Green Hairstreak/ Grøn Busksommerfugl

photo: stig bachmann nielsen, naturplan.dk

 Callophrys rubi

Green Hairstreak is an early butterfly species. They might be seen already at the end of March, the flight time usually extend until the end of June, sometimes they were seen in July and early August, but they usually flies from late April until mid June in one generation and overwinters as a cocoon upon the surface of the soil. The genus name Callophrys is a Greek word meaning "beautiful eyebrows", while the species Latin name rubi derives from Rubus, one of the hostplants. This butterfly is often called rubi among butterfly collectors.


Callophrys rubi is found in most of Europe, from the Arctic Ocean till the south of Spain. Outside Europe from North Africa till Sibiria. 


Wingspan: 22-27 mm. It is easily recognized because of its small size, quick flight and the green underside. The green colour of the underside varies from golden green till grass green or verdigris green, and the white spots can form an almost continuous line or lack completely.  The upperside of the wing is a uniform dull brown with two paler patches on the male's forewings made up of scent scales. The Green Hairstreak is almost always seen with folded wings and therefore you can usually only see the pretty green underside.


Early butterfly collectors thought that the only foodplant was Bramble (blackberry), Rubus fruticosus, but as its habits became better understood the list grew and will probably continue to do so. Depending on the habitat it will use: Common Rock Rose (Helianthemum nummularium), Bird's Foot-Trefoil ( Lotus corniculatus), Gorse (Ulex europaeus), Broom (Cytisus scoparius), Dyer's Greenweed (Genista tinctoria), Bilberry ( Vaccinium myrtillus), Dogwood ( Cornus sanguinea), Buckthorn (Rhamnus cathartica), Cross-leaved heather (Erica tetralix) and Bramble. The larva is also recorded as feeding on Birch (Betula), Raspberry (Rubus idaeus), Bird vetch (Vicia cracca), Zigzag clover (Trifolium medium), Common heather (Calluna vulgaris), Spiraea, Siberian pea tree (Caragana), Sweetvetch (Hedysarum) and Hawthorn (Hippophae rhamnoides) in different parts of its range. The wide range of foodplants means that this butterfly is able to use a wide range of habitats including chalk downland, heathland, moorland and clearings in woodland.  It is present in wetlands as well as on poor dry meadows, at an elevation of about 0–2,300 metres.



 
The eggs are laid singly. The caterpillars are not known to be tended by ants like some lycid larvae but the pupae, which are formed at ground level, emit squeaks which attract ants and it is thought that ants will always bury any that are found. The whistling squeaks can be heard by humans. Green Hairstreaks overwinter as pupae and are univoltine, having one generation of adult butterflies per year.  The larvae is ab. 15 mm long. It is green yellow and has short light hairs, the larvae itself seems transparent. Upon its back it has two rows of yellow spots and a yellow stripe upon the side.


The flight is lightning fast and restless, but even in flight the green colour is visible. The butterflies however spend much of the time resting upon leaves of small birch trees and other low trees or bushes, where the males maintain territories. The resting places of the males are maintained through most of the flight time, but they are used by many other various butterflies, since each male only use the resting place for an hour or two. In cool sunshine the species rest with its side tilted towards the sun - it looks like the butterfly lies upon its side and it is seen upon willow catkins, various composites, marsh daisy and other flowers, but it is not especially seeking nectare. The Green Hairstreak is very shy and fast, and you'll have to be more than good to follow its flight with the eyes if it gets scared and flies up. It often comes back to the same spot after a short flight. That's worth to remember if you want to take a photo!

In Denmark: 

The Green Hairstreak (DK: Grøn Busksommerfugl)  is impossible to confuse with any other Danish butterfly. The green colour is very marked and the black and white stripes of the tentacles and the legs are very distinct. The backwing has a little tip. 
The fodderplant of the larvae in Denmark: The larvae may live upon a number of low bushes, but it seems to prefer bog bilberry ( Vaccinium uliginosum), cranberry (Oxycoccus palustris) alder buckthorn  (Frangula alnus), broom (Sorothamnus scoparius) and blackberry  (Rubus fruticosus )lotus corniculatus birds' foot trefoil. the geeen hairsteak is spread and common in Jutland, but  rare on the Isles and not existing at Bornholm.It's habitat are various pandscapes from dry hills and pastures with broom till heaths and heath moors or peat bogs. On the Isles the species are mostly found in peat bogs and raised bogs.



Source: Dagsommerfugle i Danmark, Michael Stoltze, 1998; Danmarks insekter 2012.

photo Gammel Ry, 24. maj 2009: grethe bachmann
photo Kongsø hede, April 2006: stig bachmann nielsen, naturplan.dk