Female meerkats compete to outgrow their sisters
By Anonymous from University of Cambridge - Department of Zoology. Published on May 26, 2016.
Meerkats live in groups of up to 50 individuals, yet a single dominant pair will almost completely monopolise reproduction, while subordinates help to raise offspring through feeding and babysitting. Since only a small minority of individuals ever get to be dominants, competition for the breeding role is intense in both sexes and females are unusually aggressive to each other.
Within groups, subordinate females are ranked in a hierarchy based on age and weight, forming a “reproductive queue”. When dominant females die, they are usually replaced by their oldest and heaviest daughter, though younger sisters sometimes outgrow their older sisters and can replace them in breeding queues.
University of Cambridge scientists working on wild Kalahari meerkats identified pairs of sisters and artificially increased the growth of the younger member of each pair by feeding them three times a day with hard-boiled egg.
The scientists weighed them and their (unfed) older sisters daily for three months. The results, published today in the journal Nature, show that the increased growth of younger females stimulated their older sisters to increase their daily food intake and weight gain in an attempt to outgrow their rivals.
Tellingly, the extent to which the older sister increased her weight was greater when her younger sister’s weight gain was relatively large than when it was slight.
These results suggest that subordinate meerkats are continually keeping tabs on those nearest them in the breeding queue, and make concerted efforts to ensure they are not overtaken in size and social status by younger and heavier upstarts.
But competitive growth does not stop there. If a female meerkat gets to be a dominant breeder, her period in the role (and her total breeding success) is longer if she is substantially heavier than the heaviest subordinate in her group.
During the three months after acquiring their new status, dominant females gain further weight to reduce the risk of being usurped. Regular weighing sessions of newly established dominants showed that that, even if they were already adult, they increased in weight during the first three months after acquiring the dominant position – and that the magnitude of their weight increase was greater if the heaviest subordinate of the same sex in their group was close to them in weight.
This is the first evidence for competitive growth in mammals. The study’s authors suggest that other social mammals such as domestic animals, primates and even humans might also adjust their growth rates to those of competitors, though these responses may be particularly well developed in meerkats as a result of the unusual intensity of competition for breeding positions.
“Size really does matter and it is important to stay on top,” said senior author Professor Tim Clutton-Brock, who published the first major overview of research on mammalian social evolution this month in the book Mammal Societies (Wiley).
“Our findings suggest that subordinates may track changes in the growth and size of potential competitors through frequent interactions, and changes in growth rate may also be associated with olfactory cues that rivals can pick up,” Clutton-Brock said.
“Meerkats are intensely social and all group members engage in bouts of wrestling, chasing and play fighting, though juveniles and adolescents play more than adults. Since they live together in such close proximity and interact many times each day, it is unsurprising that individual meerkats are able to monitor each other’s strength, weight and growth.”
Male meerkats leave the group of their birth around the age of sexual maturity and attempt to displace males in other groups, and here, too, the heaviest male often becomes dominant. The researchers found a similar strategy of competitive weight-gain in subordinate males.
The data was collected over the course of twenty years and encompassed more than forty meerkat groups, as part of the long-term study of wild meerkats in the Southern Kalaharu at the Kuruman River Reserve, South Africa, which Clutton-Brock began in 1993. In the course of the study, the team have followed the careers of several thousand individually-recognisable meerkats – some of which starred in the award winning docu-soap Meerkat Manor, filmed by Oxford Scientific Films.
The meerkats were habituated to humans and individually recognisable due to dye marks. Most individuals were trained to climb onto electronic scales for their weigh-ins, which occurred at dawn, midday and dusk, on ten days of every month throughout their lives. This is the first time it has been feasible to weigh large numbers of wild mammals on a daily basis.
Weighing meerkats. Image credit: Tim Clutton-Brock
Latest research shows subordinate meerkat siblings grow competitively, boosting their chance of becoming a dominant breeder when a vacancy opens up by making sure that younger siblings don’t outgrow them.
Genes discovered that enable birds to produce the colour red
By fpjl2 from University of Cambridge - Department of Zoology. Published on May 20, 2016.
Right across the bird and animal kingdoms, the colour red is used for communication, often to attract mates, and zebra finches are no different: the males have a distinctive red beak, which is a sexually selected trait - as females prefer males with redder beaks.
New research on zebra finches has identified for the first time the genes that allow some bird species to produce the red pigment that plays such a critical role in attraction and mating.
The genes belong to a wider family of genes that also play an important role in detoxification, suggesting how heightened redness may be a sign of mate quality: it indicates a bird's ability to cleanse harmful substances from its body.
This could explain what's known as 'honest signaling': where an evolved trait is a genuine sign of better, fitter genes - in this case the ability to better deal with anything toxic.
The research is published today in the journal Current Biology.
Birds such as the zebra finch obtain yellow pigments, known as carotenoids, from their diet of seeds, or insects in the case of other bird species.
Prior to the latest findings, it was known that such birds must have a way of converting these yellow dietary pigments into the red pigments - the ketocarotenoids - that colour the beaks, feathers or bare skin of many species. However, the mechanism for this process was unclear.
Nick Mundy from Cambridge's Department of Zoology, along with colleagues including Staffan Andersson from the University of Gothenburg and Jessica Stapley from the University of Sheffield, compared the gene sequences of wild, red-beaked zebra finches with captive finches that had a mutant, recessive gene causing yellow beaks.
They identified a cluster of three genes in the wild finches that were either missing or mutated in this genetic region in the 'yellowbeak' birds.
