For a number of months now, on a daily basis, I’ve been seeing leps and odes in my neck of the woods. I just haven’t written about any of my sightings until now.

So what prompts me to write about the pink-edged sulphur (Colias interior) at this time? Could it be because it is such a gorgeous insect? That is certainly true, but is not the main reason.

Rather, I’m prompted by the “Butterflies of Ontario” saying its upper side is “rarely seen.” Until June 22 of this year, I’d only seen the upper side of road-killed, pink-edged sulphurs – never a living one.

What changed on June 22? Luckily, I got some pictures at 1,250th of a second of the upper sides of living pink-edged sulphurs. A male and female at high speed were literally checking each other out as potential mates.

A pink-edged sulphur nectars on its favorite: a red clover.
A pink-edged sulphur nectars on its favorite: a red clover.John Weber/For the Enterprise Aug. 2021

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Upper sides revealed

The upper side of the male is trimmed with a black border. The female is quite different, having a charcoal-black smudge at the tips of the forewings. So, if you can see the upper sides, you can readily tell the genders apart. That’s certainly a big “if” when it comes to living pink-edged sulphurs!

Blueberry connection

So far, I haven't said anything about blueberries. As lovers of blueberries, we have a choice: to eat or not eat them. That is not an option for pink-edged caterpillars. Their diet totally consists of blueberry leaves.

By midsummer, the pink-edged sulphurs lay eggs on blueberry leaves. Caterpillars begin to feed. However, they stop feeding and spend the winter as caterpillars. The next spring, they resume feeding when fresh blueberry leaves emerge.

Unlike vegetable gardeners who have legitimate concerns about cabbage white infestations, blueberry lovers need not worry that pink-edged caterpillars will defoliate those plants.

Imposters

Not all butterflies having a pink edge are truly pink-edged sulphurs. One such imposter is a male clouded sulphur. You see the pink edge; however, there is not a clean, silver spot on the hindwing. Most telling of all are the three brownish-black spots toward the edge of the hindwing. By comparison, the true pink-edged sulphur lacks those spots, giving it a cleaner appearance.

This imposter is actually a clouded sulphur. It can be distinguished from a pink-edged sulphur because of the three brown-black spots on its wings. Plus, the central spot on its hindwing is muddier on the edges.
This imposter is actually a clouded sulphur. It can be distinguished from a pink-edged sulphur because of the three brown-black spots on its wings. Plus, the central spot on its hindwing is muddier on the edges.John Weber/For the Enterprise Aug. 2021

Closing thoughts

I’m glad I’ve been able to share what the upper sides of a living pink-edged sulphur look like – a view that they normally keep to themselves.

For a number of reasons, let’s hope some relief from severe drought is on the way. That would encourage a lot of fresh growth on blueberries in 2022. I’m sure that other blueberry lovers, such as people and black bears, would agree!

John Weber is a local butterfly and dragonfly enthusiast. Since 1997, Weber has been meticulously recording every dragonfly sighting. He’s counted butterflies since 1993. “Leps” is short for the insect order of lepidoptera, meaning butterflies and moths. “Odes” is short for odonata, or dragonflies and damselflies.