Small heath (butterfly)

Small heath
In Poland
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Lepidoptera
Family: Nymphalidae
Genus: Coenonympha
Species: C. pamphilus
Binomial name
Coenonympha pamphilus
(Linnaeus, 1758)

The small heath (Coenonympha pamphilus) is a butterfly species belonging to the family Nymphalidae, subfamily Satyrinae (commonly known as "the browns"). It is widespread in Eurasia and north-western Africa, preferring drier habitats than other Coenonympha. The larval host plants are grasses, notably sheep's fescue and rough meadow grass Poa trivialis.

Habitat

Well-drained meadow and steppe habitats. In the mountains it reaches the subalpine zone (1,500–2,000 m above sea level)

Early stages

Life cycle

The egg is green at first, afterwards becoming whitish or bone-coloured; later on, a brownish irregular ring appears a little above the middle, and there are various brownish freckles. It is finely ribbed, and the top is depressed, forming a hollow with a central boss. Laid in a cluster of four on a blade of grass, but this may have been accidental. Others were deposited singly on muslin and on fine grass, all in mid-June.

The caterpillar is a clear green, "with darker green dorsal stripe, and a spiracular stripe not so dark; the anal points pink" (John Hellins).

The chrysalis is "a delicate pale rather yellowish-green, with a faintly darker green dorsal stripe, the edge of the projecting wing-covers on each side whitish, outlined with a streak of reddish-brown; the abdomen freckled very delicately with paler green; the tip of the anal point, with a short streak of brownish-red on each side; the wing-cases faintly marked with darker green nervures" (South, 1906).

The larvae have lifespans of varying length, even within the same climate, thus the imagines of one generation may be seen over a long period. The butterfly usually has two, occasionally three, broods and is on wing from mid-May until early October (late June to mid-August in colder climates). The insect overwinters in its larval stage.

Decline in England

The small heath, like its cousin the wall brown, has been in serious decline across much of southern England for reasons unclear, and was accordingly designated as a UK Biodiversity Action Plan Priority Species (research only) by DEFRA in 2007.

Subspecies

Similar species

The butterfly loosely resembles a small meadow brown, but the brown of the wings appears noticeably paler in flight. Unlike the meadow brown and other common members of Satyrinae, the small heath is a lateral basker, only ever resting with its wings closed and angled at 90° to the sun. It more closely resembles Coenonympha caeca (forewing without apical spots), Coenonympha tullia (forewing apical spot smaller), Coenonympha symphita (underside of hindwing without white spot and almost always with a complete row of spots on the forewing).

References

  1. ↑ "Coenonympha Hübner, [1819]" at Markku Savela's Lepidoptera and Some Other Life Forms
  2. ↑ Brakefield, P.M.; Emmet, A. M. (1990), Emmet, A. M.; Heath, J., eds., "Coenonympha pamphilus (Linnaeus). Pages", The Moths and Butterflies of Great Britain and Ireland, Colchester, UK: Harley Books, 7 (1 (Hesperiidae to Nymphalidae)): 277–279
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