Why is Gulf Fritillary Butterfly here in winter ?

[bluemoth]

I have a friend who has "Gulfs" in her yard. Very surprisingly the larva survived the freezing temperatures near the San Fransisco bay in CA a few weeks ago. My friend had ice on her car that is how cold it got there ware she lives. She calls these over wintering larva frosties because they turn almost all white on their backs. So how can this warm weather loving butterfly survive cold weather that would kill most other species of butterflies? This is the second winter her "gufls" have stayed alive in such cold. Any one got any ideas what is going on here ? Is any one studying cold hardness in Gulf Fritillaries that can shed some light on this subject?

[prillbug4]

In Peoria, Illinois, today it reached the 60's, even though it rained. I walked around and found some flies flying in the dead of winter. If this mild winter continues, we may see butterflies on the wing in late February and March. Not to mention that winter moths are very active, right now.
Jeff Prill

[wollastoni]

Could we use latin names on this forum ?
Thanks

[mygos]

Jan 30, 2013 1:33:22 GMT -8 wollastoni said:

Could we use latin names on this forum ?
Thanks

+1 !

Michel

[evra]

She's talking about Agraulis (Dione) vanillae. I'm surprised they ranged as far north as the SF Bay area at all. People in the southern U.S. plant their host, Passiflora in their yards because it has a very interesting flower.

[prillbug4]

Many insects have glycol in their blood stream which acts like an anti-freeze. It protects them during cold weather, and that is why a number of butterflies like Nymphalis, and Polygonia can overwinter.
Jeff Prill

[mantisboy]

I have personally collected one that was in San Jose, and that's only about an hour away from San Francisco.