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Baby mantises harness mid-air ‘spin’ during jumps for precision landings

By fpjl2 from University of Cambridge - Department of Zoology. Published on Mar 05, 2015.

The smaller you are, the harder it is not to spin out of control when you jump. Miniscule errors in propulsive force relative to the centre of mass results in most jumping insects – such as fleas, leafhoppers and grasshoppers – spinning uncontrollably when they jump.

Until now, scientists worked under the hypothesis that such insects can’t control this, and spin unpredictably with frequent crash landings.

But new high-speed video analysis of the jumps of wingless, baby praying mantises has revealed a technique which actually harnesses the spinning motion, enabling them to jump with accuracy at the same time as repositioning their body mid-air to match the intended target – all in under a tenth of a second.

Researchers used a thin black rod distant from the platform on which the mantises sat as a target for them to jump at.

During the jumps, the insects rotated their legs and abdomen simultaneously yet in varying directions – shifting clockwise and anti-clockwise rotations between these body parts in mid-air – to control the angular momentum, or ‘spin’. This allowed them to shift their body in the air to align themselves precisely with the target on which they chose to land.

And the mantises did all of this at phenomenal speed. An entire jump, from take-off to landing, lasted around 80 milliseconds – literally faster than the blink of a human eye.

At first, scientists believed the mantis had simply evolved a way to mitigate the natural spin that occurs when such small insects jump at speed.

On closer inspection, however, they realised the mantis is in fact deliberately injecting controlled spin into the jump at the point of take-off, then manipulating this angular momentum while airborne through intricate rotations of its extremities in order to reposition the body in mid-air, so that it grasps the target with extreme precision.

For the study, published today in the journal Current Biology, the researchers analysed a total of 381 slowed-down videos of 58 young mantises jumping to the target, allowing them to work out the intricate mechanics used to land the right way up and on target virtually every time.  

“We had assumed spin was bad, but we were wrong – juvenile mantises deliberately create spin and harness it in mid-air to rotate their bodies to land on a target,” said study author Professor Malcolm Burrows from Cambridge University’s Department of Zoology, who conducted the research with Dr Gregory Sutton from Bristol University.

“As far as we can tell, these insects are controlling every step of the jump. There is no uncontrolled step followed by compensation, which is what we initially thought,” he said.

In fact, when the researchers moved the target closer, the mantises spun themselves twice as fast to ensure they got their bodies parallel with the target when they grasped it. 

For Sutton, the study is similar to accountancy, only with distribution of momentum instead of money. “The mantis gives itself an amount of angular momentum at take-off and then distributes this momentum while in mid-air: a certain amount in the front leg at one point; a certain amount in the abdomen at another – which both stabilise the body and shift its orientation, allowing it to reach the target at the right angle to grab on,” he said.

The researchers tested what would happen if they restricted the ability of the mantis to harness and spread the ‘spin’ to its extremities during a jump. To do this, they glued the segments of the abdomen together, expecting the mantis to spin out of control.

Intriguingly, the accuracy of the jump wasn’t impeded. The mantises still reached the target, but couldn’t rotate their bodies into the correct position – so crashed headlong into it and bounced off again.

The next big question for the researchers is to understand how the mantis achieves its mid-air acrobatics at such extraordinary speeds. “We can see the mantis performs a scanning movement with its head before a jump. Is it predicting everything in advance or does it make corrections at lightning speed as it goes through the jump? We don’t know the answer between these extreme possibilities,” said Burrows.
 
Sutton added: “We now have a good understanding of the physics and biomechanics of these precise aerial acrobatics. But because the movements are so quick, we need to understand the role the brain is playing in their control once the movements are underway.”

Sutton believes that the field of robotics could learn lessons from the juvenile mantis. “For small robots, flying is energetically expensive, and walking is slow. Jumping makes sense – but controlling the spin in jumping robots is an almost intractable problem. The juvenile mantis is a natural example of a mechanical set-up that could solve this,” he said.

High-speed videos reveal that, unlike other jumping insects, the juvenile praying mantis does not spin out of control when airborne. In fact, it both creates and controls angular momentum at extraordinary speeds to orient its body for precise landings.

As far as we can tell, these insects are controlling every step of the jump
Malcolm Burrows
Video still of jumping mantis and illustration of mid-air rotations

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Amazon deforestation ‘threshold’ causes species loss to accelerate

By fpjl2 from University of Cambridge - Department of Zoology. Published on Mar 04, 2015.

One of the first studies to map the impact of deforestation on biodiversity across entire regions of the Amazon has found a clear ‘threshold’ for forest cover below which species loss becomes more rapid and widespread.    

By measuring the loss of a core tranche of dominant species of large and medium-sized mammals and birds, and using the results as a bellwether, the researchers found that for every 10% of forest loss, one to two major species are wiped out.

This is until the threshold of 43% of forest cover is reached, beyond which the rate of biodiversity loss jumps from between two to up to eight major species gone per 10% of disappeared forest.

While current Brazilian law requires individual landowners in the Amazon to retain 80% forest cover, this is rarely achieved or enforced. Researchers say that the focus should be shifted to maintaining 50% cover – just half the forest – but over entire landscapes rather than individual farms, in a bid to stop whole regions losing untold biodiversity by slipping below the 43% threshold at which species loss accelerates.

Unless urgent action is taken to stem deforestation in key areas that are heading towards or have just dipped below the forest cover ‘threshold’ – which, according to the research team’s models, amounts to a third of the Amazon – these areas will suffer the loss of between 31-44% of species by just 2030.  

“These results support the need for a major shift in the scale at which environmental legislation is applied in Brazil and the tropics,” said Dr Jose Manuel Ochoa-Quintero, from Cambridge University’s Department of Zoology, who led the study, published recently in the journal Conservation Biology.

