Tom Evans awarded the John Ray Science Prize 2015
From Department of Zoology. Published on Sep 01, 2015.
M is for Midge
By amb206 from University of Cambridge - Department of Zoology. Published on Aug 26, 2015.
Dr Henry Disney (Department of Zoology) has been fascinated by insects since he was four years old. His career has taken him all over the world. Despite losing 75% of his sight in 2012, Disney walks every day to his lab, where use of the latest imaging and magnifying technology enables him to continue his research. Below, Disney answers questions about the tiny insects that can, during summer months, turn a camping holiday on the beautiful west coast of Scotland into a nightmare.
What are midges?
Midges are classified as Diptera – which comes from the Greek for two wings. Diptera fall into three main groups: higher flies, middle flies and lower flies. Midges, like mosquitoes, fall into the lower group, which are the most ancient. They are typified by long antennae which have many segments. Some Diptera are enormously important as a threat to human health: they include many species in which the females suck blood and, in many parts of the world, transmit diseases such as yellow fever and malaria.
What is the life cycle of a midge?
The speed at which midges reproduce is temperature dependent. In the UK, you might get two or three generations a year. In the hot and steamy environment of Cameroon, where I’ve worked as a medical entomologist, you might see a new generation emerging every three weeks. Adult females lay their eggs in the water or on the margins of water. The eggs hatch into free-living larvae which go through several moults before they pupate. The adult emerges and sits on its empty case for a moment to open its wings before buzzing off.
When are midges most visible?
Midges are easiest to spot when groups of them dance in mid-air. What you’re seeing are the males saying to the females: here we are, where are you? They give off a signal that's partly smell and partly sound. If you watch really carefully, you might see a pair of midges dropping out of the group to mate. Midges swarm near an object such as a branch which gives them a point of reference. Sometimes they gather in such numbers that they make huge towers. So many midges once swarmed on Salisbury Cathedral that the fire brigade was called; it looked as if the spire was swathed in smoke.
How many species of midge are there?
In the UK, alone there are more than 500 species of non-biting midges and more than 150 species of biting midges. Identification of the species is primarily based on details of the male genitalia examined under a microscope. Increasingly this is supplemented by the use of DNA ‘barcodes’.
Why do midges bite?
Only the females bite. They need a protein-rich meal of fresh blood in order to mature their eggs. Both the males and the females rely on sugar meals for energy for flight but the females need more than this to ensure the next generation. Female midges feed on the blood of birds as well as mammals. Each species has its own preferred choice of host.
What is the midge's place in the ecosystem?
Meniscus midges live at the point where air and water meet – a zone known as the surface film. It’s a habitat that supports a whole community of plants and animals, many of them still unexplored. Some minute organisms spend their lives within the surface film; others, like meniscus midges, spend their larval lives feeding on it.
The boundary where air and water connect is rich in resources. The larvae of non-biting midges feed on algae and bacteria, filtering micro-organisms out of the water, but some are predators. The larvae of phantom midges live in the open water and prey on water fleas and small larvae. Adult midges are eaten by all kinds of things - from spiders to swallows. The larvae are eaten by fish, dragonfly larvae, water beetles and other predators.
What can midges tell us about the environment?
The apparent boundary between air and water of ponds and other bodies of water is masked by a layer of lipoprotein leached from organic materials. Within this ‘membrane’ live all kinds of microorganisms – bacteria and so on. Some of it drops in from above and some of it rises up from below. Hundreds of species depend on the ‘membrane’ for food as well as on the prey that inhabits it. Changes to the structure and content of this membrane will affect all these species.
Research has shown that midges are some of the most sensitive indicators of pollution in water. The presence of some species is a sign of a healthy water course with normal oxygen levels; their absence is a sign of lower oxygen levels and can point to pollution. Water authorities sample the numbers and species of midges present in a water course above and below a discharge – for example from a sewage treatment plant – to monitor contamination of the water by organic matter.
Oil, and detergents used to disperse oil, also alter the character of the surface layer – and will have a negative effect on species such as meniscus midge larvae that depend on this delicately balanced habitat.
What more is there to learn about midges?
Some insects have economic and medical importance. For example, there's a huge body of literature devoted to mosquitoes. Anything that bites and transmits disease is likely to attract research funding. A Scandinavian team showed that midge bites could lead to a mild fever but its effects were short-lived and quickly alleviated. Although midges are known as ‘Scotland's secret weapon’, there is no need to worry about being bitten leading to serious problems. However, biting midges have been implicated in transmitting a disease of livestock. In hot climates, midges are known to spread both African Horse Sickness and Blue Tongue virus.
There is still much to learn about midges and novel biological methods of control, that avoid the use of pesticides, for those species posing problems.
How did you get interested in insects?
I was always fascinated by natural history. When I was around four, I disappeared and everyone was out looking for me. I was found sitting among some cabbages watching a caterpillar. An aunt hugely encouraged me and left me a small legacy with which I bought my first microscope. I'm still using it more some 50 years later. My career has been immensely varied - I've worked in medical entomology in Belize and Cameroon. Since my move to Cambridge, I’m occasionally asked to report on specimens from forensic cases - including some involving infamous crimes – as well as pest problems and medical cases. I’ve authored, and contributed to, several books and written hundreds of papers. I’m never bored.
