The Brown Whitespot

In the 2002 annual review Dave Howson wrote a piece called “Looking for the Brown Whitespot”. This gave some interesting background information on the history of the Northern Brown Argus, which still causes debate amongst experts even today:

In 1795 William Jones, a prosperous wine merchant and distinguished watercolourist, painted a hitherto unknown small butterfly, which he called the Brown Whitespot, from Scottish specimens. Although the name was soon changed to Northern Brown Argus (NBA), it was finally recognised as a distinct species only in the 1960s! In 1828 a similar butterfly was discovered in Durham, and later in small scattered colonies across the North of England including the Yorkshire Dales. Only very recently has it been established by genetic analysis that these butterflies are also predominantly NBA, although with traces of the very similar Brown Argus found further South.

The butterfly is thought to exist as two distinct subspecies: artaxerxes, found in Scotland, and salmacis found in northern England. Artaxerxes can be distinguished from salmacis by a distinctive white spot found on the upper forewing (see featured image) and many of the texts lead you to believe these are absent in those found in northern England. The reality, from our surveys on two sites in Wharfedale, has found this is very variable as you can see from the selection of NBA images below, some where there is almost quite a pronounced white spot, others where there is a black spot with a white surround and some where it is absent altogether. So things are not always as simple as the books suggest!

Wharfedale Northern Browns
White spot absent	White outline	White spot