These genes encode enzymes called cytochrome P450s, which play an important role in breaking down and metabolising toxic compounds, primarily in the liver of vertebrates. In humans, these enzymes are well-studied, as they are strongly associated with drug metabolism.
"It was known that birds have an unusual ability to synthesize red ketocarotenoids from the yellow carotenoids that they obtain in their diet, but the enzyme, gene or genes, and anatomical location have been obscure," said Mundy. "Our findings fill this gap and open up many future avenues for research on the evolution and ecology of red coloration in birds."
Red colour in birds is thought to signal individual genetic quality, and the researchers argue that one way it can do this is if the amount of red colour relates to other beneficial physiological processes, such as detoxification.
"Our results, which link a detoxification gene to carotenoid metabolism, shed new light on this old hypothesis about the honesty of signalling," said co-author Staffan Andersson.
The researchers found the specific expression of one or more of the identified 'red' gene cluster in the tissues where the red pigments were deposited: the beak, the tarsus in the bird's feet - as well as in the retina.
The structure of retinas in the eye includes cone-shaped photoreceptor cells. Unlike mammals, avian retinal cones contain a range of brightly-coloured oil droplets, including green, yellow and red. These oil droplets allow birds to see many more colours than mammals.
Mundy says that the newly-discovered genetic links between red beaks and feathers and the internal red retina droplets suggest that producing red pigment evolved for colour vision before it developed a function for external display - as, while red oil eye droplets are ubiquitous across bird species, external reds are only patchily distributed.
"It was quite a surprise that the same genes are involved both in seeing red colours and making red coloration," said Mundy.
Mundy says he and his colleagues are now working on the genetics of red coloration in African widowbirds and bishops, which show "spectacular differences among different species."
Latest research suggests a new mechanism for how sexual displays of red beaks and plumage might be ‘honest signals’ of mate quality, as genes that convert yellow dietary pigments into red share cofactors with enzymes that aid detoxification – hinting that redness is a genetic sign of the ability to better metabolise harmful substances.
Natural selection sculpts genetic information to limit diversity
By tdk25 from University of Cambridge - Department of Zoology. Published on May 13, 2016.
A study of tropical butterflies has added to growing evidence that natural selection reduces species’ diversity by moulding parts of their genetic structure, including elements that have no immediate impact on their survival.
The research, by a University of Cambridge-led team of academics, focused on genetic data from South American Heliconius butterflies. It showed that when these butterflies develop a beneficial adaptation through a mutation in their DNA, other parts of the same chromosome – the long strings of DNA that make up the butterfly’s genome – may end up being defined by the fact that they are “linked” to the point where the mutation took place. Natural selection ends up influencing the fate of these linked sites, even though they have no impact on the species’ fitness and long-term survival prospects.
As the adaptation is passed down through the generations as a result of natural selection, this collection of linked genetic sites can be passed on intact, removing genetic variation that previously existed in the population at these sites. This effectively limits the overall amount of variation in the butterfly population.
The study complements similar findings in other species, including humans and fruit flies, which together offer one possible solution to a long-standing paradox in population genetics. This is the fact that while species with bigger populations should be more genetically diverse – because there is more potential for new mutations to occur – in practice they often only exhibit as much diversity as smaller populations.
For example, in the Cambridge-led study, the researchers found that the genetic diversity of Heliconius butterflies is very similar to that of fruit flies, even though fruit flies are far more numerous. They also estimated that the amount of adaptation within Heliconius butterflies caused by natural selection is probably about half that of fruit flies. In other words, because natural selection affects the fruit flies more, reducing variation, they end up exhibiting roughly the same amount of genetic diversity, even though there are more of them.
The researchers stress that this explanation for variable levels of genetic diversity between different species is still, at the moment, a theory. Not all scientists are convinced that natural selection has this effect and argue that the variable diversity of species relative to population size may well have other causes.
Understanding more about what these causes are will, however, help to answer even more fundamental scientific questions – such as how and why species vary in the first place, and when they can really be said to have become distinct enough from their ancestors to represent a species in their own right.
Dr Simon Martin, a Research Fellow at St John’s College, Cambridge, who led the study, said: “We will only be able to understand this fully if we can compare results from across different species. Extending our knowledge to butterflies is a step towards explaining these much broader patterns in nature; it’s only by doing this kind of research that we will know whether these ideas are right or not.”
Martin and his colleagues examined a very large data set of 79 whole genome sequences representing 12 related species of Heliconius butterfly. This large-scale data has only become available in recent years, as a result of advances in genome sequencing which have made the process both easier and more affordable.
The study involved scouring the sequences for an apparent pattern of association between particular sites within the genome and low variation. “That acts as a kind of signature,” Martin said. “If you can see that in a genome, then as far as we can tell it is an indication of selection.”
In addition, the researchers compared the number of variations in the parts of the genome where proteins are coded – and therefore may be responsible for adaptations – with the number of variations in other parts of the genome. It is possible to predict what this ratio would be if variations only occurred by chance. The difference between that prediction, and the actual statistics, suggests the extent to which natural selection has shaped species differences.
The study estimated that around 30% of the protein differences between species of Heliconius are adaptations caused by natural selection. In keeping with theories about diversity in the population of other species, this turned out to be about half the number of protein variations in fruit flies – a larger population with less genetic diversity overall.
Intriguingly, the study effectively suggests that natural selection could limit a species' ability to adapt to future environmental change by removing linked variations that, despite having no immediate beneficial impact on the species, could become relevant to its survival and capacity to cope with its environment in the future.
“Variation is a kind of raw material and you don’t necessarily use it all at any one time,” Martin explained. “It’s something that could be used to adapt and change in the future.”
