Painted Lady Butterfly (photo courtesy Dr. Paul Levine)
March 29th, 2009
This weekend was extremely nice for March in the Bay Area. I was able to spend plenty of time outside enjoying the warm sunny day. A friend asked me if I noticed all the butterflies and when I looked I was in total awe of the sight. I found the following article on the migration of the Painted Lady Butterfly.
This week we're right smack in the middle of a butterfly superhighway. My first inkling of this was a few days ago, as I pulled out of the parking lot at Trader Joe's. I spotted a quickly moving smear of color - orange, black and white - flying in a choppy arc towards the Santa Clara River. Ah...the Painted Ladies are back!
Painted Lady butterflies often migrate north around March or April - heading to Oregon and British Columbia. But their numbers are usually smaller. The last time we had a superhighway-sized migration was March of 2005.
Painted Ladies begin their migration in our southwestern deserts and northern Mexico. When the desert has received sufficient winter rains, plants begin to grow, providing ample food for the butterfly larvae.
Click here for an amazing time-lapse video showing how the Painted Lady caterpillar transforms from a larvae into a butterfly. First, it sheds its skin to form a pupa and 12-14 days later, emerges from its chrysalis as a butterfly.
Painted Lady larvae feed on a wide variety of plants, such as lupine and thistles. When enough Painted Lady butterflies have emerged, they head north.
No one really knows for sure what triggers their migration. Population pressure, more daylight, warmer temperatures? I like to think it has something to do with the lure of the open road:
"Green, green, it's green , they say
On the far side of the hill
Green, green, I'm going away
To where the grass is greener still."
- "Green,Green" by The New Christy Minstrels, 1963
As written By Wendy Langhans
http://www.hometownstation.com/local-news/butterfly-superhighway-langhans-2009-03-20-09-07.html