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Purple Hairstreak (Neozephrus (Quercusia) quercus)
© Eddie John
The Purple Hairstreak is primarily a butterfly of oak woodland that spends most of its time in the tree canopy and is infrequently seen on butterfly transects though it may be one of the commonest butterflies on a site. Caterpillars feed exclusively on oaks (Quercus spp.) and colonies can sometimes be found on isolated trees. (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 38.9%
Status over the last 20 years is Rapid increase with an increase of 145.9%
Status over the last 10 years is Rapid decline with a decrease of -49.2%
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:
This elusive canopy dwelling butterfly does not lend itself to being monitored by the transect method. Therefore not surprisingly the data show no significant trend, though at some sites numbers recorded are sufficient to show both increases and declines.
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, Purple Hairstreak has been recorded from 409 transects in the Butterfly Monitoring Scheme. Of these, annual indices of abundance have been calculated from 429 sites, with an average index of 5 individuals per site.
For 219 of these sites, Purple Hairstreak has been recorded well enough to calculate annual indices of abundance in 6 or more years, allowing trends to be calculated.
In 2006, 1265 individuals were recorded from 117 sites, producing annual indices at 101 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 (8)
• Colonised sites (9)
- Stable sites (89)
- Declining sites (14)
- Increasing sites (11)
