Meet the Colorado Potato Beetle.
If I had to make a list of ten insects all people should know, I’d probably put this one on it. Leptinotarsa decemlineata is a walking case study in evolutionary ecology.
Anyone with a potato patch will recognize this large, pin-striped beetle as a particularly voracious consumer of potato leaves. And that’s true- the insect is a major agricultural pest. But it has only been eating potato plants for 150 years or so. Before that, L. decemlineata was an obscure insect found in the mountains of western North America where it fed on native Solanaceae that no one cared about.
When European settlers pushed west in the 1840’s with their newly-planted potato fields, a world of culinary possibilities opened up for this native beetle. A few gave the novel plant a try and never looked back. The population exploded and rapidly spread eastward across the continent. The beetles even reached Eurasia, too. It’s a textbook case of an evolutionary host-switch.
The colorado potato beetle evolves in other ways, too. Leptinotarsa decemlineata has become the poster child for pesticide resistance, and its various populations developed resistant to more agrochemicals than any other insect species. Organophosphates? Carbamates? Pyrethroids? No problem- thanks to a prolific life cycle and indiscriminate pesticide application, this beetle can now detoxify all of them.
photo details: Canon EOS 7D camera
Canon f2.8 100mm macro lens
ISO 100, f/8 (top) f/13 (bottom), 1/160sec