The most important question of all: how do you keep midges at bay if you have to work in areas where they are rife?
The most effective solution for people working outdoors is to wear a loose net over-garment with a hood, impregnated with DEET, over one's normal clothing. This lasts longer than applying DEET to one's skin or normal clothing. We used to test these against alternatives when running the annual field course at my field centre in Yorkshire for the London School of Hygiene and Tropical Medicine.
Next in the Cambridge Animal Alphabet: N is for an animal that won't win any beauty contests, but can live for 30 years and may be able to help in the development of new therapies for chronic pain.
Have you missed the series so far? Catch up on Medium here.
Inset images: Adult Dixella in side view (from British Dixidae (Meniscus Midges) and Thaumaleidae (Trickle Midges) by Henry Disney, published by the Freshwater Biological Association); Dorsal view of adult Dixa BM, BL, median and lateral bands on the scutum (from British Dixidae (Meniscus Midges) and Thaumaleidae (Trickle Midges) by Henry Disney, published by the Freshwater Biological Association).
Home page banner image: A chironomid midge. Credit: S Rae
The Cambridge Animal Alphabet series celebrates Cambridge's connections with animals through literature, art, science and society. Here, M is for Midge as we talk to eminent ecologist Dr Henry Disney about his lifelong interest in Diptera.
Claire Feniuk successful at 2015 International Conference on Conservation Biology in Montpellier
From Department of Zoology. Published on Aug 13, 2015.
Predators might not be dazzled by stripes
By fpjl2 from University of Cambridge - Department of Zoology. Published on Aug 12, 2015.
Stripes might not offer protection for animals living in groups, such as zebra, as previously thought, according to research published today in the journal Frontiers in Zoology.
Humans playing a computer game captured striped targets more easily than uniform grey targets when multiple targets were present. The finding runs counter to assumptions that stripes evolved to make it difficult to capture animals moving in a group.
“We found that when targets are presented individually, horizontally striped targets are more easily captured than targets with vertical or diagonal stripes. Surprisingly, we also found no benefit of stripes when multiple targets were presented at once, despite the prediction that stripes should be particularly effective in a group scenario,” said Anna Hughes, a researcher in the Sensory Evolution and Ecology group and the Department of Physiology, Development and Neuroscience.
“This could be due to how different stripe orientations interact with motion perception, where an incorrect reading of a target’s speed helps the predator to catch its prey.”
Stripes, zigzags and high contrast markings make animals highly conspicuous, which you might think would make them more visible to a predator. Researchers have wondered if movement is important in explaining why these patterns have evolved. Striking patterns may confuse predators and reduce the chance of attack or capture. In a concept termed ‘motion dazzle’, where high contrast patterns cause predators to misperceive the speed and direction of the moving animal. It was suggested that motion dazzle might be strongest in groups, such as a herd of zebra.
‘Motion dazzle’ is a reference to a type of camouflage used on ships in World Wars One and Two, where ships were patterned in geometric shapes in contrasting colors. Rather than concealing ships, this dazzle camouflage was believed to make it difficult to estimate a target's range, speed and heading.
A total of 60 human participants played a game to test whether stripes influenced their perception of moving targets. They performed a touch screen task in which they attempted to ‘catch’ moving targets - both when only one target was present on screen and when there were several targets present at once.
When single targets were present, horizontal striped targets were easier to capture than any other target, including uniform color, or vertical or diagonal stripes. However, when multiple targets were present, all striped targets, irrespective of the orientation, were captured more easily than uniform grey targets.
“Motion may just be one aspect in a larger picture. Different orientations of stripe patterning may have evolved for different purposes. The evolution of pattern types is complex, for which there isn’t one over-ruling factor, but a multitude of possibilities,” said Hughes.
“More work is needed to establish the value and ecological relevance of ‘motion dazzle’. Now we need to consider whether color, stripe width and spatial patterning, and a predator’s visual system could be important factors for animals to avoid capture.”
Anna Hughes has written a blog post on this research for the journal publisher BioMed Central. Above story adapted from a BioMed Central press release.
New research using computer games suggests that stripes might not offer the ‘motion dazzle’ protection thought to have evolved in animals such as Zebra and consequently inspired ship camouflage during both World Wars.
Hugh Cott - master of camouflage
From Department of Zoology. Published on Aug 11, 2015.
Close-up film shows for the first time how ants use ‘combs’ and ‘brushes’ to keep their antennae clean
By jeh98 from University of Cambridge - Department of Zoology. Published on Jul 27, 2015.
For an insect, grooming is a serious business. If the incredibly sensitive hairs on their antennae get too dirty, they are unable to smell food, follow pheromone trails or communicate. So insects spend a significant proportion of their time just keeping themselves clean. Until now, however, no-one has really investigated the mechanics of how they actually go about this.
In a study published in Open Science, Alexander Hackmann and colleagues from the Department of Zoology have undertaken the first biomechanical investigation of how ants use different types of hairs in their cleaning apparatus to clear away dirt from their antennae.
