Frequent inbreeding may have caused skeletal abnormalities in early humans

By Michael PriceNov. 5, 2018 , 3:05 PM

Early humans faced countless challenges as they fanned out of Africa: icy conditions, saber-tooth cats, and, according to a new study of ancient skeletons, an unusually high number of birth defects, both debilitating and relatively inconsequential. It’s unclear why such abnormalities seem to be so common, but scientists say one strong possibility is rampant inbreeding among small hunter-gatherer groups.

“This paper represents a valuable compilation,” says Vincenzo Formicola, an anthropologist at the University of Pisa in Italy who wasn’t involved in the new work. “Many cases reported in the list were unknown to me and, I assume, to many people working in the field.”

Many human fossils from the Pleistocene (roughly 2.5 million B.C.E. to 9700 B.C.E.) have unusual features. For example, femur bones with abnormal bowing have been found from China to the Czech Republic. The skull of a toddler found in the Qafzeh cave in Israel had a swollen braincase consistent with hydrocephalus, a condition in which fluid floods the skull. And a fossilized man in Liguria in Italy had a bowed right upper arm bone but a normal left one.

Continued  

Inbred animals face greater threat from changes to environment

Date: June 27, 2018

Source: University of Edinburgh

Animals that are inbred make mistakes in response to changes in their surroundings, which threatens their survival, research has found.

A study found that inbred beetles were more likely to make bad decisions amid developing circumstances -- at a cost to themselves and their offspring.

The findings could inform conservation programmes and aid the understanding of wild animals, especially where shrinking populations raises the likelihood of inbreeding.

Researchers from the University of Edinburgh observed hundreds of female burying beetles as they raised their offspring.

Continued  

Killer whale genetics raise inbreeding questions

Endangered orca population in Washington acts genetically smaller than it really is

Date:  April 24, 2018

Source:  NOAA Fisheries West Coast Region

A new genetic analysis of Southern Resident killer whales found that two male whales fathered more than half of the calves born since 1990 that scientists have samples from, a sign of inbreeding in the small killer whale population that frequents Washington's Salish Sea and Puget Sound.

Only about 26 of the 76 endangered whales in the Southern Resident population are currently breeding, according to the analysis published this week in Animal Conservation. The limited number of breeding whales reduces the effective size of the population, leaving it less resilient to change and possibly compromising the survival of individual animals, said lead author Michael Ford, a conservation biologist at NOAA Fisheries Northwest Fisheries Science Center in Seattle.

"The effective size of this population is really small," he said. "It's acting like a population of only 20-30 individuals."

Authors of the research also include scientists from the North Gulf Oceanic Society and Center for Whale Research. While the new paper builds on earlier genetic studies, it also raises new questions about whether inbreeding may be contributing to the population's struggles. Southern Resident numbers have fallen to their lowest point in 30 years.

Continued  

Two in the pack: No changes for Isle Royale wolves

Date: April 18, 2017

Source: Michigan Technological University


For the second year in a row, the Isle Royale wolf population remains a mere two. Researchers from Michigan Tech say that as the wolf population stays stagnant, the moose population will continue to grow at a rapid pace. And this could have a significant impact on the island's famed forests.

According to Rolf Peterson, a research professor at Michigan Tech and co-author of the report, the Isle Royale wolves are no longer serving their ecological function as the island's apex predator -- the creature at the top of the food chain. With only two wolves left on the island, the moose population has grown to an estimated 1,600.

Without wolf predation, says John Vucetich, a professor of ecology at Michigan Tech and report co-author, the moose population could double over the next three to four years. And more moose means more vegetation is eaten. The observations were reported in this year's Winter Study, which marks the 59th year of monitoring wolves and moose on Isle Royale, the longest running predator-prey study in the world.

Wolf Genetics
Where have all the island wolves gone? The answer lies in genetics. The population crash on Isle Royale is the result of inbreeding -- the remaining wolves are not only father and daughter, they are also half siblings who share the same mother.