“We need to move from thinking in terms of compliance at a farm scale to compliance at a landscape scale if we are to save as many species as we can from extinction."
  
The researchers worked across an area of the North West Amazon over three million hectares in size. They then divided the region into 1,223 squares of 10,000km, and selected 31 squares representative of the spectrum of forest cover across the region (12-90% cover). 27 squares consisted of private land; only four were protected areas (PAs). PAs were only areas in region with almost complete forest cover. 

Within the 31 squares, researchers analysed the presence of 35 key species of mammals and birds for which these regions are natural habitats, such as pumas, giant anteaters and red howler monkeys. This was done through a combination of direct observation and recording evidence such as footprints and faeces, as well as in-depth interviews with landowners and residents, who were quizzed about species presence through photographs, animal noises and local knowledge.  

The researchers found a cut-off, conservatively given as 43% forest cover, below which the squares held “markedly fewer species”, with up to eight key species lost for every 10% of further deforestation beyond this threshold.  

“This is not just a result of overall loss of habitat, but also reduced connectivity between remaining forest fragments, causing species to hunt and mate in ever-decreasing circles,” said Ochoa-Quintero. “This fragmentation may be the key element of the ‘threshold’ tipping point for biodiversity.”

Encroaching agriculture – from beef to soya production – to feed a growing and more affluent human population means that, at the current rates, the number of 10,000km2 landscapes in the Amazon that fall below the species loss threshold of 43% forest cover will almost double by just 2030. At current rates, by 2030 only a mere 22% of landscapes in the region will be able to sustain three quarters of the key species surveyed for the study.        

The expansion of agriculture in recent decades means that around 41% of the original forest in the study region – some two million hectares – has been lost over just the last 40 years. 

Researchers say that while PAs can counter agricultural expansion – and many have increasingly called for PAs to expand across the planet amid dire evidence of rapid species decline – the limits on land that can be set aside for PAs means that biodiversity conservation success depends on protecting native vegetation on private lands.

The highest priority landscapes, some 33% of land in the region, are those that either just dipped below the 43% threshold in 2010, or are expected to in the next 20 years.

“Avoiding deforestation and focusing reforestation in the areas that teeter on the species loss threshold will be the most direct and cost-effective way to prevent further species loss in the Amazon region,” added Ochoa-Quintero.

Inset image: Local farmer with a Scarlet Macaw (Credit: JM Ochoa-Quintero)

One of the largest area studies of forest loss impacting biodiversity shows that a third of the Amazon is headed toward or has just past a threshold of forest cover below which species loss is faster and more damaging. Researchers call for conservation policy to switch from targeting individual landowners to entire regions.

We need to move from thinking in terms of compliance at a farm scale to compliance at a landscape scale if we are to save as many species as we can from extinction
Jose Manuel Ochoa-Quintero
Corn plantation nearby remaining forest in the Amazon region

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Museum of Zoology plans boosted

From Department of Zoology. Published on Mar 02, 2015.

Congratulations to Nick Crumpton and Robert Brocklehurst

From Department of Zoology. Published on Feb 26, 2015.

World’s protected natural areas receive eight billion visits a year

By fpjl2 from University of Cambridge - Department of Zoology. Published on Feb 24, 2015.

The world’s national parks and nature reserves receive around eight billion visits every year, according to the first study into the global scale of nature-based tourism in protected areas. The paper, by researchers in Cambridge, UK, Princeton, New Jersey, and Washington, DC, published in the open access journal PLOS Biology, is the first global-scale attempt to answer the question of how many visits protected areas receive, and what they might be worth in terms of tourist dollars.

The authors of the study say that this number of visits could generate as much as US$600 billion of tourism expenditure annually - a huge economic benefit which vastly exceeds the less than US$10 billion spent safeguarding these sites each year.

Scientists and conservation experts describe current global expenditure on protected areas as “grossly insufficient”, and have called for greatly increased investment in the maintenance and expansion of protected areas – a move which this study shows would yield substantial economic return – as well as saving incalculably precious natural landscapes and species from destruction.

“It’s fantastic that people visit protected areas so often, and are getting so much from experiencing wild nature – it’s clearly important to people and we should celebrate that,” said lead author Professor Andrew Balmford, from Cambridge University’s Department of Zoology.

“These pieces of the world provide us with untold benefits: from stabilising the global climate and regulating water flows to protecting untold numbers of species. Now we’ve shown that through tourism nature reserves contribute in a big way to the global economy – yet many are being degraded through encroachment and illegal harvesting, and some are being lost altogether. It’s time that governments invested properly in protected areas.”

Dr Andrea Manica, a corresponding author also at Cambridge, said these are ballpark estimates based on limited data, so the researchers have been careful not to overstate the case: “These are conservative calculations. Visit rates are likely to be higher than eight billion a year, and there’s no doubt we are talking about hundreds of billions of tourism dollars a year,” he said. 

The attempt to calculate these figures was in part borne from frustration, said Balmford. “We study what people get out of nature, so-called ‘ecosystem services’. While some ecosystem services are difficult to measure – such as cultural or religious benefits – we thought that nature-based recreation would be quite tractable: there’s a market and tangible visits you can count.   

“However, when we started to investigate we found no-one had yet pieced the data together. So we got to work trawling for figures ourselves. After a few months we had constructed a database from which we could build our models. It’s limited, but it’s the best there is at the moment,” Balmford said. 

The database consists of visiting figures for 550 sites worldwide, which were then used to build equations that could predict visit rates for a further 140,000 protected areas based on their size, remoteness, national income, and so on.

The results surprised even seasoned conservation researchers. Nature tourism expert and team member Dr Matt Walpole of the UN’s World Conservation Monitoring Centre calls their cautious estimate of eight billion annual visits an “astonishing figure that illustrates the value people place on experiencing nature”.

