The Gorgeous Dogbane Leaf Beetle

Dogbane Leaf Beetle

I’ve spent some time birding around home recently, visiting places in Stony Swamp and Shirley’s Bay looking for breeding birds and butterflies. Hairstreaks have been on my mind, and after lunch on July 4th I headed up to Shirley’s Bay where I have seen both Banded (June 2012) and Coral (July 2016) Hairstreaks along Hilda Road in years past. I also thought I might find some baskettails patrolling the open trails, as I’ve seen both Common and Prince Baskettails there as well. Finally, Giant Swallowtails breed on the Prickly Ash plants in the area, and I was hoping to add Ottawa’s largest butterfly to my year list with a visit. Unfortunately it was much quieter than expected, with no baskettails zipping along above my head and no hairstreaks or swallowtails of any kind despite the gorgeous 30°C temperature. The only butterfly I noticed was a very worn skipper in the clutches of Goldenrod Crab Spider hiding in the Purple Cow Vetch.

Birds were quiet too, though I did hear an Eastern Wood-pewee and two American Redstarts. I also saw a House Wren carrying nesting material into one of the metal tubes attached to the power lines.

House Wren

After leaving Shirley’s Bay I stopped in at another spot where I’d seen Banded Hairstreaks in the past: the boardwalk leading from the P6 parking lot on Old Richmond Road. I have seen them in the same sunny openings just beyond the parking lot in at least three different years following my first sighting in 2012. This time I found a single individual resting on a leaf in the sunshine, likely a male defending his territory; the population is obviously doing well. Banded Hairstreaks live in sunny clearings and forest edges where oaks, walnuts, and hickories provide food for the caterpillars. Like other hairstreaks, the adult Banded Hairstreak loves the nectar of flowers such as milkweeds, spreading dogbane, and sweet clovers, although I have never seen any visiting flowers at this particular trail.

Banded Hairstreak

I decided to check the small wet meadow close to the end of the boardwalk; there are often skippers present visiting the flowers. I didn’t see any skippers, but at the end of the boardwalk a fresh Eyed Brown was fluttering through the vegetation. When it landed on a blade of grass I thought it looked quite photogenic:

Eyed Brown

Before I left the Rideau Trail I returned to the parking lot and climbed over the fence to check the trail beneath the hydro cut. This is another great spot for looking for butterflies, as Harris’s Checkerspot and Coral Hairstreak used to be found here. Again not much was flying, but I did come across a new crab spider resting on a withered Oxeye Daisy. Unlike the more familiar Goldenrod Crab Spider, this one was a reddish-brown in colour with a paler brown stripe down the middle of its body. It held its front legs in the classic crab spider position, welcoming prey with open arms. So far no one on iNaturalist has been able to identify it to species; the closest anyone has come to an identification is “Ground Crab Spider”.

Ground Crab Spider

Ground Crab Spider

A few days later I headed over to the Beaver Trail. It was too gray and wet to look for butterflies, but after seeing the gorgeous Dogbane Leaf Beetle at Marlborough Forest on Canada Day, I decided to check the patch of Spreading Dogbane in the Beaver Trail meadow to see if I could find more. The Dogbane Leaf Beetle goes by the scientific name of Chrysochus auratus, which is a reference to the metallic hues of its body: iridescent shades of green, gold, red and even blue can be seen depending on the angle of the light shining upon it. Although they are larger than a lady beetle, they are still hard to find despite their amazing colours. Still, I managed to find one resting on a rain-soaked leaf.

Dogbane Leaf Beetle

The Dogbane Leaf Beetle gets its common name from its habit of feeding almost exclusively on plants in the genus Apocynum, namely dogbane. These red-stemmed perennials can be identified by their oval leaves and clusters of small white and pink bell-shaped flowers. Like Common Milkweed and Foxglove, dogbane contains highly poisonous compounds which are lethal to mammals but harmless to certain insects. The harm from these compounds – called cardenolides – comes from their binding specifically to cell membranes and interfering with the electrolyte balance, often causing cardiac arrest. Such toxins are an evolutionary defense mechanism designed to prevent herbivores from eating the plants that contain them. However, a mere swap of a single amino acid in the cardenolide-binding sites of the membrane allows insects such as the Monarch butterfly and Dogbane Leaf Beetle to ingest these chemicals without being affected. Instead, the cardenolides are stored in glands, and released when threatened by their own predators. With such a potent defense, the Dogbane Leaf Beetle has no need for protective colouration or camouflage; its bright colours are a sign of its toxicity, allowing it to feed and rest out in the open without fear of being devoured by a predator.

Dogbane Leaf Beetle

It sure is one heck of a gorgeous beetle, and probably my favourite beetle species because of its shimmering metallic colours. After not seeing any since the Deep River bioblitz in 2013, I was thrilled to find these beetles in two places close to home. It turns out that merely being able to identify them isn’t the key to finding them – it’s being able to identify its chief food source, the Spreading Dogbane plant!

After taking my fill of pictures I continued my walk. Birds of interest included an Ovenbird (the only warbler present other than the usual Common Yellowthroats in the various marshes), a Red-eyed Vireo dive-bombing a Blue Jay, a Green Heron, a Gray Catbird, a Chipping Sparrow, and four flycatcher species, with only singles of each: Eastern Wood-pewee, Eastern Kingbird, Eastern Phoebe, and Great Crested Flycatcher. My most interesting sighting was not a bird, however, but a rather large Snowshoe Hare munching on the grass adjacent to the parking lot. I got in my car, rolled down the window, and took a few photos:

Snowshoe Hare

The thing I love best about nature is that no matter how often I visit the same trails, and no matter how many years I’ve been going to the same ones, each experience is different: no two visits feature the same birds or the same bugs, and even those that I see or hear fairly often display different behaviours – for example, watching the Red-eyed Vireo interacting with the Blue Jay. Even now I’m discovering new species in places I’ve visited many, many times, and adding to the list of fauna at those trails on iNaturalist. The variety and diversity of wildlife found at places like the Beaver Trail, Jack Pine Trail and South March Highlands are why summer is my favourite season and why Ottawa is such a fantastic place to live!


2 thoughts on “The Gorgeous Dogbane Leaf Beetle

  1. Hello, Gillian,

    I think I remember seeing dogbane beetles in a clearing in the Marlborough Woods, at least ten years ago. They are amazingly showy – definitely standing up to any of the tropical borer or scarab beetles for gaudiness!


    • Hi Alison, I haven’t blogged about my Marlborough sighting yet, but that’s the first place I found them here in Ottawa! There is Spreading Dogbane all along the trails there, but I never realized what it was until I posted it on iNaturalist. When I learned what it was I started checking a particularly large patch for these beetles – and voila, there it was! I can’t wait to go back this summer. 🙂

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