Galapagos

Scientists Watched a New Bird Species Evolve on Galapagos in Just 2 Generations

Posted by

0


Scientists in the Galápagos have observed something amazing: the evolution of a completely new species, in the wild, in real-time. And it took just two generations.

Back in 2017, genomic sequencing and the analysis of physical characteristics officially confirmed the new species of Darwin’s finch, endemic to a small island called Daphne Major in the Galápagos. Its discoverers nicknamed it Big Bird.

There are at least 15 species of Darwin’s finches, so named because their diversity helped famed naturalist Charles Darwin figure out his theory of evolution by natural selection – that is, mutations can help species become better adapted to their environment, and be passed down to subsequent generations.

It’s two of these species that came together in what is called species hybridisation to create an entirely new one.

big bird finch galapagos new speciesHere’s what Big Bird looks like.

While on expedition on the Daphne Major island, Peter and B. Rosemary Grant, biologists at Princeton University, noticed the presence of a non-native interloper, Geospiza conirostris.

It’s also known as the large cactus finch, and is native to other Galapagos islands, namely Española, Genovesa, Darwin, and Wolf.

As one of the larger species of Darwin’s finches, and with a different song than the three native Daphne Major species, the newcomer – a male – stood out.

“We didn’t see him fly in from over the sea, but we noticed him shortly after he arrived. He was so different from the other birds that we knew he did not hatch from an egg on Daphne Major,” Peter Grant said.

But then it mated with two females of one of those native species, Geospiza fortis, the medium ground finch. And the mating produced offspring.

Mating between different species that results in offspring isn’t that unusual – famous examples include mules, the product of mating between a male donkey and a mare. There are also ligers, a cross between a male lion and female tiger.

finches parents new hybrid speciesG. conirostris (left) and G. fortis (right).

But hybrid species are often sterile, or reproduce with difficulty – and that did not prove to be the case with these new chicks. A new lineage began – it had to.

The birds had a different song from G. fortis, as well as different beak size and shape, and these are what the finches use to attract mates. Reproductively, the new species was completely isolated, and had to mate within its own kind to survive.

But it was an uphill battle. During droughts on the island in 2002-2003, when the new lineage was in its fourth generation, all but two of the birds died.

Then they rallied.

“When the rains came again, the brother and sister mated with each other and produced 26 offspring,” Rosemary Grant said in an interview last year.

“All but nine survived to breed – a son bred with his mother, a daughter with her father, and the rest of the offspring with each other – producing a terrifically inbred lineage.”

Because the hybrid finches were bigger than the native populations, they were able to access previously unexploited food choices, and survive. At the Grants’ most recent visit to the island in 2012, they counted 23 individuals and 8 breeding pairs of the birds.

This success means, the researchers noted, that hybridisation could have occurred many times in Darwin’s finches in the past, resulting in new species that either became extinct or evolved to become the species we know today.

“A naturalist who came to Daphne Major without knowing that this lineage arose very recently would have recognised this lineage as one of the four species on the island,” said Leif Andersson of Uppsala University in Sweden, who conducted the genetic analysis.

“This clearly demonstrates the value of long-running field studies.”

Charles Darwin would have been delighted.

The theory of evolution has its origins in the Galápagos.

Posted by

0


Now climate change is rapidly heating the ocean here.
Darwin’s creatures are threatened.

As Seas Warm, Galápagos Islands Face a Giant Evolutionary Test

Nicholas Casey, a New York Times correspondent based in Colombia, and Josh Haner, a Times photographer, traveled 600 miles off the coast of Ecuador to see how ocean warming is affecting Darwin’s first laboratory.

DEC. 18, 2018 Leer en español

ALCEDO VOLCANO, Galápagos — When the clouds break, the equatorial sun bears down on the crater of this steaming volcano, revealing a watery landscape where the theory of evolution began to be conceived.

Across a shallow strip of sea lies the island of Santiago, where Charles Darwin once sighted marine iguanas, the only lizard that scours the ocean for food. Finches, the product of slow generational flux, dart by. Now, in the era of climate change, they might be no match for the whims of natural selection.