Researchers believe the two have probably mated at least once in the past: in 2015, an approximately nine-month-old pup was spotted with the two adults. That pup, however, did not appear healthy. Researchers noted a visibly deformed tail, small stature and possibly abnormal posture. Peterson and Vucetich were not surprised when the pup failed to appear with the adults in 2016.

 

Continued 

English bulldogs now so inbred their appalling health problems will not improve

'The English bulldog has reached the point where popularity can no longer excuse the health problems that the average bulldog endures in its often brief lifetime'

Ian Johnston Science Correspondent 

The unnatural wrinkles on this dog's face – breed into them by humans – are prone to infection unless regularly cleaned

The English bulldog is now so inbred that there is little chance of improving its notoriously poor health, geneticists have concluded.

The lead researcher of a study condemned dog breeders and owners, saying more people appeared to be “enamoured with its appearance than concerned about its health”.

English bulldogs suffer from a range of horrendous health problems.

Its excessive wrinkles are prone to infection unless they are regularly cleaned. The dog also has breathing problems due to its narrow nostrils and a number of eye conditions that cause chronic irritation and pain. Its deformed spinal bones that can also lead to incontinence and the loss of the use of its back legs.

Attempts have been made by some breeders to improve the animal's’ health.

However, a study published in the journal of Canine Genetics and Epidemiology found this would be difficult to do from the existing gene pool because it has been inbred to an extreme degree.

The lead author of the paper, Professor Niels Pedersen, said: “The English bulldog has reached the point where popularity can no longer excuse the health problems that the average bulldog endures in its often brief lifetime. 

“More people seemed to be enamoured with its appearance than concerned about its health.

“Improving health through genetic manipulations presumes that enough diversity still exists to improve the breed from within, and if not, to add diversity by outcrossing to other breeds. 

“We found that little genetic 'wiggle room' still exists in the breed to make additional genetic changes.”

Continued … 

How female mountain gorillas in Rwanda avoid inbreeding with their fathers

Mountain gorillas in Rwanda could run the risk of inbreeding, as females often stay in their natal group well into adulthood, which means living closely with their fathers, usually the dominant male in the group.

However, in these circumstances they appear tactically to avoid mating with their fathers, according to Linda Vigilant and her research group from the Max Planck Institute for Anthropology in Germany, published in Springer’s journal Behavioral Ecology and Sociobiology.

This strategy works so well that the chances of alpha gorilla males siring the offspring of their own daughters are extremely remote. 

To clearly establish the paternity of 97 mountain gorillas, Vigilant’s group did genetic tests on fecal samples collected since 1999. These included 79 gorillas born into four of the mountain gorilla groups monitored since 1967 by Dian Fossey Gorilla Fund researchers.

The researchers found that on average seven out of every 10 offspring (72 per cent) in a group with more than one male present, are sired by the dominant male.

Continued ...

Inbreeding makes mountain gorillas genetically healthy

Presented by

Zoe Gough

Mountain gorillas (Gorilla beringei beringei) are among the most iconic endangered species in the world and, as such, have become a prominent focus for conservation.

Surviving in only two small and fragile populations in central Africa, there are currently estimated to be about 800 individuals, with just over half living in three national parks on the Virunga mountain range.

The Virunga population of gorillas was made famous by primatologist Dian Fossey’s book and subsequent film, Gorillas in the Mist. Numbers have doubled from a low point of about 253 gorillas in 1981 thanks to conservation efforts and support from the public, but they remain at risk of extinction.

The drop in population size led to extensive inbreeding which raised concerns that a small gene pool could harm the gorillas' long-term future, particularly their ability to survive infectious diseases and cope with environmental change.

Continued ...

Rare rays' DNA mapped to prevent inbreeding

Marine biologists want to take DNA samples from 120 rays in European aquariums to find out how diverse DNA is within the species, which will give clues as to how inbred individuals are.

