Twin-spot Fritillary (Brenthis hecate)

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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.

29423_male_Var_17May12 34971_male_Var_27May14 37332_male_Var_16May15
35481_male_Var_19Jun14 10875_female_Var_26May08 29730_female_Var_5Jun12
29487_male_Var_17May12 10833_pair_Var_26May08 20693_sex?_Var_13Jun10

This butterfly of the far south of France is quite uncommon (except in one region of eastern Var and western Alpes-Maritimes) and could easily be confused with the Lesser Marbled Fritillary (B. ino) based on the upperside alone. The male hecate is a clear bright orange and the female more heavily suffused grey, dulling the orange; it seems often to have a sheen which confuses the camera, especially at certain angles. Hecate has series of quite round post-discal spots on both upperside wings, as well as a series of submarginal spots which are shown in T&L as being essentially round on the uph, and a continuous black margin. Ino is very similar and is usually depicted as having a series of somewhat indistinct non-round submarginal marks. This originally had me fooled, as the submarginal marks of some individuals (e.g. 29423) look non-round and more like ino than hecate according to T&L.

 

But hecate has a complete series of post-discal spots on both the upf and uph of similar size, and ino has no (or very small) spot in the upf s4 and a significantly smaller spot in the uph s4 (see illustrations below). Curiously, I can't seem to find any mention of this in the books. The underside is quite distinctive, though. The two series of unh black spots are characteristic of hecate and give it its name.

The flight period is stated as from the end of May to mid-June, so unless you are visiting possible sites at this time, you are unlikely to see it. However, in central Var it is on the wing from mid-May onward. I originally saw one hecate in 2000 at this time, and it was not until 2006 that I started to visit Var regularly in May, since when I have seen it at many locations within the region indicated opposite. One of these sites was at an altitude of 1400m, which is about the upper limit of the altitude range for this species.

 

The larval hostplant is Filipendula vulgaris (English name: Dropwort), a white-flowered plant of about one metre height. It is not uncommon in the region, and I have found that wherever Filipendula grows, there is often hecate to be found there.

ref sex

observations

alt. m
29423 M a fresh male, just beginning to roost at the end of the day, when hecate seems to like basking in the final rays of the sun. 29487 is the underside, after it had closed up for the night. 220
34971 M a typical male. 220
37332 M a fresh male with rather heavy black borders. 220
35481 M a male, from a location at higher altitude. 780
10875 F

this is the female from the mating pair in 10833. The weather was dull and the pair remained as in 10833 for some time, but then the sun came out briefly and the female opened up, still connected to the male although this is not obvious and needs a close look at the photograph to confirm that the foreground obstruction is, in fact, the male.

140
29730 F a female, also enjoying the last rays of the sun. The sheen gives the orange a rather dulled appearance and makes it almost impossible to capture the image as seen in the field. 220
29487 M a male, known to be so as the upperside is 29423. 220
10833 PAIR

the mating pair (the same as 10875), female on the right, posing nicely in dull weather. The foothold of the male seems tenuous to say the least.

140
20693 ?

difficult to say whether this is a male or female, as the series of unh post-discal black spots is rather midway between the heavy spots of the female and the lighter spots of the male.

140

  

hecate                                                                 ino

 

29423_male_Var_17May12

 

34971_male_Var_27May14

 

37332_male_Var_16May15

 

35481_male_Var_19Jun14

 

10875_female_Var_26May08

 

29730_female_Var_5Jun12

 

29487_male_Var_17May12

 

10833_pair_Var_26May08

 

20693_sex?_Var_13Jun10