In the struggle against extinction on these islands, Darwin saw a blueprint for the origin of every species, including humans.

Yet not even Darwin could have imagined what awaited the Galápagos, where the stage is set for perhaps the greatest evolutionary test yet.

Marine iguanas on Fernandina Island.

As climate change warms the world’s oceans, these islands are a crucible. And scientists are worried. Not only do the Galápagos sit at the intersection of three ocean currents, they are in the cross hairs of one of the world’s most destructive weather patterns, El Niño, which causes rapid, extreme ocean heating across the Eastern Pacific tropics.

Research published in 2014 by more than a dozen climate scientists warned that rising ocean temperatures were making El Niño both more frequent and more intense. Unesco, the United Nations educational and cultural agency, now warns the Galápagos Islands are one of the places most vulnerable to the impacts of climate change.

“You can see them laying one or two eggs and being attacked by the ants,” said Christian Sevilla, a conservationist at the national park here. “They’re just throwing off the rest of the eggs as they walk off trying to escape, with the ants still biting at their legs.”

(Not without irony, Darwin was a predator of the tortoises well before the ants were. “The young tortoises make excellent soup,” he wrote in 1839.)

Mr. Sevilla and other workers at the park are now considering mitigation efforts to try to protect threatened species from the more frequent El Niño events that have come with climate change. The park already has a program to breed giant tortoises in captivity.

SAVE THE GALAPAGOS WITH GMO RATS. WHAT COULD GO WRONG?

Posted by

0


Volcanic crater (aerial), Isabela Island, Galapagos Islands
A volcanic crater in the Galapagos Islands
The Galapagos Islands are famous for exotic birds, tortoises, and iguanas, but recently the archipelago had become overrun with more prosaic animals: rats and mice. Rodents that came on old sailing ships. Rodents that stowed away on modern cruises. Wherever they came from, rodents that eat the eggs and chicks and hatchlings of the animals that so dazzled Charles Darwin.The same story plays out on islands all over the world. SoIsland Conservation, a nonprofit that rids islands of invasive species, has come up with a daring plan: genetically engineer the rodents so that they all turn into males, shrinking the population one lonely pest at a time.

This plan is far from going into effect, but it gets a serious airing in a report out today from the National Academy of Sciences, a prestigious group that often makes recommendations on controversial areas of research. The make-all-rodents-boys idea is one of seven case studies for the use of “gene drives”—engineered pieces of DNA that spread more quickly through a wild population than any normal gene would. You might say gene drives are a way to cheat evolution. Gene drives could also be dangerous and unpredictable; once a manmade DNA sequence gets into a wild population, it’s hard to get back out again. The National Academy’s report lays out guidelines for scientists to responsibly study this method of genetically altering wild plants and animals.

Environmentalists have long decried genetically modified organisms, but will they embrace them for conservation?

Gene drives have gotten a lot of attention as a way to prevent mosquitoes from spreading disease: Scientists have engineered mosquitoeswith gene drives that kill the parasite behind malaria, and they’re working on gene drives that either eradicate the mosquitoes that spread dengue, chikungunya, and Zika or make them resistant to the viruses. The recent rise of Crispr gene-editing technology has made it easier than ever for scientists to construct gene drives.

But using gene drives not to benefit humans but to restore natural habitats—like tropical islands beset with invasive rats—forces you to answer a very basic question: What is natural? What does it mean to engineer animals to restore nature? Environmentalists have long decried genetically modified organisms, but will they embrace them for conservation?

A New Natural

Kent Redford, former director of the Wildlife Conservation Society Institute, has questioned the working definition of “natural,” and in 2013 he wrote about the lack of dialogue between synthetic biologists and conservationists. The reaction among conservationists he says, was “a range of anger and disgust to enthusiasm and excitement.” Since then Redford, along with Ryan Phelan, executive director of Revive and Restore—an organization that promotes synthetic biology for the “genetic rescue” of endangered and extinct species—have held meetings to get the two groups talking about specific problems, like invasive rodents on islands.

