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Brown Hairstreak in Worcestershire - Bulletin 29

June 2006

Dear Brownhairstreakers,

Thought people might enjoy this photo of two Brown Hairstreak larvae (Deborah and Dennis) 'cosying up' in Grafton Wood.

Deborah was originally found and named by Becky Lashley on our Brown Hairstreak Caterpillar Day on 28th May. At that point, she was around 8 mm in length and sitting on a blackthorn along the main ride. Our next sighting of Deborah was on 3rd June where she was re-found still on the same plant but around 3 foot from her original position and now grown to 11 mm. This is obviously a girl that gets around! The fact that I was away for a week meant there was a bit of a gap in reports of Deborah until the week beginning 12th June when she was spotted by John Tilt. Interestingly, she appeared to have an ant in close attendance which is a very interesting observation. Many of the Lycaenid family of butterflies which includes the hairstreaks, blues and coppers have a close relationship with ants. The most famous of course being the Large Blue whose larvae are taken by ants into their nests where they feed on ant grubs and actually pupate underground. The exact relationship, if any, between Brown Hairstreaks and ants is very unclear but it is thought that the caterpillars become attractive to ants at the point of pupation and are tended by them at the chrysalis stage. In Deborah's case, it may be that the ant was drawn by some 'signal' that she was nearing the point of pupation. If this is indeed what occurred, then the signal must have been heightened by the fact that on 15th June Deborah was joined by a second larva which was immediately christened Dennis. Quite where Dennis had come from was a mystery, as he had not been recorded on our previous visits, and it is certainly the first time I have heard of two caterpillars appearing on the same leaf in this way. Deborah at 16 mm was approaching full size while Dennis on the left was slightly smaller at 13 mm. The ant question is certainly something that would be worthy of further study and I would be interested in receiving any other observations on this subject. A visit on 17th June failed to locate any of the remaining larvae so we must hope that Arthur, Becky, Colin et al have been able to take advantage of the very warm conditions of the past ten days and that at least some of them have successfully made it to the pupal stage.

The next main event on the Brown Hairstreak calendar is our Assembly Tree survey planned for 29th July and again the following Saturday, 5th August led by Rob Mabbett. The first date forms part of national Save our Butterflies week organised by Butterfly Conservation and aimed at raising the profile of work being done to conserve our butterfly and moth heritage and heightening public awareness of some of problems which they face. There will be more information on these events in the next ebulletin. A special offer during the week is one year's free membership of Butterfly Conservation with no obligation and, if anyone is interested in taking up this offer, please let me know and I will provide further details. Members receive a national magazine three times a year and also automatically become members of the West Midlands branch which produces its own newsletter detailing field trips, talks and events within the local area. Our current newsletter lists almost fifty between now and the end of September so hopefully something for everyone. For those more recent members of the Brown Hairstreak egroup, copies of previous ebulletins can be accessed by visiting www.westmidlandsbutterflyconservation.org.uk which also details the summer programme.

Mike Williams,
Brown Hairstreak Species Champion