This information will allow aquariums to pair up breeding adults that are more genetically diverse in the hope they produce healthier offspring. Inbreeding within a small breeding group can cause stillbirths and shorten individuals’ lifespans.

Undulate rays – which are found in the Atlantic including around the UK, and the Mediterranean Sea – are listed as endangered on the IUCN (International Union for the Conservation of Nature) Red List of Threatened Species.

Continued ...

Inbred wolves struggle, moose proliferate at Isle Royale National Park

Date:

May 2, 2014

Source:

Michigan Technological University

Summary:

Inbreeding is killing off the wolves of Isle Royale National Park, and as a result, the moose are proliferating, threatening the vegetation on the remote Lake Superior island.

Continued

Habitat Fragmentation Causes Inbreeding in California Cougars

By Laura Poppick, Staff Writer | January 10, 2014 04:13pm ET

P-32, shown here, is one of three mountain lion kittens born

 recently in the Santa Monica Mountains that are the result 

of first-order inbreeding.

Credit: National Park Service

Three mountain-lion cubs born recently in Southern California have been identified as inbred, adding to a growing list of inbreeding cases amongst these animals as a result of habitat fragmentation in this region, according to a statement from the National Park Service.

The three cubs — two females and one male — were born last month in the Santa Monica Mountains outside Los Angeles. Researchers at the University of California, Los Angeles, conducted preliminary DNA tests on all three of the cubs and their parents to identify their genetic makeup, and found that the cubs' father was also the father of their mother. 

Read more

Skulls of Early Humans Carry Telltale Signs of Inbreeding

Mar. 18, 2013 — Buried for 100,000 years at Xujiayao in the Nihewan Basin of northern China, the recovered skull pieces of an early human exhibit a now-rare congenital deformation that indicates inbreeding might well have been common among our ancestors, new research from the Chinese Academy of Sciences and Washington University in St. Louis suggests.

The skull, known as Xujiayao 11, has an unusual perforation through the top of the brain case -- an enlarged parietal foramen (EPF) or "hole in the skull" -- that is consistent with modern humans diagnosed with a rare genetic mutation in the homeobox genes ALX4 on chromosome 11 and MSX2 on chromosome 5.

This is a view of the Xujiayao site (below) and internal 

and external view of the Xujiayao 11 skull piece

 with its position indicated on the drawing of a complete

 skull (above). (Credit: Erik Trinkaus/WUSTL)

These specific genetic mutations interfere with bone formation and prevent the closure of small holes in the back of the prenatal braincase, a process that is normally completed within the first five months of fetal development. It occurs in about one out of every 25,000 modern human births.

Continued:  http://www.sciencedaily.com/releases/2013/03/130318180411.htm

Imperiled Orangutans Need Key Forest Corridor

Sumatran orangutans are in trouble: Only about 6,600 of the animals are left, scattered throughout the northern tip of the Indonesian island where they once flourished.

A new genetic study of the animals has found that deforestation on Sumatra has isolated different groups of the primates, which could lead to inbreeding and further decline. But the research also identified a critical corridor of forested hills that orangutans still travel though, which, if protected, could help the species rebound, according to a release describing the study.

The investigators took DNA from wild orangutan's hair and fecal samples, as well as blood samples from orangutans from known areas that were kept as pets before being confiscated by authorities.

Continued:  http://www.livescience.com/24001-orangutan-decline-conservation.html

Meerkat survival 'threatened by inbreeding'

The survival chances of meerkats is being threatened by inbreeding, according to a new study.

Researchers spent 20 years studying data from almost 2,000 meerkats living in clans in South Africa's Kalahari Desert.

They found almost half of the animals showed some evidence of inbreeding.

Meerkat pups that are inbred are smaller, lighter and less likely to survive in the wild than their counterparts.