“Insects have developed ingenious ways of cleaning very small, sensitive structures, so finding out exactly how they work could have fascinating applications for nanotechnology – where contamination of small things, especially electronic devices, is a big problem. Different insects have all kinds of different cleaning devices, but no-one has really looked at their mechanical function in detail before,” explains Hackmann.
Camponotus rufifemur ants possess a specialised cleaning structure on their front legs that is actively used to groom their antennae. A notch and spur covered in different types of hairs form a cleaning device similar in shape to a tiny lobster claw. During a cleaning movement, the antenna is pulled through the device which clears away dirt particles using ‘bristles’, a ‘comb’ and a ‘brush’.
To investigate how the different hairs work, Hackmann painstakingly constructed an experimental mechanism to mimic the ant’s movements and pull antennae through the cleaning structure under a powerful microscope. This allowed him to film the process in extreme close up and to measure the cleaning efficiency of the hairs using fluorescent particles.
What he discovered was that the three clusters of hairs perform a different function in the cleaning process. The dirty antenna surface first comes into contact with the ‘bristles’ (shown in the image in red) which scratch away the largest particles. It is then drawn past the ‘comb’ (shown in the image in blue) which removes smaller particles that get trapped between the comb hairs. Finally, it is drawn through the ‘brush’ (shown in the image in green) which removes the smallest particles.
“While the ‘bristles’ and the ‘comb’ scrape off larger particles mechanically, the ‘brush’ seems to attract smaller dirt particles from the antenna by adhesion,” says Hackmann, who works in the laboratory of Dr Walter Federle.
Where the ‘bristles’ and ‘comb’ are rounded and fairly rigid, the ‘brush’ hairs are flat, bendy and covered in ridges – this increases the surface area for contact with the dirt particles, which stick to the hairs. Researchers do not yet know what makes the ‘brush’ hairs sticky – whether it is due to electrostatic forces, sticky secretions, or a combination of factors.
“The arrangement of ‘bristles’, ‘combs’ and ‘brush’ lets the cleaning structure work as a particle filter that can clean different sized dirt particles with a single cleaning stroke,” says Hackmann. “Modern nanofabrication techniques face similar problems with surface contamination, and as a result the fabrication of micron-scale devices requires very expensive cleanroom technology. We hope that understanding the biological system will lead to building bioinspired devices for cleaning on micro and nano scales.”
Dr Federle’s laboratory and, in part, this project receive financial support from the Biotechnology and Biological Sciences Research Council (BBSRC).
Inset images: Scanning electron micrograph of the antenna clamped by the cleaner (Alexander Hackmann); Scanning electron micrograph of the tarsal notch (Alexander Hackmann).
Alexander Hackmann, Henry Delacave, Adam Robinson, David Labonte, Walter Federle. Functional morphology and efficiency of the antenna cleaner in Camponotus rufifemur ants. Open Science; 22 July 2015.
Using unique mechanical experiments and close-up video, Cambridge researchers have shown how ants use microscopic ‘combs’ and ‘brushes’ to keep their antennae clean, which could have applications for developing cleaners for nanotechnology.
Stressed young birds stop learning from their parents and turn to wider flock
By fpjl2 from University of Cambridge - Department of Zoology. Published on Jul 23, 2015.
Highly-social zebra finches learn foraging skills from their parents. However, new research has found that when juvenile finches are exposed to elevated stress hormones just after hatching, they will later switch strategies and learn only from unrelated adult birds – ignoring their parents’ way of doing things and instead gaining foraging skills from the wider network of other adult finches.
Researchers say that spikes in stress during early development may act as a cue that their parents are doing something wrong, triggering the young birds to switch their social learning strategy and disregard parental approaches in favour of acquiring skills exclusively from other birds in the flock.
This stress cue and subsequent behavioural change would then allow the juveniles to bypass a “potentially maladaptive source of information” – possibly the result of low-quality parental investment or food scarcity at birth – and consequently avoid a “bad start in life”, say the researchers.
The changes this stress could create in the patterns of individuals' social interactions may impact important population-wide processes, such as migration efficiency and the establishment of animal culture, they say. The new study is published today in the journal Current Biology.
“These results support the theory that developmental stress may be used as an informative cue about an individual’s environment. If so, it may enable juveniles to avoid becoming trapped in a negative feedback loop provided by a bad start in life – by programming them to adopt alternative, and potentially more adaptive, behaviours that change their developmental trajectories,” said Dr Neeltje Boogert, from Cambridge University’s Department of Zoology, who authored the study with colleagues from the universities of Oxford and St Andrews.
For the study, the research team took 13 broods of zebra finch hatchlings and fed half of the chicks in each brood with physiologically relevant levels of the stress hormone corticosterone dissolved in peanut oil, and the other half – their control siblings – with just plain peanut oil. The chicks were treated each day for 16 days from the ages of 12 days old.
Once the chicks reached nutritional independence, they were released with their families into one of two free-flying aviaries, where researchers tracked their social foraging networks using radio tags called PIT tags (Passive Integrated Transponder), about the size of a grain of rice. Each bird's unique PIT tag was scanned when a bird visited a feeder, allowing the researchers to track exactly who was foraging where, when and with whom.