No matter how you feel about genetic modification, the current approach to killing island invasives might make you understand the “enthusiasm” for gene drives. It is not pretty. Recently, on the British island of South Georgia, pilots spread 200 tons of bait one helicopter load at a time, blanketing the island in a rat poison called brodifacoum. Brodifacoum keeps blood from clotting, so the rodents die of internal bleeding—as can birds and other mammals at high enough doses. But gene drives? “We could do it in the most humane way possible by having them just turn to an all-male population and live out their natural lives,” says Heath Packard, communications director for Island Conservation.

Islands are also well suited for gene drive solutions because the ocean is a natural barrier against their spread. And invasive rodents are a critical problem: As Darwin discovered, islands are hotbeds of biodiversity, and 40 percent of the critically endangered species in the world live on islands. Plus rats and mice are an easy genetic target because scientists have long tinkered with their genetics in the lab. The downside, of course, are unintended consequences. Ecology is complicated, and nobody has put a gene out in the wild before.

Island Conservation’s scientists were investigating gene drives as a possible “game-changing” eradication technology even before Crispr became hot. Their research partners at Texas A&M University and North Carolina State University are studying a naturally-occurring gene drive in mice that doesn’t even require Crispr technology. Island Conservation has also partnered with the US Department of Agriculture and Australia’s national Commonwealth Scientific and Industrial Research Organisation so when the time comes, it gets regulatory approval for field tests in the future. That’s all years away, says Packard, though the group is now planning to fundraise for the gene drive research.

The National Academy report considers other conservation scenarios for gene drives: killing off mosquitoes that spread avian malaria in Hawaii and controlling invasive knapweeds in US forests. But reading the report, you get a sense that the scientists realize they are out of their depth. “Questions about how to define ‘nature’ and how to understand the value attached to nature raise a number of difficult philosophical and social problems,” says the report. “They are left here as open questions, and are part of a growing and heated debate among environmentalists about the values that underpin environmentalism.” Consider this: Gene drives may be “unnatural,” but how natural is dropping tons of rat poison out of the sky?

In any case, if scientists can construct such a gene drive, if conservationists can get permission to release mice carrying them, and if everything goes as planned, then islands like the Galapagos stand to benefit. A huge rat poisoning campaign from 2007 to 2014 rid the Galapagos of most of its pests, but with so much boat traffic there, rodents could make their way to the islands again. Where Darwin first made the observations that led him to understand the laws of evolution, scientists could use the technology that will try to cheat the game.

Malaria threat to Galapagos birds

Posted by

0


Blue-footed booby
The blue-footed booby was first extensively studied by Charles Darwin on his visit to the Galapagos

The Galapagos Islands may have inspired Charles Darwin’s theory of evolution, but scientists fear some of the species he observed may not be capable of adapting to new environmental challenges.

Experts say the introduction of foreign parasites to the islands and the increase in frequency of El Nino events, which scientists recently attributed to global warming, could push bird species in the Galapagos towards extinction.

“The situation is precarious,” says Dr Patricia Parker, Endowed Professor of Zoological Studies at the University of Missouri St Louis (UMSL), “particularly for species such as the Galapagos penguin, which live in very small populations.”

The Galapagos Islands

  • The Galapagos Islands comprise a volcanic archipelago west of Ecuador
  • Together the islands have an area of just over 8,000 sq km (3,000 sq mi)
  • They are well known for a huge number of species that are unique to the islands (endemic)
  • Charles Darwin studied the islands’ wildlife during the voyage of the Beagle
  • His observations made a significant contribution to his theory of evolution by natural selection

Foreign parasites have contributed to mass extinctions in Hawaii, which has lost up to 30% of its endemic birds.

Hitherto, the Galapagos Islands have avoided a similar fate. But Dr Parker, who contributed towards a new report about avian malaria on the archipelago, believes it could be just a matter of time before the virus claims its first species.

The disease is already prevalent in the yellow warbler and Galapagos penguin, which has an estimated population of just 3,000 individuals.