The project was a collaboration between scientists at the universities of Edinburgh, Cambridge and Zurich, as well as the Zoological Society of London.

They recorded births and deaths and the movement of meerkats between colonies in the Kuruman River Reserve.

Continued:  http://www.bbc.co.uk/news/uk-scotland-edinburgh-east-fife-18227745

Adder study to monitor inbreeding in isolated population

Sunderland researchers' genetic study into adder abnormalities

March 2012. Researchers want to find out if decreasing numbers of adders in the North East has led to inbreeding among colonies of the UK's only venomous snake.

The University of Sunderland has teamed up with Durham Wildlife Trust and Durham County Council to carry out a genetic survey of the adder population in geographically isolated areas of west Durham, testing DNA samples to reveal how much genetic diversity there is among the adder population.

Are adders suffering from inbreeding?
This is the first survey of its kind in this region, and is a result of growing concerns that adders are at risk as their numbers decline through loss of natural habitat and breeding grounds.

Skin & dead snakes being studied
Samples of the adders' skins are being collected over the next several weeks, as the snakes emerge from hibernation and start shedding. Dead snakes are also being analysed in the laboratories at the university, checking for markers which suggest inbreeding has taken place.

Isolated populations
Dr Noel Carter, a Senior Lecturer in Molecular Biology, said: "The adder project highlights a growing concern for wildlife in the UK, maintaining genetic diversity in isolated populations.

"With our research we hope to generate some preliminary data for substantial research, with a view to protecting this species for generations to come before they become dangerously inbred.

"While genetic surveys of adder populations have taken place in other areas of the UK, this is the first in the North East, looking initially at the Durham area, amid fears that dwindling populations will lead to inbreeding depression, a condition that could cause problems such as mutations from missing eyes to deformed spines, to adders being born dead."

Researchers will compare DNA samples in the university's new multi-million pound Sciences Complex, to see if the smaller clan groups are genetically impoverished.

If the levels of inbreeding can be pinpointed by researchers, results will strengthen the case for better protection off adder populations, by enhancing key areas through the linkage of habitats using landscape scale conservation, and by identifying hibernacula areas thus guiding proactive "best practice" management conservation.

As well as adders, if the project shows success, Dr Carter says the research may extend to other wildlife species considered ‘at risk', such as the water vole.

Durham Wildlife Trust experts will simultaneously conduct a number of surveys at different locations assessing the potential for "adder inbreeding depression" by determining the extent of inward and outward migration of adders (especially males) between sites through "capture mark and release".

Sarah Edwards, Heart of Durham project officer for Durham Wildlife Trust, said: "These dwindling numbers are very worrying and with the university's help we are trying to assess whether there is a lack of genetic diversity. This project is essential to establish suitable ‘Best Practice' methodology for future monitoring through the training of volunteers to carry out surveys and to record these findings on regional and national data bases, and to raise the profile of the adder and increase awareness of adder conservation issues.

http://www.wildlifeextra.com/go/news/adder-inbreeding.html

Bedbugs Inbreeding But Still Thriving: Research

PITTSBURGH — Bedbugs aren't just sleeping with you. They're sleeping with each other.

Researchers now say that the creepy bugs have a special genetic gift: withstanding incest.

It turns out that unlike most creatures, bedbugs are able to inbreed with close relatives and still produce generally healthy offspring. That means that if just a few bedbugs survive in a building after treatment, they repopulate quickly.


Coby Schal and Ed Vargo are entomologists at North Carolina State University, and they presented preliminary research on genetic diversity in bedbug populations on Tuesday in Philadelphia, at the annual meeting of the American Society of Tropical Medicine and Hygiene.


"We kept discovering the same thing. Within a given apartment, or even a given building, there was extremely low genetic diversity," said Schal. "In most cases there's just a single female that founded the population."

Schal said that was a surprise, since an animal or insect population with limited diversity will usually build up and then crash, because genetic defects tend to magnify with inbreeding.

