Yellow Sulfur Butterfly - thousands of them

We usually don't go camping so late in the year, but 2022 was unique in its own right.  The summer had been spent working on the house and garden instead of enjoying our RV as was our custom.  I was desperate to get away.  Fall was fast approaching and the temperatures were steadily dropping.  It was now or never.

With gas prices being so high and our desire to spend more time exploring the interior of BC we headed northwest from Kelowna toward Kamloops.  As we travelled an unfamiliar highway we noticed an increasing number of yellow butterflies in the air.  Soon we spotted thousands of yellow dots littering the road and shoulders, victims of collisions with moving vehicles.  We were not exempt from causing the decimation; our windshield bore the markings of many such impacts.

We soon reached our destination and set up camp.  With camera in hand, I went off to discover what the yellow hoard was made of.  I found many on the roadside and selected one relatively intact.  My butterfly field guide (yes, I have one - Butterflies of the Pacific Northwest by William Neill) told me it was an orange sulfur butterfly.

The caterpillars eat plants from members of the pea family, but they have an affinity for alfalfa, a fact that gives them a certain notoriety with some farmers.  They are common in much of North America.

An interesting fact associated with many butterflies is that their eyes can detect UV light.  Male orange sulfur butterflies have scales that strongly reflect UV light producing an iridescence that females can detect.  Females, on the other hand, have scales that absorb UV light and appear much darker.  Directionality of light and position also is a factor in how the males are perceived; this appears to function in helping potential pairs orientate themselves prior to mating.

This is one of the wonderful things about nature.  There is always something interesting to learn.

Thanks for reading.

Eric Svendsen     www.ericspix.com