Category Archives: Pest Control

Bad Ladybug

Different types of Harlequin ladybug, a rapidly spreading invasive pest. ©Entomart

Different types of Harlequin ladybug, a rapidly spreading invasive pest. ©Entomart

Ladybugs, once the championed protectors of backyard gardens, are showing spots of a less flattering color, and their public image looks like it could be taking an even bigger turn for the worse. A new study has found that invasive Harlequin ladybugs crossbreeding with a species of flightless ladybugs are creating a super strain of a buggy pest.

In recent years, ladybugs have taken their voracious appetites around the world, and they don’t just gobble up target insects. Couple this with plagues of ladybugs infesting homes, and you’ve got an unseemly problem on your hands.

To fight their spread, flightless ladybugs were released as a biological control agent. The idea being that the walk-only ladybugs wouldn’t spread as far as quick. Harlequin’s aren’t to be put off it would seem. The two types of ladybugs can hybridize, giving rise to offspring that are larger, faster-growing, and generally more robust than either of its parent species. Preliminary research suggests that the cross-bred young are even better-equipped to deal with starvation.

The findings by BenoÎt Facon of UMR Centre de Biologie et de Gestion des Populations in Cedex, France, and his colleagues are just a beginning. Researchers want to test multiple generations of hybrid and subject them to different conditions to unravel the magnitude of the Harlequin ladybug dilemma.

You can read more about their discoveries in the current issue of Evolutionary Applications.


Cane toads heart climate change

Cane Toad, AKA Bufo marinus, AKA troublemaker extraordinaire (Photo/ Eli Greenbaum)

Cane toads like it hot, and with climate change poised to raise temps in Australia, this persistent, invasive species could soon be living it up even more.

At least that’s the word coming out of new research from the University of Sydney and presented at the Society for Experimental Biology’s annual conference in Prague.

A lot of what we hear about climate change focuses on habitat loss (cue rising sea levels) or species extinction (sorry red wolf and coral reefs), but here’s another way the pesky, poisonous cane toad can flip the amphibian bird to mankind – warmer climes mean prolific times as far as the toad is concerned.

“The negative effect of high temperature does not operate in cane toads, meaning that toads will do very well with human induced global warming,” said Professor Frank Seebacher from the University of Sydney in a press release.

Many of you reading this are probably familiar with the story of the cane toad, but here’s the quick shake down. In the mid 1930s, Australian biologists, hoping to stem the onslaught of beetles ravaging cane fields, introduced cane toads to Queensland and the Northern Territory. Unfortunately, toads passed on the beetles, instead turning their appetites towards lizards, snakes and other native wildlife. To compound factors, the toads secrete a toxic substance that can do a serious number on just about anything that tries to eat it. So the cane fields now have beetles and bucket loads of poisonous toads. Sigh.

And because of research by Seebacher, we now have a good idea that toads are going to thrive even more as temperatures rise from climate change. Warmer weather makes for stronger, or at least more efficient, heart and lungs in the cane toad, Seebacher found. And if that’s not unsettling enough, the study also states “the cane toad can adapt its physiology in response to a changing environment repeatedly and completely reversibly many times during its lifetime.”

Will nothing temper their proliferation?

Before you totally throw up your hands and say, “Why do I read this if all you’re going to tell me is bad news,” here’s a ray, or sliver, of hope. Maybe, just maybe, this phenomenon will prove true for other toads, ones we actually would like to see stick around. I’ll get back to you when Seebacher conducts that study.


Saving snails: an invasive species becomes an unlikely hero

A land snail (Photo/ Petr Kratochvil)

Now, I know snails don’t come with the same poster-child charisma factor of more fuzzy, wide-eyed creatures  like pandas or baby tigers. But I hope you’ll imagine a tiny, high-pitched, “Help me!” issuing from the leaf litter at your feet, and stick with these little guys for a minute.