Using these feeder visit data, the researchers were able to build finch social foraging networks, as the thirteen zebra finch families in the two aviaries foraged and interacted over the course of 40 days.
They found that the juveniles administered with the stress hormone were less likely to spend time with their parents, spent more time with other unrelated birds and were far less choosy about which birds they foraged with; whereas the control group stuck more closely to their parents, and foraged more consistently with the same flock mates.
To test whether these stress-hormone induced differences in social network positions affected who learned from whom, Boogert devised a food puzzle for the birds, and recorded exactly when each bird started solving it.
In the new test, the birds had to learn to flip the lids from the top of a grid of holes to reach the food reward of spinach underneath. All other feeders were removed from the aviaries, and the researchers filmed a series of nine one-hour trials over three days, monitoring and scoring how each bird learned to get to the bait.
They found that, while the control group of juvenile finches did also learn from some unrelated adults, they mostly copied their parents to find out how to get the spinach. In sharp contrast, the developmentally-stressed chicks exclusively copied unrelated adults instead – not one looked to a parent to figure out the key to the spinach puzzle.
In fact, the stressed juveniles actually solved the task sooner than their control siblings, despite not using parents as role models to focus on. Boogert says this may be because they relied more on trial-and-error learning, or that they simply had access to the information sooner because they copied a large number of unrelated adult finches rather than just one of their two parents.
"If developmentally stressed birds occupy more central network positions and follow many others around, this might make them especially efficient spreaders of disease, as stressed individuals are also likely to have weakened immune systems," said Boogert.
"The next step is to explore the implications of our results for important population-level processes, such as the spread of avian pox or flu."
Inset image: Zebra finches in the ‘food puzzle’ experiment. Credit: Dr Neeltje Boogert
Juvenile zebra finches that experience high stress levels will ignore how their own parents forage and instead learn such skills from other, unrelated adults. This may help young birds avoid inheriting a poor skillset from parents – the likely natural cause of their stress – and becoming trapped by a “bad start in life”.
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.
Women’s faces get redder at ovulation, but human eyes can’t pick up on it
By fpjl2 from University of Cambridge - Department of Zoology. Published on Jun 30, 2015.
Previous studies have shown that men find female faces more attractive when the women are ovulating, but the visual clues that allow this are unclear. Now, new research investigating whether it might be to do with subtle changes in skin colour has shown that women’s faces do increase in redness during ovulation, but the levels of change are just under the detectable range of the human eye.
Researchers say this may mean that facial redness in females was once an involuntary signal for optimal fertility, but has since been “dampened” by evolution as it is more beneficial for females to hide or control outward signs of peak fertility.
Involuntarily signalling ovulation can prevent longer-term investment from males. In primate species that advertise ovulation, males only express sexual interest in females when they appear to be fertile. In humans, ovulation is less conspicuous and sexual behaviour is not restricted to the period of peak fertility.
The research, published today in the open-access journal PLOS ONE, is the most complete objective study of female faces during the ovulatory cycle, say researchers. Twenty-two women were photographed without make-up at the same time every working day for at least one month in the same environment and using a scientific camera modified to more accurately capture colour (usually used for studying camouflage in wildlife).
A computer programme was designed to select an identical patch of cheek from each photograph. The participants also self-tested for hormone changes at key times dictated by the research team’s “period maths”.
A surge in luteinising hormone told researchers that ovulation would occur in roughly the next 24 hours, so they knew which photographs were taken when the women were most fertile. The team converted the imagery into red/green/blue (RGB) values to measure colour levels and changes.
They found that redness varied significantly across the ovulatory cycle, peaking at ovulation and remaining high during the latter stages of the cycle after oestrogen levels have fallen. Skin redness then dips considerably once menstruation begins. The research suggests facial redness closely maps fluctuations in body temperature during the cycle.
However, when running the results through models of human visual perception, the average difference in redness was 0.6 units. A change of 2.2 units are needed to be detectable to the naked human eye.
“Women don’t advertise ovulation, but they do seem to leak information about it, as studies have shown they are seen as more attractive by men when ovulating,” said Dr Hannah Rowland, from the University of Cambridge’s Zoology Department, who led the study with Dr Robert Burriss, a psychologist from Northumbria University.
“We had thought facial skin colour might be an outward signal for ovulation, as it is in other primates, but this study shows facial redness is not what men are picking up on - although it could be a small piece of a much larger puzzle,” she said.
Primates, including humans, are attracted to red, say the study’s authors. Women may subconsciously augment the naturally-occurring facial redness during ovulation through make-up such as blusher or red clothing, they say.
“As far back as the 1970s, scientists were speculating that involuntary signals of fertility such as skin colour changes might be replaced with voluntary signals, such as clothing and behaviour,” said Burriss. “Some species of primate advertise their fertility through changes in the colour of their faces. Even if humans once advertised ovulation in this way, it appears that we don’t anymore.”
It may be that, during ovulation, women have a greater propensity for blushing when around men they find attractive, say the researchers. “Other research has shown that when women are in the fertile phase of their cycle they are more flirtatious and their pupils dilate more readily, but only when they are thinking about or interacting with attractive men,” said Burriss. “We will need to do more research to find out if skin redness changes in the same way”.
