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Small Blue (Cupido minimus)
© Nick Greatorex-Davies
The Small Blue is a small, very localised and easily overlooked butterfly that occurs in small discrete colonies on herb-rich grassland on calcareous soils where its foodplant Kidney Vetch (Anthyllis vulneraria) grows. It has declined throughout most of its British range. (For further details on this species see http://www.butterfly-conservation.org/).
Family: Lycaenidae
Status: Stable
Status details:
Status since 1976 is Stable with a decrease of -2.3%
Status over the last 20 years is Stable with a decrease of -44.4%
Status over the last 10 years is Stable with an increase of 64.3%
Back to the topLog collated index plot
This chart shows the index of abundance (LCI = Log Collated Index) over time. It shows fluctuations in populations from year to year, and is scaled so that the average index over the whole series is equal to 2 (horizontal line). For greater detail about how this index is derived, click on the green question mark above.
Trend description:
The butterfly is recorded regularly on a relatively small number of transects and the data show no significant trend. This was once considered a normally single-brooded species in Britain and Ireland, but in recent years it has shown an increasing tendency to produce a second brood, presumably in response to a warming of the climate. At site level, data show some declines but also some increases, most notably at Oxwich in South Wales. Changes in management are likely to affect the quantity and quality of foodplant (Kidney Vetch) available for oviposition and subsequent survival of the larvae. Some disturbance is usually necessary to provide good germination sites for the establishment of new plants of this biennial or short-lived perennial.
Distribution...
This map shows the distribution between 1995 and 1999. Data is derived from the Butterflies for the New Millenium dataset via the NBN Gateway (www.searchnbn.net).
View the distribution on the NBN GatewayPhenology...
Phenology plot
Phenology plot
This chart shows the average number of butterflies seen on transects between Arpil and October. The black line gives average counts over the full BMS series (1976 to date) and the red line gives the average for the last year.
Abundance...
Abundance
This map shows symbols for the mean abundance at transect sites, with the size of symbol reflecting the level of abundance. Means are over all years.
Coverage
In total, Small Blue has been recorded from 282 transects in the Butterfly Monitoring Scheme. Of these, annual indices of abundance have been calculated from 257 sites, with an average index of 15 individuals per site.
For 84 of these sites, Small Blue has been recorded well enough to calculate annual indices of abundance in 6 or more years, allowing trends to be calculated.
In 2006, 2714 individuals were recorded from 83 sites, producing annual indices at 69 of these.
This map shows the trend in abundance at particular transect sites. Trends (increasing, declining or stable) are assessed at sites where the species has more than five years of annual index data. Click on the green question mark next to the species name above for more details on how trends are calculated.
Links to lists of sites with particular statuses
• Extinct sites (1)
• Colonised sites (1)
- Stable sites (36)
- Declining sites (7)
- Increasing sites (8)