"But somehow bedbugs are able to able to withstand the effects of inbreeding, and do quite well," he said.

The new research is important, said Zachary Adelman, an entomologist at Virginia Tech University who wasn't part of the North Carolina State team.

"No one had looked at these things," he said of the genetic makeup of bedbugs. "It's pretty exciting."

And pretty depressing.

The researchers also found that while the community within a building tends to be similar, there are many different strains of bedbugs throughout the East Coast, suggesting that new colonies also get introduced through foreign travel or commerce



Read more here ...

Scientists might have explained promiscuous behaviour

Scientists have shown that inbreeding can lead to female promiscuity.

The team, which reports its findings in the journal Science, witnessed a change in mating behaviour when they bred female flour beetles with their close relatives.

The researchers suspect that promiscuous females are avoiding the ill-effects of inbreeding by exposing themselves to a larger pool of sperm.

The results help explain why females of some species mate with several males.

For females, sex can be traumatic. In some insects, insemination involves wounding females and infecting them with dangerous microbes. In many other species, mating reduces females' lifespans.

Given that in most species, a single mating is generally enough to fertilise all a female's eggs, she has little incentive to mate again. And yet in many species, females mate multiple times with different males.

The new results help evolutionary biologists explain this perplexing phenomenon.

Driving extinction
By driving a population of flour beetles, Tribolium castaneum, to the brink of extinction, and then allowing their numbers to recover from a few individuals, the researchers at the University of East Anglia (UEA) created highly inbred populations.

The researchers found that females in these inbred populations were more eager to mate than those that had not been forced through a bottleneck.

Attempting to explain why unbridled mating was on the increase, the researchers went on to show that inbred females left twice as many descendents as those that mated with just one male.

"It is quite easy to imagine how promiscuity could spread through the population if [promiscuous females] leave more descendents," explained UEA evolutionary biologist Matthew Gage.

When a population is inbred, the chances of mating with a genetically similar male are heightened, so hedging your bets and mating with more suitors is a sensible strategy, he explained.

Dr Gage suspects that promiscuous females amass a large pool of sperm, and select ones that are more genetically dissimilar to them to fertilise their eggs. Mating with more males gives females a larger range of sperm from which to select.

However, Dr Gage warned that he and his colleagues might not have witnessed "the evolution" of a new mating behaviour.

Rather than changing genetically, he explained, the females might simply have been adjusting their behaviour to their new environmental conditions.

Dr Gage and his team are now looking into this.

By Jennifer Carpenter Science reporter, BBC News
http://www.bbc.co.uk/news/science-environment-15002277

Smells May Help Birds Find Their Homes, Avoid Inbreeding; Research May Bring Help to Endangered Species

ScienceDaily (Sep. 22, 2011) — Birds may have a more highly developed sense of smell than researchers previously thought, contend scholars who have found that penguins may use smell to determine if they are related to a potential mate.The research by the University of Chicago and the Chicago Zoological Society, which manages Brookfield Zoo, shows how related birds are able to recognize each other. The study, published Sept. 21 in the journal PLoS ONE, could help conservationists design programs to help preserve endangered species.

"Smell is likely the primary mechanism for kin recognition to avoid inbreeding within the colony," said Heather Coffin, lead author of the paper.

Coffin conducted the research while a graduate student at UChicago and was joined in writing the paper by Jill Mateo, associate professor in Comparative Human Development at UChicago, and Jason Watters, director of animal behavior research for the Chicago Zoological Society.

"This is the first study to provide evidence for odor-based kin discrimination in birds," said Mateo, who is a specialist on kin recognition.

Experts said the work offers important insights into how birds use smell to guide behavior.

"The work by the research group is truly groundbreaking in that it shows for the first time ever in birds how the olfactory sense of captive penguins is both informative and functional in a behaviorally critical context: namely the recognition of friends from foes in general, and relatives from non-relatives in particular," said Mark E. Hauber, professor of psychology at Hunter College, a specialist on bird social recognition.