Visit rates were highest in North America, where protected areas receive a combined total of over three billion visits a year, and lowest in Africa, where many countries have less than 100,000 protected area visits annually.

The Golden Gate National Recreation Area near San Francisco had the highest recorded visit rate in the database with an annual average of 13.7m visits, closely followed by the UK’s Lake District and Peak District National Parks, with 10.5m and 10.1m. By contrast, Tanzania’s Serengeti National Park got an annual average during the study period of 148,000 visits.

Team member Dr Jonathan Green, based in Cambridge, points out that it is far from just exotic places and large national parks that contribute to the visitation value of protected areas. “For many people, it’s the nature reserve on their doorstep where they walk the dog every Sunday”. Fowlmere nature reserve, a few miles south of Cambridge University, receives an average of almost 23,000 visits a year. 

By combining regional visit rates with region-specific averages for visitor spending – on everything from entry fees to transport and accommodation – the researchers were able to derive the most complete picture yet of the global economic significance of protected area visitation.  

“Our US$600 billion figure for the annual value of protected area tourism is likely to be an underestimate – yet it dwarfs the less than US$10 billion spent annually on safeguarding and managing these areas,” said Dr Robin Naidoo of World Wildlife Fund, another author of the study. “Through previous research, we know that the existing reserve network probably needs three to four times what is currently being spent on it”.

“While that may seem a lot of money, it’s a fraction of the economic benefit we get from protected areas – nature-based tourism is just one part,” said Balmford.

By way of context, he points to the recent announcement by computing giant Apple of record profits of US$18 billion in a single quarter. “Stopping the unfolding extinction crisis is not unaffordable. Three months of Apple profits could go a long way to securing the future of nature. Humanity doesn’t need electronic communication to survive. But we do need the rest of the planet.”

Researchers say that the first study to attempt to gauge global visitation figures for protected areas reveals nature-based tourism has an economic value of hundreds of billions of dollars annually, and call for much greater investment in the conservation of protected areas in line with the values they sustain – both economically and ecologically.

We’ve shown that through tourism nature reserves contribute in a big way to the global economy – yet many are being degraded through encroachment and illegal harvesting
Andrew Balmford
Visitors in Namib-Naukluft National Park, Namibia
Top ten most visited Protected Areas:
Protected Area Average annual visit numbers
Golden Gate National Recreation Area, US 13.7m
Lake District National Park, UK 10.5m
Peak District National Park, UK 10.1m
Lake Mead National Recreation Area, US 7.7m
North York Moors National Park, UK 7.3m
Delaware Water Gap National Recreation Area, US 5m
Dartmoor National Park, UK 4.3m
New Forest National Park, UK 4.3m
Grand Canyon National Park, US 4.29m
Cape Cod National Seashore, US 4.1m

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Museum of Zoology on BBC Look East

From Department of Zoology. Published on Feb 20, 2015.

Ants prefer to pick on ants their own size

From Department of Zoology. Published on Feb 11, 2015.

Graduate student discovers new species of dragonfly in Sabah, Malaysian Borneo

From Department of Zoology. Published on Jan 30, 2015.

Zoology staff feature on TV and radio

From Department of Zoology. Published on Jan 29, 2015.

Julian Jacobs wins Employee Recognition Award

From Department of Zoology. Published on Jan 26, 2015.

'Going for Gold' with Professor Tom Welton

From Department of Zoology. Published on Jan 21, 2015.

Cambridge Biotomography Centre officially open

From Department of Zoology. Published on Jan 20, 2015.

A very personal perspective on Dengue fever

By cjb250 from University of Cambridge - Department of Zoology. Published on Jan 20, 2015.

Aedes aegypti mosquito

Dengue outbreaks, caused by bites from infected mosquitoes, are common in many developing countries. Four billion people live in areas with the disease, although mortality is relatively low. There are 400 million infections a year: 500,000 people develop severe infection symptoms and approximately 25,000 of these die. However, it places a huge burden on the health services of countries where there are major outbreaks. “Epidemics can swamp public health and intensive care services,” says Leah. “They create fear even if there is a low likelihood of death and in many countries virtually everyone knows someone who has died from it, most of whom are children.”

For her PhD she has been working with both human and non-human primate sera in partnership with the US-based National Institutes of Health. Isolates from some of the main strains of the dengue virus are injected and Leah studies the immune sera to chart the inter-relationship between the four main strains of the virus. Dengue only causes mild infection in the non-human primates she works with.

Leah, who majored in anthropology as an undergraduate in the US, travelled to Nicaragua in her third year as part of a summer fellowship programme on international health. Her aim was to learn about different health systems and beliefs about health. Her research involved talking to people in non-governmental organisations (NGOs) about their aims and talking to people on the ground about how the NGOs were perceived. Then she contracted dengue fever and became very sick and was admitted to hospital.

“There is no cure for dengue and only the symptoms can be treated. In the most mild cases dengue is asymptomatic. Normally people suffer from joint ache, headaches, pain behind the eyes and a strange rash on the hands. In the most extreme cases they suffer from haemorrhagic fever and a rapid drop in platelet count and blood pressure which can cause the body to go into shock. Children who go into shock have a high mortality rate, but if they get good healthcare they can survive,” says Leah.

She spent a week in hospital being monitored for possible shock. Her vascular system was so traumatised afterwards that she felt very weak. The experience led to her doing a lot of research on dengue fever and caused her to rethink her future since people who have been exposed to dengue fever before are more likely to suffer the more extreme form the next time round.  As an anthropologist she would have needed to travel and mainly to places where there was dengue fever, but she did not want to risk getting it again.

Leah applied for a fellowship from Williams College in the US to study at Cambridge and spent the summer before in a dengue laboratory in North Carolina estimating transmission of dengue fever in Sri Lanka.

