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Why the spongy moth outbreak has vanished in Québec – The Conversation

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Last year, forests across southern Québec and Ontario and much of New England turned eerily leafless. The air hummed with the sound of munching mandibles and tree trunks were covered with a writhing carpet of caterpillars, while showers of caterpillar poop fell softly on the heads of unsuspecting hikers and campers.

The population of the European spongy moth, which had been gradually increasing since 2019, reached a dramatic peak in 2021 and completely vanished this year.

In 2020, the hungry caterpillar damaged 583,157 hectares of forests in Ontario and this number is bound to go up when the 2021 numbers are revealed.

Insect outbreaks are one of the most important natural disturbances in Canadian forests. As a biologist who has been working on plant-insect interactions for over 20 years, I see that the frequency, intensity and range of insect outbreaks keeps changing. To protect trees in our forests and cities, we need tree diversity.

Insect outbreaks

An insect outbreak can be frightening. In deserts around the world, vast swarms of locusts can blot out the sun for hours as they fly overhead. In the Rocky Mountains, hillsides are covered with dead trees, killed by the inner-bark-eating mountain pine beetle.

Trees with their leaves eaten by spongy moth caterpillars seen on Montréal’s Mount Royal on July 7, 2021. Insect outbreaks stimulate nutrient cycling, accelerate forest succession and can renew forests.
THE CANADIAN PRESS/Paul Chiasson

However, insect outbreaks are not a new phenomenon. Chinese historical records document locust outbreaks for almost 2,000 years, while paleo-ecological studies show that Québec’s boreal forests have witnessed spruce budworm outbreaks for at least 8,000 years.

Such insect outbreaks are part of how temperate and boreal forests — as well as semi-arid grasslands and deserts — function. Insect outbreaks stimulate nutrient cycling, accelerate forest succession and can renew forests.

A moth laying eggs
Female insects can produce hundreds of offspring and only two of these need to survive for a stable population.
(AP Photo/Bob Child, File)

Female insects can produce hundreds of offspring and for the population to remain stable, only two of these need to survive. A small increase in survival, due to factors like favorable weather conditions, can lead to a population explosion and an outbreak.

In the case of the mountain pine beetle and the desert locust, warming temperatures, increased cyclone activity and other such effects of climate change are bringing these favorable conditions more frequently to new areas, thus dramatically increasing the extent of outbreaks.

However, these outbreaks always come to an end because of what ecologists call lagged-density dependent population dynamics. Here, density-dependent means that the insects’ mortality rate depends on the density of its population. As the population increases, mortality also increases and survival rate decreases. Meanwhile, lagged means there is a delay in this process — the insect mortality increases more slowly than population growth, causing an outbreak.

The outbreak crashes when the insect mortality eventually catches up with its population size. This usually happens due to a combination of factors including low food supply and increase in predators, parasitoids — insects that lay their eggs inside other insects — and diseases.

Where did the spongy moth go?

Students in my laboratory have been rearing spongy moth caterpillars for the past three years and have found that the mortality of these caterpillars gradually increased as the population grew.

In 2019, one student, Pamela Yataco Marquez reared over 300 caterpillars and observed an 80 per cent survival rate. However, this year, despite an extensive search, Marie-Eve Jarry, Geovana Demarchi and Victoria Yip were able to find and rear only 97 caterpillars and only six survived to adult.

A freshly emerged lab-reared moth.
This freshly emerged lab-reared female spongy moth is one of the few survivors of 2022.
(Victoria Yip), Author provided

Several mortality agents including a virus Lymantria dispar multiple nucleopolyhedrovirus, the fungal disease Entomophaga maimaiga and two tiny parasitoid wasps called Cotesia melanoscela and Ooencyrtus kuvanae finally caught up with the insect population.

When parasitoids eggs — laid inside either the eggs or the bodies of other insects — hatch, they devour their host from the inside and eventually emerge from the dead host, ready to start the life-cycle anew.

They are more like predators than parasites because they kill their host, and are efficient biocontrol agents that decrease pest insect populations.

Creeping across borders

While the spongy moth is native to Europe, it has been in eastern North America since the 1860s and is part of our fauna now.

It has not reached the western part of the continent yet and the best way to stop this is to inspect outdoor gear for caterpillars or egg masses before travelling and not to move firewood.

The Asian spongy moth population has not spread in North America yet, and entomologists are working hard to keep it out.

