By Wendy Langhans
What does it mean to be a cold-blooded creature? It means – if it’s hot, you’re hot – if it’s not, you’re not. Cold-blooded creatures, such as butterflies, take on the temperature of their surroundings. Butterflies have an optimum body temperature that ranges between 82 and 100 degrees Fahrenheit. So what can they do on a really hot or cold day?
Butterflies have a few behavioral tricks up their sleeves (wings?). They can warm up by opening their wings and basking in the sun. Or they can cool down by sitting quietly in the shade.
This Painted Lady butterfly has found a way to get warm on both sides.
Or they can “Get out of Dodge”. Some butterfly species, like Monarchs, migrate. But a recently published story suggests there are other changes happening.
Every two weeks for 34 years, Dr. Art Shapiro, professor of evolution and ecology at UC Davis, has been patiently collecting data on over 150 species of butterflies. He has been monitoring “butterfly population trends at ten sites on a transect across central California”. What he’s found is NOT good news: “Butterfly diversity (the number of different species) is falling fast at all the sites at sea level.”
He attributes this decline to two causes: climate change and urban/suburban development. How did he come to these conclusions? By comparing his population data with other information, such as climate data and land-use data.
It’s not surprising that habitat loss plays a role: “Land-use data show that the butterfly losses have been greatest where habitat has been converted from rural to urban and suburban types.”
But his data also shows an interesting anomaly: while butterfly diversity is declining at sea level sites, it is INCREASING at the tree-line sites. That’s because lower elevation species are moving upslope to cooler areas. Anyone who has ever driven from Sacramento to Lake Tahoe in August knows exactly what we’re talking about.
Butterflies don’t fly when it’s too hot or too cold, only when the air temperature is between 60 and 108 degrees Fahrenheit. And if I were stuck in 108 degree temperatures, I’d head to the mountains for the summer too.
Upcoming Outdoor Events:
For Facebook Users: 90 Days of Santa Clarita Valley Wildflowers.
Here’s a new way to familiarize yourself with our local wildflowers. Become a fan of the page, “90 Days of Santa Clarita Valley Wildflowers” and from now through April, each day you’ll receive a photo of a local wildflower and a link to a website where you can learn more.
Saturday, January 16, 8 – 10 AM. Bird Walk at Towsley Canyon. It takes some unique birds to stick around in our winters. Meet at the front entrance to the park. Beginners are welcome. Heavy rains cancel. For map, click here.
Saturday, January 23, 1-3 PM. Hibernate, Migrate or Tolerate. On this easy afternoon walk at Towsley Canyon, we’ll take a look at how animals and plants cope with winter. Heavy rains cancel.
You can listen to stories like this every Friday morning at 7:10 a.m. on “The Hike Report”, brought to you by your hometown radio station KHTS (AM1220) and by the Mountains Recreation and Conservation Authority.
For the complete MRCA hike and activity schedule and for trail maps, click here or go to www.LAMountains.com.