Sphinx surprise

A lazy, summer Sunday afternoon – the garden is a familiar scene; flowers waving in the breeze, insects buzzing in the air, and birds singing from the forest behind. And then, in an instant, the scene changes. Something different was hovering and flying around the bright pink campion flowers growing in the back border. A small hummingbird, perhaps a rare visitor, it was definitely not one of our regular Rufous or Anna’s types. My birder brain went rapidly into full attention mode. What was this?

Hovering at each flower before rapidly moving on to the next, the new visitor was actually a sphinx moth or hawkmoth taking nectar from the blossoms. Not the rare hummingbird I first imagined, but nonetheless an animal that I haven’t seen for many years in the area. And just maybe as exciting. Also called a hummingbird moth because, as I just demonstrated, the species is frequently mistaken for a hummingbird.

Grabbing the camera, I headed out into the yard to see if I could get a picture. This was one fast-moving insect, and a real challenge to photograph as the picture below attests. The wing beats are so fast, I never did capture an unblurred picture of them.

Bedstraw or Gallium sphinx moth

However, it was captivating to watch the moth flying around the bright pink campions. Perhaps the pictures do indeed capture the action.

With its wings a constant blur, the moth presented the next challenge. Did I see and photograph enough detail of the moth to make a correct indentification? Now, as you know, I’m a birder so I had to do a little research on-line for this one. I knew enough to recognize it as a sphinx moth, but as to exactly which species. Well!

My first impressions led me to decide is was likely a white-lined sphinx moth. This is the common and widespread species in our area; the default sphinx moth so to speak. However, digging a little deeper, I found that there is another, less common, but very similar species, the bedstraw or gallium sphinx moth. Careful study of many on-line pictures and reading various descriptions led me to decide that our visitor was indeed the bedstraw species.

Like hummingbirds, sphinx moths hover at flowers to suck up and drink the nectar that they need for energy – a good example of the convergent evolution of two unrelated species. The hummingbird uses its extendable tongue, the sphinx moth uses its extendable proboscis to draw the nectar into its mouth. Here’s a close up of the sphinx moth’s specialized mouthpiece at work.

Bedstraw sphinx moth, nectaring

To see what’s going on here, click once on the photo above to enlarge it. The proboscis is the dark coloured, thin tube that extends a short distance horizontally from the head of the moth, and then makes a 90 degree downturn before entering the centre of the flower. When not in use, the long proboscis is carried coiled-up at the front of the head.

But why “bedstraw”? Adult sphinx moths feed exclusively on nectar of many flowers, but it’s the food plant of the caterpillar which gives the species its name. Both bedstraw and fireweed, another favourite larval-stage food plant, are common plants in Deer Lake Park, which is right behind my house, and I’m sure this is the place where this adult spent its early life as a caterpillar.

Bedstraw (Galium sp), Deer Lake Park

And here’s the other favourite food plant of the caterpillar.

Fireweed, Deer Lake Park

The visitor didn’t stay long. It flew along the forest edge, seemingly looking for more flowers for nectar, and then disappeared into the park.

July is the peak of the adults’ flight season, so keep your eyes open for this beautiful moth in our parks. Like most moths, the sphinx moth does fly at night, but this species also flies in the afternoons, and we then have the chance to see this hovering beauty.

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