Weaver's Fritillary (Boloria dia)

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2023 photographs highlighted in green. Click on any photograph to go to an enlarged picture, or simply scroll down the page.

7440_male_Alpes-Maritimes_25Jun07 25497_male_Alpes-Maritimes_08Jun11 35463_male_Var_18Jun14 36730_male_Var_11Sep14
50493_male_Var_31Aug22 50521_male_Var_3Sep22 36761_female_Var_11Sep14 27884_female_Côte-d'Or_26Jul11
34341_female_Var_10Sep13 42479_female_Var_24Apr17 48908_female_Var_9Sep21 51490_female_Lozère_13Jul23
48928_female_Var_9Sep21 42463_female_Var_24Apr17 5789_female_Var_26May07 36751_female_Var_11Sep14
   
16777_sex?_Var_25Jun09 8613_sex?_Var_27Jul07    

A relatively small fritillary, the upperside being superficially similar to the Pearl-bordered Fritillary (B. euphrosyne) and the Titania's Fritillary (B. titania) although easily distinguishable by the sharply-angled hindwing of dia, more readily apparent from an underside view. Titania is an altitude species, so any specimens at low altitudes are bound to be dia. The undersides of dia and titania are quite similar but can easily be differentiated on close examination.

 

However, something I had not previously considered is that dia e.g. 50521 is (or can be) remarkably similar to the female of Small Pearl-bordered Fritillary (B. selene), although their distributions generally do not overlap, although in 2023 I did find one instance (51490) of a location where it appears they co-exist.

It seems to be reasonably widespread throughout southern France as I have seen at least one at most places I have visited, and it was only in September 2006 that I found a location at 765m altitude in northern Var where it was common, and in this location each September it has been very common indeed. It seems to vary in size, often producing very small individuals, sometimes with very narrow wings. It is also (and perhaps more widely) known as the Violet Fritillary.

 

A superb video of the life-cycle of dia has been produced by Filming VarWild and can be viewed on YouTube here: www.youtube.com/watch?v=Jys3FXFS32o

ref sex

observations

alt. m
7440 M a male, based on body shape (not 100% certain, though) and some subtleties of the black markings. Other subsequent photographs on this page of males do, in fact, suggest that this is a female. 1080
25497 M a male, based on body length, and more heavily marked which is possibly an altitude effect. 1320
35463 M a male, with rather narrow wings (top to bottom) but rather wide across. It may be a second brood, as dia may be triple brooded in southern Var, the first brood appearing in April. 220
36730 M a male of the (probable) third brood. 220
50493 M a very heavily-marked male, quite noticeable in flight. 780
50521 M a male, quite fresh as apparent from the state of the fringes, but slightly dull with the black markings not as strongly contrasted as the norm for dia. 220
36761 F a female of the third brood, with a rather suffused appearance. 36751 is the underside. 220
27884 F a female, quite dark and heavily suffused, but the low altitude indicates that this is not an altitude effect. 320
34341 F a female. 220
42479 F a female, quite heavily marked, especially in the marginal region of the uph. 42463 is the underside. It was photographed in overcast conditions, and dia sits with open wings which tend to curve downward at the edges making it difficult to get them into focus, given the limited depth of field of macro lenses. 220
48908 F a female, I feel, on its general appearance (wing shape, dusky colouring, heavier markings), although the body length gives me cause to wonder. This open-winged pose is typical of when the sky clouds over and the wing area is maximised to make use of what remains of the sun's rays prior to closing up completely as in 48928, which is the underside. 220
51490 F a female, very heavily marked, especially the uph post-discal series of spots. I originally thought this was selene based almost entirely on the location and altitude and the distribution maps that showed selene at that location and dia not in the same general region. Given that the location was well known and well-surveyed, it seemed highly unlikely that dia had not previously been recorded there. 

I then consulted the local experts, both of whom were unequivocally of the opinion that it is a female selene, so I put it originally on the selene page.

However... a sharp-eyed contributor to the excellent UK Butterflies web site noticed that just enough of the hindwing was showing to reveal a degree of angularity that points very strongly to dia, probably conclusively, and almost certainly rules out selene.

1540
48928 F the underside of 48908. 220
42463 F a female, the underside of 42479. It is a beautifully cleanly marked underside, with strong violet (hence the alternative name) marbling effect. 220
5789 F

a quite light and subtly-marked underside. It shows up the beautiful red-brown markings to good effect. I'm not sure why I originally thought this was a female, but a female upperside was photographed within 60 seconds, and so they may well be the same butterfly.

220
36751 F known to be a female from a view of the upperside (36761 is the upperside). The delicate violet marbling shows why its alternative name is perhaps more appropriate. 220
16777 M?

a fairly typical dia underside, midway between 5789 and 8613 in terms of strength of markings.

220
8613 M?

a very darkly-marked underside. The angularity of the hindwing is visible, and this is a clear pointer to dia. I am not sure whether it is male or female, possibly male based on the slightly territorial-looking pose.

780

 

7440_male_Alpes-Maritimes_25Jun07

 

25497_male_Alpes-Maritimes_08Jun11

 

35463_male_Var_18Jun14

 

36730_male_Var_11Sep14

 

50493_male_Var_31Aug22

 

50521_male_Var_3Sep22

 

36761_female_Var_11Sep14

 

27884_female_Côte-d'Or_26Jul11

 

34341_female_Var_10Sep13

 

42479_female_Var_24Apr17

 

48908_female_Var_9Sep21

 

51490_female_Lozère_13Jul23

 

48928_female_Var_9Sep21

 

42463_female_Var_24Apr17

 

5789_female_Var_26May07

 

36751_female_Var_11Sep14

 

16777_sex?_Var_25Jun09

 

8613_sex?_Var_27Jul07