Columbine flowers, new research


This 26 April 2020 video says about itself:

Learn all the information you need to grow Columbine Flowers, aka Wild Columbine, aka Eastern Red Columbine, Aquilegia canadensis.

Grow this hardy perennial (USDA zones 3-8) in full sun to shade. Columbine will grow just about anywhere as long as the soil drains well. But in this video, I teach you how to germinate columbine seeds, save seeds, identify Columbine, and numerous other tips from pests to diseases and how to avoid them. I also show you just how much Columbines spread. I hope you like it, and please ask any questions in the comments!

We have a very detailed article on this flower here.

From the University of California – Santa Barbara in the USA:

Biologists discover gene critical to development of columbines‘ iconic spurs

August 24, 2020

Once in a while, over the history of life, a new trait evolves that leads to an explosion of diversity in a group of organisms. Take wings, for instance. Every group of animals that evolved them has spun off into a host of different species — birds, bats, insects and pterosaurs. Scientists call these “key innovations.”

Understanding the development of key innovations is critical to understanding the evolution of the amazing array of organisms on Earth. Most of these happened deep in the distant past, making them difficult to study from a genetic perspective. Fortunately, one group of plants has acquired just such a trait in the past few million years.

Columbines, with their elegant nectar spurs, promise scientists an opportunity to investigate the genetic changes that underpin a key innovation. After much research, UC Santa Barbara professor Scott Hodges, research associate Evangeline Ballerini, and their coauthors at Harvard University have identified a gene critical to the development of these structures. And to their knowledge, this is among the first key innovations for which a critical developmental gene has been identified. Their findings appear in the journal PNAS.

The researchers named the gene after Gregg Popovich, head coach of the San Antonio Spurs basketball team. “This gene is a transcription factor, which means it controls spur development in columbines by regulating the activity of other genes,” explained Ballerini. “So I chose the name POPOVICH because as coach, Popovich controls San Antonio Spurs development, in a sense, by regulating the activity of his players.”

The evolution of spurs in columbines’ ancestors seems to have led to rapid expansion in the genus. Around 70 species evolved over the past 5 to 7 million years, compared to its spurless sister genus, which counts only four species among its members.

And columbines aren’t the only flowers with spurs. The trait evolved independently in many different plants, including nasturtiums, larkspurs and impatiens. “And in each of those groups, the ones that have spurs have far more species than their closest relatives that don’t have spurs,” said Hodges.

“We think that diversity is linked to the evolution of this spur because the spur produces nectar, which attracts animal pollinators,” Ballerini said. Changing the length or shape of the spur changes the animals that can pollinate the flower. “Bees are only moving pollen between bee flowers, hummingbirds are only moving pollen between hummingbird flowers, so you’re not exchanging genes between those two different populations.” Eventually, the two can split into different species.

The question the researchers were trying to answer was how innovations like these develop in the first place. “If we can find genes that are important in the development of a key innovation, that will help us understand this kind of process,” said Hodges.

“In most of these cases — like in the wing example with birds, bats and insects — those evolved so long ago that it’s hard to find a particular gene that was critical for evolving that trait,” he added. “Here we have a fairly recent origin of a key innovation, only 5 to 7 million years ago, and it’s a fairly simple trait, so it’s a little more straightforward.”

Finding POPOVICH

Since columbines evolved so recently, most of them can form fertile hybrids with each other. In the 1950s and ’60s, a Polish geneticist crossed a spurless species — appropriately named the spurless columbine — with its spurred cousins. She found that in the first generation of offspring all had spurs, but self-pollinating these yielded a second generation where spurlessness reappeared in a quarter of the plants.

That ratio was crucial to Hodges and Ballerini’s work some half a century later. This simple fraction suggested that a single gene controlled the development of spurs. But columbines have roughly 30,000 genes, and only one was the gene they were looking for.

Following in the footsteps of his predecessor, Hodges also crossed the spurless columbine with a spurred species, and then self-pollinated the offspring. But unlike in the previous experiment, Ballerini and Hodges now had the tools to search the plants’ genetic code.

