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Cupido amyntula Hübner, [1819]
Tailed Blues; Western Tailed Blue
Family: Lycaenidae (Gossamer Wings)
Species account authors: Crispin Guppy and Jon Shepard.
Extracted from Butterflies of British Columbia.
Introduction to the Lepidoptera of BC
Introduction to the Butterflies of BC
The Families of Lepidoptera of BC

Photograph

© Jeremy Gatten     (Photo ID #5976)

Map

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Distribution of Cupido amyntula in British Columbia.
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Source: Butterflies of British Columbia by Crispin Guppy and Jon Shepard © Royal BC Museum

Illustration

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Illustration Source: : Butterflies of British Columbia by Crispin Guppy and Jon Shepard © Royal BC Museum

Species Information


Adult

The Western and Eastern tailed blues are the only BC species of blues with tails. The Western Tailed Blue is slightly larger and has a somewhat whiter ground colour on the underside of the wings, but the two species can be reliably told apart only by dissection of the male genitalia. Females can be identified only by association with males.

Immature Stages

Comstock and Dammers (1936) described the immature stages. The egg is green and typical of Iycaenid eggs. The mature larva is grey green with white bristles along either side of the dorsal ridge. The body is covered with fine white hairs. Basally on each side there is a cream-coloured line. The pupa is yellow green with a white abdomen. By contrast, Hardy (GAH) found that Vancouver Island eggs were white. The larval body was pale green, with a dark green dorsal line and a pale cream spiracular line. The underside was a darker green. The hibernating larvae changed to a light brown.

Subspecies

BC populations are the nominate subspecies; TL: 2 mi. W. Quincy, Plumas Co., CA (Emmel et al. 1998a).

Genus Description


The origin of the name Everes is unknown (Emmet 1991). The common name "tailed blues" refers to the adults having small tails on the hindwings, which is unusual in temperate species of blues. Scudder (1875) first used the name "tailed blue" for the Eastern Tailed Blue.

This is the only genus of blues in BC with tails on the hindwings.lt is also the only genus of blues with a well-developed uncus in the male genitalia. The eyes are smooth and the palpi are porrect and twice as long as the head. The genus is Holarctic, with a total of five species, two of which are found in the Nearctic and BC. The larvae of all species in the genus feed on perennial Fabaceae.

There are two very similar species of tailed blues in BC. Where the two species distributions overlaps, the species can be differentiated only by examination of the male genitalia.

Biology


The Western Tailed Blue flies from late April to mid-June in the south and into July in the north; there is one generation per year. Hardy (GAH) observed oviposition on Vicia americana in late April. Hardy also found eggs on a stem of Lathyrus nevadensis var. nuttallii, near the flowers. The eggs hatched on 10 May and mature larvae quit feeding by 8 June. The larvae remained dormant through 12 October. Apparently Hardy did not get the larvae through the winter.

Outside BC, others have observed eggs laid at the base of developing pods of the larval foodplants, including Astragalus and Lathyrus. The newly hatched larva bores into a pod, seals the opening, and completes larval development undisturbed. In California, where there are two generations per year, Wright (1884) found that the second-generation larvae go into hibernation. He assumed that they did not pupate until the following spring.

Habitat


The Western Tailed Blue is found throughout BC in open meadows, in the understorey of mature, open forests, and in riparian situations wherever the larval foodplants occur.

Distribution

Distribution

The Western Tailed Blue occurs from central AK south through BC to Baja California and NM, and east to the Great Lakes.

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)		COSEWIC
NativeS5YellowNot Listed



BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

Synonyms and Alternate Names

Everes amyntula (Boisduval, 1852)

General References

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