Butterfly Conservation
Hertfordshire and Middlesex Target Species Guide 2005

Wall Brown (Lasiommata megera)

© photo: Liz Goodyear	© photo: Alan Downie	© photo: Richard Bigg

Status
The Wall Brown is identified in the Thames Regional Action Plan as having Medium Priority status.

Identification
The Wall Brown is unlikely to be mistaken for any other butterfly with the possible exception of the Speckled Wood, which is it’s closest relation. Whereas the Speckled Wood, however, likes shaded or partially shaded areas, the Wall loves hot sunny places where it can bask. The base colour of the upper side is a bright orange-brown with brown lined markings and prominent eye spots towards the tips of the forewings with a single central white dot. The wings are edged with brown and the hind wing has a line of dark spots centrally dotted with white. The colouring of the underside of the forewing is similar to the upperside, again with prominent ringed eye spots. The underside of the hind wing is duller with little or no orange present. There are again a line of spots which follow the contour of the outer edge. The male (illustrated) has a broad brown sex brand crossing the upperside of the forewing.

Speckled Wood © photo: Lee Browne

Habitat and behaviour The Wall Brown is usually found in open lightly grassed areas where there are patches of bare earth, earth banks, walls or fences which allow it to bask in the sun with wings spread. It requires relatively high temperature to be active and is a very alert butterfly, difficult to approach. The sound of a camera shutter is sufficient to cause it to fly. Various native grasses form the larval food plant, but heavily grassed areas are avoided and eggs are laid on clumps along the edges of bare areas, footpaths for example Life Cycle The adult first appears in May and is in flight until mid or late June. A second brood can be expected in August and last into September. The appearances are dependent on weather conditions the butterfly needing warm sun. The butterfly overwinters as a caterpillar. Past Appearances in Hertfordshire and Middlesex In the mid – 1980’s the Wall Brown was a common species throughout the area, being recorded in perhaps 80% of Tetrads (The Butterflies of Hertfordshire by Brian Sawford), although significant fluctuations in numbers from year to year were noted. By the mid – 1990’s a sharp decline had occurred. Over a 50% decrease was noted in 1995. The Wall had all but disappeared from the southern areas. Table 1 attempts to show the distribution of the species across the Herts and Middlesex area 1995 to 2001. 10 Km squares are taken working from south to north and west to east, and the number of 2 Km squares in which the Wall was recorded in each of the 10 Km squares is shown. The table indicates that the strongest colonies lie across the center of Hertfordshire and towards the north of the region. The table also shows clearly a sharp drop in numbers in 2000 and 2001, but this may be misleading since the number of records registered and the number of tetrads covered in those years were significantly reduced. (See Table 2) Table 1

10 km square			Number of 2 Km Squares
W o E			1995	1996	1997	1998	1999	2000	2001
		SP90
		SP91	1	2	4	6	6	1	1
	S o N	TQ7
		TQ8
		TQ9
		TL00				2	2	1	1
		TL01	3	1	4	4	4		1
	S o N	TQ17	1		1	1	1	1	1
		TQ18
		TQ19	1		1	2	2		1
		TL10	4	2	5	5	5
		TL11	5		5	5
		TL12	1	1	3	3	3	1	1
		TL13	2	1	3	4	4	1	2
	S o N	TQ27
		TQ28	1		1	1	1
		TQ29	2		2	2	2		1
		TL20	3		3	3	3
		TL21	1		1	1	2
		TL22			2	3
		TL23	11		1	1	1
	S o N	TQ38
		TQ39					1	1	1
		TL30					1
		TL31		2	4	5	5
		TL32	2	1	5	5	5
		TL33					1
		TL41	1		2	2	2
		TL42

Table 2 Year Tetrads visited 1996 976 1997 1138 1998 1214 1999 1362 2000 605 2001 607 To assess this possibility I looked at the results of those transects where the Wall was recorded.  The number counted at Highdown overshadowed results elsewhere, and since Highdown was not covered in some years the counts appeared somewhat erratic. If the Highdown figure is subtracted then fairly consistent results are obtained (see Table 3) which tends to support the idea that the 2000 and 2001 counts had not dropped as sharply as at first appeared  Table 3  1995   1996   1997   1998   1999   2000   2001   2002  25 6 9 2 7 3 0 3 The 2002 season In 2002, a total of only six individual Wall butterflies were recorded in five tetrads. The tetrads were SP91L, TL13K, SP91B, TL31N and TL12E All except one of these sightings were on the chalk ridge in the north west of Hertfordshire, where the strongest colonies are expected to be found. The 2003 Season The season produced a long period of hot, dry sunny weather, conditions which suit this species. However, May, when the first brood of the Wall is expected, was a month of cool strong winds and heavy showers. The hot weather started in June and went on more or less continuously through to August. The reported sightings of this butterfly numbered seven. 5 April - One was reported in a garden at Gustard Wood near Wheathampstead. If correct, this was an extremely early specimen. 5 May - Tony Clancy reported seeing one at William Girling Reservoir (TQ363928) 9 May - Stuart Pittman reported one seen at Highdown 12 June - Michael Healy recorded one on his transect at TL1213 22 July - Nick Sampford reported one seen in Ware on Park Road (TL348147) 23 July - Nick Sampford again saw one, this time in Jewson's yard at Hertford (TL339125) 3 August - Tom Gladwin reported seeing one at Datchworth (TL2618T) The 2004 Season The weather remained fairly cool during the early part of the season, temperatures only getting above 20 degrees infrequently. It was not until well into July that the mid and upper 20's were reached for any length of time. Only one individual was reported towards the end of July. 31 July - Nick Sampford reported seeing one at a garden centre near Buntingford (TL367294) Action Recommended for the 2006 season: Recording should concentrate on those tetrads where the Wall was present in the last 3 years to try to re-establish continued presence or otherwise. Acknowledgements Text by Richard Bigg Updated October 2005 Records Please send any records of colonies, singletons or potential sites to: Richard Bigg 91, Fordwich Rise Hertford Hertfordshire, SG14 2DF Telephone: 01992 582815

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