Once at Cambridge, she googled dengue fever research on the university website and the only person she came across who mentioned it was Professor Derek Smith, who studies infectious disease in the Department of Zoology. She read his paper on antigenic cartography and the evolution of flu viruses and felt it could be applied to the four different types of dengue and the complex interaction between those types. She wanted to design an antigenic map for dengue which would show the relationship between the different viruses and how having one might protect you from having that same strain again while having the others could make your feel worse.

She emailed Professor Smith and put her proposal to him. He said there was no funding for a project on dengue. However, Leah’s fellowship allowed her to switch the focus of her studies after a year. That meant she could get funding for a year. She then applied to do a PhD to continue her work and for a Gates Cambridge Scholarship to support her.

Leah began her PhD in 2012 and hopes to complete it next year.  She has been working round the clock on her research and says it was initially terrifying since her background was in anthropology rather than lab-based science. Since then she has been presenting her findings at international meetings such as the World Health Organization and has submitted a paper for review to a top journal. She plans to keep working on dengue fever after her PhD is completed and to better understand the human immune response to dengue virus infection so that scientists can limit its impact.

Leah Katzelnick was all set for a career as an anthropologist until she contracted dengue fever. She was in hospital for a week with severe symptoms. It changed her life. She is now working on a new perspective on dengue fever which involves mapping the complex interaction between different strains of the virus, based on similar work done by Cambridge experts on flu.

There is no cure for dengue and only the symptoms can be treated
Leah Katzelnick
Aedes aegypti mosquito

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License type: 

The Janet Moore Prize for supervising in Zoology

From Department of Zoology. Published on Dec 22, 2014.

Christmas Library Closure

From Department of Zoology. Published on Dec 17, 2014.

It’s lonely at the top: stickleback leaders are stickleback loners

By amb206 from University of Cambridge - Department of Zoology. Published on Dec 02, 2014.

Throughout the animal kingdom, individuals often live and move together in groups, from swarms of insects to troops of primates. Individual animals may benefit from being part of groups, which provide protection from predators and help in finding food. To ensure that individuals reap the benefits of togetherness, group members coordinate their behaviour. As a result, leaders and followers emerge.

Within groups, animals differ from each other in how they cope with their environment and often exhibit distinctive traits, such as boldness or sociability. Even three-spined sticklebacks, the ‘tiddlers’ collected from streams and ponds by generations of schoolchildren, can be described in terms of their personalities: some are bolder and take more risks, while others are more timid and spend more of their time hiding in the weeds.

Research carried out in the Zoology Department at the University of Cambridge suggests that observations of these tiny fish, and how they interact with one another, could provide important insights into the dynamics of social groups, including humans. The findings are published today (2 December 2014) in Animal Behaviour.

Jolle Jolles, lead author of the study, said: “Although we now know that the spectacular collective behaviours we find throughout the animal kingdom can often be explained by individuals following simple rules, little is known about how this may be affected by the personality types that exist within the group.

“Our research shows that personality plays an important role in collective behaviour and that boldness and sociability may have significant, and complementary, effects on the functioning of the group.”

In the study, the researchers studied the behaviours of sticklebacks in tanks containing gravel and weed to imitate patches of a riverbed. The tanks were divided into two lanes by transparent partitions and randomly-selected pairs of fish were placed one in each lane. Separated by the see-through division, the fish were able to see and interact with one another.

The positions and movements of the individual sticklebacks were recorded using sophisticated tracking technology, enabling accurate comparisons to be made of each fish’s role in the collective movement of the pair.

“We found that individuals differed considerably and consistently in their tendency to approach their partner,” said Jolles. The study showed that more sociable individuals tended to be coordinated in their behaviour while less sociable individuals were more inclined to lead.

Dr Andrea Manica, reader at the Department of Zoology and co-author of the paper, added: “Our research revealed that the tendency of fish to approach their partner was strongly linked to their boldness: bolder fish were less sociable than their more timid group mates.”

Jolles explains that sociability may form part of a broader behavioural syndrome. “Our results suggest that bolder, less sociable individuals may often lead simply because they are less reluctant to move away from their partners, whereas shyer, more sociable, individuals become followers because they prioritise staying close to others,” he said.

“Differences in boldness and sociability may be expressions of underlying risk-prone or risk-averse behavioural types, as risk-averse individuals may be more motivated to group together and to respond to other individuals in order to avoid predation.”

The findings of this study suggest that leadership and group coordination can be strongly affected by personality differences in the group and that boldness and sociability may play important but complementary roles in collective behaviour.

“Now we know these personality traits affect the collective movements of pairs of fish, the next step is to understand their role in the functioning and success of larger, more dynamic groups,” said Jolles.

“Although our study was conducted with fish and its results are therefore not directly applicable to humans, it provides new insights into the mechanisms that underlie group behaviour and may therefore even tell us something about ourselves.”

The study, ‘The role of social attraction and its link with boldness in the collective movements of three-spined sticklebacks, is published today (2 December 2014) in Animal Behaviour.

 

Research reveals that sticklebacks with bolder personalities are not only better leaders but also less sociable than more timid fish. The behaviour of these bolder fish shapes the dynamics of the group.

Our results suggest that bolder, less sociable individuals may often lead simply because they are less reluctant to move away from their partners, whereas shyer, more sociable, individuals become followers because they prioritise staying close to others.
Jolle Jolles
Three-spined sticklebacks

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Biobullets

By cleh3 from University of Cambridge - Department of Zoology. Published on Nov 28, 2014.

By developing BioBullets – an elegant and environmentally-sensitive way of controlling one of the world's most invasive freshwater pests – University of Cambridge scientists will help utility companies save millions of pounds.

On target

Since Dr David Aldridge and Dr Geoff Moggridge set up BioBullets in 2000, the company has achieved remarkable success in developing products to combat zebra mussels. One of the world's most invasive freshwater pests, the zebra mussel costs utility companies worldwide billions of dollars to control.

