cupido minimus/cupido osiris

Small (little) Blue (cupido minimus) and Osiris Blue (cupido osiris)

2008 photos highlighted green. Click on any photo to go to an enlarged picture, or simply scroll down the page.


13331_male_Valais, Switzerland_20Jul08 - minimus	11880_male_Alpes Maritimes_1Jul08 - minimus	2059_female_Isere_30Jun06 - minimus

11774_pair_Alpes Maritimes_30Jun08 - minimus	0508_male_Var_10May06 - osiris	10565_male_Var_15May08 - osiris

5250_male_Var_9May07 - osiris	5472_female_Var_15May07 - osiris	10264_female_Var_6May08 - osiris

10280_female_Var_6May08 - osiris	10262_pair_Var_6May08 - osiris

Minimus is common in France, often very common, and occasionally, especially at altitude, where it can sometimes be seen in huge numbers. The underside sometimes need a close look to differentiate from the Mazarine Blue (cyaniris semiargus) especially when the uns spots are bolder and rounder. Minimus has (it seems to me) to have a great variety in the uns black spots, from quite light to very strong, from round to elongated, and the general arrangement of spots is very similar to osiris. The clue is that the unh series of four spots is in a straight line for osiris, although sometimes the lowest spot is very slightly displaced inwardly, while for minimus the lowest spot is usually clearly displaced internally. However, this is not always explicitly clear, compare 11880 and 10280, and I have found the osiris unh spots in s2 and s3 to be completely missing, as in 5250, or just vestigial in s3 and missing in s2, as in 10565. Also, the unf series of post-discal spots (except s6 at the top) is fairly straight in osiris but more clearly arched in minimus, although this is not always convincing. Minimus sometimes has faint unh marginal markings, which I have not seen in osiris.

However, if the upperside is visible, the male osiris is unmistakeable with a clear bright blue colour and a neat thin black border, whereas the male minimus is brown with a varying amount of dusting of pale blue scales, but never complete. The female osiris is essentially plain dark brown to black with a varying degree of basal blue scaling, whereas minimus is plain brown with no blue scaling. Osiris seems to be closely tied to its larval foodplant sainfoin (onobrychis viciifolia), especially the female, so if it's sitting on sainfoin, the odds are that it is osiris.

They could both (the male osiris in particular) be confused with the Provencal Short-tailed Blue (everes alcetas) as they are of similar size and general markings, but alcetas has a hindwing bump, sometimes almost indiscernible, where the vestigial tail occurs, which osiris does not have.

Osiris is considered to be uncommon, but I am coming to the conclusion, after three seasons in Var, that it is more widespread than is generally reported in the books, although in low densities. I suspect it is often missed as it is very similar to several other small bright blues, notably Common Blue (polyommatus icarus). It is an early season butterfly in Var, and I have not seen it later than about the first week in June, although it does have a second brood in other areas.

13331: a male, puddling. Very few blue scales which might have suggested female, were it not for the fact that it is puddling (which I believe to be an exclusively male activity).

11880: a male, puddling. The unh series of spots is almost completely in line, suggesting confusion with osiris, although it was clearly minimus.

2059: female minimus, not a great shot, but it does show the similarity to the female osiris in 0451.

11774: a mating pair of minimus. I suspect the female is on the right based on size and colouring, also that it is fresher. Whenever you see a mating pair, if one is worn or damaged, it is odds-on to be the male, because it emerges earlier on balance and fights territorial battles.

0508: male osiris, quite a bright blue that could also be confused with the Chapman's Blue (P. thersites) in that the black borders are quite similar, and it is sometimes of similar size.

10565:a male osiris. The unh spot in s3 is vestigial and in s2 completely missing. However, the visible blue confirms male osiris without doubt.

5250: a male osiris puddling. A very clean underside with a strong basal blue flush. As noted above, there are usually four post-discal spots in a straight line, but for some inexplicable reason this specimen only has the top two in s4 and s5, with no sign of even vestigial lower spots in s2 and s3. The just-visible blue of the uph confirms osiris, rather than minimus. Altitude 780m.

5472: a female osiris, with a sprinkling of blue scales on the basal area of the forewing. It is, as always, sitting on sainfoin (onobrychis viciifolia). Altitude 340m.

10264: a fresher female osiris, again with a sprinkling of blue scales on the basal area of the forewing.

10280: a female osiris, the underside of 10264.

10262: a pair of osiris, male above. The female is the same as 10264/10280, but I included the photo because it captured both sexes in the same shot.

13331_male_Valais, Switzerland_20Jul08 - minimus