“Something that has turned up during the last few years in research of this kind is a phenomenon where we see that a species has adapted, and we discover, when we look for the origin of that adaptation, that the mutation was not actually new. Instead, it was a variation that previously existed in the population. So while we cannot forecast the future, an emerging idea is that mutations that have no effect on survival today may be a source of beneficial variation in the future.”
The study appears in the May 2016 issue of Genetics.
A study of butterflies suggests that when a species adapts, other parts of its genetic make-up can be linked to that adaptation, limiting diversity in the population.
Youngest Ancient Egyptian human foetus discovered in miniature coffin at the Fitzwilliam Museum
By fpjl2 from University of Cambridge - Department of Zoology. Published on May 12, 2016.
A miniature ancient Egyptian coffin measuring just 44cm in length has been found to contain the youngest ever example of a human foetus to be embalmed and buried in Egyptian society. This discovery is the only academically verified specimen to exist at only sixteen to eighteen weeks of gestation.
This landmark discovery from the Fitzwilliam Museum in Cambridge, is remarkable evidence of the importance that was placed on official burial rituals in ancient Egypt, even for those lives that were lost so early on in their existence. Curators at the Fitzwilliam made the discovery, during their research for the pioneering bicentennial exhibition Death on the Nile: Uncovering the afterlife of ancient Egypt.
The tiny coffin was excavated at Giza in 1907 by the British School of Archaeology and came into the collection at the Fitzwilliam Museum the same year. It is a perfect miniature example of a wooden coffin of the ancient Egyptian ‘Late Period’ and may date to around 664-525 BC. The lid and box are both made from cedar wood. Although the coffin is deteriorated, it is clear that the wood was carefully carved on a painstakingly small scale and decorated. This gave the curators at the Fitzwilliam the first very clear indication of the importance given to the coffin’s contents at this time in ancient Egyptian society.
The diminutive wrapped package inside was carefully bound in bandages, over which molten black resin had been poured before the coffin was closed. For many years it was thought that the contents were the mummified remains of internal organs that were routinely removed during the embalming of bodies.
Examination using X-ray imaging at the Fitzwilliam Museum was inconclusive, but suggested that it may contain a small skeleton. It was therefore decided to micro CT (computed tomography) scan the tiny bundle at Cambridge University’s Department of Zoology. The cross-sectional images this produced gave the first pictures of the remains of a tiny human body held within the wrappings, which remain undisturbed.
Dr Tom Turmezei, recently Honorary Consultant Radiologist at Addenbrooke’s Hospital in Cambridge collaborated with the Fitzwilliam Museum, alongside Dr. Owen Arthurs, Academic Consultant Paediatric Radiologist at Great Ormond Street Hospital, London. The ground-breaking results were based on their extensive knowledge of CT imaging and paediatric autopsy.
Five digits on both hands and feet and the long bones of the legs and arms were all clearly visible. Although the soft skull and pelvis were found to be collapsed the categorical consensus was that inside the bundle was a human foetus estimated to be of no more than eighteen weeks gestation. It was impossible to give a gender to the specimen and it is thought that the foetus was probably the result of a miscarriage, as there were no obvious abnormalities to explain why it could not have been carried to full-term.
From the micro CT scan it is noticeable that the foetus has its arms crossed over its chest. This, coupled with the intricacy of the tiny coffin and its decoration, are clear indications of the importance and time given to this burial in Egyptian society.
"CT imaging has been used successfully by the museum for several projects in recent years, but this is our most successful find so far," Dr. Tom Turmezei explained. "The ability of CT to show the inner workings of such artefacts without causing any structural damage proved even more invaluable in this case, allowing us to review the foetus for abnormalities and attempt to age it as accurately as possible."
Julie Dawson, Head of Conservation at the Fitzwilliam Museum said, "Using non-invasive modern technology to investigate this extraordinary archaeological find has provided us with striking evidence of how an unborn child might be viewed in ancient Egyptian society. The care taken in the preparation of this burial clearly demonstrates the value placed on life even in the first weeks of its inception."
Tutankhamun’s tomb contained two small foetuses that had been mummified and placed in individual coffins, but these infants were both significantly more developed, at about 25 weeks and 37 weeks into gestation. Very few other examples of burials of miscarried babies have so far been identified from ancient Egypt.
The miniature coffin is currently on display as part of the exhibition Death on the Nile: Uncovering the Afterlife of ancient Egypt until 22nd May 2016 at the Fitzwilliam Museum Cambridge.
Inset image: Micro CT scan image of the upper limbs
Tiny coffin excavated at Giza in 1907 is remarkable evidence of importance placed on official burial rituals in ancient Egypt.
Opinion: There’s a reason why Africa’s migratory songbirds sing out of season
By Anonymous from University of Cambridge - Department of Zoology. Published on May 09, 2016.
Bird song has fascinated scientists for decades. Songs can be intricate, loud and, as it turns out, very important for reproductive success. In many species the males with the most complex songs secure the highest quality breeding territories and mates, and end up producing the most young. For species that spend their summers in Europe, almost every hour of daylight is crammed full with energetic and often very loud song.
For songbirds that have migrated to Africa at the end of the breeding season, singing shouldn’t be on their to-do list. Singing requires a big energetic investment and increases vulnerability to predators. The only time males should be willing to pay these costs is when there is a good chance of attracting females as mates, and that is not going to happen in Africa outside of the breeding season.