Rowland and Burriss first conceived of the experiment seven years ago, but it wasn’t until Rowland arrived at Cambridge that they were able to do the research, thanks to the University’s collegiate system. “We were able to recruit undergraduates in a number of colleges and photograph the women just before they had dinner in the college hall every evening. The collegiate routines and networks were vital to collecting data with such regularity,” said Rowland.
Past research shows men find female faces more attractive at peak fertility. A new study shows an increased redness of women’s face skin at the most fertile point of ovulatory cycle, but just under the threshold for detectability, ruling out skin colouration as a driver of the attractiveness effect.
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.
Cuckoos mimic 'harmless' species as a disguise to infiltrate host nests
By fpjl2 from University of Cambridge - Department of Zoology. Published on Jun 10, 2015.
Brood parasites are reproductive cheats that evolve ways of duping other birds into raising their young. Examples such as mimicry of host eggs, chicks and fledglings by brood parasitic eggs, chicks and fledglings are amongst the most iconic examples of animal deception in nature.
New research shows that adult brood parasitic female cuckoo finches have evolved plumage colours and patterns to mimic a harmless and abundant species, such as southern red bishops, to deceive possible host birds and reduce the risk of being attacked when approaching host nests to lay their eggs.
Researchers say this is the first time that "wolf in sheep's clothing" mimicry has been shown to exist in any adult bird.
While other brood parasites watch the movements of their host victims by hiding in nearby foliage, the openness of the African savannahs mean that mimicking a plentiful and nontoxic species might be the best way cuckoo finches have of sneaking up on host nests without raising the alarm.
However, the researchers found that the most common victim of the cuckoo finch, the tawny-flanked prinia, has evolved an awareness of the cuckoo finch's disguise and takes no chances - acting with equal aggression towards a female cuckoo finch and bishop alike.
Prinias attacked female cuckoo finches and female bishops equally, and increased the rate of egg rejection after seeing either a female cuckoo finch or female bishop near the nest. Egg rejection involves physically removing the parasitic egg from their nest, allowing them to salvage the majority of their reproductive effort.
At the study site in Zambia, the researchers found a consistently high rate of parasitism by cuckoos among the prinia population, with almost a fifth of all prinia eggs hatching as fledgling cuckoo finches. Cuckoo finches usually remove at least one egg on parasitism, and their hatchlings will out-compete all the host's young.
Researchers say these rates of parasitism might explain the willingness of prinias to attack anything that looks like a dangerous female cuckoo finch and reject more eggs when the risk of parasitism is high. But, the cost of this strategy can be high: during the researchers' experiments, some of the eggs rejected by prinia were their own, triggered by nothing more than a harmless bishop bird that resembles the mimetic cuckoo finch.
"Our findings suggest that female cuckoo finches are aggressive mimics of female bishops, and that prinia hosts have responded to this successful deception with generalised defences against cuckoo finches and harmless bishops alike. This suggests these prinias have decided that it's best to 'play it safe' when the risk of parasitism is high because they can't distinguish between the two species" said Dr William Feeney from Cambridge University's Department of Zoology, who led the research.
"While other brood-parasite species monitor host behaviour from concealed perches in nearby trees, cuckoo finches must seek host nests in open grasslands and savannahs. In such exposed circumstances, resembling an abundant and harmless model may allow female cuckoo finches to remain unnoticed when monitoring hosts nests at a medium range," he said.
The research is published today in the journal Proceedings of the Royal Society B.
To investigate the cuckoo finch's disguise, the research team conducted plumage and pattern analysis using cuckoo skins from the Natural History Museum in Tring. They compared plumage to the cuckoo finches closest evolutionary relatives (Vidua finches), as well as with the skins of similar-looking birds (bishops) that share the same habitat.
In both human and bird visual systems, they found that the plumage of a female cuckoo finch is far closer to the bishops and other species in the weaver family than to those of its closest relative, the Vidua finches.
The researchers also investigated the reaction of prinia breeding pairs to models of female cuckoo finches and bishop birds, as well as the males of both species.
While prinias had very little reaction to the males, the female cuckoo finch and the harmless female bishop bird both received similarly high levels of alarm calls and group attacks from the prinia, known as 'mobbing'.
The researchers then did a final experiment where they presented a male bishop, female bishop and female cuckoo finch and then placed a fake egg in their nest. They found that after seeing the harmful female cuckoo finch or harmless (but similar-looking) female bishop, they increased their rate off egg rejection compared to when they saw a male bishop near their nest.
Added Feeney: "This study is interesting as it's the first time anyone has quantitatively tested for 'wolf in sheep's clothing' mimicry in any adult bird, and also suggests that this type of mimicry is used by brood parasites to deceive hosts at all stages of their nesting cycle."
First time ‘wolf in sheep’s clothing’ mimicry has been seen in birds. Host birds have evolved a general counter-strategy in which they defend against all birds with the mimicked plumage - cuckoos and harmless species alike.
All Museum creatures great and small
From Department of Zoology. Published on Jun 09, 2015.