Ballerini sequenced the genome of each of the nearly 300-second generation plants and looked for instances in which the spurless plants had inherited two copies from their spurless grandparent. This narrowed the search to around 1,100 genes on one of the plants’ chromosomes.

Still, 1,100 genes are a lot to sort through. “There was no guarantee that these methods would lead us to the gene we were looking for,” Ballerini said. “There was definitely quite a bit of work that went into all of the experiments and analyses, but in the end, there was a bit of luck too.”

Ballerini examined the expression of genes during five stages of early petal development in the spurless columbine and three other spurred species. She sequenced all the genes that were turned on in each stage and looked for consistent differences between the spurless and spurred plants. Eventually, with input from one of her collaborators at Harvard, Ballerini suspected she had identified the right gene. It was always turned off in the spurless species, turned on in the spurred species and was one of the 1,100 genes previously identified as associated with spurless flowers in the genetic cross. Now it was time to test her hypothesis.

She used a genetically modified virus to knock down the expression of the gene in question as well as a gene critical for producing red pigment. This way they could tell which petals were affected just by looking at the color.

Wherever POPOVICH was sidelined, the flowers developed diminutive spurs. But spur length depends both on the number and the size of cells. So the researchers worked with collaborators to count the number and measure the length of each cell making up these diminutive spurs.

“The longer spurs had more cells, and the shorter spurs had fewer cells,” Hodges noted. “So the gene must have been acting by affecting how many cells were produced.”

Ballerini remembers sitting in her office after finishing her final analyses. She began throwing out potential gene names to graduate student Zac Cabin, a fellow sports enthusiast. “At the same time Zac and I turned to each other and both said ‘POPOVICH!'” she recalled. The name seemed a perfect fit. “And it leaves open the possibility that, if we identify other genes at play in spur development, we can name them after some of the players on the Spurs.”

A path to new discoveries

While identifying POPOVICH is certainly an achievement, the true value of the discovery lies in what it reveals about the evolution of key innovations. Before this work, none of the plant groups that had well-known genomes also made spurs. “We had no idea where to start,” said Hodges. “This discovery provides us a foothold.”

“Once we identify one gene — like this gene, which seems to be key in the process of forming spurs — then we can start to figure out all of the components,” he added. The team can now begin investigating which genes POPOVICH regulates, and which genes regulate POPOVICH. “This is a place to start to understand the whole system.”

While the researchers don’t know how POPOVICH functions in other groups of plants, it appears to influence the number of leaflets that grow on bur clovers. Columbines also express the gene in their leaves; perhaps it was recruited from the leaves into petal development, Ballerini suggested.

Novel adaptations don’t appear out of nowhere, she explained. “When you’re evolving a new structure, usually you’re not evolving a whole brand new gene.” Generally, organisms repurpose or add a purpose to an existing gene.

The authors are also interested in identifying genes involved in the second phase of spur formation: the elongation of the cells in the spur cup.

“These are things that we will want to do now that we’ve identified this gene,” Hodges said. “And since it’s a transcription factor, it must have particular genes that it’s affecting. The next logical step would be to identify the targets of this gene, and that would tell us a lot more about how it functions.”

The researchers expressed their gratitude toward Harvey Karp, who generously funded the Karp Discovery Award that made their research possible. “We really couldn’t have done this project without it,” Ballerini said.

Golden-winged and blue-winged warblers, new research


This 2011 video from the USA says about itself:

Blue-winged and Golden-winged Warblers and Hybrids in Connecticut. ©JimZipp.com

Note that the Blue-winged has yellowish wingbars and the Golden-winged sings a Blue-winged song. Lots of interbreeding in this area and Golden-winged Warblers are rarer every year.

From Penn State University in the USA:

What determines a warbler’s colors?

Researchers use hybrid birds to narrow genetic region underlying difference in color between blue-winged and golden-winged warblers

July 14, 2020

A new study has narrowed down the region of the genome that drives the black color in throat and face of warblers by studying the hybrid offspring produced when two species mate. The hybrids of golden-winged and blue-winged warblers have a mix of coloration from the parent species, which allows researchers to identify which regions of the genome are associated with which color patterns. The study, led by researchers at Penn State, also reveals a more complex basis for the amount of yellow in warbler bellies and raises concerns about how hybrids of these species are classified.

