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Adonis Blue (Polyommatus (Lysandra) bellargus)
© Nick Greatorex-Davies
The Adonis Blue is a scarce butterfly in Britain, and like its relative the Chalkhill Blue, occurs only on herb-rich chalk and limestone grassland where its foodplant Horseshoe Vetch (Hippocrepis comosa) grows, usually on south or south-west facing slopes. It requires shorter turf than the Chalkhill Blue where the microclimate is particularly warm. (For further details on this species see http://www.butterfly-conservation.org/).
Family: Lycaenidae
Status: Stable
Status details:
Status since 1976 is Stable with an increase of 92.4%
Status over the last 20 years is Rapid increase with an increase of 391.9%
Status over the last 10 years is Stable with an increase of 115.5%
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:
Both generations show positive trends but only that of the second generation is statistically siignificant, indicating an increase in abundance. Climate change and the resulting warmer microclimate at ground level and the increase in rabbit grazing have benefitted this butterfly, making more of its hostplant suitable for breeding. Consequently it has spread onto sites where it used to occur but which had become unsuitable. Data indicate that colonisation has taken place at several scheme sites during the monitoring period.
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, Adonis Blue has been recorded from 247 transects in the Butterfly Monitoring Scheme. Of these, annual indices of abundance have been calculated from 137 sites, with an average index of 149 individuals per site.
For 60 of these sites, Adonis Blue has been recorded well enough to calculate annual indices of abundance in 6 or more years, allowing trends to be calculated.
In 2006, 23800 individuals were recorded from 70 sites, producing annual indices at 61 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 (2)
• Colonised sites (5)
- Stable sites (34)
- Declining sites (2)
- Increasing sites (9)