With that said, I’d like to tell you a story of a rat, a snail and a tree. They all live on the tiny island of Anijima, one of several in a chain of islands off the southeastern coast of Japan. The snail is critically endangered. The rat and tree are invasive species. You know those bullies of the natural world, the unwelcome visitors, the home wreckers of entire ecosystems. But before you go, “Oh here comes another invasive species story,” here’s the kicker – one of these encroachers, the tree, is actually in a sense the hero of this story, buying time for the snail and those trying to save it. The study, published online in the journal Conservation Biology, offers conservationists a new framework for restoring native ecosystems.

Anijima is part of the Ogasawara Island chain, a remote group of islands off Japan nominated for World Heritage listing. It’s also snail central. These islands are home to more than 100 species of land snail, 94 percent of which are endemic to those islands. Many of the snails have disappeared over the years, thanks in part to habitat loss and introduced predators.

Anijima was the exception. No one has lived there since the 1830s, and until recently, the environment looked much like it did 100 years ago. But a plant, the Casuarina tree has taken over the mid-western part of the island, converting natural forestland into a monoculture of dry coniferous forest. This delivered a significant blow to the land snails, as the snail’s home was turned into less ideal living quarters. Another blow came with the introduction of black rats in the 1930s. These voracious predators, gobble up the slow-movers, and since about 2006, have enjoyed an unprecedented population boom on the island, likely due to the eradication of goats – a competitor for food – and of feral cats – the rat’s main predator. In short, things weren’t looking good for the snails.

One might think, “Well, if you want to save the snails, just go in there and clear out the invasives.” But not all invasive species are created equal, and one scientist, Satoshi Chiba, with Tohuku University in Japan, has figured out that the Casuarina tree is actually helping the snail weather the rat boom.

Chiba looked specifically at the Ogasawarana genus of snails, a critically endangered group of snails considered a “natural monument” by the Japanese government. They are the only group of snails on the island still living on native vegetation on the island. Chiba surveyed plots in both Casuarina-laden habitat and native habitat, clearing sites of leaf litter, counting and identifying snail species and then returning everything to its place. Chiba also checked for rat carnage, and found that while initially, the tree causes a decline in snail populations, once the rat population went crazy, the Casuarina tree actually provided the snail with a better refuge from the predator than the snail’s native habitat.

The ground litter in the Casuarina habitat is deeper and denser than the snails’ natural environment. Black rats like to forage at the surface, and thus, the snails stand a better chance of avoiding a rat’s tooth and claw in the debris of a Casuarina forest.

The lesson here is not that an invasive species is necessarily good, but that there is an order to things when it comes to restoring an environment impacted by multiple non-native species. For Anijima Island, and the Ogasawarana snails, if they are to be saved, it’s likely that the black rats need to go before the invasive trees.

So, do you care a little more about a tiny mollusk? I don’t know, but at the very least, the story has a rich history, and just think how many other species suffering from a similar tale this study could help.


Looking to the skies to predict hantavirus outbreaks

Captive bred Peromyscus maniculatus (Deer Mouse). Originally published at RodentFancy.com (Photo Courtesy 6th Happiness)

When faced with plagues of deer mice and outbreaks of deadly hantavirus, checking in with the weatherman probably isn’t on most people’s minds. But new science shows that maybe it should be.

Scientists report in the Journal of Animal Ecology that they have been able for the first time to quantify the link between weather events, like El Niño, and booms in potentially hazardous deer mouse populations. Best take this news seriously. We’re in the middle of an El Niño season.

Their findings may help public health officials develop better hantavirus prevention strategies as well as enable scientists to predict how climate change could affect the severity and locations of deer mouse outbreaks.

The Sin Nombre hantavirus is an illness not worth wishing on your worst enemy. It’s a zoonotic disease, meaning it can be transferred from animal to human. The first recognized U.S. outbreak occurred in 1993 in the Four Corners region, and on average, 20 to 40 cases are reported each year, according the U.S. Centers for Disease Control. Unlucky victims can look forward to flu-like symptoms and respiratory and heart failure, and survivors face recurring symptoms for the rest of their lives. The disease is transferred by deer mouse droppings, urine and the animal itself.

Biologist Angela D. Luis with Pennsylvania State University, Richard J. Douglass at the University of Montana and colleagues combined capture-release, climate and vegetation data with computer models to find out if deer mouse population and disease presence were influenced by weather. 15 years and more than 4,700 mice later, Luis and her colleagues found the connection.

At first glance, it sounds like more rain means more food, more mice and more hantavirus, as rainy years create better food crops for the cute but pesky disease carriers. But the relationship is not so straightforward. The “more rain equals more everything else” scenario is partially influenced by season. Luis found that higher temperatures and rain in the summer through early winter months bode well for mouse populations, but not so well during the spring.

This could be particularly key for the Southwest, as during El Niño years, this region typically experiences significantly more rainfall. The study isn’t perfect, factors like predation, migration, and competition could also be affecting deer mouse outbreaks, but the weather connection appears to be strong.

Right now Luis and her colleagues are expanding their study. So far they’ve looked at habitat in Montana only. They are looking at more types of environments throughout the state, including sagebrush and pine forests, which will help determine whether their model could be applied to multiple regions.


Lady bug swarm turns Green Mountain red

more about “Lady bug swarm turns Green Mountain red“, posted with vodpod

Lady bugs unite! When a friend of mine posted some photos she took while on a hike on Boulder’s Green Mountain, I couldn’t believe my eyes. I saw entire tree trunks covered in red. The red was lady bugs, a mass gathering of a gardener’s best friend, as they search for mates and prepare to hibernate for the winter. Now this was something I had to see for myself.

Of course, not everyone can make the hike to Green Mountain, but hopefully you can live a little vicariously through this slide show, and learn a little something new about this “cuter” member of bug-dom.

There are more than 400 species of lady bugs, (or as they’re more officially known ladybird beetles), in North America. This year has been an unusual one for lots of natural phenomena in Colorado — a wet, cool summer has led to an endless green summer and multitudes of wildflowers — and this year’s lady bug gathering is no exception. Boulder Open Space and Mountain Parks estimates that this could be a record-setting year for the annual swarm.

Besides the slideshow, I’ve made a little list of interesting lady bug facts you might not know.

  • They’re cannibals.
    • at least during their larval stage. Researchers recently discovered lady bug babies hatch and eat their siblings. Don’t get too disillusioned. They grow out of it.
  • They don’t change their spots.
    • Some people think you can tell the beetle’s age by the number of its spots, but according to the Boulder Open Space and Mountain Parks, you keep what you’re born with when it comes to the dots.
  • They “play dead.”
    • If an adult ladybug feels threatened it will fall down and “die,” or let off a foul yellow ooze from its leg joints that most animals won’t want to eat, (University of Arizona)

Woe betide the lovesick lamprey

Love is in the water, and the lamprey swears she’s found her match. She swims the corner ready to score. That’s when they spring the trap. 

Scientists out of Michigan State University are using chemical trickery to seduce and capture female sea lampreys, a devastatingly invasive species found in the Great Lakes. A single lamprey can eat up to 40 pounds of fish, and they’re to blame for the extinction of at least three whitefish species.  The voracious predators have proven difficult and expensive to control, costing the U.S. and Canadian governments $10 to $15 million a year.

But males it turns out, release an irresistible chemical into the water attracting females from more than a hundred meters away, and this mojo might just be the key to the lamprey’s undoing.  Weiming Li, a professor of fisheries and wildlife at MSU, and his team spent years isolating and synthesizing a fake version of sea lamprey love potion. Now they’ve landed on a treatment that is as effective as the lamprey’s own and when used in small doses could effectively treat sea lamprey infested waters. 

“The commission considers regulating spawning and migrating behavior with pheromones the most promising control method for implementation,” Li said in a press release. “So we’re excited about the possibilities.”

You can learn more about this promising new treatment method in the latest version of the Proceedings of the National Academy of Sciences.


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