A moth caterpillar on a partially eaten leaf.
The current range of the spongy moth distribution in North America extends up to southern Canada.
(Geovana Demarchi), Author provided

In the past 150 years, many of the European spongy moth’s natural enemies, including the fungal disease mentioned above and several parasitoids, have also been introduced, either inadvertently or deliberately. Our findings show that these natural enemies are well established in our region and have been effective in collapsing the outbreak.

The current range of the spongy moth distribution in North America extends up to southern Canada. Here, the eggs that spend the winter on tree trunks suffer high mortality due to cold, knocking down the survival rate irrespective of population size.

Forest managers in Québec and Ontario are on the alert for increases in spongy moth outbreaks — including both more severe and longer duration outbreaks similar to those seen in the U.S. — and a possible northward shift of the distribution range.

Diverse forests

While a tree that is leafless in July may appear dead, many trees can survive a few years of defoliation, drawing on stored reserves to flush out new leaves.

The spongy moth outbreak in the Montréal area in the late 1970s slowed tree growth, but did not cause the widespread death of forest trees. However, tree mortality does occur further south in the U.S. and depends on the diversity of trees in the forest area. The death of tree species preferred by the caterpillar is lower in diverse forests that mix in less-vulnerable species.

Diverse forests are more resilient under various stresses than more homogeneous ones. We need to create and preserve such diverse forests to help prepare for new types of insect outbreaks in our changing world.

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Here’s how Helene and other storms dumped a whopping 40 trillion gallons of rain on the South

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More than 40 trillion gallons of rain drenched the Southeast United States in the last week from Hurricane Helene and a run-of-the-mill rainstorm that sloshed in ahead of it — an unheard of amount of water that has stunned experts.

That’s enough to fill the Dallas Cowboys’ stadium 51,000 times, or Lake Tahoe just once. If it was concentrated just on the state of North Carolina that much water would be 3.5 feet deep (more than 1 meter). It’s enough to fill more than 60 million Olympic-size swimming pools.

“That’s an astronomical amount of precipitation,” said Ed Clark, head of the National Oceanic and Atmospheric Administration’s National Water Center in Tuscaloosa, Alabama. “I have not seen something in my 25 years of working at the weather service that is this geographically large of an extent and the sheer volume of water that fell from the sky.”

The flood damage from the rain is apocalyptic, meteorologists said. More than 100 people are dead, according to officials.

Private meteorologist Ryan Maue, a former NOAA chief scientist, calculated the amount of rain, using precipitation measurements made in 2.5-mile-by-2.5 mile grids as measured by satellites and ground observations. He came up with 40 trillion gallons through Sunday for the eastern United States, with 20 trillion gallons of that hitting just Georgia, Tennessee, the Carolinas and Florida from Hurricane Helene.

Clark did the calculations independently and said the 40 trillion gallon figure (151 trillion liters) is about right and, if anything, conservative. Maue said maybe 1 to 2 trillion more gallons of rain had fallen, much if it in Virginia, since his calculations.

Clark, who spends much of his work on issues of shrinking western water supplies, said to put the amount of rain in perspective, it’s more than twice the combined amount of water stored by two key Colorado River basin reservoirs: Lake Powell and Lake Mead.

Several meteorologists said this was a combination of two, maybe three storm systems. Before Helene struck, rain had fallen heavily for days because a low pressure system had “cut off” from the jet stream — which moves weather systems along west to east — and stalled over the Southeast. That funneled plenty of warm water from the Gulf of Mexico. And a storm that fell just short of named status parked along North Carolina’s Atlantic coast, dumping as much as 20 inches of rain, said North Carolina state climatologist Kathie Dello.

Then add Helene, one of the largest storms in the last couple decades and one that held plenty of rain because it was young and moved fast before it hit the Appalachians, said University of Albany hurricane expert Kristen Corbosiero.

“It was not just a perfect storm, but it was a combination of multiple storms that that led to the enormous amount of rain,” Maue said. “That collected at high elevation, we’re talking 3,000 to 6000 feet. And when you drop trillions of gallons on a mountain, that has to go down.”

The fact that these storms hit the mountains made everything worse, and not just because of runoff. The interaction between the mountains and the storm systems wrings more moisture out of the air, Clark, Maue and Corbosiero said.

North Carolina weather officials said their top measurement total was 31.33 inches in the tiny town of Busick. Mount Mitchell also got more than 2 feet of rainfall.