Penguins are ideal subjects because they typically live in colonies made up of thousands of birds. They live in monogamous pairs -- an arrangement that facilitates rearing of their young, since parents frequently take turns leaving the nest to gather food. Despite the size of the community, mates are able to find each other after traveling for days foraging for food in the ocean.

Research on other sea birds has shown that smell helps guide birds to their home territory and helps them forage for food. Other research has shown that birds could use sound and sight to recognize each other, but no other studies have shown that smell might be used in connection with kin recognition, Mateo said.

In the study conducted at Brookfield Zoo, researchers first sought to determine if the penguins were able to recognize familiar individuals by smell. They constructed an experiment using a dozen penguins, from a group that included breeding pairs, their offspring and nonbreeding individuals. The birds -- all Humboldt penguins -- endangered natives of Peru -- were from groups either on exhibit or off exhibit.

The zoo is an ideal setting for the research, as it has extensive records on which penguins are related and have been housed together, Watters said.

Researchers took odor samples from glands near the penguins' tails, where an oil that the birds use for preening is secreted. They put the oil on cotton swabs and rubbed the odor inside dog kennels, similar to the enclosures penguins at a zoo use for their nests. They also put the odor on paper coffee filters and placed them under mats inside the kennels.

When the penguins were released to the area containing the kennels, the researchers found that penguins spent more time in the kennels with familiar odors. The penguins were able to distinguish between the odors of birds they spent time with and the odors of unfamiliar penguins.

"What I found particularly notable about the study was that the authors identified the oil secreted from the penguins' preen gland, which is rubbed on the feathers to make them water repellent, as the odor source used in recognition," said Bryan D. Neff, professor and associate chair of biology, University of Western Ontario and an expert on kin recognition. "Oils are used in kin recognition by species of other animals, most notably a variety of insect species, including bees and wasps, which when considered with the penguin data provide a wonderful example of convergent evolution."

"It's important for birds that live in large groups in the wild, like penguins, to know who their neighbors are so that they can find their nesting areas and also, through experience, know how to get along with the birds nearby," Watters said.

Because offspring usually return to the same colony for nesting, siblings have the potential of becoming mates, something that can be avoided by their smell mechanism, the new research shows.
Researchers also found that when the birds were exposed to the odors of unfamiliar kin and unfamiliar non-kin, they spent more time in the kennels with odors of unfamiliar non-kin, indicating they were probably able to determine by smell which animals they were related to and were more curious about the novel odors. Being able to make the distinction may help the penguins avoid mating with kin, researchers said. The discovery also could assist zoos in managing their breeding programs.

"It could also be true that birds may be able to help zoo 'matchmakers' in determining potential mates," Watters said.

The ability of birds to be able to recognize familiar scents and thus be guided to their home territory also has potential value to naturalists, he said.

"You could imagine that if you were trying to reintroduce birds to an area, you could first treat the area with an odor the birds were familiar with. That would make them more likely to stay."
http://www.sciencedaily.com/releases/2011/09/110921172834.htm

Paternity Testing Helps Fill in Family Tree for Puget Sound's Killer Whales: Inbreeding Could Reduce Whales' Genetic Diversity

ScienceDaily (July 21, 2011) — In a study published online this month in the Journal of Heredity, NOAA researchers and others, using DNA testing to fill in a missing link in the lives of killer whales that seasonally visit Washington's Puget Sound, have discovered that some of the progeny they studied were the result of matings within the same social subgroups, or pods, that are part of the overall population.


One implication of this inbreeding behavior is a significant reduction in the genetic diversity of what is already a perilously small population of animals, formally known as Southern Resident killer whales. That population numbers only about 85 animals and was listed as endangered under the federal Endangered Species Act in 2005.


Southern resident killer whales, which also visit the waters of British Columbia and are occasionally found as far south as Monterey Bay, Calif., consist of three pods called J, K and L pod. Inter-pod mating has never been detected in studies of Northern Resident killer whales, which range from Washington to southern Alaska, and until now researchers assumed that Southern Residents exhibited similar mating patterns. The two populations are distinct and do not socialize with each other.

The study, titled "Inferred paternity and male reproductive success in a killer whale (Orcinus orca) population," involved researchers from NOAA's Fisheries Service, the University of Washington, Cascadia Research Collective and the Center for Whale Research.

"We were surprised that, in many cases, the father was from the same pod as the mother. Based on earlier studies, we didn't think killer whales mated within their own pod," said Dr. Michael Ford, lead author of the study and a scientist with NOAA's Northwest Fisheries Science Center in Seattle.

"This behavior may be unique to the Southern Resident population, perhaps related to the population's small size," Ford added.

The researchers analyzed 78 individuals for 26 different genetic markers, or DNA fingerprints, and inferred the paternity for 15 mother-calf pairs. The study found no evidence that Southern Residents mate outside their population, but clear evidence that they do sometimes mate with members of their own pod.

"Even though some of the fathers were in the same pod as the mothers, none of them were really closely related to each other. Our results suggest that Southern Residents avoid mating with their siblings or parents, but we aren't really sure of the social process that results in this avoidance," Ford said.

Compared to many mammalian species, males within the Southern Resident community were also found to have a relatively low variance of reproductive success, meaning several males are responsible for offspring production in the population rather than just one or two. This contrasts with some other marine mammals like elephant seals, where a handful of males completely dominate the breeding and may reflect the difficulty male killer whales have in controlling other males' access to females.

However, the study also revealed that the older and larger males appeared to be responsible for most of the successful matings, indicating that females may choose to mate only with older males, or possibly that older males may prevent the younger males from breeding successfully.

Ford said he and his colleagues are particularly worried about the group's lack of genetic diversity, which he characterized as a "bottleneck." "Since this population remains isolated from other killer whale populations, mating within pods puts Southern Residents at risk of genetically deteriorating further from a potential increase in inbreeding or harmful mutations," he said.

http://www.sciencedaily.com/releases/2011/07/110721131206.htm

US sees massive drop in bumble bees: study

WASHINGTON (AFP) – Weakened by inbreeding and disease, bumble bees have died off at an astonishing rate over the past 20 years, with some US populations diving more than 90 percent, according to a new study.


The findings are of concern because bees play a crucial role in pollinating crops such as tomatoes, peppers and berries, said the findings of a three-year study published in the Proceedings of the National Academy of Sciences (PNAS).

Similar declines have also been seen in Europe and Asia, said Sydney Cameron, of the Department of Entomology and Institute for Genomic Biology at the University of Illinois, the main author of the study.

"The decline of bumble bees in the US is associated with two things we were able to study: the pathogen Nosema bombi and a decline in genetic diversity. But we are not saying Nosema is the cause. We don't know," said Cameron.

"It's just an association. There may be other causes."

He added that the decline is "huge and recent," having taken place in the last two decades.

Nosema bombi is a bee pathogen that has also afflicted European bumble bees.

Researchers examined eight species of North American bumble bees and found that the "relative abundance of four species has dropped by more than 90 percent, suggesting die-offs further supported by shrinking geographic ranges," said the study.

"Compared with species of relatively stable population sizes, the dwindling bee species had low genetic diversity, potentially rendering them prone to pathogens and environmental pressures."

Their cousins, the honey bees, have also experienced catastrophic die-offs since 2006 in a phenomenon known as "colony collapse disorder," though the causes have yet to be fully determined.

Bumble bees also make honey, but it is used to feed the colony, not farmed for human consumption.

They are however raised in Europe for pollinating greenhouse vegetables in a multi-billion-dollar industry that has more recently taken off in Japan and Israel and is being developed in Mexico and China, Cameron said.