Today, BioBullets boasts a unique patented product, a UK-based manufacturing plant in Bristol capable of producing 3,000 tonnes a year, plus UK Drinking Water Inspectorate approval for two of its key products – Silver Bullets 1000 and Silver Bullets 2000.

BioBullets products have been successfully tested in full-scale trials in three of the UK's largest water companies including Thames Water, which in 2010 alone spent £1m clearing zebra mussels from its raw water pipes.

BioBullets is now developing products aimed at other economically and ecologically important aquatic pests, such as Asian clams and sea squirts. And, because behind BioBullets is a new and innovative way of delivering molecules to filter feeders, it is also being harnessed to boost productivity in shellfish aquaculture – a major market with a key role in global food security.


Invasive mussel

Native to the Caspian and the Black seas, the zebra mussel has invaded most of western Europe and large parts of North America. Unlike native mussels, zebra mussels have a beard-like thread that makes them adept at attaching to solid surfaces from other shellfish to water pipes.

As a result, zebra mussels are causing major ecosystem change around the world, driving native species to extinction, and having a major economic impact on water companies and powers plants. In North America alone, zebra mussels cause damage costing an estimated US$5 billion a year.

Current control methods rely on chlorine, but as a means of killing zebra mussels, chlorine is far from efficient. When they detect chlorine in the water, the mussels close their shells, and can remain shut for up to four weeks, meaning continual dosing with chlorine is required.

Chlorine is also dangerous to store and handle, damages other freshwater organisms, and because it reacts with organic matter to produce carcinogens, its use in raw water is being outlawed worldwide.


Lethal weapon

Imagining a better solution, in 1998 Aldridge and Moggridge began experimenting with ways to encapsulate a biocide that would evade zebra mussels' defences. Their aim was to design a Trojan horse – a lethal particle that the zebra mussel thought was a food item, and that would kill the zebra mussel without harming non-target species.

Key to success was learning more about how zebra mussels feed, something Aldridge uncovered using a tiny endoscope.

Then came the clever chemistry needed to disguise a biocide as a tasty morsel for a zebra mussel, finding not only the right size of particle, but the correct shape, surface texture and buoyancy.

Finally they found a manufacturing partner who could help them build a plant and produce products with reliable formulations, and packaging that would give BioBullets the correct shelf life as well as making them safe and easy to handle and deliver.

We believe BioBullets will save hundreds of thousands of pounds in operational costs in a way that has no adverse impact on the environment

Dr Piers Clark, Thames Water

Amazing feet of science: Researchers sequence the centipede genome

By cjb250 from University of Cambridge - Department of Zoology. Published on Nov 25, 2014.

Strigamia maritima male, Loch Linnhe, Scotland

An international team comprising more researchers than the arthropod has legs (106 researchers) has sequenced the genome of Strigamia maritima, a Northern European centipede, and found that its genome, while less than a tenth the size of a human’s, has around two-thirds the number of genes, distributed across one pair of large chromosomes and seven pairs of tiny ones, including X and Y sex chromosomes. The results are published today in the journal PLOS Biology.

Arthropods are the most species-rich group of animals on Earth. There are four classes of arthropods alive today: insects, crustaceans, chelicerates (which include spiders and scorpions) and myriapods. This latter class, which includes centipedes, is the only class for which no genome has yet been sequenced.

Myriapods arose most likely from marine ancestors that invaded the land more than 400 million years ago. All myriapods have a large number of near-identical segments, most bearing one or two pairs of legs. However, despite their name, centipedes never have a hundred legs. Strigamia maritima, which lives in coastal habitats, can have from 45 to 51 pairs – but the number of pairs is always odd, as it is in all centipedes.

Credit: Carlo BrenaThe team found that the centipede genome is more conserved than that of many other arthropods, such as the fruit fly, with less gene loss and scrambling. This suggests that the centipede has evolved slowly from their common ancestor and should allow researchers to draw comparisons between very different animals, which are not obvious when working with fruit flies or other fast evolving insects.  For example, the researchers found parallels in the way that the brain is patterned between centipedes and other very distantly related animals such as marine worms.  Such comparisons will enable scientists to build an overall picture of how genetic changes underlie the diversity of all animals.

“With genomes in hand from each of the four classes of living arthropod, we can now begin to build a picture of the genetic make-up of their common ancestor,” says Dr Frank Jiggins, of the Department of Genetics at the University of Cambridge, one of the researchers involved “For example, by comparing flies and mosquitoes with centipedes, we have shown that the innate immune systems of insects are much older than previously appreciated.”

One of the most surprising findings is that these centipedes appear to have lost the genes encoding all of the known light receptors used by animals, as well as the genes controlling circadian rhythm, the body clock.

“Strigamia live underground and have no eyes, so it is not surprising that many of the genes for light receptors are missing, but they behave as if they are hiding from the light. They must have some alternative way of detecting when they are exposed,” says Professor Michael Akam, Head of the Department of Zoology at Cambridge and one of the lead researchers. “It’s curious, too, that this creature appears to have no body clock – or if it does, it must use a system very different to other animals.”

The centipede’s genome sequence is of more than just scientific interest, argues Professor Akam. “Some of its genes may be of direct use.  All centipedes inject venom to paralyse their prey,” he explains. “Components of venom often make powerful drugs, and the centipede genome will help researchers find these venom genes.”

Reference
Chipman, AD et al. The First Myriapod Genome Sequence Reveals Conservative Arthropod Gene Content and Genome Organisation In the Centipede Strigamia maritima. PLOS Biology; 25 Nov 2014

What it lacks in genes, it certainly makes up for in legs: the genome of the humble centipede has been found to have around 15,000 genes – around 7,000 fewer than a human.

