Comma (Polygonia c-album)
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© Nick Greatorex-Davies
The Comma butterfly is a relatively mobile species of woodland rides and edges but it can also be found in parks, gardens and lanes with trees and tall hedges. Having declined in range in Britain during the first part of the 20th century it has experienced a rapid and dramatic expansion in range over the past few decades. Larvae feed solitarily on Stinging Nettle (Urtica dioica), Hop (Humulus lupulus) and Elm (Ulmus spp.). (For further details on this species see http://www.butterfly-conservation.org/).
Status details :
Status since 1976 is Rapid increase with a increase of 129%
Status over the last 20 years is Stable with a increase of 3%
Status over the last 10 years is Stable with a decrease of -14.2%
Log 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 all-sites collated indices for the Comma butterfly produce a highly significant positive trend in abundance over the monitoring period. Much of this increase occurred during the early years of the scheme following the drought of 1976 after which numbers dropped sharply before quickly rising again. Data for the Millennium Atlas show that this butterfly has expanded its range northwards in the period 1982-1999 more than any other British species. The range expansion has been dramatic and to some extent has been picked up by the UKBMS where sites have been colonised by this species. UKBMS data also indicate an increase in abundance as well as range. Undoubtedly these increases are largely in response to the warming climate.
This map shows the distribution between 1995 and 2016. Data is derived from the Butterflies for the New Millenium dataset via the NBN Gateway
This chart shows the average number of butterflies seen on transects between Arpil and October across all sites (fitted values from a Generalised Additive Model). The blue line gives average counts over the full BMS series (1976 to date) and the red line gives the average for the last year.
This map shows symbols for the mean abundance at transect sites, with the colour of the symbol reflecting the level of abundance. Means are over all years. Grey background squares are the occupied cells as shown by the Butterflies for the New Millenium over the previous ten year period.
In total, Comma has been recorded from 821 transects in the Butterfly Monitoring Scheme. Of these, annual indices of abundance have been calculated from 939 sites, with an average index of 12 individuals per site.
For 439 of these sites, Comma has been recorded well enough to calculate annual indices of abundance in more years, allowing trends to be calculated.
In 2018, 9064 individuals were recorded from 535 sites, producing annual indices at 428 of these.
Links to counts
This map shows the trend in abundance at particular transect sites for which data has been received within the last five years. Trends (increasing, declining or stable) are assessed at sites where the species has more than five years of annual index data. Use the option boxes below to view plots for individual sites.
Links to lists of sites with particular statuses
|Colonised sites (24)|
|Extinct sites (2)|
|Stable sites (567)|
|Increasing sites (157)|
|Declining sites (32)|