The Asian giant hornet (Vespa mandarinia) is getting a lot of press this month. The so-called “murder hornets” are scary. It is big and kills honeybees. Though as a wildlife biologist, I can tell you it isn’t much to worry about.
In North America, it’s only found in Washington and Canada right around the border so far. It’s also big and impressive but not necessarily more dangerous to people or honeybees than many of the other hornets, wasps, mites, and various other things we already have in the US killing us and bees. But be afraid, be very afraid…
Here are 6 invasive species way scarier than some silly hornets.
SHOT HOLE BORER
Many of us are familiar with beetles and disease that kill trees. These killers range from native fungus and beetles to invasive moths. The big kicker, though, is that most of these dangerous pests kill one or a handful of related species of trees. We can then replant with trees not likely to be killed and the tree loss is bad, but we or nature can survive.
Then there’s our new friend, polyphagous shot hole borer (Euwallacea species and their associated fungus).
As the name suggests – polyphagous or multiple eating – this little beetle feeds on dozens if not hundreds of tree species. It farms a fungus that moves through the tree and eats all the nutrients and cells, killing the tree. The beetle then moves on to raise its fungus food in a new tree. As of 2020, this non-native beetle from Asian can infect at least 110 native and ornamental tree species, a good majority of those then die after a year or 3 of being infected.
Kudzu (Pueraria species) were brought to the US as ornamental plants and used as cattle fodder. They were also planted widely to prevent soil erosion during the dust bowl. They did help with soil erosion. They didn’t stop there.
Kudzu are so out of control in parts of the Southeast that they’ve gotten the colorful nickname “the vine that ate the south”. As the climate has warmed, they’ve expanded and cover nearly 7.5 million acres of the US. They grow on structures, damaging them. They cover trees and cause them to die and collapse. They out compete other plants, survive drought, and create vast areas where they are the only or dominant plant, crowding out our native species and making life miserable for people.
Everyone is tough until the fish start walking.
The walking catfish (Clarias batrachus) are exactly what they sound like. They are catfish found in wetlands, creeks, lakes, and seasonally wet areas. But they also have an amazing ability. If it rains or is otherwise really humid, they can decide to leave their home and go cruise around looking for another home or food.
They pack a double punch in the areas of the US where they are invasive. They can go to any water, move in quickly, and then they. Eat. Everything. Their are so damaging to the environment because they are opportunistic omnivores that can grow to nearly 2 feet long. They will eat plants. They will eat molluscs, frogs, snakes, birds, other fish, insects, and pretty much anything they an shovel into their mouth.
Chytrid fungus (Batrachochytrium dandrobatidis) isn’t really that dangerous to people. Yet. But most of our native amphibians aside from probably bullfrogs are being decimated by climate change, pollution, habitat loss, and this fungus. Those amphibians that aren’t immune to the fungus see infections in their skin where the fungus literally eats them alive, digesting and taking nutrients from their delicate skin cells. And if enough of our amphibians collapse, we will see a startling increase in insects like mosquitoes. Oh, speaking of.
The USA has plenty of native mosquitoes to annoy us. In fact, most male mosquitoes drink nectar and mind their own business. The females bite to get blood meals in order to help their developing eggs grow. Even then, most mosquitoes are annoying but harmless.
The US now has two very deadly mosquitoes: The tiger mosquito (Aedes albopictus) and the malaria mosquito (Anopheles quadrimaculatus). These love insects can bring with them a host of lovely diseases – malaria, yellow fever, dengue fever, Chikungunya fever, and a handful of infectious nematodes. Those disease aren’t necessarily here yet but their hosts are. If one sick person gets bit, it could spread through the mosquitoes and then us. Malaria alone causes nearly half a million deaths worldwide a year and can lead to a rare blood cancer.
Imagine you go out to the garden and pull a few weeds. One of them looks like some parsnip or Queen Anne’s lace, but it’s like 7 feet tall. You pull it and mulch it. A few hours later, you walk back out into the sun and are now covered in painful, oozing blisters that end up becoming awful scars. Congratulations, you met giant hogweed (Heracleum mentegazzianum)!
Unlike poison ivy, poison oak, or stinging nettle, most people in the US have yet to run into giant hogweed. That makes it’s phototoxic (toxic in the sun) sap more dangerous. Also, it can reach around 10 feet or more tall. So, good luck getting rid of this in your yard.
THE GOOD NEWS
Invasive and non-native species can destroy entire ecosystems. The worst of the worst like rats and brown tree snakes can eat entire islands full of wildlife, killing countless species or spread terrible disease. But most non-native species are either mostly benign or beneficial. Honeybees, many ladybugs, most of the ornamental plants in your yard, and the wall geckos that eat the moths in parts of the US at night are all non-native and aren’t destroying the planet. Plus, there are some amazing scientists and field workers actively working on ways to keep these dangerous species from ending up in your back yard.
At least until some terrible tree disease shows up and kills all the trees in your state.