The parasite that causes avian malaria (Plasmodium) requires passage through the digestive and circulatory systems of a biting insect in order to reproduce.

“The insect is considered the primary host of the parasite,” explains Dr Parker.

Suitable hosts

However, for the Plasmodium parasite to complete its life-cycle it must then be transmitted to a suitable bird host through the saliva of the biting insect.

“The parasite then goes through a massive multiplication phase in the liver of the animal before entering the bloodstream,” says Dr Parker. “From there, the next biting insect that takes a blood meal picks them up.”

But not all birds are competent hosts.

“We are trying to identify which species of mosquito is responsible for vectoring it and which bird species is the reservoir for this parasite,” says Dr Parker.

After studying 3,726 samples from 22 endemic birds, Dr Parker and her team – scientists from UMSL, Galapagos National Park, Charles Darwin Foundation and Saint Louis Zoo – believe the parasite is not completing its life-cycle in endemic birds.

Yellow warbler The disease is already prevalent in the yellow warbler

“We don’t think Galapagos natives are part of the transmission cycle,” says Dr Parker. “They become infected but they don’t actually allow the parasite to complete its life-cycle.”

Attention has now shifted to three introduced birds; the domesticated fowl, the cattle egret and the smooth-billed ani, a species thought to have been brought here by farmers because it removes ticks from cattle.

“If we discover that one of these introduced species is responsible for the transmission of this potentially dangerous parasite then the Galapagos National Park would consider whether they want to mount an eradication effort,” says Dr Parker.

“There is a sense of urgency about this because it’s only a matter of time until one of the endemic birds will become a successful host – all host and parasite relationships evolve.”

Scientists suspect an introduced mosquito is acting as the primary host and, if this is confirmed, authorities will also consider eradicating the insect.

The Galapagos National Park has experience exterminating foreign species, having successfully eliminated disease-spreading rock pigeons.

El Nino year

However, preserving native species could prove trickier; scientists say global warming is likely to increase the frequency of El Nino events, which can have a devastating effect on Galapagos wildlife.

“In the El Nino events of 1982 and 1996 the population of penguins declined to approximately 300 and 400 individuals respectively,” says Gustavo Jimenez, wildlife veterinarian at the Charles Darwin Foundation.

“The increased frequency of El Nino could mean there is not enough time for the recovery of the species that are affected, which would lead not only to their populations reaching critically low numbers but possibly extinction.”

Galapagos penguin An increased frequency of El Nino events and avian malaria could consign the Galapagos penguin to history

During El Nino, the Humboldt Current, which brings cold, nutrient-rich waters from Antarctica, is reversed.

“Instead what hits the islands are warm equatorial waters,” explains Dr Parker. “So the birds that rely on marine life; their numbers plummet.”

Scientists fear future El Nino events coupled with an outbreak of avian malaria could consign species such as the Galapagos penguin and flightless cormorant to the history books.

“It is possible that in a situation where there are multiple environmental stresses – less food, strange weather conditions and so on – these Plasmodium infections might be much more damaging than they appear to be under more benign circumstances,” says Dr Parker.

On the edge

Concern is also mounting for the critically endangered mangrove finch, which is being ravaged by an introduced fly called Philornis downsi.

“In 2013, 37% of mangrove finch nestlings were killed by Philornis downsi,” says conservationist Francesca Cunninghame, of the Charles Darwin Foundation.

“This is a loss which cannot be sustained in a population as reduced as that of the mangrove finch – in the same year, there were only 14 breeding pairs.”

Philornis downsi colonises nests and finds its way into the nasal cavities of fledglings, where it can cause beak deformation and blood loss leading to death.

It was first identified in the 1990s and recent tests indicate that fumigating nests with permethrin, an insecticide which is not harmful to birds, can dramatically improve the health of a brood.

Scientists are also experimenting with captive breeding programmes in an attempt to boost numbers.

“The Galapagos has had zero bird extinctions and we want to keep it that way,” says Dr Parker. “We need to find answers now while the potential exists to do something about it – before Galapagos becomes another Hawaii.”