Birds ‘cry hawk’ to give offspring chance to escape predators
By fpjl2 from University of Cambridge - Department of Zoology. Published on Jun 03, 2015.
New research has found that the 6 gram brown thornbill mimics the hawk alarm calls of neighbouring species to scare a nest predator by convincing it that a much bigger and scarier predator – the brown goshawk – is on its way.
Currawongs, which raid the nests and hunt the chicks of thornbills, are also prey to goshawks. Although currawongs normally benefit from listening in on hawk alarm calls of other species, thornbills exploit this and turn it against them.
As well as issuing their own hawk alarm call, thornbills mimic those of the local species to create the impression of an impending hawk attack, which in turn distracts the pied currawong - a predator 40 times larger than the thornbill - providing thornbill nestlings with an opportunity to escape.
While animals often mimic dangerous or toxic species to deter predators, the thornbill is a surprising example of a species mimicking another harmless species to trick a predator.
The research, conducted by scientists at the University of Cambridge and the Australian National University (ANU), is published today in the journal Proceedings of the Royal Society B.
“The enormous size difference between a tiny thornbill and a 0.5kg goshawk might make it difficult for thornbills to mimic hawk vocalisations accurately, limiting them to mimicking the chorus of hawk alarm calls given by small local species instead,” said Jessica McLachlan, a PhD student from Cambridge’s Department of Zoology, who co-authored the study.
“As hawks are silent when hunting, the alarm calls of local species may be the only sound that warns of a hawk’s presence,” she said.
The researchers studied the thornbills and currawongs living in and around the Australian National Botanic Gardens in Canberra. They devised a series of experiments in which they placed stuffed currawongs in front of thornbill nests to test when thornbills use such trickery, followed by experiments testing how currawongs respond to the calls of thornbills.
They found that thornbills used their own and mimicked hawk alarm calls when their nests are under attack. They also found that currawongs delayed attacks for twice as long when mimetic and non-mimetic alarm calls were played together as opposed to non-mimetic calls played alone.
“Distracting a currawong attacking the nest could give older thornbill nestlings a chance to escape and hide in the surrounding vegetation,” said Dr Branislav Igic from ANU, who led the study.
“It’s perhaps the thornbills best nest defence in this circumstance because physical attacks on the much larger currawong are hopeless,” Igic said.
Inset image: Pied currawong. Credit: Jessica McLachlan
Surprising finding shows that thornbills simulate a ‘chorus of alarm’ to distract predators by convincing them something scarier is on its way.
A is for Albatross
By amb206 from University of Cambridge - Department of Zoology. Published on Jun 01, 2015.
In June 1910 Dr Edward Wilson set sail from Cardiff to Antarctica on board the Terra Nova as the Chief of the Scientific Staff on the British Antarctic Expedition led by Captain Scott. On 1 November the following year a group from the Terra Nova set out from Cape Evans across the ice with the intention of reaching the South Pole. The venture ended in tragedy. The members of the British expedition perished on their return from the pole having discovered that the Norwegians had got there first.
Wilson was a talented artist as well as a doctor. He began drawing as a child and throughout his life he made meticulous sketches and watercolours of the natural world.
After his death, his final sketchbook was retrieved from the tent where he and his companions spent their last days. His watercolours were returned from the Cape Evans hut where they had been produced.
Artworks made by Wilson on both the Discovery Expedition of 1901 and the Terra Nova Expedition are testimony to the spirit of discovery and the splendour of the Antarctic.
The Scott Polar Research Institute (SPRI) is fortunate in holding around 1,900 of Wilson’s drawings and sketches, the majority of them given to SPRI by his wife Oriana. Nineteen of these artworks depict the albatross – several species of which Wilson shows both in close-up studies and soaring above the ocean.
Mrs Heather Lane, former Keeper of the Polar Museum, says: "Wilson is undoubtedly one of the greatest artists of the heroic age of polar exploration. He was one of Scott’s closest friends and on expeditions the person to whom others looked for stability.
"As an artist he was self-taught yet he captured with stunning accuracy both the anatomical structure and the fragile beauty of living things. He was particularly fascinated by birds."
The wandering albatross has the largest wingspan (up to 12 foot) of any bird. Its flight is so efficient that it expends as little energy soaring on currents of air (a type of flight known as 'dynamic soaring') as it does sitting on its nest. In all, there are 22 species of albatross, most of them living in the southern oceans. The majority are under threat, chiefly from longline fishing. Attracted by the bait, the birds become entangled by the hooks and drown. Estimates put the annual death toll at 100,000 birds.
PhD candidate Tommy Clay (Department of Zoology) is contributing to a British Antarctic Survey (BAS) programme that is creating a detailed picture of their migratory movements. The research is made possible by lightweight battery-powered devices capable of tracking the birds’ movements over multiple years.
Albatrosses pair for life: Wanderers raise at most one chick every two years. They spend a whole year incubating their one egg and looking after the chick. Once the chick is independent, its parents enjoy a recovery period before they breed again, returning to the same breeding spots on remote islands in the southern ocean.
