Seasonal Variation in Lysandra bellargus

[nomad]

By the 1970's the populations of Lysandra bellargus in the U. K. had reached an all time low. Mismanagement of the chalk downlands and the spread of myxomatosis saw the grasses grow too tall for this species to breed and it disappeared from many of its sites where it once thrived. In my home county of Wiltshire it was once widespread with good colonies but by 1975 there was only one left, on the banks of a Iron-age hill fort. However better management of its habitat from the 1980's onwards has seen this butterfly make a remarkable comeback and it has been able to recolonize most of its former localities. I have noticed while studying and photographing some populations in North Wilts during 2012 & 2013 that although the females of this species are very variable , some of the differences may be seasonal. The second brood at these localities seems in many instances to have larger more pronounced orange outer margin markings. Has anyone else noticed if there are any recognizable differences between the Spring and Summer broods in some sites. I should be interested to hear of your experiences with this species and what you think on this matter. Below is a selection of images from two nearby sites on the North Wiltshire Downs. At one of these sites, because of the hot summer L. bellargus second brood was in much greater numbers than in recent years. In Britain the first brood occurs in May and June and the second brood in August and September.

Although this species produces good aberrations they never obtain the frequency of those that appear in L. coridon. One of the localities that I visit, was formely outstanding for L. bellargus aberrations . These are much scarcer today. Recent DNA testing of set specimens and today's populations of L. bellargus has shown that much genetic variation was lost during the bottleneck years of 1955 to 1980.

First and second brood female Lysandra bellargus 2012 & 2013


Typical first brood female


Typical second brood female


First brood female showing some blue scales resting on the foodplant Horseshoe Vetch [ Hippocrepis comosa ]


Second brood female with blue scales


Second brood female, chocolate with extra large orange markings without blue edging


First brood, blue female aberration


Second brood female aberration, blue spots on hindwing

[nomad]

The habitat at one site, a steep chalk downland south-facing coombe.