Loosestrife Beetles Lend a Helping Hand (or Six)

Though a protected site, Volo Bog is no stranger to invasive species. Invasive species are species that are introduced to a new environment and then become a nuisance, usually through out-competing native species - at Volo Bog we primarily see this with plants. Glossy buckthorn and purple loosestrife are the major suspects.

Purple loosestrife comes from Eurasia, but has spread across North America since its introduction to the east coast in the early 1800s. It’s most common in glaciated wetlands - does that sound familiar? At Volo Bog, it grows throughout the marsh zone and in sunny parts of the shrub zone. It’s easily identified by its tall spikes of magenta flowers.

Unfortunately, purple loosestrife likes to form dense colonies that often displace native plants & wildlife. This is especially troublesome in an area like Volo Bog, where we have many rare plants that need all the growing space they can get. Thankfully, people have been coming up with ways to manage purple loosestrife for a long time.

One solution may surprise you: it involves the introduction of another non-native species, the loosestrife beetle. Loosestrife beetles are a kind of European insect that were released in the late 1900s to combat North America’s purple loosestrife problem. While you may be worried that these bugs would just become another invasive species, they actually pose very little threat to the ecosystem. They’re so reliant on purple loosestrife that they don’t impact other plant species. If the purple loosestrife that a beetle colony relies upon dies, they’ll simply disperse to another patch nearby.

Because of this, loosestrife beetles are a surprisingly effective method of biological control. They don’t eradicate purple loosestrife - one stroll through the marsh will tell you that - but they’re very good at limiting its success, which makes it easier for human managers to clear it further with cutting & controlled herbicide application.

At Volo Bog, you can see the impact of loosestrife beetles on almost any specimen of purple loosestrife: holes chewed in the leaves! Next time you see this, look closely for beetles and thank them for their helping hand in our conservation work.