Strigamia live underground and have no eyes, so it is not surprising that many of the genes for light receptors are missing, but they behave as if they are hiding from the light
Michael Akam
Strigamia maritima male, Loch Linnhe, Scotland

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Staying ahead of the game: Pre-empting flu evolution may make for better vaccines

By cjb250 from University of Cambridge - Department of Zoology. Published on Nov 20, 2014.

Flu vaccine

In a study published today in the journal Science, the researchers in the UK, Vietnam, The Netherlands and Australia, led by the University of Cambridge, describe how an immunological phenomenon they refer to as a ‘back boost’ suggests that it may be better to pre-emptively vaccinate against likely future strains than to use a strain already circulating in the human population.

Influenza is a notoriously difficult virus against which to vaccinate. There are many different strains circulating – both in human and animal populations – and these strains themselves evolve rapidly. Yet manufacturers, who need to produce around 350 million doses ahead of the annual ‘flu season’, must know which strain to put in the vaccine months in advance – during which time the circulating viruses can evolve again.

Scientists at the World Health Organisation (WHO) meet each February to select which strain to use in vaccine development. Due to the complexity of human immune responses, this is decided largely through analysis of immune responses in ferrets to infer which strain best matches those currently circulating. However, vaccination campaigns for the following winter flu season usually start in October, by which time the virus may have evolved such that the effectiveness of the vaccine match is reduced.

“It’s a real challenge: the WHO selects a strain of flu using the best information available but is faced with the possibility that the virus will evolve before the flu season,” explains Dr Judy Fonville, one of the primary authors on the paper and a member of WHO Collaborating Centre for Modelling, Evolution and Control of Emerging Infectious Diseases at the University of Cambridge. “Even if it does, though, it’s worth remembering that the flu vaccine still offers much greater protection than having no jab. We’re looking for ways to make an important vaccine even more effective.”

According to the WHO, seasonal influenza causes between 3 and 5 million cases of severe illness each year worldwide, up to 500,000 deaths, as well as significant economic impact. Vaccination policies vary per country, but are typically recommended for those at risk of serious complications, such as pregnant women and the elderly. The seasonal flu vaccine has been described as one of the most cost-effective measures of disease prevention, and vaccination therefore has a large health economic benefit. Currently 350 million people partake in annual vaccination programmes. Yet there is room for improvement.

After gathering an extensive amount of immunological data, the team modelled the antibody response to vaccination and infection using a newly developed computer-based method to create an individual’s ‘antibody landscape’. This landscape visualises an individual’s distinct immune profile like a three dimensional landscape with mountains in areas of immune memory and valleys in unprotected areas. The technique enables a much greater understanding of how our immune system responds to pathogens such as flu that evolve and re-infect us.



A key finding from the work is that upon infection, a response is seen not just to the infecting influenza strain, but to all the strains that an individual has encountered in the past. It is this broad recall of immunity, that they term the ‘back-boost’, that is the basis for the proposed vaccine improvement.

Dr Sam Wilks, one of the primary authors, explains: “Crucially, when the vaccine strain is updated pre-emptively, we see that it still stimulates better protection against future viruses yet this comes at no cost to the protection generated against currently circulating ones.

“Faced with uncertainty about how and when the flu virus might evolve, it’s better to gamble than to be conservative: if you update early, you still stimulate protection against current strains – much worse is if you update too late. Rather than trying to play ‘catch-up’, it’s better to anticipate and prepare for the likely next step of influenza evolution – and there is no penalty for doing it too soon.”

Professor Derek Smith, also from Cambridge, adds why this may lead to improved vaccines in a relatively short timeframe: “The beauty of this approach is that it would not require any change to the current manufacturing process. From the point that the new strain has been selected through to an individual receiving their shot, the steps will be exactly the same. The only difference would be greater protection for the recipient.”

The team is now combining this research with their other work on predicting the way in which the virus will evolve, and plan to combine these two major pieces of work in prospective clinical trials.

The international collaboration included researchers from: the Erasmus Medical Center, the Netherlands; the Oxford University Clinical Research Unit & Wellcome Trust Major Overseas Programme and the National Institute of Hygiene and Epidemiology, Vietnam; and the WHO Collaborating Centre for Reference and Research on Influenza at the Victorian Infectious Diseases Reference Laboratory in Melbourne. Its principal funders were the Wellcome Trust and the US National Institutes of Health Centers of Excellence for Influenza Research and Surveillance (CEIRS).

Reference
Fonville, JM et al. Antibody landscapes after influenza virus infection or vaccination. Science; 20 Nov 2014

An international team of researchers has shown that it may be possible to improve the effectiveness of the seasonal flu vaccine by ‘pre-empting’ the evolution of the influenza virus.

Faced with uncertainty about how and when the flu virus might evolve, it’s better to gamble than to be conservative
Sam Wilks
Flu Vaccination Grippe (cropped)

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Females protect offspring from infanticide by forcing males to compete through sperm instead of violence

By fpjl2 from University of Cambridge - Department of Zoology. Published on Nov 13, 2014.

Previous research has shown that infanticide by males is widespread in many mammal species, but most commonly occurs in those species where females live in social groups dominated by one or a few males.

Outsiders will fight dominant males for access to females. When a rival male takes over a group, they will kill the infants of previously dominant males to render the females ‘sexually receptive’ again, so that they can sire their own offspring. This may be the main cause of infant mortality in some species, such as Chacma baboons.

Now, a new study published today in the journal Science shows that these brutal acts are strategic; males may only have a short time in charge before they themselves are deposed, and want to ensure the maternal investment of females is directed towards their own future offspring for the longest time possible.     

However, the females of some species - such as the mouse lemur - have evolved a highly-effective counter-strategy to stop males from killing their offspring: by having as many mates as possible in a short amount of time. By confusing the paternity of the infants, known as ‘paternity dilution’, any male act of infanticide risks the possibility of killing his own offspring.

