Large Wall (Lasiommata maera)

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2016 photographs highlighted in green. Click on any photograph to go to an enlarged picture, or simply scroll down the page.

7900_male_Isère_5Jul07 41833_male_Savoie_21Jul16 19142_male_Gard_28Aug09
22875_female_Valais, Switzerland_21Jul10 18612_female_Isère_14Jul09 33645_female_Alpes-de-Haute-Provence_10Jul13
30168_female_Alpes-Maritimes_1Jul12 15047_male_Var_09May09 12324_male_Isère_9Jul08
   
13031_male_Valais, Switzerland_16Jul08    

Maera is superficially quite similar to the Wall (L. megera), although there are significant differences on close inspection. Megera is declining alarmingly in the UK but still reasonably common in southern France, although maera sometimes seems commoner, especially at medium and high altitudes. Maera does not occur in the UK.

 

Maera often poses quite obligingly for photographs, although it has a habit of settling in the dark shady areas on walls and rocks, presumably to escape the heat in the middle of the day. The nominate form of maera is easy to differentiate from megera as it is almost uniformly dark brown (not to mention maera usually being appreciably larger). However, the female of the maera southern subspecies adrasta, which is said (in H&R) to be predominant in southern France and Iberia, has lighter markings and is more extensively orange, making differentiation from megera slightly more difficult. I have seen adrasta in the Pyrénées, but on balance I believe the maera in Var are of the nominate form, so I wonder if H&R is right on this point.

Tim Cowles' detailed analysis points up the key differentiators between megera and maera, including the underside where three of the maera ocelli (s2, s3 and s6) are appreciably larger (clear in 15047 and to a lesser extent in 13031), whereas the six megera unh ocelli are of broadly equal size. You don't tend to find invaluable information like this in books.

 

There is also the Northern Wall Brown (L. petropolitana) which is very similar to the nominate form of maera, which belies its name as it is found in Scandinavia and the Alpes and Pyrénées, but not in between. Petropolitana is slightly smaller and darker and has a clear, although sometimes not very distinctive, discal line on the uph.

 

ref

sex

observations

alt. m

7900

M

a typical male of the nominate form.

1450

41833

M

a beautiful deep brown male maera, really a spectacularly attractive butterfly.

1680

19142

M

a male megera, I originally thought, even though Lafranchis cites the absence of a uph orange discal band as a key indicator of maera. Certainly, 19142 lacks this orange band, where one would normally expect to see one for megera. However, it looks completely unlike any other maera I have ever seen in southern France where maera is relatively common, and exactly like megera which is really quite common. The reason for this is that 19142 is a male of the subspecies adrasta. I invited comment and Guy Padfield kindly pointed out that the upf s6 basal bar is always present in megera and not in maera (compare with megera 10376), and that the sex brand (the darker band in the middle of the upf) is wide and dark in megera and narrower and lighter in maera. It seems fairly conclusive that 19142 is indeed maera, despite winning first prize in a megera lookalike competition.

580

22875

F

a female.

1740

18612

F

a female of the nominate form.

1230

33645

F

a particularly bright and fresh female. The white margin sets off the orange-brown to good effect.

1000

30168

F

a beautifully marked fresh female.

1320

15047

M

a male, based on body shape.

450

12324

M

a male underside of the nominate form.

1470

13031

M

a male underside of the nominate form.

1700

 

7900_male_Isère_5Jul07

 

41833_male_Savoie_21Jul16

 

19142_male_Gard_28Aug09

 

22875_female_Valais, Switzerland_21Jul10

 

18612_female_Isère_14Jul09

 

33645_female_Alpes-de-Haute-Provence_10Jul13

 

30168_female_Alpes-Maritimes_1Jul12

 

15047_male_Var_09May09

 

12324_male_Isère_9Jul08

 

13031_male_Valais, Switzerland_16Jul08