Their results appear online in the journal The Auk: Ornithological Advances.

“The distinct plumage of these otherwise very similar birds has perplexed ornithologists for more than a hundred years,” said Marcella Baiz, postdoctoral researcher at Penn State and first author of the paper. “Our research team previously compared the genomes of golden-winged and blue-winged warblers and identified 6 regions that differed between them, some of which may control color. In this study, we used hybrid birds of these species, which mix and match the features of their parent species, to help identify which regions of the genome are associated with which color patterns.”

Color is an important cue for warblers and is prominently displayed during mating and other behaviors. Blue-winged warblers have yellow throats and bellies, while golden-winged warblers have white bellies and a black throat patch and face mask. Hybrids of these species vary in amounts of yellow and whether they have a black face mask and throat, and these characteristics are commonly used to categorize birds into different classes of hybrids.

The research team rated hybrid birds based on their plumage color and genetic likeness to the two parental species. They found that the amount of yellow in hybrids, which is produced by pigments called carotenoids, is not directly related to a bird’s genetic likeness to the parent species — for example, hybrids with more yellow were not genetically closer to blue-winged warblers. Additionally, the extent of yellow in hybrids re-captured in subsequent years appeared to decline over time.

“Some researchers have hoped that the extent of yellow could indicate how many generations a hybrid is removed from the parent species,” said David Toews, assistant professor of biology at Penn State and leader of the research team. “Our results indicate that it isn’t quite so straightforward, and that classifying hybrids into groups based on the amount of yellow can be misleading.”

The inheritance of a black throat patch and face mask, however, appears to be much more straightforward. The research team previously identified a genetic region related to black coloration in warblers. In the current study, the team used a rarer type of hybrid to narrow that to a region about five times smaller.

“This one type of very rare hybrid looks almost entirely like a blue-winged warbler, with a yellow body but with a black throat patch and face mask, like a golden-winged warbler,” said Baiz. “By comparing its genome to that of blue-wing warblers, we were able to identify a much smaller genetic region where the birds differed, which we believe drives the black coloration.”

The genetic region is located near the Agouti-signaling protein (ASIP) gene, which is thought to regulate production of the pigment melanin in some birds. Next, the research team would like to confirm that this section of the genome affects expression of the ASIP protein in warblers and underlies differences in their black plumage patches.

“We plan to continue to study the evolution of color across the 110 species of warblers, which have incredibly diverse plumage,” said Toews. “Now that we have identified a starting point, this narrowed down genetic region, we won’t be stabbing in the dark.”

In addition to Baiz and Toews, the research team includes Gunnar Kramer and Henry Streby from the University of Toledo, Scott Taylor from the University of Colorado, Boulder, and Irby Lovette from the Cornell Lab of Ornithology. This research was supported by the Cornell Lab of Ornithology, the U.S. Geological Survey, and the National Science Foundation.

New list of American bird species


This is a video about a turquoise-browed motmot in Costa Rica.

From the American Ornithological Society Publications Office:

Goodbye northwestern crow, hello Mexican duck

Updates to the official list of North and Central American bird species

June 30, 2020

The latest supplement to the American Ornithological Society’s Checklist of North and Middle American Birds, published in The Auk: Ornithological Advances, includes several major updates to the organization of the continent’s bird species, including the addition of the Mexican Duck and the removal of the Northwestern Crow. The official authority on the names and classification of the region’s birds, the checklist is consulted by birdwatchers and professional scientists alike and has been published since 1886.

The Northwestern Crow has long been considered a close cousin of the more familiar and widespread American Crow, with a range limited to the Pacific Northwest. However, a recent study on the genetics of the two species prompted AOS’s North American Classification Committee to conclude that the two species are actually one and the same. “People have speculated that the Northwestern Crow and the American Crow should be lumped for a long time, so this won’t be a surprise to a lot of people,” says the U.S. Geological Survey’s Terry Chesser, chair of the committee. “Northwestern Crows were originally described based on size, being smaller than the American Crow, and behavior, but over the years the people who’ve looked at specimens or observed birds in the field have mostly come to the conclusion that the differences are inconsistent. Now the genomic data have indicated that this is really variation within a species, rather than two distinct species.”