In such species, reproductive competition shifts to after copulation, not before - so that the most successful male is the one whose sperm outcompetes those of the others. This leads to males producing ever larger quantities of sperm, leading in turn to increases in testis size. The testes of male mouse lemurs swell 5-10 times larger during the breeding season.

“In species in which infanticide occurs, testis size increases over generations, suggesting that females are more and more promiscuous to confuse paternity,” said lead author Dr Dieter Lukas, from University of Cambridge’s Department of Zoology.

“Once sperm competition has become so intense that no male can be certain of his own paternity, infanticide disappears - since males face the risk of killing their own offspring, and might not get the benefit of siring the next offspring.”

Closely related species that differ in infanticide and testes size include chimpanzees (males commit infanticide) versus bonobos (males have not been observed to kill offspring). Bonobos have testes that are roughly 15% larger than those of chimpanzees.

Male Canadian Townsend voles don’t commit infanticide, and have 50% larger testes compared to infanticidal males of close relatives the North American meadow voles, says Lukas.

He conducted the research with colleague Dr Elise Huchard, who is now based at the CNRS Centre d’Ecologie Fonctionnelle et Evolutive in Montpellier.

Fifty years ago, observations of wild Hanuman langurs shattered previous depictions of monkey groups as peaceful, supportive societies, says Lukas, as new males that had just taken control of a group of females frequently killed all juveniles.

Subsequent observations have accumulated over the years on various mammals to show that infanticide by males is a widespread phenomenon, occurring in species from house mice to lions and gorillas. In some species, he says, the biggest risk faced by infants might not actually be predators or diseases, but the adult males of their own species.

In the latest study, Lukas and Huchard compiled and compared detailed field observations for 260 mammalian species to show that male infanticide occurs in species where sexual conflict is most intense, and reproduction is monopolised by a minority of males. The researchers’ findings indicate that infanticide is a manifestation of sexual conflict in mammalian social systems.



“While it had previously been suggested that infanticide might be an evolutionary driver in mammalian societies - leading to females allying themselves with other females or forming bonds with a specific male in order to defend their offspring - we’ve now shown that this isn’t the case: male infanticide is a consequence of variation in sociality, most commonly occurring in species where both sexes live together in stable groups,” said Lukas. 

The researchers say the new study supports the idea that infanticide isn’t a general trait present in all species, but is strategic and occurs only when it is advantageous to males. The study reveals the reversible nature of male infanticide, and that it is successfully prevented by the ‘paternity dilution’ strategy of female sexual promiscuity.

Added Huchard: “Male infanticide appears and disappears over evolutionary times according to the state of the evolutionary arms race between the sexes. Although infanticide may not have contributed to shape the diversity of mammalian social systems, it has deeply influenced the evolution of sexual behaviour and sex roles.

“This study also highlights that some of the greatest challenges faced by mammals during their lifetime come from others of their own species.”

Inset images: A male mouse lemur with large testes (credit: Cornelia Kraus). A Chacma baboon with dead infant (credit: Alice Baniel)

Latest research shows the females of some mammal species will have many mates to ensure unclear paternity, so that males can’t resort to killing their rival’s offspring for fear of killing their own. This forces males to evolve to compete through sperm quantity, leading to ever-larger testicles. Scientists find that as testis size increases, infanticide disappears.

Once sperm competition has become so intense that no male can be certain of his own paternity, infanticide disappears
Dieter Lukas
Baboon fight

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Ancient DNA shows earliest European genomes weathered the ice age, and shines new light on Neanderthal interbreeding and a mystery human lineage

By fpjl2 from University of Cambridge - Department of Zoology. Published on Nov 06, 2014.

A ground-breaking new study on DNA recovered from a fossil of one of the earliest known Europeans - a man who lived 36,000 years ago in Kostenki, western Russia - has shown that the earliest European humans’ genetic ancestry survived the Last Glacial Maximum: the peak point of the last ice age.

The study also uncovers a more accurate timescale for when humans and Neanderthals interbred, and finds evidence for an early contact between the European hunter-gatherers and those in the Middle East – who would later develop agriculture and disperse into Europe about 8,000 years ago, transforming the European gene pool.

Scientists now believe Eurasians separated into at least three populations earlier than 36,000 years ago: Western Eurasians, East Asians and a mystery third lineage, all of whose descendants would develop the unique features of most non-African peoples - but not before some interbreeding with Neanderthals took place.

Led by the Centre for GeoGenetics at the University of Copenhagen, the study was conducted by an international team of researchers from institutions including the University of Cambridge’s Departments of Archaeology and Anthropology, and Zoology, and is published today in the journal Science

By cross-referencing the ancient man’s complete genome – the second oldest modern human genome ever sequenced – with previous research, the team discovered a surprising genetic “unity” running from the first modern humans in Europe, suggesting that a ‘meta-population’ of Palaeolithic hunter-gatherers with deep shared ancestry managed to survive through the Last Glacial Maximum and colonise the landmass of Europe for more than 30,000 years.

While the communities within this overarching population expanded, mixed and fragmented during seismic cultural shifts and ferocious climate change, this was a “reshuffling of the same genetic deck” say scientists, and European populations as a whole maintained the same genetic thread from their earliest establishment out of Africa until Middle Eastern populations arrived in the last 8,000 years, bringing with them agriculture and lighter skin colour.

“That there was continuity from the earliest Upper Palaeolithic to the Mesolithic, across a major glaciation, is a great insight into the evolutionary processes underlying human success,” said co-author Dr Marta Mirazón Lahr, from Cambridge’s Leverhulme Centre for Human Evolutionary Studies (LCHES).

“For 30,000 years ice sheets came and went, at one point covering two-thirds of Europe. Old cultures died and new ones emerged - such as the Aurignacian and the Grevettian - over thousands of years, and the hunter-gatherer populations ebbed and flowed. But we now know that no new sets of genes are coming in: these changes in survival and cultural kit are overlaid on the same biological background,” Mirazón Lahr said. “It is only when famers from the Near East arrived about 8,000 years ago that the structure of the European population changed significantly.”