Despite this, several species of migratory songbirds, from Wood Warblers to Nightingales, are known to sing a great deal in Africa. This prompted us to ask: what is the purpose of singing in Africa, when the breeding grounds are thousands of kilometres away? To answer this question, we focused on a drab-looking but raucous singer, the Great Reed Warbler. This species breeds in Europe and spends the northern winter in the wet grasslands and savannahs of sub-Saharan Africa.
Testing a long-held hypothesis
We began by testing a long-held hypothesis for the persistence of singing in Africa. Perhaps singing is being used as a means to defend individual winter-feeding territories. It might be acting as a “keep out” sign to other individuals encroaching on the territory holder’s space.
In territorial systems, distinct boundaries are expected between the spaces used by each individual in combination with an aggressive reaction when that territorial boundary is breached. We used radio transmitters to track bird movements through the tall grasses of the study site in Zambia, and used models of Great Reed Warblers with recorded song to simulate territory intrusions. We found no support for the expectations of territoriality. Great Reed Warblers overlapped widely in their use of space, and individuals were unperturbed by other birds in their space.
Given that Great Reed Warblers did not have a territorial system, this long-held hypothesis of singing for territorial protection didn’t hold up.
Singing for song improvement
Next, we tackled an intriguing but yet untested hypothesis. Perhaps, given the importance of song quality for males during breeding, they were using their downtime in Africa to improve the quality of their songs.
To find out, we combed through the literature and spoke to other researchers in Africa to determine which of the 57 migratory songbird species that migrate from Europe sing while in Africa and, importantly, how much. If this hypothesis is true, the benefits of singing in Africa should be most important for species in which song is especially valued when choosing a mate. Those should be species with the most complex songs, but conversely with the dullest appearance. So, when males are drab, females are expected to pay more attention to flashy song rather than flashy plumage.
Sure enough, we found that species with more complex songs, and those with drab plumage colouration, sing most often when in Africa. We argue that the costs associated with practice are probably well worth the investment for those species that stand to benefit most from producing the highest-quality songs.
A final piece of evidence comes from the Great Reed Warblers themselves. If songs function to defend territories, then they should sing the short territorial warnings they use to defend their breeding territories. But instead, recordings from Zambia showed that African songs are much more like those sung during mate attraction on the breeding grounds, when attracting a female is paramount. But there are a couple of important differences.
In Africa, songs are much longer and with many more switches between syllables than those sung in Europe. Given that songs in Africa are sung without a female receiver in mind, this may be the best way to practice. In Europe, when songs are mixed amongst the racket from competing males, repeating complex syllables up to five times is important to ensure that they are received loud and clear by females.
With the evidence tallied, both from Great Reed Warblers and across the dozens of songbird species that migrate between Africa and Europe, this puzzling non-breeding singing behaviour appears best explained as a rehearsal period before the big show the following spring.
To conclusively test this hypothesis, researchers would need to follow individual birds between their breeding and non-breeding grounds and monitor changes to their song and their breeding success. But this is close to impossible given the current tracking devices available. For now, this study points towards an intriguing new explanation for this previously unstudied behaviour. It also offers insight into the lives of migratory songbirds during the lengthy, but little-known part of their lives spent in Africa.
The opinions expressed in this article are those of the individual author(s) and do not represent the views of the University of Cambridge.
Claire Spottiswoode (Department of Zoology) and Marjorie Sorensen (Goethe University Frankfurt am Main) discuss why several species of migratory songbirds sing a great deal in Africa when their breeding grounds are thousands of kilometres away.
Raising the Whale: defining zoology at Cambridge
From Department of Zoology. Published on Apr 29, 2016.
Threat of novel swine flu viruses in pigs and humans
By Anonymous from University of Cambridge - Department of Zoology. Published on Apr 27, 2016.
While swine flu viruses have long been considered a risk for human pandemics, and were the source of the 2009 pandemic H1N1 virus, attention has recently turned to the transmission of flu viruses from humans to pigs.
"Once in pigs, flu viruses from humans continue to evolve their surface proteins, generically referred to as antigens, resulting in a tremendous diversity of novel flu viruses that can be transmitted to other pigs and also to humans," explains first author Nicola Lewis from the University of Cambridge.
"These flu viruses pose a serious threat to public health because they are no longer similar enough to the current human flu strains for our immune systems to recognise them and mount an effective defence. Understanding the dynamics and consequences of this two-way transmission is important for designing effective strategies to detect and respond to new strains of flu."
Humans and pigs both experience regular outbreaks of influenza A viruses, most commonly from H1 and H3 subtypes. Their genetic diversity is well characterised. However, the diversity of their antigens, which shapes their pandemic potential, is poorly understood, mainly due to lack of data.
To help improve this understanding, Lewis and her team created the largest and most geographically comprehensive dataset of antigenic variation. They amassed and characterised antigens from nearly 600 flu viruses dating back from 1930 through to 2013 and collected from multiple continents, including Europe, the US, and Asia. They included nearly 200 viruses that had never been studied before.
Analysis of their data reveals that the amount of antigenic diversity in swine flu viruses resembles the diversity of H1 and H3 viruses seen in humans over the last 40 years, driven by the frequent introduction of human viruses to pigs. In contrast, flu from birds has rarely contributed substantially to the diversity in pigs. However, little is currently known about the antigenic relationship between flu in birds and pigs.
"Since most of the current swine flu viruses are the result of human seasonal flu virus introductions into pigs, we anticipate at least some cross-protective immunity in the human population, which could potentially interfere with a re-introduction of these viruses. For example, the H1N1pdm09 viruses circulating in both humans and pigs are antigenically similar and therefore likely induce some immunity in both hosts," says Lewis.
"However, for the H1 1C, H3 3A, and H3 3B human seasonal lineages in pigs, the risk of re-introduction into the human population increases with the number of people born after the circulation of the human precursor virus, and is increased by the antigenic evolution of these viruses in pigs. Earlier introduced lineages of human H1 and H3 viruses therefore pose the greatest current risk to humans, due to the low or negligible predicted levels of cross-immunity in individuals born since the 1970s."
Swine flu causes symptoms such as coughing, fever, body aches, chills, and fatigue in humans. Pigs can also experience fever and coughing (barking), along with discharge from the nose or eyes, breathing difficulties, eye redness or inflammation, and going off feed - although some display no clinical signs at all.
Vaccination to control flu in pigs is used extensively in the US and occasionally in other regions. Control strategies vary by region, with some countries not using any vaccinations, while others produce herd-specific vaccines for individual producers. There is no formal system for matching vaccine strains with circulating strains, however, and no validated protocols for standardisation and effective vaccine use.
"The significant antigenic diversity that we see in our data means it is highly unlikely that one vaccine strain per subtype would be effective on a global scale, or even in a given region," says co-author Colin Russell, also from the University of Cambridge.
"Our findings therefore have important implications for developing flu vaccines for pigs. They also emphasise the need for more focused surveillance in areas with a high pig population density, such as China, and situations where humans and pigs have close contact, in order to better assess the incidence of transmission between the animals and risk of spreading to humans."
The paper 'The global antigenic diversity of swine influenza A viruses' can be freely accessed online at http://dx.doi.org/10.7554/eLife.12217.
Originally published as a press release by eLife.
The wide diversity of flu in pigs across multiple continents, mostly introduced from humans, highlights the significant potential of new swine flu strains emerging, according to a new study.
Threat of novel swine flu viruses in pigs and humans
From Department of Zoology. Published on Apr 26, 2016.
Does nature make you happy? Crowdsourcing app looks at relationship between the outdoors and wellbeing
By cjb250 from University of Cambridge - Department of Zoology. Published on Apr 26, 2016.
NatureBuzz, which is available to download free on iOS and Android platforms, asks participants three times per day to answer questions about how they feel, whether they are outside or indoors, who they are with, and what they are doing. At the same time, it records their location using GPS data.
NatureBuzz also provides information about UK nature reserves and ‘protected areas’ and will provide users with feedback on how their happiness has fluctuated, where it was highest, with whom and during which activities.
“Apps provide a great way of collecting data from thousands – possibly tens of thousands – of users, a scale that is just not possible in lab experiments,” explains research associate Laurie Parma from the Department of Psychology, who coordinates the study. “We’ll use this data to answer some fascinating and potentially very important questions about our relationship with nature.”
Studies have suggested that people are happier and reinvigorated when living in more natural settings. For example, a 2011 study from the United States found that people who live in inner cities were the least happy, while those who live in rural areas are the happiest. However, it is not clear whether all green spaces promote happiness equally.
Diversity – the number and abundance of different species in particular systems – is thought to be important in increasing the resilience of some so-called ecosystem services - such as climate regulation and pest control – that underpin human wellbeing. However, the more immediate role that biodiversity may play in affecting happiness is unclear.
“We know that people quickly become familiar with – and immune to – happiness-inducing stimuli and one potential way to combat this phenomenon is to provide new and varied stimuli,” adds Professor Andrew Balmford from the Department of Zoology. “Natural environments with greater biodiversity – different flowers, different birds, for example – present a rich variety of stimuli, so it’s possible they will keep the ‘happiness factor’ fresh for visitors.”
The researchers hope that by crowdsourcing data, they will be able to answer questions such as whether the type of green space – gardens, city parks, countryside or nature reserves, for example – have the same impact on an individual’s wellbeing, and whether someone needs to be interested in nature to benefit more from the natural environment. They believe their findings may have important consequences for how policymakers promote biodiversity and how reserve managers enable people to make the most of the happiness-improving potential of access to nature.
The app is part of a broader study of happiness and nature developed by the Departments of Psychology and Zoology, University of Cambridge, RSPB, UNEP-WCMC and Cardiff University. It is funded by the Cambridge Conservation Initiative and is part of a research programme on human happiness.
NatureBuzz is available to download from the iPhone App Store and from Google Play.
A new app will crowdsource data to help scientists understand the relationship between biodiversity and wellbeing. The app, developed at the University of Cambridge, maps happiness onto a detailed map that includes all the UK’s nature reserves and green spaces.
A damn close run thing (as Wellington probably did not say)
From Department of Zoology. Published on Apr 22, 2016.
Baboons watch neighbours for clues about food, but can end up in queues
By fpjl2 from University of Cambridge - Department of Zoology. Published on Apr 20, 2016.
Latest research on social networks in wild baboon troops has revealed how the animals get information from each other on the whereabouts of food. However, once information reaches a high status baboon, subordinates often end up in a queue for scraps.
A new study, by researchers from the University of Cambridge and the Zoological Society of London, shows how baboons monitor each other for changes in behaviour that indicate food has been found, such as hunching over to scoop it up.
This ‘socially learned’ information gets transmitted through proximity: those with more neighbours are more likely to spot when someone starts feeding. Once they do, baboons will head towards the food.
Information then starts to spread through the troop, as more baboons observe feeding behaviour or notice their neighbours moving in the direction of food. However, troop hierarchy ultimately kicks in – with the most dominant member in the vicinity, usually a male, wading in to claim the spoils.
At this point, surrounding baboons will often form what can appear to be a queue, to determine who gets to explore that patch of ground next.
These queues reflect the complex interactions within a baboon troop. The sequence of baboons in a queue depends on status – sometimes through birth-right – as well as social and familial relationships to the particular baboon occupying the food patch.
The new research, published in the open access journal eLife, breaks down the transmission of social information through a baboon troop into three stages:
- Acquiring information: observing behaviour that suggests food.
- Applying information: exploring the food patch (even if no food is left).
- Finally, exploiting information: actually getting to eat.
The researchers used social networking models to show how being close enough to spot behaviour change is the only driver for acquiring knowledge.
When it comes to applying and exploiting social knowledge, however, the characteristics of individual baboons – whether its sex, status, boldness, or social ties in grooming networks – determine who gets to eat, or where they are in any queue that forms.
Baboon troops can be sizable, sometimes as many as 100 members, with the troops in the latest study numbering around 70. On average, less than 25% of a troop – around 10 individuals – acquired information of a food patch, with less than 5% of the troop actually exploiting it.
“Who actually gets to eat is only half the story,” says Dr Alecia Carter, from Cambridge’s Department of Zoology, who led the research.
“Just looking at the animals that capture the benefits of information, in this case food, doesn’t reflect the real pattern of how information transmits through groups. Many more animals acquire information, but are limited in their use of it for a variety of reasons.”
To conduct the study, researchers snuck handfuls of maize corn kernels, a high-energy baboon favourite (“like finding a stash of chocolate bars”) into the path of two foraging troops of wild chacma baboons in Tsaobis Nature Park, Namibia.
Once a troop member found the food, the researchers recorded the identities of baboons that spotted the animal eating, accessed the food patch, and got anything to eat.
Carter says that the best place for low-ranking baboons is often the peripheries, in the hopes of finding food and grabbing a few kernels before information spreads, and they are supplanted by the local dominant.
“The more dominant a baboon is, the more spatially central in the troop they tend to be – as they can afford to be there. This provides more opportunities to gain information through the wider network,” says Carter.
Low-rankers that discover food will sometimes try to eat as stealthily or as quickly as they can, but, once a dominant has taken control of the food patch, a queue will often form. Grooming relationships to the feeding dominant can help a subordinate jump up a queue, although much of it is dictated by status.
For females, status is a birth-right that remains fixed throughout a baboon’s life. While human societies historically privilege the firstborn, in baboon troops maternal lineage is ranked by lastborn – with each new female baby replacing the last in terms of hierarchy.
Young males hold the same rank as their mother until they reach adolescence, usually around the age of six, and start asserting dominance through their bigger size, leading to shifts in status.
“It is relatively easy to collect dominance data, as baboons are constantly asserting dominance,” explains Carter. “Low-cost assertions of dominance, such as pushing an individual out of small patches of food, help to mitigate high-cost assertions, such as fights, and maintain the order.”
“However, baboons can mediate their status to a minor extent by having good grooming relationships, and low-ranking individuals have a slightly higher chance of applying and exploiting information if they are central in a grooming network. Over a lifetime of food opportunities, this may prove important for fitness.”
While baboons acquire information about food locations from watching others, they can also use social learning to see when that food is likely to be gone. Interestingly, the researchers found that males and females will often use this information in different ways.
“Baboons are highly vigilant, and constantly pay attention to what their neighbours are up to. When those in a food patch are sifting through dirt and clearly coming up empty-handed, most females will walk off, and won’t waste their time,” says Carter.
“Males on the other hand, particularly young males, are amazingly persistent, and will stay in a patch shifting sand around for a very long time in the hopes of finding a stray kernel.
“We hypothesise that, while males can afford to expend the energy, adult females are lactating or pregnant most of the time, so need to conserve their strength, and often end up using the information in a more practical way as a result.”
Baboons learn about food locations socially through monitoring the behaviour of those around them. While proximity to others is the key to acquiring information, research shows that accessing food depends on the complex hierarchies of a baboon troop, and those lower down the pecking order can end up queuing for leftovers.
Baboons queue for food - report by Alecia Carter
From Department of Zoology. Published on Apr 20, 2016.
Sonic hedgehog gene provides evidence that our limbs may have evolved from sharks’ gills
By jeh98 from University of Cambridge - Department of Zoology. Published on Apr 19, 2016.
An idea first proposed 138 years ago that limbs evolved from gills, which has been widely discredited due to lack of supporting fossil evidence, may prove correct after all – and the clue is in a gene named for everyone’s favourite blue hedgehog.
Unlike other fishes, cartilaginous fishes such as sharks, skates and rays have a series of skin flaps that protect their gills. These flaps are supported by arches of cartilage, with finger-like appendages called branchial rays attached.
In 1878, influential German anatomist Karl Gegenbaur presented the theory that paired fins and eventually limbs evolved from a structure resembling the gill arch of cartilaginous fishes. However, nothing in the fossil record has ever been discovered to support this.
Now, researchers have reinvestigated Gegenbaur’s ideas using the latest genetic techniques on embryos of the little skate – a fish from the very group that first inspired the controversial theory over a century ago – and found striking similarities between the genetic mechanism used in the development of its gill arches and those in human limbs.
Scientists say it comes down to a critical gene in limb development called ‘Sonic hedgehog’, named for the videogame character by a research team at Harvard Medical School.
The new research shows that the functions of the Sonic hedgehog gene in human limb development, dictating the identity of each finger and maintaining growth of the limb skeleton, are mirrored in the development of the branchial rays in skate embryos. The findings are published today in the journal Development.
Dr Andrew Gillis, from the University of Cambridge’s Department of Zoology and the Marine Biological Laboratory, who led the research, says that it shows aspects of Gegenbaur’s theory may in fact be correct, and provides greater understanding of the origin of jawed vertebrates – the group of animals that includes humans.
“Gegenbaur looked at the way that these branchial rays connect to the gill arches and noticed that it looks very similar to the way that the fin and limb skeleton articulates with the shoulder,” says Gillis. “The branchial rays extend like a series of fingers down the side of a shark gill arch.”
“The fact that the Sonic hedgehog gene performs the same two functions in the development of gill arches and branchial rays in skate embryos as it does in the development of limbs in mammal embryos may help explain how Gegenbaur arrived at his controversial theory on the origin of fins and limbs.”
In mammal embryos, the Sonic hedgehog gene sets up the axis of the limb in the early stages of development. “In a hand, for instance, Sonic hedgehog tells the limb which side will be the thumb and which side will be the pinky finger,” explains Gillis. In the later stages of development, Sonic hedgehog maintains outgrowth so that the limb grows to its full size.
To test whether the gene functions in the same way in skate embryos, Gillis and his colleagues inhibited Sonic hedgehog at different points during their development.
They found that if Sonic hedgehog was interrupted early in development, the branchial rays formed on the wrong side of the gill arch. If Sonic hedgehog was interrupted later in development, then fewer branchial rays formed but the ones that did grow, grew on the correct side of the gill arch – showing that the gene works in a remarkably similar way here as in the development of limbs.
“Taken to the extreme, these experiments could be interpreted as evidence that limbs share a genetic programme with gill arches because fins and limbs evolved by transformation of a gill arch in an ancestral vertebrate, as proposed by Gegenbaur,” says Gillis. “However, it could also be that these structures evolved separately, but re-used the same pre-existing genetic programme. Without fossil evidence this remains a bit of a mystery – there is a gap in the fossil record between species with no fins and then suddenly species with paired fins – so we can’t really be sure yet how paired appendages evolved.”
“Either way this is a fascinating discovery, because it provides evidence for a fundamental evolutionary link between branchial rays and limbs,” says Gillis. “While palaeontologists look for fossils to try to reconstruct the evolutionary history of anatomy, we are effectively trying to reconstruct the evolutionary history of genetic programmes that control the development of anatomy.”
Paired appendages, such as arms and hands in humans, are one of the key anatomical features that distinguish jawed vertebrates from other groups. “There is a lot of interest in trying to understand the origins of jawed vertebrates, and the origins of novel features like fins and limbs,” says Gillis.
“What we are learning is that many novel features may not have arisen suddenly from scratch, but rather by tweaking and re-using a relatively small number of ancient developmental programmes.”
Gillis and his colleagues are further testing Gegenbaur’s theory by comparing the function of more genes involved the development of skates’ unusual gills and mammalian limbs.
“Previous studies haven’t found compelling developmental genetic similarities between gill arch derivatives and paired appendages – but these studies were done in animals like mice and zebrafish, which don’t have branchial rays,” says Gillis.
“It is useful to study cartilaginous fishes, not only because they were the group that first inspired Gegenbaur’s theory, but also because they have a lot of unique features that other fishes don’t – and we are finding that we can learn a lot about evolution from these unique features.”
“Many researchers look at mutant mice or fruit flies to understand the genetic control of anatomy. Our approach is to study and compare the diverse anatomical forms that can be found in nature, in order to gain insight into the evolution of the vertebrate body.”
This research was funded by the Royal Society, the Isaac Newton Trust and a research award from the Marine Biological Laboratory.
Inset images: Skeletal preparation of an embryonic bamboo shark (Andrew Gillis); A skate embryo that has been stained for expression of the Shh gene - staining can be seen as dark purple strips running down the length of each gill arch (Andrew Gillis); Late stage skate embryo (Andrew Gillis).
Latest analysis shows that human limbs share a genetic programme with the gills of cartilaginous fishes such as sharks and skates, providing evidence to support a century-old theory on the origin of limbs that had been widely discounted.
Sir David Attenborough abseils down building bearing his name
From Department of Zoology. Published on Apr 07, 2016.
Best Student Talk prize for Syuan-Jyun Sun
From Department of Zoology. Published on Apr 04, 2016.
Crawling with Life: Flower drawings from the Henry Rogers Broughton Bequest
From Department of Zoology. Published on Apr 01, 2016.
Department of Zoology Seminar Day 2016 - winning posters
From Department of Zoology. Published on Mar 21, 2016.
David Labonte awarded ZSL Thomas Henry Huxley and Marsh Prize
From Department of Zoology. Published on Mar 16, 2016.
Peter Lawrence writes in 'Current Topics in Developmental Biology' 50th anniversary edition
From Department of Zoology. Published on Mar 08, 2016.
520 million-year-old fossilised nervous system is most detailed example yet found
By sc604 from University of Cambridge - Department of Zoology. Published on Feb 29, 2016.
Researchers have found one of the oldest and most detailed fossils of the central nervous system yet identified, from a crustacean-like animal that lived more than 500 million years ago. The fossil, from southern China, has been so well preserved that individual nerves are visible, the first time this level of detail has been observed in a fossil of this age.
The findings, published in the Proceedings of the National Academy of Sciences, are helping researchers understand how the nervous system of arthropods - creepy crawlies with jointed legs - evolved. Finding any fossilised soft tissue is rare, but this particular find, by researchers in the UK, China and Germany, represents the most detailed example of a preserved nervous system yet discovered.
The animal, called Chengjiangocaris kunmingensis, lived during the Cambrian ‘explosion’, a period of rapid evolutionary development about half a billion years ago when most major animal groups first appear in the fossil record. C. kunmingensis belongs to a group of animals called fuxianhuiids, and was an early ancestor of modern arthropods – the diverse group that includes insects, spiders and crustaceans.
“This is a unique glimpse into what the ancestral nervous system looked like,” said study co-author Dr Javier Ortega-Hernández, of the University of Cambridge’s Department of Zoology. “It’s the most complete example of a central nervous system from the Cambrian period.”
Over the past five years, researchers have identified partially-fossilised nervous systems in several different species from the period, but these have mostly been fossilised brains. And in most of those specimens, the fossils only preserved details of the profile of the brain, meaning the amount of information available has been limited.
C. kunmingensis looked like a sort of crustacean, with a broad, almost heart-shaped head shield, and a long body with pairs of legs of varying sizes. Through careful preparation of the fossils, which involved chipping away the surrounding rock with a fine needle, the researchers were able to view not only the hard parts of the body, but fossilised soft tissue as well.
The vast majority of fossils we have are mostly bone and other hard body parts such as teeth or exoskeletons. Since the nervous system and soft tissues are essentially made of fatty-like substances, finding them preserved as fossils is extremely rare. The researchers behind this study first identified a fossilised central nervous system in 2013, but the new material has allowed them to investigate the significance of these finding in much greater depth.
Click to enlarge
The central nervous system coordinates all neural and motor functions. In vertebrates, it consists of the brain and spinal cord, but in arthropods it consists of a condensed brain and a chain-like series of interconnected masses of nervous tissue called ganglia that resemble a string of beads.
Like modern arthropods, C. kunmingensis had a nerve cord – which is analogous to a spinal cord in vertebrates – running throughout its body, with each one of the bead-like ganglia controlling a single pair of walking legs.
Closer examination of the exceptionally preserved ganglia revealed dozens of spindly fibres, each measuring about five thousandths of a millimetre in length. “These delicate fibres displayed a highly regular distribution pattern, and so we wanted to figure out if they were made of the same material as the ganglia that form the nerve cord,” said Ortega-Hernández. “Using fluorescence microscopy, we confirmed that the fibres were in fact individual nerves, fossilised as carbon films, offering an unprecedented level of detail. These fossils greatly improve our understanding of how the nervous system evolved.”
For Ortega-Hernández and his colleagues, a key question is what this discovery tells us about the evolution of early animals, since the nervous system contains so much information. Further analysis revealed that some aspects of the nervous system in C. kunmingensis appear to be structured similar to that of modern priapulids (penis worms) and onychophorans (velvet worms), with regularly-spaced nerves coming out from the ventral nerve cord.
In contrast, these dozens of nerves have been lost independently in the tardigrades (water bears) and modern arthropods, suggesting that simplification played an important role in the evolution of the nervous system.
Possibly one of the most striking implications of the study is that the exceptionally preserved nerve cord of C. kunmingensis represents a unique structure that is otherwise unknown in living organisms. The specimen demonstrates the unique contribution of the fossil record towards understanding the early evolution of animals during the Cambrian period. “The more of these fossils we find, the more we will be able to understand how the nervous system – and how early animals – evolved,” said Ortega-Hernández.
The research was supported in part by Emmanuel College, Cambridge.
Jie Yang et. al. ‘The fuxianhuiid ventral nerve cord and early nervous system evolution in Panarthropoda.’ PNAS (2016). DOI: 10.1073/pnas.1522434113
A 520 million-year-old fossilised nervous system – so well-preserved that individually fossilised nerves are visible – is the most complete and best example yet found, and could help unravel how the nervous system evolved in early animals.
Simon Laughlin's book wins a Prose Award
From Department of Zoology. Published on Feb 09, 2016.
Defending larvae from microbial attack
From Department of Zoology. Published on Jan 28, 2016.
Professor Jenny Clack awarded the Palaeontological Association's Lapworth Medal
From Department of Zoology. Published on Dec 18, 2015.
Nancy Lane awarded Doctorate of Science by Heriot-Watt University
From Department of Zoology. Published on Nov 23, 2015.
Pevensey giant whale remembered 150 years on
From Department of Zoology. Published on Nov 16, 2015.
Changes in DNA are NOT random - a Naked Scientists podcast featuring Professor Bill Amos
From Department of Zoology. Published on Nov 05, 2015.
Tom Evans awarded the John Ray Science Prize 2015
From Department of Zoology. Published on Sep 01, 2015.
Claire Feniuk successful at 2015 International Conference on Conservation Biology in Montpellier
From Department of Zoology. Published on Aug 13, 2015.
Hugh Cott - master of camouflage
From Department of Zoology. Published on Aug 11, 2015.
Isabel Palacios helps African universities reap fruits of fly research
From Department of Zoology. Published on Jul 10, 2015.
Why insects are marvels of engineering
From Department of Zoology. Published on Jul 03, 2015.
Emeritus Professor Sir Pat Bateson awarded the ZSL Frink Medal 2014
From Department of Zoology. Published on Jun 25, 2015.
Richard Preece and Roz Wade on 'Wildlife Wednesday'
From Department of Zoology. Published on Jun 18, 2015.
Prof. Simon Laughlin publishes new book on brain design
From Department of Zoology. Published on Jun 15, 2015.
Nick Davies appears on 'Springwatch'
From Department of Zoology. Published on Jun 12, 2015.
Janet Moore Prize for Supervising in Zoology
From Department of Zoology. Published on Jun 12, 2015.
All Museum creatures great and small
From Department of Zoology. Published on Jun 09, 2015.