Mother-of-pearl blue (Polyommatus nivescens)
|Also known as:||mother of pearl blue|
The mother-of-pearl blue is classified as Near Threatened (NT) on the IUCN Red List (1).
The mother-of-pearl blue (Polyommatus nivescens) is a small, delicately-marked butterfly found only in Spain (1). This elegant species has pale blue uppersides, which look almost white when the butterfly is in flight (2), and paler undersides with numerous black, eye-like spots. It also has very short antennae that terminate in club-like structures, which have a point on one side. The palp (small projections from the head which are covered in scent detecting sensors) are rather small (3).
Occurring only in Spain, the mother-of-pearl blue has a scattered distribution, ranging from Granada and Murcia in the south, to the Pyrenees and Cantabrian Mountains (1). There are also records of this species from France; however, the accuracy of these records has been questioned, meaning the species presence there is uncertain (4).
The mother-of-pearl blue is found in flower-rich grasslands and on warm, dry chalk rock with scattered patches of grassy vegetation and bushes. It occurs between elevations of 200 and 2,100 metres (1).
The mother-of-pearl blue is most active between June and July, but may emerge from hibernation as early as May and remain active until as late as August (2). The female mother-of-pearl blue lays a clutch of eggs each year on the leaves of the kidney-vetch (Anthyllis vulneraria), preferring to lay the eggs on smaller plants. Once hatched, the small caterpillars immediately go into hibernation. The following spring the caterpillars feed voraciously and grow rapidly, before pupating on the ground at the end of spring (1) (5).
The major threat to the mother-of-pearl blue is thought to be global climate change. Butterflies populations are subject to considerable annual fluctuations due to changes in their environment, making them particularly vulnerable to changing climatic conditions (1) (5). Climate change may adversely affect butterfly populations by altering the distribution of climatically-suitable habitat, by changing the vegetation structure of their habitats, or by changing patterns of land-use (5). The mother-of-pearl blue is also threatened in parts of its range by the conversion of its habitat to eucalyptus plantations (1).
A conservation priority for the mother-of-pearl blue is further research into its distribution and ecology. To mitigate the threat of climate change, remaining areas of suitable habitat should also be protected and appropriately managed, such that the species is given enough area to adapt to a changing climate and perhaps even disperse to new areas. As much of its habitat is severely fragmented, restoring habitat and improving connectivity between fragments would also greatly benefit the mother-of-pearl blue (1) (5).
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- Antennae: pair of sensory structures on the head of invertebrates.
- Hibernation: also known as ‘diapause’ in insects. It is a temporary pause in development and growth. Any stage of the lifecycle (eggs, larvae, pupae or adults) may enter diapause, which is typically associated with winter.
- Pupate: the process of forming a pupa, the stage in an insect’s development when huge changes occur that reorganise the larval form into the adult form.
IUCN Red List (April, 2011)
Eurobutterfies.com - Mother of pearl blue (April, 2011)
- Duncan, J. and Cuvier, G. (1835) The Natural History of British Butterflies. WH Lizars, UK.
- Tennent, W.J. and Munguira, M.L. (2008) Does Polyommatus (Plebicula) nivescens Keferstein, 1851, occur in France? (Lepidoptera: Lycaenidae). SHILAP Revista de Lepidopterología, 36: 527-530.
Settele, J. et al. (2008) Climatic risk atlas of European butterflies. Pensoft, Sofia. Available at: