Chapman's Blue (Polyommatus thersites)

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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.

6516_male_Var_5Jun07 24049_male_Var_13Apr11 32417_female_Var_21May13
24669_female_Var_09May11 29202_female_Var_12May12 29180_male_Alpes-Maritimes_12May12
14785_male_Var_28Apr09 22123_male_Hautes-Alpes_14Jul10 24670_female_Var_09May11
41407_pair_Hautes-Alpes_14Jul16 39283_female_Var_30Aug15 24609_pair_Var_07May11

Very similar to the Common Blue (P. icarus), usually slightly smaller. The male upperside is bright blue with a violet tinge, and there is a narrow, but strong and even, black border on both wings. The underside is very similar to icarus although the key identifier is the absence of a unf cell spot which icarus nearly always has, even if sometimes very small. It is not always easy to see this as it is near the base of the wing, especially if the forewing is tucked down and the cell spot (or lack of it) is not visible.

 

The unh marginal orange lunules tend to be brighter and more elongated with pointed ends, and the black “dashes” inside the white marginal areas tend to be more centrally located within these white areas, compared to icarus where they are usually close to the orange, if not actually touching it.

The underside ground colour is pale brown in the female and greyish in the first brood males, although second brood males seem usually to have a brownish ground colour.

 

First brood females have a good degree of blue scales, whereas second brood females are more classically brown with orange lunules. First brood females could be confused with icarus - see the icarus page for possible means of differentiating. It is an early emerger, usually being on the wing in April in the south of France.

 

This species is referred to as Agrodiaetus thersites in T&L, but is now classified as a member of the Polyommatus genus.

 
ref sex

observations

alt. m
6516 M

this male shows the strong deep blue, deeper than icarus, with the clear clean black border of constant width.

140
24049 M another male upperside, the blue colour perhaps not quite as deep as the norm, and a rather narrow black border. This could easily be confused with icarus from the upperside alone. 140
32417 F a first brood female, perhaps typical of the degree of blue scaling. 220
24669 F a first brood female, showing the extent of the blue scaling. 220
29202 F a first brood female, perhaps with more blue scaling than the norm. 220
29180 M a male, perhaps quite dark grey. 900
14785 M

a male underside, quite a cold grey (even the male underside can be quite brownish, as shown on this page), and with some slight aberration of the unf black spots.

185
22123 M

a male, puddling at an altitude of 2100m, about the upper limit of its altitude range.

2020
24670 F a fairly standard female, except that the black unh marginal marks are in some cases touching the orange, whereas normally for thersites there is a small amount of clear white between them. 220
41407 PAIR a mating pair, the male on the left. They are, as is so often the case, on Sainfoin, an Onobrychis species, probably saxatilis, given the altitude. This species has a wide altitude range, probably most common at low altitudes, but can be encountered from time to time at Alpine levels of around 2000m, as this mating pair. 1960
39283 F a second brood female. 680
24609 PR a mating pair, the female on the left looking pristine as is nearly always the case. 185

 

6516_male_Var_5Jun07

 

24049_male_Var_13Apr11

 

32417_female_Var_21May13

 

24669_female_Var_09May11

 

29202_female_Var_12May12

 

29180_male_Alpes-Maritimes_12May12

 

14785_male_Var_28Apr09

 

22123_male_Hautes-Alpes_14Jul10

 

24670_female_Var_09May11

 

41407_pair_Hautes-Alpes_14Jul16

 

39283_female_Var_30Aug15

 

24609_pair_Var_07May11