St. John’s Wort Beetle - Chrysolina hyperici or C. quadrigemina
There still aren’t enough images in my gallery to have complete set of this specimen, but I’m hoping to change that with a better grasp on their diet and the times at which they are active throughout the year. For the latter, both of these finds were during June, so that will hopefully be the best time to find them. Furthermore, it looks like they’ll be easy to spot as they feed among the flowers. They can eat quite a bit, so much so that when I first found a few (all those years ago), I mistook them for Japanese Beetles due to their similar coloration and feeding habits. It wasn’t until 4 years later that I took a closer look and realized that the St. John’s Wort Beetle belongs to the Leaf Beetle family. For a comparison to similarly shaped cousin, consider revisiting the section of the blog detailing the Dogwood Calligrapha. As the name suggests, this reflective Beetle’s preferred host plant is the St. John’s Wort and other wort plants that belong to the Hyperici genus.
The larvae are the major consumers of leaves (and shoots), but their diet shifts to flower parts upon reaching their armored adult stage. The individual in Picture number 2 appears to have found a tasty specimen of spotted St. John’s wort (H. punctatum) and will goes straight for the buds and the flower innards. The individuals in Picture 1 haven’t found a St. John’s wort to feed on, but seem inquisitive on the daisies and may see it as a viable food source. Humorously, daisies were once called worts, but that is simply a historic word meaning plant, not that these Beetles would know. In all seriousness, their ability to feed on St. John’s wort and manage the plant’s ability to spread led to the importing of these insects to North America, and thus we find them now. It’s handy to have them around given the toxicity of the unrefined plant to mammals. If you can find the flowers, hopefully these little gems are to be found as well. You’d do well to remember the occasion when you see your reflection in the Beetle’s shell.
Pictures were taken in June 12, 2016 with a Samsung Galaxy S4 and June 27, 2020 with a Google Pixel 4.
