The study led by William Jaeger of the OSU College of Agricultural Sciences is based on an analysis of 50 years of data suggesting that while hatchery-reared salmon numbers have increased, there is no evidence of a net increase in wild, naturally spawning salmon and steelhead.

Findings were published today in PLOS One.

Jaeger, a professor of applied economics, notes that steelhead and Chinook, coho and sockeye salmon numbers have been under heavy pressure in the Columbia River Basin for more than a century and a half — initially from overharvesting, then from hydropower beginning in 1938 with the opening of Bonneville Dam, the lowermost dam on the mainstem Columbia.

“Also, farming, logging, mining and irrigation caused landscape changes and habitat degradation, which compounded the problems for the fish,” said Jaeger, who collaborated on the paper with Mark Scheuerell, a biologist with the U.S. Geological Survey and the University of Washington.

An estimated 16 million salmon and steelhead once returned from the Pacific to the portions of the basin above Bonneville Dam, but by the 1970s there were fewer than 1 million fish, prompting the federal government to intervene.

The Northwest Power Act of 1980 required fish and wildlife goals to be considered in addition to power generation and other objectives. The act created the Northwest Power and Conservation Council to set up conservation programs financed by Bonneville Power Administration revenues.

The cost and scale of restoration efforts grew considerably in the 1990s, Jaeger said, following the listing of 12 Columbia River runs of salmon and steelhead as threatened or endangered under the Endangered Species Act.

The public’s tab for conservation spending now exceeds $9 billion in inflation-adjusted 2020 U.S. dollars, the researchers said, which does not take into account all monies that have been spent by local governments and non-governmental agencies.

“The actual impact of all of these efforts has always been poorly understood,” Jaeger said. “Lots of people have long been concerned about a lack of evidence of salmon and steelhead recovery. One of the issues is that most studies evaluating restoration efforts have examined individual projects for specific species, life stages or geographic areas, which limits the ability to make broad inferences at the basin level.”

Thus, Jaeger notes, a key question has persisted, and its answer is critical for sound policy and legal decisions: Is there any evidence of an overall boost in wild fish abundance that can be linked to the totality of the recovery efforts?

Based on a half-century of fish return data at Bonneville Dam, the single entry point to the basin above the dam, the evidence does not support a yes answer.

“We found no evidence in the data that the restoration spending is associated with a net increase in wild fish abundance,” Jaeger said.

He said the Northwest Power and Conservation Council set a goal of increasing total salmon and steelhead abundance in the basin to 5 million fish by 2025, but annual adult returns at Bonneville Dam averaged less than 1.5 million in the 2010s.

And while hatchery production has helped with overall numbers of adult fish, Jaeger added, it has also adversely affected wild stocks through a range of mechanisms including genetics, disease, competition for habitat and food, and predation on wild fish by hatchery fish.

“The role of hatcheries in recovery plans is controversial for many reasons, but results do indicate that hatchery production combined with restoration spending is associated with increases in returning adult fish,” Jaeger said. “However, we found that adult returns attributable to spending and hatchery releases combined do not exceed what we can attribute to hatcheries alone. We looked at ocean conditions and other environmental variables, hatchery releases, survival rates for hatchery released fish, and conservation spending, and we saw no indication of a positive net effect for wild fish.”

Even expenditures on “durable” habitat improvements designed to cumulatively benefit naturally spawning wild salmon and steelhead over many years did not lead to evidence of a return on these investments, he added.

For the first time, scientists have managed to induce virgin birth in an animal that usually reproduces sexually: the fruit fly Drosophila melanogaster.

Once induced in this fruit fly, this ability is passed on through the generations: the offspring can reproduce either sexually if there are males around, or by virgin birth if there aren’t.

For most animals, reproduction is sexual — it involves a female’s egg being fertilised by a male’s sperm. Virgin birth, or ‘parthenogenesis’, is the process by which an egg develops into an embryo without fertilisation by sperm — a male is not needed.

The offspring of a virgin birth are not exact clones of their mother but are genetically very similar, and are always female.

“We’re the first to show that you can engineer virgin births to happen in an animal — it was very exciting to see a virgin fly produce an embryo able to develop to adulthood, and then repeat the process,” said Dr Alexis Sperling, a researcher at the University of Cambridge and first author of the paper.

She added: “In our genetically manipulated flies, the females waited to find a male for half their lives — about 40 days — but then gave up and proceeded to have a virgin birth.”

In the experiments, only 1-2% of the second generation of female flies with the ability for virgin birth produced offspring, and this occurred only when there were no male flies around. When males were available, the females mated and reproduced in the normal way.

Switching to a virgin birth can be a survival strategy: a one-off generation of virgin births can help to keep the species going.

The study is published today in the journal Current Biology.

To achieve their results, researchers first sequenced the genomes of two strains of another species of fruit fly, called Drosophila mercatorum. One strain needs males to reproduce, the other reproduces only through virgin birth. They identified the genes that were switched on, or switched off, when the flies were reproducing without fathers.