However, birdwatchers disappointed to lose the Northwestern Crow from their life lists can take solace in the addition of a new species to the official checklist: the Mexican Duck. “The checklist recognized Mexican Duck until 1973, when it was lumped with Mallard,” says Chesser. “But the Mexican Duck is part of a whole complex of Mallard-like species, including Mottled Duck, American Black Duck, and Hawaiian Duck, and all of those are considered distinct species except for, until recently, the Mexican Duck. Now genomic data have been published on the complex and on the Mexican Duck and Mallard in particular, and they show that gene flow between them is limited, which was enough to convince the committee to vote for the split.”

Additional changes introduced in this year’s checklist supplement include a massive reorganization of a group of Central American hummingbirds known as the emeralds — adding nine genera, deleting six others, and transferring seven additional species between already-recognized genera — as well as an update to the criteria for adding introduced, non-native species to the list that raises the bar for introduced species to officially be considered established.

North American migratory birds, video


This 10 June 2020 video from the USA says about itself:

More than half of the migratory bird species in North America are declining. In order to conserve these migrating birds, conservation scientist and National Geographic explorer Kristen Ruegg is tracking bird DNA with the Bird Genoscape Project.

American robin migration and climate change


This 2019 video from the USA is called 5 Lovable Things About American Robins.

From the Earth Institute at Columbia University in the USA:

American robins now migrate 12 days earlier than in 1994

New GPS data show birds adjust to shifting snow conditions as climate warms

April 1, 2020

Summary: A new study concludes that robin migration is kicking off earlier by about five days each decade. The study is also the first to reveal the environmental conditions along the migration route that help the birds keep up with the changing seasons.

Every spring, American robins migrate north from all over the U.S. and Mexico, flying up to 250 miles a day to reach their breeding grounds in Canada and Alaska. There, they spend the short summer in a mad rush to find a mate, build a nest, raise a family, and fatten up before the long haul back south.

Now climate change is making seasonal rhythms less predictable, and springtime is arriving earlier in many parts of the Arctic. Are robins changing the timing of their migration to keep pace, and if so, how do they know when to migrate? Although many animals are adjusting the timing of their migration, the factors driving these changes in migratory behavior have remained poorly understood.

A new study, published in Environmental Research Letters, concludes that robin migration is kicking off earlier by about five days each decade. The study is also the first to reveal the environmental conditions along the migration route that help the birds keep up with the changing seasons. Lead author Ruth Oliver completed the work while earning her doctorate at Columbia University’s Lamont-Doherty Earth Observatory.

At Canada’s Slave Lake, a pit stop for migrating birds, researchers have been recording spring migration timing for a quarter-century. Their visual surveys and netting censuses revealed that robins have been migrating about five days earlier per decade since 1994.

In order to understand what factors are driving the earlier migration, Oliver and Lamont associate research professor Natalie Boelman, a coauthor on the paper, knew they needed to take a look at the flight paths of individual robins.

Their solution was to attach tiny GPS “backpacks” to the birds, after netting them at Slave Lake in mid-migration. “We made these little harnesses out of nylon string,” Oliver explained. “It basically goes around their neck, down their chest and through their legs, then back around to the backpack.” The unit weighs less than a nickel — light enough for the robins to fly unhindered. The researchers expect that the thin nylon string eventually degrades, allowing the backpacks to fall off.

The researchers slipped these backpacks onto a total of 55 robins, tracking their movements for the months of April through June. With the precise location from the GPS, the team was able to link the birds’ movements with weather data on air temperature, snow depth, wind speed, precipitation, and other conditions that might help or hinder migration.

The results showed that the robins start heading north earlier when winters are warm and dry, and suggest that local environmental conditions along the way help to fine-tune their flight schedules.

“The one factor that seemed the most consistent was snow conditions and when things melt. That’s very new,” said Oliver. “We’ve generally felt like birds must be responding to when food is available — when snow melts and there are insects to get at — but we’ve never had data like this before.”

Boelman added that “with this sort of quantitative understanding of what matters to the birds as they are migrating, we can develop predictive models” that forecast the birds’ responses as the climate continues to warm. “Because the timing of migration can indirectly influence the reproductive success of an individual, understanding controls over the timing of migratory events is important.”