The Kostenki genome also contained, as with all people of Eurasia today, a small percentage of Neanderthal genes, confirming previous findings which show there was an ‘admixture event’ early in the human colonisation Eurasia: a period when Neanderthals and the first humans to leave Africa for Europe briefly interbred.

The new study allows scientists to closer estimate this ‘event’ as occurring around 54,000 years ago, before the Eurasian population began to separate. This means that, even today, anyone with a Eurasian ancestry – from Chinese to Scandinavian and North American – has a small element of Neanderthal DNA.   

However, despite Western Eurasians going on to share the European landmass with Neanderthals for another 10,000 years, no further periods of interbreeding occurred.

“Were Neanderthal populations dwindling very fast? Did modern humans still encounter them? We were originally surprised to discover there had been interbreeding. Now the question is, why so little? It’s an extraordinary finding that we don’t understand yet,” said co-author Professor Robert Foley, also from LCHES.      

Unique to the Kostenki genome is a small element it shares with people who live in parts of the Middle East now, and who were also the population of farmers that arrived in Europe about 8,000 years ago and assimilated with indigenous hunter-gatherers. This early contact is surprising, and provides the first clues to a hereto unknown lineage that could be as old as – or older than – the other major Eurasian genetic lines. These two populations must have interacted briefly before 36,000 years ago, and then remained isolated from each other for tens of millennia.   

“This element of the Kostenki genome confirms the presence of a yet unmapped major population lineage in Eurasia. The population separated early on from ancestors of other Eurasians, both Europeans and Eastern Asians,” said Andaine Seguin-Orlando from the Centre for GeoGenetics in Copenhagen.

Mirazón Lahr points out that, while Western Eurasia was busy mixing as a ‘meta-population’, there was no interbreeding with these mystery populations for some 30,000 years – meaning there must have been some kind of geographic barrier for millennia, despite the fact that Europe and the Middle East seem, for us at least, to be so close geographically. But the Kostenki genome not only shows the existence of these unmapped populations, but that there was at least one window of time when whatever barrier existed became briefly permeable.

“This mystery population may have remained small for a very long time, surviving in refugia in areas such as the Zagros Mountains of Iran and Iraq, for example,” said Mirazón Lahr. “We have no idea at the moment where they were for those first 30,000 years, only that they were in the Middle East by the end of the ice age, when they invented agriculture.”

Lead author and Lundbeck Foundation Professor Eske Willerslev added: “This work reveals the complex web of population relationships in the past, generating for the first time a firm framework with which to explore how humans responded to climate change, encounters with other populations, and the dynamic landscapes of the ice age.”

Inset images (top-bottom): Russian archeologist Mikhail Mikhaylovich Gerasimov taking the Kostinki skull out of the ground in 1954; the Kostinki skull; Marta Mirazón Lahr and Robert Foley

A genome taken from a 36,000 year old skeleton reveals an early divergence of Eurasians once they had left Africa, and allows scientists to better assess the point at which ‘admixture’ - or interbreeding - between Eurasians and Neanderthals occurred. The latest research also points to a previously unknown population lineage as old as the first population separations since humans dispersed out of Africa.

These changes in survival and cultural kit are overlaid on the same biological background
Marta Mirazón Lahr
Kosenki fossil skull, and and illustration of the Kosteni find

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Croonian Lecture awarded to Prof Nick Davies

From Department of Zoology. Published on Aug 04, 2014.

Professor Ron Laskey awarded CRUK Lifetime Achievement Prize

From Department of Zoology. Published on Jul 31, 2014.

Professor Jenny Clack awarded Honorary Doctor of Science Degree

From Department of Zoology. Published on Jul 10, 2014.

Butterflies show how patterns evolve on the wing

From Department of Zoology. Published on Jul 10, 2014.

Neal Maskell – retirement party

From Department of Zoology. Published on Jun 26, 2014.

Part II Zoology Class List

From Department of Zoology. Published on Jun 16, 2014.

Academic Promotions 2014

From Department of Zoology. Published on Jun 11, 2014.

Many congratulations to two members of the Department who have received awards in this year's Academic Promotions exercise, to take effect from 1 October 2014:

Philine zu Ermgassen awarded a CUSU Teaching Excellence Award

From Department of Zoology. Published on May 27, 2014.

Paul Brakefield elected member of EMBO

From Department of Zoology. Published on May 09, 2014.

A view from the roof: Arup works are progressing well

From Department of Zoology. Published on May 07, 2014.

Compressed and Cryogenic Gas Safety Training Course

From Department of Zoology. Published on Apr 08, 2014.

Two recent prizes for Sarah Luke

From Department of Zoology. Published on Apr 04, 2014.

Claire Feniuk wins first prize at the Student Conference on Conservation Science

From Department of Zoology. Published on Mar 31, 2014.

Gerit Linneweber wins 3rd prize in GSLS image competition

From Department of Zoology. Published on Mar 25, 2014.

Museum wins £1.8 million grant from Heritage Lottery Fund

From Department of Zoology. Published on Mar 20, 2014.

Alex Hackmann wins Graduate School of Life Sciences Image Competition

From Department of Zoology. Published on Mar 17, 2014.

David Williams wins first prize at Clare Graduate Symposium

From Department of Zoology. Published on Mar 17, 2014.

The Department launches a mentoring scheme for post-docs

From Department of Zoology. Published on Mar 12, 2014.

Dr Nancy Lane featured in Dalhousie University Alumni magazine

From Department of Zoology. Published on Mar 11, 2014.

Wendy Whitmore visits the Department

From Department of Zoology. Published on Mar 06, 2014.