Glanville Fritillary - Caterpillar

[Sylvie_h]

I saw a dozen caterpillars of the Glanville Fritillary in the Rhone (69) in France feeding and resting on plantain. Here is a couple of pictures.
The caterpillars are very active during the day and can be found easily on this site which I visited twice already. I did find about the same number of caterpillars back in 2015, always on plantain and at the end of June.
Does anybody know whether there are 2 generations in France?
Sylvie

[David M]

Sylvie, according to Tristan Lafranchis in his book Les Papillons de Jour de France, Belgique et Luxembourg et leurs Chenilles, the biology of this species in relation to broods is:

Vol: avril - juin puis juillet - septembre en 2 générations en plaine. Une seule génération en été en montagne.

[Pete Eeles]

Great observations and insights, both; I did not know that!

Cheers,

- Pete

[Sylvie_h]

Merci David pour l'info.
It does make sense as the site is 'en plaine', alt about 200m.
Sylvie

[Matsukaze]

In Var, I have seen the adults in both May and September, and the caterpillar in July. I've seen the caterpillar in northern France in mid-April.

The excerpt from Lafranchis that David quotes suggests the butterfly is bivoltine right across (lowland) France; does this include the populations on the French north coast and, if so, do the Isle of Wight populations ever try to fit in a second brood?