This is a complement to an earlier text of mine on the same topic. We live in a small village in Southwestern France. Rue des Écoles, on its left side, an old dry-stone wall features, California poppies along about 15 m (40 ft).
How did they get there? The most likely explanation is as a spillover from the former garden above that wall. It belonged to a most likeable lady, Madame —Marthe Joulia. The mother of the current village mayor, she died in 2018, aged 88. If indeed she had planted those in her garden, she must have done so during the 1990s.
Anyway, those plants behave as bona-fide California poppies. Including their internal, phototropic motion: opening widely their four petals to sunlight and closing up at night or when the light decreases during a cloudy or rainy time. When cut and set into a vase with water, they maintain that, to-me fascinating, behavior for about a week.
To what avail? The explanation I favor is that they maximize their sun exposure so that their colorful petals — yellow due to carotenoids — show as much as possible. Indeed, those pigments are arranged in prism-like manner for that purpose — my earlier text expands on it a bit more. Why then are California poppies such show-offs?
Obviously, to attract their pollinators. Bees are foremost and, yes, are attracted to the bright blossoms. In their native California, these are bumble bees, sweat bees, mining bees and some species of butterflies. Here, in the Aveyron French region, their most likely substitutes are, likewise, bees. These are not lacking locally, inventory of wild bees from Aveyron currently stands at 199 species, including 67 Apidae (including 31 Bombus, 21 Anthophorini, 9 Xylocopini, 4 Melectini).
Thus, California poppies are good exports wherever there are bees to help as pollinators, which probably includes quite a few destinations — as long as they are reasonably sunny — the Aveyron lies at a latitude definitely more northerly than most in California.