Science news in brief: From moving otters south to plants that hide from humans

Looking for otters who might not mind relocating south

From 1969 to 1971, the United States tested nuclear weapons beneath one of Alaska’s Aleutian Islands, close to some of the world’s few surviving sea otters. The subterranean explosions prompted conservation managers to carry out a daring plan. First, they netted Alaskan sea otters and set 59 free off the coast of Washington State and 93 more near Oregon. In Washington, the transplants took, but the Oregon otters soon vanished.

One hypothesis holds that the Oregon otters simply swam off, heading back north. But another explanation suggests that the cold-water-adapted Alaskans died out because they were too different from Oregon’s original pre-fur-trade otters, who were hunted to the brink of extinction. Scientists divide sea otters into northern and southern subspecies, each adapted to its own habitat. If the state’s ancient otters were more closely related to the southern subspecies, maybe reintroduction efforts there should instead work with animals from Californian populations.

A technique borrowed from the science of human archaeology may answer this conservation question. New research suggests that the northern subspecies had long settled along the Oregon coast.

“Our recommendations are that actually Alaskan or other northern populations would be appropriate,” says Hannah Wellman, a graduate student at the University of Oregon who led the study. The research compiled the most comprehensive genetic dataset yet of Oregon’s original sea otters.

To understand which otters had once lived there, the team turned to otter teeth found in two archaeological sites in northern Oregon. Genomic sequences from both time periods show that both northern and southern sea otter populations once called Oregon’s coastline home.

This past February, the US Fish and Wildlife Service funded a feasibility study by the Elakha Alliance, the first in a long series of evaluations and steps that could ultimately bring back Oregon’s sea otters.

Shawn Larson, a conservation biologist at the Seattle Aquarium who is helping write that assessment, says she plans to incorporate the new analysis of Oregon’s past otter diversity. Perhaps reintroductions can both bring in Californian sea otters to the state’s southern shores, and Alaskan otters farther north.

“Then as the populations grow, they’ll merge, and now we’ll have a connected group that is basically continuous from southern Oregon all the way up to Russia,” she said. “Which would be awesome.”

— Joshua Sokol

The unusual bird superpower that goes back to the dinosaurs

The ibis and the kiwi are dogged diggers, probing in sand and soil for worms and other buried prey. Sandpipers, too, can be seen along the shore excavating small creatures with their beaks. It was long thought that these birds used trial and error to find their prey, but then scientists discovered that their beaks are threaded with cells that can detect vibrations travelling through the ground.

Ostriches and emus, birds that do not hunt that way, have beaks with a similar interior structure, honeycombed with pits for these types of cells, though the cells themselves are missing. Now, scientists are reporting that prehistoric bird ancestors dating nearly as far back as the dinosaurs most likely were capable of sensing vibrations with their beaks.

The birds that use this remote sensing today are not closely related, says Carla du Toit, a graduate student at the University of Cape Town in South Africa and an author of a study. That made her and her co-authors curious about when exactly this ability evolved, and whether ostriches, which are close relatives of kiwis, had an ancestor that used this sensory ability.

“We had a look to see if we could find fossils of early birds from that group,” Du Toit says. “And we’re very lucky.” There are very well-preserved fossils of birds called lithornithids dating from just after the event that drove non-avian dinosaurs to extinction.

First they had to gather data on the beaks of more than 50 bird species so that they would be able to say how similar or different the fossil birds were to modern birds. The team recorded the number of pits in the bone of the beak and the size of the beak and the head, important details because birds that dig for their food have a characteristic shape.

Then they took a look at the lithornithids. And indeed, the ancient beaks and head structure were extremely similar to the beaks of kiwis, ibises and sandpipers, much closer than any other bird in the study.

Du Toit and her colleagues are now studying the hadeda ibis, a South African bird that uses remote sensing to see just how far away it can sense hidden objects — perhaps buried as much as 8 inches below the surface.

— Veronique Greenwood

Can scientists help this bee? Actually, you can count on it

Honey bees — a European import to the Americas — and their colony-collapse problems get a lot of attention, but bees native to the United States that have their own ecological role are facing similar and perhaps additional threats. The decline among native bees like the rusty patched bumblebee, known for the patch on its back, is a recognised concern, and there are a variety of efforts to save them; however, the full extent of the problem is not well understood.

Scientists at institutions across the US have started an effort to collect better data on native bee populations, as well as efforts to conserve them, as part of the US National Native Bee Monitoring Research Coordination Network. The project, supported by the US Department of Agriculture, will train members of the public to look for and track wild bees.

The bee monitoring network will partner these citizen volunteers with experts who will identify photos and data that the contributors collect. The bee count will run through 2023, and the program encourages participants to sign up at usnativebees.com or email nationalnativebees@gmail.com.

It’s a bit like the Great Backyard Bird Count, where birders of all ages conduct a count every February to collect data about bird populations.

“We’ve learned a lot from scientists in the birding community,” says S Hollis Woodard, an entomologist at the University of California, Riverside. “We are hoping people of all ages and backgrounds will participate in monitoring bees that are local to their areas.”

Woodard and colleagues explained the problem about the lack of a nationwide effort in a paper published this month in the journal Biological Conservation.

“We’ve made collecting data easy,” Woodard says. “Once you join, you’ll get an email from a coordinator in your area and an app to use to upload photos and basic information of where the photos were taken.”

Scientists working with the program then identify the bees in the photos and record the information for their database.

Woodard expects the program to evolve over time. The website will post new information and a series of events will be listed soon.

“This is a new direction for my lab,” Woodard says. “It’s exciting that we’ll soon be collecting data from a wide variety of ecosystems across the country.”

— Michele C Hollow

This plant evolved to hide from a predator. It might be us

Climb in the Hengduan Mountains near Yulong, China, and you’ll probably spot Fritillaria delavayi. The small plants have elegant green leaves and bell-shaped yellow flowers. Each one pops against the grey scree like a statement brooch.

In the same mountain range just 65 miles away, F. delavayi plants are a dull tan, like the rocks they live on. Near Muli, they’re dark grey instead, and in Pujin, reddish-brown.

Why does this one species come in so many different colours? It might be hiding from you.

According to a paper published last month in Current Biology, F. delavayi may have evolved several distinct colour types because people often harvest its bulbs as a medicinal ingredient, the latest example of species that humans appear to have influenced into evolving new traits.

Yang Niu, a researcher at the Kunming Institute of Botany at the Chinese Academy of Sciences and the lead author of the new paper, has spent years documenting examples of how plants conceal themselves. These plants are generally trying to fool something in particular. Corydalis benecincta, another alpine plant that Niu studies, has “a specialist enemy”, he says – a butterfly that nibbles its leaves. Possibly in response, the normally green plant has evolved a subtler grey morph.

“Other such kinds of camouflaged plants reported in other places all over the world – they also have enemies,” he says. The divergent colouration of F. delavayi was initially puzzling because no animals seemed to eat it.

But the bulbs of this and other Fritillaria plants are common medicinal ingredients, used to treat coughs. People have been harvesting them for over 2,000 years. What if this plant’s enemy is us? If so, F. delavayi plants in areas that experience more intense collection should be better camouflaged than those in places where people pick them less.

The study makes “a fairly convincing case” that humans are driving the camouflage of this plant, says Ilik Saccheri, a professor of ecological genetics at the University of Liverpool who studies colour change in moths and butterflies and was not involved in this work. However, he adds, more experiments would bolster the evidence.

— Cara Giaimo

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