www.ukbutterflies.co.uk

Hello
I intend to try to rear some White-letter Hairstreak, I know it is not going to be as easy as is for many other butterflies so I wondered if anyone has experience or tips?
I intend to collect the eggs from a tree which is about to be cut because of Dutch Elm disease – carefully removing eggs from the small branches once they have been cut and before they are all burnt.
I would like to give it a try.
Even if unsuccessful in rearing, it will be interesting to record how many eggs are found.

Crispin

Hi Crispin,

I found them very easy to rear on a small branch of flowering Elm on a shaded window ledge. You are unlikely to see the actual hatch and the young larvae bury themselves in an opening bud very quickly. The first evidence of success will be minute frass on the windowsill below. Do NOT attempt to locate or move the larvae. If the Elm stems are regularly trimmed and and the water changed, they will last a couple of weeks, by which time the larvae should be visible (though incredibly well camouflaged!). Use fresh twigs as necessary and allow the cats to move over themselves. As they near pupation, they are very itinerant and may need to be sleeved - I lost a couple which appeared on the window as adults later! Keep the pupae outside or the adults will emerge too early. Good luck - the freshly emerged WLH is a pearl beyond price...

Tony M.

Eggs you do not rear through can be returned to other elms. I did this successfully last winter/spring. After keeping the eggs - windfall after horrific storms - on their twigs in the fridge over the winter, I spliced them back onto the tree by flower buds at the end of March:



In due course they hatched successfully ...



... and I found at least one of the larvae in April on my return from sad family business in the UK:





Returning eggs to a tree increases overall mortality but reduces the probability of their emerging as butterflies entirely out of synch with the wild population - a very real risk if great care is not taken.

Guy

Thanks, Tony & Guy, this is really helpful and encouraging. I hope to give it a try.
I wonder if taking eggs, on twigs, from a diseased tree and attaching to a healthy tree could result in the Dutch Elm Disease fungus being transferred?
Does anyone know?