"Until relatively recently, very little has been known about the pattern of albatross movements across their lifespans, which can be more than 60 years. We’re beginning to build up a picture of what individual birds do and why they do it. We now know that in the inter-breeding period, the birds cover huge distances. One Grey-headed albatross, for example, circumnavigated the southern hemisphere in just 46 days," says Clay.
"Albatrosses are regarded as sentinel species for the health of the marine environment. Albatrosses are scavengers – they follow ships and eat the debris thrown into the water. In the North Pacific, dead birds are found with plastic in their stomachs, showing just how widespread – and destructive – is our impact on the oceans."
The long association between the albatross and the seafarer was cemented in 1798 with the publication of Samuel Taylor Coleridge’s epic Rime of the Ancient Mariner. In the poem, which was dismissed by early critics as an extravagant cock-and-bull story, the eponymous mariner shoots an albatross in a seemingly motiveless act of cruelty.
When the ship is becalmed (Day after day, day after day,/We stuck, nor breath nor motion; /As idle as a painted ship/ Upon a painted ocean), the dead albatross is hung around the mariner’s neck by his shipmates.
The poem was famously illustrated by Gustav Doré in the 1870s and became one of the most quoted ballads in the English language. Images of the crew dying of thirst out at sea (Water, water, every where,/And all the boards did shrink;/ Water, water, every where,/ Nor any drop to drink) and the dead bird hanging around a man’s neck became embedded in the public imagination.
In the 1930s, albatross entered the Oxford English Dictionary as a word to describe an unshakeable burden.
“The indeterminacy of the mariner’s crime makes the story compelling: we don’t know what makes him pick up his crossbow and shoot a bird that the crew has befriended. Some scholars have read the poem as a Christian narrative in which evil is punished by God. Others, more recently, have argued for an environmental context in which mankind is punished for an attack on the natural world,” says Professor Heather Glen of the Faculty of English.
“Or possibly – and this is in keeping with the poem’s deliberately archaic ballad form – Coleridge is suggesting that the shooting of the albatross is a violation of a much more ancient tradition of welcome to the stranger. In the note with which he headed the poem in 1800 edition of Lyrical Ballads, Coleridge announces that it will portray ‘how the Ancient Mariner cruelly, and in contempt of the laws of hospitality, killed a sea-bird; and how he was followed by many and strange judgements’.”
For a short time, Coleridge was a student at Jesus College, Cambridge, where he described himself as ‘a library-cormorant’ greedily devouring as many books as he could. The device of the albatross was suggested to him by his close friend William Wordsworth during a walking holiday. Wordsworth had been reading George Shelvocke’s Voyage Round the World (1726) in which an albatross is shot. Both Cambridge University Library and SPRI have early editions of the book.
Next in the Cambridge Animal Alphabet: B is for an animal that roamed Cambridgeshire 120,000 years ago, provided sport for the inhabitants of Madingley Hall, and became a friend to one eccentric poet at Trinity College.
Inset images: Diomedea melanophrys. Discovery 1901. Black browed albatross, by Edward Adrian Wilson. (Scott Polar Research Institute); Wandering albatross. (Robert Paterson, British Antarctic Survey); Gustav Doré's illustration from Rime of the Ancient Mariner by Samuel Taylor Coleridge. (Cambridge University Library).
The Cambridge Animal Alphabet series celebrates Cambridge's connections with animals through literature, art, science and society. Here, A is for Albatross – in sketches retrieved from Antarctica, research into migratory patterns, and Coleridge’s famous ballad.
Henry Disney paper chosen as Science Editor's Choice
From Department of Zoology. Published on May 18, 2015.
What research would enhance business sustainability?
By sc604 from University of Cambridge - Department of Zoology. Published on May 15, 2015.
The natural world is already in peril, yet demand for water, food and energy are set to rise further as the global population grows and climate change takes hold. Increased demand for one of these will alter the availability of the others. Businesses sit at the heart of this ‘nexus’ of interactions, both depending on and impacting on the environment. What academic research could help make their operations more sustainable?
Working with leading researchers from the Departments of Geography and Zoology, the Cambridge Institute for Sustainability Leadership’s (CISL) Nexus2020 project is bringing together ideas from the 6,000 alumni of our executive education programmes, business people, academics, policy-makers and members of the general public.
The project is part of the Nexus Network, an extensive network coordinated by CISL, the University of Sussex and the University of East Anglia, and supported by the Economic and Social Research Council. With its considerable outreach across business, academia and government, CISL encourages conversation and stimulates the research that is most helpful to companies.
We want to know what you think are the most important questions around business practice that, if answered by 2020, could help companies manage their dependencies and impacts upon food, energy, water and the environment.
How can we meet future needs for food, energy and water without degrading our natural environment and putting companies out of business? Can we meet increasing demand for energy without making climate change worse? How do we produce enough food and energy with less water? These are the types of questions we are looking for.
In September, we will bring together leading members of the academic and business communities to rank the submissions and identify the most important questions for research. We’ll present these at the Nexus Network annual conference in November, by which point research will be underway.