"We need to start to develop other bees for pollination beside honey bees, because they are suffering enormously," he added.

There are around 250 species of bumble bee, including 50 in the United States alone.
http://news.yahoo.com/s/afp/20110104/ts_afp/usanimalagricultureresearch_20110104011323;_ylt=AjLRd8WnGrHkJH1uGeCbE6KFOrgF;_ylu=X3oDMTMzNDMwZnFwBGFzc2V0A2FmcC8yMDExMDEwNC91c2FuaW1hbGFncmljdWx0dXJlcmVzZWFyY2gEcG9zAzEwBHNlYwN5bl9wYWdpbmF0ZV9zdW1tYXJ5X2xpc3QEc2xrA3Vzc2Vlc21hc3Npdg--

Inbred bumblebees 'face extinction threat' (via Dawn Holloway)

Some of the UK's rarest bumblebees are at risk of becoming extinct as a result of inbreeding, research suggests.

The lack of genetic diversity is making the bees more vulnerable to a number of threats, including parasitic infection, say scientists in Scotland.

They warn that some populations of bees are becoming increasingly isolated as a result of habitat loss.

The findings are being presented at the British Ecological Society's annual meeting at the University of Leeds.

Lead researcher Penelope Whitehorn, a PhD student from Stirling University, said the study of moss carder bumblebees (Bombus muscorum) on nine Hebridean islands, off the west coast of Scotland, offered an important insight into the possible consequences of inbreeding.

"The genetic work had already been carried out on these bumblebees, so we knew that the smaller and more isolated populations were more inbred than the larger populations on the mainland," she told BBC News.

"And as it was an island system, it could work as a proxy for what could occur on the mainland if populations do become isolated from each other as a result of habitat fragmentation."

The study is believed to be the first of its kind to investigate inbreeding and immunity in wild bees.

Uncertain future
Ms Whitehorn found that, although the inbreeding did not seem to affect the bees' immune system directly, it did make the insects more susceptible to parasitic infection.

The study offered a good insight into the potential consequences for species found on the UK mainland Some of the UK's rarest bumblebees are at risk of becoming extinct as a result of inbreeding, research suggests.

The ideal habitat on the Hebridean islands offers the resident bee populations a fighting chance "We found that isolated island populations of the moss carder bumblebee with lower genetic diversity have an increased prevalence of the gut parasite Crithidia bombi," she explained.

"Our study suggests that as bumblebee populations lose genetic diversity the impact of parasitism will increase, which may increase the extinction risk of threatened populations."

She added that the populations of the bees on the islands were "quite healthy because the habitat was so good", but inbreeding did have a range of other consequences, such as the production of infertile males.

"If inbreeding occurs on mainland Britain, where the habitat is not so good, then species may well be threatened," Ms Whitehorn suggested.

Other studies of invertebrates have found other costs as a result of inbreeding, such as a loss of general fitness in the species in question.

Habitat loss is resulting in populations of bees becoming more and more isolated from their neighbours, effectively leaving them as island populations.

Ms Whitehorn cited the example of the short-haired bumblebee (Bombus subterraneus), which finally became nationally extinct in the late 1980s when a parasitic infection placed increased pressure on the remaining populations, which were already vulnerable as a result of fragmented habitats.

To date, recent attempts to re-introduce the population back into the UK from New Zealand - where it had been introduced from Britain in the late 19th Century, have not been successful.

The Bumblebee Conservation Trust said efforts to conserve bumblebees were vital as the creatures played a key role as pollinators, especially when it came to wild flowers and commercial crops.

The UK currently has 24 species of bumblebee, after seeing two species become nationally extinct in recent decades.

Of the remaining species, one quarter have been identified as being in need of conservation to prevent them from disappearing from the British landscape.

By Mark Kinver

Science and environment reporter, BBC News
http://www.bbc.co.uk/news/science-environment-11199779