For now, it seems as though the environmental cues are helping the robins to keep pace with the shifting seasons. “The missing piece is, to what extent are they already pushing their behavioral flexibility, or how much more do they have to go?” said Oliver.

Because the study caught the birds in mid-migration, the tracking data doesn’t reflect the birds’ full migration path. To overcome this limitation, the researchers plan to analyze tissue from the robins’ feathers and claws, which they collected while attaching the GPS harnesses, to estimate where each bird spent the previous winter and summer.

Over the long term, Oliver says, she hopes to use the GPS trackers to sort out other mysteries as well, such as how much of the change in migration timing is due to the behavioral responses found in the study versus natural selection to changing environments, or other factors.

“This type of work will be really cool once we can track individuals throughout the course of their life, and that’s on the near-term horizon, in terms of technological capabilities,” she said. “I think that will really help us unpack some of the intricacies of these questions.”

The new study is part of a broader NASA-funded research and outreach project, called the Arctic-Boreal Vulnerability Experiment, that is tracking how the rapid warming of the far north affects wildlife. Read more about the project on the researchers’ blog: https://earthobservatory.nasa.gov/blogs/fromthefield/2016/04/12/a-migration-mystery/

Oliver is now a postdoctoral associate at Yale University. Other authors on the study include Peter Mahoney from the University of Washington, Eliezer Gurarie from the University of Washington and the University of Maryland, Nicole Krikun from the Lesser Slave Lake Bird Observatory, Brian Weeks from the University of Michigan, Mark Hebblewhite from the University of Montana, and Glen Liston from Colorado State University.

With the western United States and northern Mexico suffering an ever-lengthening string of dry years starting in 2000, scientists have been warning for some time that climate change may be pushing the region toward an extreme long-term drought worse than any in recorded history. A new study says the time has arrived: a megadrought as bad or worse than anything even from known prehistory is very likely in progress, and warming climate is playing a key role. The study, based on modern weather observations, 1,200 years of tree-ring data and dozens of climate models, appears this week in the leading journal Science: here.

American whooping cranes in danger


This December 2013 video from the USA says about itself:

This week’s moment in nature takes us among the whooping cranes of the Aransas National Wildlife Refuge in Texas.

From ScienceDaily:

Whooping cranes form larger flocks as wetlands are lost — and it may put them at risk

April 2, 2020

Over the past few decades, the critically endangered whooping crane (Grus Americana) has experienced considerable recovery. However, in a report appearing April 2 in the journal Heliyon, researchers found that habitat loss and within-species attraction have led whooping cranes to gather in unusually large groups during migration. While larger groups are a positive sign of species recovery, the authors say that these large groups mean that a disease outbreak or extreme weather event could inadvertently impact a substantial portion of this still fragile population.

Whooping crane conservation is one of North America’s great success stories,” says Andrew Caven, Director of Conservation Research at Crane Trust, a non-profit organization dedicated to the protection of critical habitat for whooping cranes and other migratory birds. During the 1940s the whooping crane population fell to 16 birds, largely due to overhunting. However, after concerted conservation efforts, their numbers have increased 30-fold. “We had this species at the brink of extinction, and now there are over 500 birds. As conservation biologists, we’ve been extremely inspired by that.”

Even with this boom in whooping crane numbers, researchers are observing larger migratory flocks than they would expect from population growth alone. Historically, groups of migrating whooping cranes seldom exceeded a family unit. “Twenty years ago, a group of nine was notable; something you’d write in your natural history notes about. But now it’s becoming something quite regular. In the recent years we’ve seen bird groups over seventy multiple times.”

With a total population of only around 500 birds, groups of this size could potentially put the whole species at risk. “The largest group detected was about 150 birds near Marcelin, Saskatchewan, which represents over one-fourth of the population. In a group that size, extreme weather like hailstorms or an outbreak of avian cholera could be catastrophic for the species,” says Caven.

So Caven and his research team set out to understand why traveling groups of whooping cranes had grown so large. They collected sightings data from state, federal, and private conservation organizations as well as the public along the whooping cranes migratory path from their Texas wintering grounds to their breeding grounds in Alberta, Canada.