The process of gathering questions and prioritising research needs is not new: Cambridge’s Bill Sutherland identified the 100 ecological questions of high policy relevance in the UK in 2006. More recently a project led by Jules Pretty looked at the top 100 questions of importance to the future of global agriculture, and Lynn Dicks has replicated this process to look at the conservation of wild insect pollinators and the UK food system. These ranking exercises are extremely valuable and have had consequences for high-level policy, including Defra’s National Pollinator Strategy. These approaches also encouraged scientists to come together to develop workshops and led to the identification of initial priorities for programmes such as the UK’s Global Food Security Research Programme.
With the UN’s 2014 report highlighting that one-fifth of the world’s aquifers are being overexploited, how do ensure that corporate actions are alleviating water-related stresses? How do we communicate the urgency of sustainable farming methods when 10 million hectares of arable land are being eroded or degraded every year?
Whether your question is around policy, business education, rights, science, finance, or best practice, take part in this project - we want to know what you think.
A new project led by the Cambridge Institute for Sustainability Leadership is looking at how academic research can help make businesses more sustainable. Dr Jonathan Green, one of the project leads, is looking to the public to ask the questions that may form the basis of future research, and help businesses reduce their impact on the environment.
Baboons prefer to spend time with others of the same age, status and even personality
By sc604 from University of Cambridge - Department of Zoology. Published on May 13, 2015.
New research shows that chacma baboons within a troop spend more of their time with baboons that have similar characteristics to themselves: associating with those of a similar age, dominance rank and even personality type such as boldness. This is known as homophily, or ‘love of the same’.
A team of researchers led by the University of Cambridge and international conservation charity the Zoological Society of London says that this may act as a barrier to the transfer of new social information to the wider troop, as previous research done by the team shows baboons of a certain age and personality type – the younger, bolder animals – are more likely to be information ‘generators’: those who solve new foraging problems.
Given that information generators spend much of their time in the company of similar baboons, researchers say there is a risk that acquired information may end up exclusively confined to other information generators, thus decreasing the likelihood of new knowledge being disseminated to the wider troop.
Research teams tracked the same two baboon troops from dawn until dusk across Namibia’s Tsaobis Nature Park over several months each year between 2009-2014 to observe patterns of behaviour. The study is the first to monitor baboon social network structures over such a timescale and is published today in the journal Royal Society Open Science.
“Within these big troop networks over time social preferences are generally dictated by age, rank, personality and so on,” said Dr Alecia Carter, from the University of Cambridge’s Department of Zoology, first author of the study. “This happens in humans all the time; we hang out with people who have the same income, religion, education etc. Essentially, it’s the same in baboons.”
To test for the personality traits of ‘boldness’ – essentially an assertive curiosity – the researchers planted unfamiliar foods on the edge of paths commonly used by baboon troops. These stimuli included hard-boiled eggs and small bread rolls dyed red or green. The research team then measured the time spent on investigating the new foodstuff, and whether they ate it, to determine a scale of boldness for members of the baboon troops.
“Our analysis is the first to suggest that bolder and shyer baboons are more likely to associate with others that share this personality trait,” said Dr Guy Cowlishaw from the Zoological Society of London, senior author of the study. “Previous studies in other animals – from chimps to guppies – suggests that time spent in the company of those with similar personalities could promote cooperation among individuals.
“Why baboons should demonstrate homophily for boldness is unclear, but it could be a heritable trait, and the patterns we’re seeing reflect family associations.”
Perhaps surprisingly, says Carter, gender was not a particular obstacle to social interaction, with females preferring to groom males. This is, in part, due to the obvious sexual engagements for breeding, but also as a tactic on the part of females to curry favour with particular males for the sake of their offspring.
“Chacma baboon males will often commit infanticide, killing the babies of rivals. Female baboons try and get around this by being as promiscuous as possible to confuse the paternal identity – so males find it harder to tell if they are killing a rival’s offspring or their own,” added Dr Carter.
“They will also try and form bonds with particular males in the hope that they will protect their offspring and let the babies forage in good places with them – although males tend to be fairly lazy when it comes to this; it’s up to the babies to follow the males to good food.”
Latest research shows that, within large troops, baboons spend more time grooming those with similar dominance rank and boldness to themselves. Preferring such grooming partners may prevent new skills and knowledge being transmitted around the wider troop, say researchers.
Legs give moths a flying start
From Department of Zoology. Published on May 01, 2015.
The Arup Building is renamed The David Attenborough Building
From Department of Zoology. Published on Apr 22, 2015.
Wendy Gu wins first place in BSCB BSDB Student Poster prize competition
From Department of Zoology. Published on Apr 15, 2015.
Red Noses in Zoology
From Department of Zoology. Published on Mar 25, 2015.
Zoology student success in 2015 Graduate School Life Sciences Poster and Image Competitions
From Department of Zoology. Published on Mar 25, 2015.
MPhil student wins bursary
From Department of Zoology. Published on Mar 09, 2015.
Nick Davies’ new book, Cuckoo: Cheating By Nature
From Department of Zoology. Published on Mar 06, 2015.
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.
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 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.
Julian Jacobs wins Employee Recognition Award
From Department of Zoology. Published on Dec 22, 2014.
The Janet Moore Prize for supervising in Zoology
From Department of Zoology. Published on Nov 24, 2014.