Cloudless Sulphur
This photo provides a handy size comparison. The large yellow butterfly in the background is a Cloudless Sulphur, and the smaller butterfly (front right) is an Orange Sulphur. Cloudless Sulphurs are easily twice as large as our Orange and Clouded Sulphurs. These two butterflies were puddling side by side in damp mud at Cox Arboretum.
Cloudless Sulphur nectaring on a thistle flower. Cloudless Sulphurs are migrants in our area, and much less common than our resident Orange and Clouded Sulphurs. Cloudless Sulphurs are larger than those species and have a more powerful flight.
I love how this photo of a Cloudless Sulphur turned out. This butterfly was nectaring on a sunflower on the Cox Arboretum prairie. There were plenty of other plants in the background, but my camera managed to blur the background, leaving the butterfly and sunflower nice and sharp.
This Cloudless Sulphur was nectaring on a royal catchfly flower. Cloudless Sulphurs will readily investigate any red blossoms. They are much like Ruby-throated Hummingbirds in that regard!
This Cloudless Sulphur is nectaring on blazing star, a native prairie plant. Cloudless Sulphurs are usually found in open habitat like prairies and meadows.
This is another female. Cloudless Sulphurs cannot overwinter in Ohio, so their numbers vary from year to year. Cloudless Sulphurs were formerly considered rare in Ohio, but with warmer weather, they have been expanding their presence in the state. In recent years, they have become fairly common in southwestern Ohio.
This is a female Cloudless Sulphur. Females have white "leaf mold" spots on their wings, unlike the males which are usually solid yellow (see above).
Here is a Cloudless Sulphur on a Cardinal Flower, another red flower. I have seen Cloudless Sulphurs from late May through the end of October in our area (weather permitting), but they are most numerous in late summer and fall.
Last but not least, here is a Cloudless Sulphur with its wings open. These butterflies never rest with their wings open. I only got this photo because this male was fluttering around a newly emerged female. You can see part of her chrysalis in the background. Males have unmarked yellow wings. (Females might have a very thin black border.) Orange and Clouded Sulphurs, by contrast, have a thick dark border on the dorsal surface of their wings.
The host plants for Cloudless Sulphurs are wild senna and partridge peas. I usually find these butterflies in locations where these plants are common. Cox Arboretum, the Caesar Creek Wildlife Area, and the Meadow Ridge area of Elk Creek MetroPark are all good locations.
This pair of Cloudless Sulphurs was visiting monkeyflowers at Caesar Creek Wildlife Area.