Amynthas<\/em> worms raise not only the frequent disgust of gardeners, but also serious concern for land management experts. By churning through such high volumes of surface mulch and litter (and not allowing it to decompose more naturally into the soil), these worms seem to tie up plant-friendly nutrients into their dry castings, which are then easily washed away. They can physically undermine plants by loosening the top layer of soil \u2014 especially when hundreds of them are at work \u2014 and make it less able to retain moisture. They also seem to eradicate European earthworms, which help mix and aerate healthy soil, wherever they arrive. <\/p>\nSo, it\u2019s panic time, right? <\/p>\n
It turns out we know very little about these annelid invaders beyond their self-fertilizing fecundity, physical vigor, and prolific digestive habits. It is true that they are changing the landscapes they enter, but some researchers say that while we should work to control jumping worms, we also need to learn more about them \u2014 and, yes, learn how we can live with them, too. <\/p>\n<\/div>\n<\/div>\n
This is a second-wave invasion <\/p>\n
America didn\u2019t always have worms. At least not of the familiar earthworm variety. <\/p>\n
European earthworms were once an invader to North America, too. When they arrived from across the Atlantic in the 1600s, much of the continent had been free of a meaningful earthworm population since at least the last ice age. When they got here, they brought their share of changes to the landscape, including altering native forests. But in the intervening centuries, we have learned to live with \u2014 and sometimes even love \u2014 them. <\/p>\n
Amynthas <\/em>worms, by contrast, are slightly newer, second-wave invaders. Although the first documented observations of them in the US reach back to the 1930s, their arrival in many regions has been within just the past decades or even years. When such a vigorous organism moves in, the early results can be shocking, especially with jumping worms. \u201cThere are so many of them, and they\u2019re so active, people get really disturbed by them,\u201d Williams says.<\/p>\nThe Amynthas<\/em> species we have in the US (most commonly Amynthas agrestis<\/em> and Amynthas tokioensis<\/em>) are primarily from Japan and the Korean peninsula. In their home habitats, they evolved along with the local ecosystems \u2014 and the ecosystems along with them. But here, \u201cjust like any other invasive species that are displaced into a brand new habitat that might not have controls, they\u2019re able to take advantage of that and go gangbusters,\u201d says Brad Herrick, an ecologist at the University of Wisconsin-Madison Arboretum. <\/p>\nBut buried in this issue is a big and more concerning mystery: Researchers don\u2019t know why, over the past decade and a half, these worms seem to be spreading so much farther and faster. <\/p>\n
The worm invasion may be getting worse<\/p>\n
It\u2019s believed Amynthas<\/em> worms are primarily spread through moved mulch and compost; soil transported with plants or on vehicles; streams by natural distribution and use as fishing bait; and, of course, by snaking their way across the landscape. (Part of Amynthas<\/em>\u2019s success <\/em>lies in the hardiness of their tiny cocoons, which are just 1 to 3 millimeters in diameter, can survive temperatures ranging from about -15 to 103 degrees Fahrenheit, and some of which are thought to hide cryptically in the soil for more than a year before hatching.)<\/p>\nWhy are we now seeing so many more of them, and in so many more places? Part of it might be due to increased awareness, but Herrick and others also think there is more to it than that. Climate change could be one possibility, he says, opening up more northern latitudes to their liking. Another is that they have reached a population tipping point that makes mass spreading more likely, Herrick notes. <\/p>\n
Although much remains unknown about these worms, we do have some good reason to worry about them \u2014 and to do our best to limit their spread. <\/p>\n
Take the way they move through the soil, for example. European earthworms, on the one hand, are wide-ranging feeders. They make their way through surface, mid-, and lower levels of the soil. In this ambling habit, they circulate nutrients (ingesting some debris here, leaving their castings there) and break up the soil among strata, providing air and water to the layers below.<\/p>\n
