Davey, P., 2009: Two races of this species occur in the British Isles and each occupies a different biotype. Until recently, confusion has reigned over the status of all five spotted Burnets in Dorset because adults closely resemble one another. The larva of the Narrow-bordered Five-spot Burnet171 is 'hairy' relative to the other Burnet caterpillars, and this difference is a useful determining factor. Furthermore, the distribution of the respective host plant species of the Five-spot Burnets tends not to overlap, so the nature of the habitat is usually helpful in telling the two races apart.
ssp. decreta Verity 1926
A local sub-species found in England and Wales, commonest in the south-west and declining in the south-east, the larva feeding on greater bird's-foot trefoil (Lotus pedunculatus). In Dorset, the moth is decidedly local forming scattered and small colonies on marshy ground and wet flushes on sandy soils, and within unimproved grassland and broad woodland rides on ill-drained clay soil. In such places it may be common wherein it is often seen visiting greater bird's-foot trefoil plants and flowers.
ssp. palustrella Verity 1926
A local and decreasing sub-species that is confined to the chalk and limestone soils south of the Thames, the larva feeding on common bird's-foot trefoil (Lotus corniculatus). In Dorset, this, the smallest burnet, colonises unimproved chalk downland harbouring good stocks of the foodplant. On the best sites it is abundant, and easily observed visiting flower-heads of knapweed and scabious. The overall impression is that this sub-species is doing rather well, albeit locally, and may be bucking the national trend. The adult tends to be on the wing up to a fortnight earlier than ssp. decreta.