Chalkhill Blue
This photograph was more difficult to capture than it looks. That is because I wanted the entire flower and butterfly to be in focus, but I did not want the background grassland to look cluttered. I used a Nikon 105mm macro f2.8 on a Nikon D810 full frame body with an aperture of f18, but I moved in quite close so this has very little cropping. I discovered recently that Chalkhill Blues (Polyommatus coridon) have disappeared from many of their downland localities. They need short-grazed turf with lots of their larval foodplant Horsehoe Vetch. But they also need the right kind of ants which thrive in short turf. Their relationship with ants is truly mutually beneficial as the ants protect them from predators and parasites, and in return the caterpillar exudes fluid with sugar and amino acids which the ants drink. The UK population declined by about a third (34%) between 1995 and 2004. Declines are probably attributed to loss of short turf when vegetation grows tall. This can be lack of agricultural grazing, or more likely rabbits, which suffer population crashes due to periodic outbreaks of myxomatosis. I photographed this male near the north of its British range in Cambridgeshire, although its foodplant Horseshoe Vetch (Hippocrepis comosa) also occurs on limestone in the north of England.
Chalkhill Blue
This photograph was more difficult to capture than it looks. That is because I wanted the entire flower and butterfly to be in focus, but I did not want the background grassland to look cluttered. I used a Nikon 105mm macro f2.8 on a Nikon D810 full frame body with an aperture of f18, but I moved in quite close so this has very little cropping. I discovered recently that Chalkhill Blues (Polyommatus coridon) have disappeared from many of their downland localities. They need short-grazed turf with lots of their larval foodplant Horsehoe Vetch. But they also need the right kind of ants which thrive in short turf. Their relationship with ants is truly mutually beneficial as the ants protect them from predators and parasites, and in return the caterpillar exudes fluid with sugar and amino acids which the ants drink. The UK population declined by about a third (34%) between 1995 and 2004. Declines are probably attributed to loss of short turf when vegetation grows tall. This can be lack of agricultural grazing, or more likely rabbits, which suffer population crashes due to periodic outbreaks of myxomatosis. I photographed this male near the north of its British range in Cambridgeshire, although its foodplant Horseshoe Vetch (Hippocrepis comosa) also occurs on limestone in the north of England.