with up to 3 extra spots on the upperside of the hindwing.

Paul Simmons last updated 26/11/20