Before 2017’s Hurricane Harvey, “I said to our colleagues, you know, I never thought in my career that we would measure rainfall in feet,” Clark said. “And after Harvey, Florence, the more isolated events in eastern Kentucky, portions of South Dakota. We’re seeing events year in and year out where we are measuring rainfall in feet.”

Storms are getting wetter as the climate change s, said Corbosiero and Dello. A basic law of physics says the air holds nearly 4% more moisture for every degree Fahrenheit warmer (7% for every degree Celsius) and the world has warmed more than 2 degrees (1.2 degrees Celsius) since pre-industrial times.

Corbosiero said meteorologists are vigorously debating how much of Helene is due to worsening climate change and how much is random.

For Dello, the “fingerprints of climate change” were clear.

“We’ve seen tropical storm impacts in western North Carolina. But these storms are wetter and these storms are warmer. And there would have been a time when a tropical storm would have been heading toward North Carolina and would have caused some rain and some damage, but not apocalyptic destruction. ”

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Follow AP’s climate coverage at https://apnews.com/hub/climate

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Follow Seth Borenstein on Twitter at @borenbears

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Associated Press climate and environmental coverage receives support from several private foundations. See more about AP’s climate initiative here. The AP is solely responsible for all content.

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‘Big Sam’: Paleontologists unearth giant skull of Pachyrhinosaurus in Alberta

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It’s a dinosaur that roamed Alberta’s badlands more than 70 million years ago, sporting a big, bumpy, bony head the size of a baby elephant.

On Wednesday, paleontologists near Grande Prairie pulled its 272-kilogram skull from the ground.

They call it “Big Sam.”

The adult Pachyrhinosaurus is the second plant-eating dinosaur to be unearthed from a dense bonebed belonging to a herd that died together on the edge of a valley that now sits 450 kilometres northwest of Edmonton.

It didn’t die alone.

“We have hundreds of juvenile bones in the bonebed, so we know that there are many babies and some adults among all of the big adults,” Emily Bamforth, a paleontologist with the nearby Philip J. Currie Dinosaur Museum, said in an interview on the way to the dig site.

She described the horned Pachyrhinosaurus as “the smaller, older cousin of the triceratops.”

“This species of dinosaur is endemic to the Grand Prairie area, so it’s found here and nowhere else in the world. They are … kind of about the size of an Indian elephant and a rhino,” she added.

The head alone, she said, is about the size of a baby elephant.

The discovery was a long time coming.

The bonebed was first discovered by a high school teacher out for a walk about 50 years ago. It took the teacher a decade to get anyone from southern Alberta to come to take a look.

“At the time, sort of in the ’70s and ’80s, paleontology in northern Alberta was virtually unknown,” said Bamforth.

When paleontogists eventually got to the site, Bamforth said, they learned “it’s actually one of the densest dinosaur bonebeds in North America.”

“It contains about 100 to 300 bones per square metre,” she said.

Paleontologists have been at the site sporadically ever since, combing through bones belonging to turtles, dinosaurs and lizards. Sixteen years ago, they discovered a large skull of an approximately 30-year-old Pachyrhinosaurus, which is now at the museum.

About a year ago, they found the second adult: Big Sam.

Bamforth said both dinosaurs are believed to have been the elders in the herd.

“Their distinguishing feature is that, instead of having a horn on their nose like a triceratops, they had this big, bony bump called a boss. And they have big, bony bumps over their eyes as well,” she said.

“It makes them look a little strange. It’s the one dinosaur that if you find it, it’s the only possible thing it can be.”

The genders of the two adults are unknown.

Bamforth said the extraction was difficult because Big Sam was intertwined in a cluster of about 300 other bones.

The skull was found upside down, “as if the animal was lying on its back,” but was well preserved, she said.

She said the excavation process involved putting plaster on the skull and wooden planks around if for stability. From there, it was lifted out — very carefully — with a crane, and was to be shipped on a trolley to the museum for study.

“I have extracted skulls in the past. This is probably the biggest one I’ve ever done though,” said Bamforth.

“It’s pretty exciting.”

This report by The Canadian Press was first published Sept. 25, 2024.

The Canadian Press. All rights reserved.

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The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

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TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.

Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.

Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.

The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.

The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.

It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.

Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.

Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.

Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.

Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.

Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.

The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”

The Canadian Press. All rights reserved.

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