Amynthas <\/em>worms, on the other hand, stick to the surface. So not only do they not perform the helpful mixing, but they also leave all of their castings \u2014 which Herrick likens to \u201ccoffee grounds or taco meat\u201d \u2014 on the surface, where they are easily washed away by rain and irrigation. \u201cThey can transform the soil in one growing season,\u201d Herrick says. This can cause problems for cultivated landscapes, such as gardens and urban areas, as they lose nutrients in runoff and have less stable upper soil layers for plants to root into. (Their potential impact on US agriculture has not yet been well studied, although heavily tilled and treated cropland is a less welcoming habitat for them.) <\/p>\nThey also seem to be altering forests. In North American forests, which evolved over more than 10,000 years without earthworm populations, earthworms of any kind can undermine the soil\u2019s density and change its composition. Amynthas<\/em> worms also pose a threat to the many organisms \u2014 plants, bugs, microorganisms \u2014 that make up the established understory ecosystem. \u201cOnce this layer disappears, this whole biodiversity disappears, and impacts forest ecology as a whole,\u201d explains Katalin Szlavecz, a soil ecologist at Johns Hopkins University. This disturbance can also make it easier for other invasive species to move in, Herrick adds. <\/p>\nAnd then there\u2019s jumping worms\u2019 uncanny ability to push out established European earthworm populations. They clearly seem poised to outcompete their more methodical relatives. After an invasion, \u201cIt\u2019s almost like War of the Worlds<\/em>: what happened?\u201d says Williams.<\/p>\nThe reason for the decimation remains unclear. \u201cIs it a virus? Is it an associated nematode? Do they have a chemical release? There\u2019s a huge mystery here,\u201d she says. <\/p>\n
\u201cThe can of worms is open, and you can\u2019t put them back in\u201d<\/p>\n
In light of these unhelpful doings, some states have tried to slow the spread by listing Amynthas<\/em> worms as prohibited species. And to try to beat back existing infestations, researchers have investigated using everything from controlled burns to sulfur treatments, with moderate localized success. But, says Szlavecz, \u201cI don\u2019t think, on a large scale, any of these are efficient.\u201d <\/p>\nSome commercial processes might help stop them. For example, Herrick has found that heating the cocoons to 104 degrees for three days kills them. And others are investigating different types of soil applications, including worm-killing fertilizers and fungi. <\/p>\n
Gardeners, meanwhile, have been fighting their own battles against Amynthas<\/em>. Some are still trying to prevent them from entering by erecting a shallow barrier of metal flashing to serve as a subterranean wall. Williams recommends also not picking up roadside compost, mulch, or plants, and asking nursery staff about the potential for jumping worms in products. There may be some that get in anyway: \u201cyou can\u2019t stop birds from flying, you can\u2019t stop worms that like to wriggle across the soil,\u201d Williams says. <\/p>\nStill, others dealing with current infestations can try solarizing soil with plastic in the spring or forcing worms to the surface with a \u201cmustard pour\u201d \u2014 mixing powdered mustard with water and pouring it over the soil surface \u2014 and then handpicking them out. <\/p>\n
While most land management experts encourage all of the reasonable steps we can take to control these voracious worms, there is little hope of eradicating them from North America. \u201cThe can of worms is open, and you can\u2019t put them back in,\u201d Williams says. <\/p>\n
In other words, we now have our own adapting to do. <\/p>\n
Herrick and his colleagues are currently enlisting local gardeners and others to help learn what native and ornamental plants might survive well or even thrive in jumping worm-modified soil. <\/p>\n
\u201cThere are more question marks here,\u201d Szlavecz adds. Which is why, she argues, continued research \u2014 as well as individuals\u2019 observation \u2014 of these worms needs to continue. She argues for a rebranding as well. Not only do they not jump<\/em>, \u201cthey\u2019re not \u2018crazy\u2019 \u2014 it\u2019s a big enough problem that they are invasive. Calling them \u2018crazy\u2019 just adds to the panic.\u201d <\/p><\/p>\n","protected":false},"excerpt":{"rendered":"Tiny, wriggling horrors are hatching right now, under our feet, across the country. No, not the billions of Brood X cicadas emerging throughout the eastern US. I\u2019m talking instead about baby invasive \u201ccrazy worms\u201d that thrash through garden, farm, city, and forest soil, growing to 3 to 6 inches in length, sucking up nutrients, and…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-9805","post","type-post","status-publish","format-standard","hentry","category-news"],"_links":{"self":[{"href":"https:\/\/googmn.com\/index.php?rest_route=\/wp\/v2\/posts\/9805","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/googmn.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/googmn.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/googmn.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/googmn.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=9805"}],"version-history":[{"count":0,"href":"https:\/\/googmn.com\/index.php?rest_route=\/wp\/v2\/posts\/9805\/revisions"}],"wp:attachment":[{"href":"https:\/\/googmn.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=9805"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/googmn.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=9805"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/googmn.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=9805"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}