With the candidate genes for virgin birth ability identified in Drosophila mercatorum, the researchers altered what they thought were the corresponding genes in the model fruit fly, Drosophila melanogaster. It worked: Drosophila melanogaster suddenly acquired the ability for virgin birth.

The research involved over 220,000 virgin fruit flies and took six years to complete.

Key to the discovery was the fact that this work was done in Drosophila melanogaster — the researchers say it would have been incredibly difficult in any other animal. This fly has been the ‘model organism’ for research in genetics for over 100 years and its genes are very well understood.

Sperling, who carried out this work in the Department of Genetics, has recently moved to Cambridge Crop Science Centre to work on crop pests and hopes to eventually investigate why virgin birth in insects may be becoming more common, particularly in pest species.

“If there’s continued selection pressure for virgin births in insect pests, which there seems to be, it will eventually lead to them reproducing only in this way. It could become a real problem for agriculture because females produce only females, so their ability to spread doubles,” said Sperling.

The females of some egg-laying animals — including birds, lizards and snakes, can switch naturally to give birth without males. But virgin birth in animals that normally sexually reproduce is rare, often only observed in zoo animals, and usually happens when the female has been isolated for a long time and has little hope of finding a mate.

Parents the world over are prone to worry about their children getting either too little or too much sleep.

But a new study published today reveals that some children are more efficient at consolidating information during sleep, so they nap less frequently.

Meanwhile others, usually those with fewer words and poorer cognitive skills, need to nap more frequently.

The research team say that reducing naps for these children will not improve brain development, and that they should be allowed to nap as frequently and for as long as they need.

Lead researcher Dr Teodora Gliga said: “There is a lot of parental anxiety around sleep. Parents worry that their kids don’t nap as much as expected for their age — or nap too frequently and for too long.

“But our research shows that how frequently a child naps reflects their individual cognitive need. Some are more efficient at consolidating information during sleep, so they nap less frequently.

“Children with smaller vocabularies or a lower score in a measure of executive function, nap more frequently.

“Young children will naturally nap for as long as they need and they should be allowed to do just that,” she added.

The research team studied 463 infants aged between eight months and three years during lockdown in 2020.

Parents were surveyed about their children’s sleep patterns, their ability to focus on a task, keep information in their memory, and the number of words that they understood and could say.

They also asked parents about their socio-economic status — including their postcode, income, and education — and about the amount of screen time and outdoors activities their child engaged in.

Dr Gliga said: “Lockdown gave us an opportunity to study children’s intrinsic sleep needs because when children are in childcare, they rarely nap as much as they need to.

“Because nurseries were closed, it meant less disturbance to the children’s natural sleep patterns. None of the children taking part were attending day care.

“What we found is that the structure of daytime sleep is an indicator of cognitive development.

“Infants with more frequent but shorter naps than expected for their age had smaller vocabularies, and worse cognitive function.

“We also found that this negative association between vocabulary and frequency of naps was stronger in older children,” she added.

“While the majority of parents told us that their child’s sleep was unaffected by lockdown, parents from lower socio-economic backgrounds were more likely to report a worsening in sleep.

“Screen time increased during lockdown and outdoor activities decreased but these did not explain differences in children’s sleep.

“Previous work suggested that caregivers should encourage frequent naps, in pre-school children.

“Our findings suggest that children have different sleep needs — some children may drop naps earlier because they don’t need them anymore. Others may still need to nap past three years of age.

“In the UK, preschools enrolling three to five-year-olds have no provisions for napping. Caregivers should use a child’s mental age and not chronological age to ascertain a child’s sleep needs,” she added.

The study was led by UEA in collaboration with researchers at the University of Oxford, Oxford Brookes University, the University of Leeds and the University of Warwick. It was funded by the Economic and Social Research Council (ESRC).

‘More frequent naps are associated with lower cognitive development in a cohort of 8 to 38- month-old children, during the Covid-19 pandemic’ is published in the journal JCPP Advances.

The idea that “time-traveling” pathogens trapped in ice or hidden in remote laboratory facilities could break free to cause catastrophic outbreaks has inspired generations of novelists and screenwriters. While melting glaciers and permafrost are giving many types of dormant microbes the opportunity to re-emerge, the potential threats to human health and the environment posed by these microbes have been difficult to estimate.

In a new study, Strona’s team quantified the ecological risks posed by these microbes using computer simulations. The researchers performed artificial evolution experiments where digital virus-like pathogens from the past invade communities of bacteria-like hosts. They compared the effects of invading pathogens on the diversity of host bacteria to diversity in control communities where no invasion occurred.

The team found that in their simulations, the ancient invading pathogens could often survive and evolve in the modern community, and about 3 percent became dominant. While most of the dominant invaders had little effect on the composition of the larger community, about 1 percent of the invaders yielded unpredictable results. Some caused up to one third of the host species to die out, while others increased diversity by up to 12 percent compared to the control simulations.

The risks posed by this 1 percent of released pathogens may seem small, but given the sheer number of ancient microbes regularly released into modern communities, outbreak events still represent a substantial hazard. The new findings suggest that the risks posed by time-traveling pathogens — so far confined to science fiction stories — could in fact be powerful drivers of ecological change and threats to human health.