Results indicated that the larger flocks of whooping crane roosted most frequently in the Southern Great Plains, where wetland habitats are sparse, but a few, high-quality conserved wetlands still stand.

“Many wetland habitats in the Great Plains have disappeared due to sedimentation or have been drained for farming” says Caven. “The rate of wetland loss has actually been quite high, particularly in these basins south of the Platte River.” With limited access to quality habitat in the southward part of their migration, it appears whooping crane have adjusted by gathering in proportionally larger assemblages.

As a sort of snowball effect, the authors say these gatherings can also be promoted by conspecific attraction or attraction to like individuals. The presence of birds in a location can make it more desirable for other cranes. “Conspecific attraction helps birds indicate optimal forging resources in these patchy environments and provide vigilance in situations that could be risky. These benefits could be a major reason we are seeing the emergence of these new behaviors as the cranes recover from near extinction,” he says.

Based on these findings, Caven suggests the best way to disperse these groups is to provide more wetland habitat throughout their migration path. “Supporting conservation groups that are restoring habitats south of the Platte River, particularly wetlands, can have a serious impact. Increasing the scale of wetland restoration within the migration corridor could break up these aggregations and provide foraging space for a ton of birds, not just whooping crane.”

The Crane Trust research team also plans to evaluate how habitat quality affects the length of time whooping cranes stay at stopover locations before continuing on in their migration. This will help determine those sites that are most essential in providing necessary resources for the birds to complete their 3,000-mile journey.

Niagara Falls, a barrier for fish


This video from North America says about itself:

Niagara River 2019

Niagara River below the surface

From the American Museum of Natural History in the USA:

Is Niagara Falls a barrier against fish movement?

March 24, 2020

New research shows that fishes on either side of Niagara Falls — one of the most powerful waterfalls in the world — are unlikely to breed with one another. Knowing how well the falls serves as a barrier to fish movement is essential to conservation efforts to stop the spread of invasive aquatic species causing ecological destruction in the Great Lakes. The study is published today in the journal Molecular Ecology.

“In the past 50 years or so, aquatic invasive species have expanded in the Great Lakes as a tremendous conservation concern, causing billions of dollars’ worth of damage,” said Nathan Lujan, lead author of the study and a Gerstner Scholar at the American Museum of Natural History. “Both Canadian and American authorities are concerned about the potential impact of these species on the Great Lakes and are very interested in installing barrier technologies in the Niagara River that would slow or stop their spread.”

For more than 11,000 years since glaciers retreated from North America, most water flowing through the Great Lakes has crossed the Niagara Falls, which has a flow rate of more than 750,000 gallons per second. There’s one other way water can get through this constriction point: through the Welland navigation canal, which was built about 200 years ago and features a series of locks that bring vessels from one side of the falls to the other. The canal is relatively small compared to the Niagara River, but questions remain about how significant it and the falls are in allowing fishes to move upstream to downstream, and vice versa. The leading idea is to install a combination of barrier technologies in the Welland Canal, including electricity, sound, light, and possible physical barriers to inhibit fish movement.

“If you’re going to spend potentially hundreds of millions of dollars on installing barrier technologies and fishes can go right over the falls, then that’s obviously not a good use of resources,” Lujan said. “If people can survive it in a barrel, you’d think a fish could.”

To investigate these questions, Lujan and colleagues examined the DNA of seven native fish species to determine whether populations above and below Niagara Falls interbreed or are reproductively isolated. By gathering data from throughout the fishes’ genomes, they found that populations of all species are genetically distinct on opposite sides of the falls.

Then they modeled how DNA from different populations mix, and determined that in four species there has been no significant migration past Niagara Falls since the falls were first formed 11,000 years ago. Two other species showed some indication of migration past the falls, yet the models indicated that no species had migrated past the falls via the Welland Canal.

“These results should reassure policymakers that infrastructure being considered to prevent the movement of invasive aquatic species will not impact native species, and that the falls themselves are an effective barrier to both upstream and downstream movement of aquatic species,” Lujan said. “Additional measures to prevent fish movement can safely be restricted to the Welland Canal.”