17 May 2014

Life History of the Gram Blue

Life History of the Gram Blue (Euchrysops cnejus cnejus)

Butterfly Biodata:
Genus: Euchrysops Butler, 1900
Species: cnejus Fabricius, 1798
Subspecies: cnejus Fabricius, 1798
Wingspan of Adult Butterfly: 20-26mm
Caterpillar Local Host Plants: Pueraria phaseoloides (Fabaceae/Leguminosae, common name: tropical kudzu), Vigna reflexopilosa (Fabaceae/Leguminosae, common name: creole bean).

The upperside view of a female Gram Blue.

Physical Description of Adult Butterfly:
On the upperside, the male is pale purple and with tornal spots in spaces 1b and 2 of the hindwing thinly crowned in orange. The female has a brown border on both wings and is pale shining blue in the basal area, and its hindwing has submarginal spots bordered with a dark sinuate line and larger and more prominent orange-crowned tornal spots in spaces 1b and 2. On the underside, both sexes are pale buff with a series of marginal, submarginal and post-discal spots, all pale brown and white-bordered. In the hindwing, there are three black basal spots, one black costal spot, two orange-crowned tornal spots in spaces 1b and 2 which are edged with metallic green scales and a white-tipped tail at the end of vein 1b.

The upperside view of a male Gram Blue.

Field Observations:
Gram Blue is moderately common in Singapore. Its distribution is rather localized and at times they can be locally abundant in wastelands or trail side where its host plants, the tropical kudzu and the creon bean, are growing as weeds. In the early morning and late afternoon sun, both sexes are often seen sunbathing on leaves with open wings. The adults have the habit of visiting flowers of various weeds for nectar.