The only true Green European Butterflies.

[nomad]

The Green Hairstreaks Callophrys rubi and the much rarer Callophrys avis are said to be our only true green European butterflies. Species such as Orange-tips and some of the Whites appear to exhibit a green colour but theirs is a illusion created by an intricate mixture of black and yellow scales while the lepidopterist Jeremy Thomas writes that in the Green Hairstreak the underside colour is " the refraction of light through a microscopic lattice of closely-packed cubes within each scale, producing a diffraction grating with peak reflectance at 0.55u, which at any angle and in the dimmest light appear green". It is interesting that C. rubi has one of the widest geographical ranges of any European butterfly and that the larvae utilizes one of the widest range of foodplants while the very local C. avis found in the Iberian Peninsula, North Africa and Mediterranean France feeds only on the Strawberry Tree. Early Entomologists that collected C. rubi seemed to know only one foodplant Rubi [ bramble ] Species, hence the latter part of its latin name. In the spring C. rubi is a delight to watch, although small it is a very beautiful butterfly, especially when fresh, the undersides are like a velvet-green. This year I have managed to find several good colonies and observe the butterfly habits. Colonies are often found in open grassland with plenty of scrub. The males are very territorial and when not feeding sit on a favourite perch and jink off at high speed to chase any other insect and any passing female. When two males meet they will often spiral high in the air before returning to exactly the same perch. The following are some photographs that I have taken while studying the Green Hairstreak this year.
On watch on one of its foodplants gorse.

Resting on another foodplant bramble.

Well camouflaged on hawthorn bush.

Feeding at buttercup.
Attachment Deleted
ab punctata, White streaks on forewing. Resting on heather yet another foodplant, taken in Scotland.

[wolf]

These are rly common in Norway but very nice, especially when fresh as you said. Here are some pics from me. I'm pretty sure the larva is C.rubi. I randomly found it on Lotus, when getting foodplant for rearing P.icarus. Unfortunatly i didn't manage to breed it to adult, as it somehow dissapeared.

Attachments:

[nomihoudai]

Nice article on a nice butterfly. I have one more addition. The cubic structure as given in these older studies seems not entirely correct. Butterfly scales often form so called "photonic crystals" made out of chitin and other materials. Photonic crystals are a new field of interest in physics and many physicists are working on photonics, which already has several applications nowadays in signal transmission and may replace electronic wiring in computers some day. Due to this new interest many studies on butterfly scales are performed recently by physicists with the proper gear. You can see here, www.sciencedirect.com/science/article/pii/S1047847711000177 , that the cubic arrangement is true on two axes of space but the other one has a more complicated pattern.

This butterfly may be common in some places. I had seen swarms of them on a peak on some mountain in the Alps. They were the only butterfly there and had plenty of food. They also seemed smaller than the regular specimen down in the valley, unfortunately I couldn't inspect them closer as it was a nature reserve and I respected the laws.

[nomad]

Wolf, the green woodlouse caterpillar pictured certainly looks like the C. rubi larvae images in my reference books. I believe the green C. rubi larvae has a pale yellow stripe down its two sides. Never found them, they are supposed to be extremely hard to find. Many years ago, I found four larvae of the lovely Thecla betulae and gave two to my brother. All came safely through to the adult butterflies.
Claude, thank you for the additional information on C. rubi.

[nomad]

Last year, Chris Dennis found a remarkable aberration of C. rubi on the chalk downland of the Chiltern Hills of Buckinghamshire. Apparently this unique abb had not been observed before. So according to one taxonomist: those that discover a new butterfly have the right to have it named after them? So this specimen of C. rubi is now called ab dennisorum. I think you will agree its pretty special.



Image copyright Chris Dennis.

[nomad]

The image of this remarkable aberration is back, sorry folks.