Our Changing World
Thursday 18 December 2014, with Alison Ballance, Ruth Beran & Veronika Meduna
On This Programme
- Bird Brains - Measuring the IQ of Bush Robins
- Using Sugars to Test Gut Health
- Aging Males and In-bred Kiwi: Genetic Updates
- Spying on Wild Animals with Remote Cameras
- Using Google Balloons to Study the Stratosphere
Bird Brains - Measuring the IQ of Bush Robins
By Alison Ballance
“Food is the way to a robin’s heart” - Rachael Shaw.
Biologist Rachael Shaw has exploited the small North Island robin’s penchant for meal worms by using them as an enticement to take part in a series of Avian Mastermind. But while the 20 male robins that live in the Zealandia Sanctuary willingly took part in Rachael’s bird IQ tests were all keen participants, not every one of them was a bird brain. Tesla – a bright spark as his name would suggest – performed well, while Darcy (an Austen-inspired naming) came near the bottom of the class.
Rachael Shaw, who won a prestigious Rutherford PhD Scholarship in 2008 to study for her PhD at Cambridge, is now a Rutherford post-doctoral fellow at Victoria University of Wellington. Testing the IQ of robins is part of a Marsden-funded research project to find out whether it’s possible to test cognition in a wild bird, and relate the bird’s cognitive ability to its breeding success. This year was the first of what will be a 3-year study.
“The aim of this year was really to develop and see how well the birds could perform tests that have only ever been done in a laboratory before,” says Rachael. “And as it turns out robins quite nicely adapt to doing tests that would normally be impossible with a wild animal. So they voluntarily come and participate, which is really nice.”
The six tests that Rachael use include learning to flip small lids to find a food reward, a colour association test in which they learn to associate a reward with a particular colour, and then a reverse colour test, in which they have to learn that the reward is now under a different colour lid; this tests their learning flexibility. There is also a symbol association test, which tests how long it takes a bird to associate a particular symbol (a cross or a square) with a food reward. This is a measure of the bird’s learning speed, and is a task that has been used with many other species. The bird is presented with a 6-well tray, containing a mealworm hidden under one of two lids, and if it flips the correctly marked lid it gets the food reward. Because the birds have a good spatial memory Rachael continually shifts the location of the lids and reward. The birds have to flip the correct lid 10 times out of 12 trials before Rachael is sure it has learnt the task.
Rachael has been following the nesting success of the robins that took part in the trials, to see if there is any correlation between a bird’s intelligence and its success in producing offspring. Robins can produce up to three clutches per breeding season, and they have just completed their first clutches of the year. Rachael is interested to follow where the chicks disperse to when they leave the nest, and is asking residents in the suburbs around Zealandia to tell her if they see robins wearing green-metal leg bands. She wants to run the chicks through the intelligence tests, to see if smart parents have smart chicks.
Rachael's 2013 Marsden-funded project is called 'The evolution of intelligence: evaluating the heritability and fitness consequences of cognition in wild North Island robins'.
In earlier Our Changing World stories on robins we heard about a study on Tiritiri Island and about robins living in a pine plantation near Dunedin.
Robins on Tiritiri Matangi Island ( 12 min 32 sec )
Robins in Douglas Fir Plantations ( 12 min 50 sec )
Listen to the story about testing robin intelligence below.
Using Sugars to Test Gut Health
by Ruth Beran
These sugars are different to ordinary sugars, like glucose, because they are not actively absorbed by the lining of the gut when ingested.
Instead, they are absorbed in the intestine by a process of diffusion. Mannitol and lactulose are also absorbed at different rates.
“Diffusion of course depends on the physical integrity and thickness of the lining of the gut,” says medical physiologist Prof Roger Lentle from Massey University. “Consequently by recording the rate at which it’s absorbed, it’s telling us something about the lining of the gut.”
Ivana Sequiera is a PhD student at Massey University who has been assessing how permeable the gut is by giving participants a solution containing the two sugars. It’s a common diagnostic tool known as the dual sugar absorption test, where a gross rate is usually measured in the urine after two to four hours, but Ivana’s been getting participants to provide a urine sample every 30 minutes to look at their rates of excretion.
“Now this hasn’t been done before, surprisingly, even though these sugars have been used routinely to assess the health of the gut in the case of for example, people who have coeliac disease which is a gluten sensitivity, which affects your permeability of your gut,” says Roger.
Tracing the sugars as they’re excreted means it’s possible to now know when more of one sugar comes out than another. For example, the peak excretion for mannitol is two hours and lactulose is four hours.
“Mannitol is largely absorbed in the small intestine, whereas lactulose the greater absorption is in the colon,” says Ivana. “Ideally we wanted to choose, probes or marker sugars that are absorbed in specific segments of the gut to have site specific permeability measurements.”
The amount that is excreted tells a clinician how leaky or permeable the gut is.
However, with better standardisation, the test is now sensitive enough to pick up the effect of a single aspirin tablet. “So you give a person an aspirin tablet, and we can statistically identify that that’s the person who had the aspirin tablet because the pattern of sugar absorption is augmented, you get much more lactulose when you’ve had this dose of aspirin,” says Roger.
The purpose of this is to see how the gut responds to a challenge or perturbation.
“We want to look at measuring health in the intestine, not illness, and that’s classically what has been done,” says Ivana. But by mimicking what goes on in the intestine, and to see how quickly the gut maintains equilibrium after a noxious stimulus, it can give an indication of gut health.
“The lactulose goes through these little holes, if the asprin increases the number of holes…then your job as a gut cell is to repair the holes, and the quicker you repair the holes the more resilient you are, the more healthy you are,” says Roger.
Ivana has also used a Smart Pill, a wireless motility capsule, to measure pressure, pH and temperature in the gut. The capsule is ingested at the same time as the sugar drink and then the changes in the profile of excretion of the two sugars can be matched with changes measured by the Smart Pill.
She now knows that the sugar probes reside in the small intestine between two and four hours. “So that’s a window period where I think you can start collecting samples, and even if you want to do a cumulative sample, it’s all fine because you know then that it resides in the small intenstine during that period,” says Ivana.
The sensitivity of the diagnostic tool may also allow other simple food components and chemicals to be tested to see if they influence the leakiness of the gut. For example, Ivana has been looking at Vitamin C and seen that a large single dose can temporarily increase the permeability of the gut.
“The test has got potential for testing individual components to see whether there having an effect on gut permeability,” says Roger.
The Ministry of Science and Innovation funded the research, which was awarded to Plant and Food Research.
Aging Males and In-bred Kiwi: Genetic Updates
By Alison Ballance
In an end-of-year science round-up we update two genetic stories that have previously featured on Our Changing World.
Bad News for Older Fathers
It’s well known that as women age their ability to become pregnant declines, and the chance of having complications and giving birth to babies with conditions such as Down’s syndrome increases. Then, with menopause, a woman’s fertility ends.
But what happens with male fertility as men get older? Yes, older men can still father children, but is their sperm as good as it was when they were younger? Until now there’s only been anecdotal evidence that suggested that the quality of sperm declines with age.
A new meta-analysis of 90 individual studies, published in Ageing Research Reviews, has confirmed that sperm quality and quantity do indeed decrease with increasing age. Semen volume and sperm performance - the sperm’s ability to swim in a forward direction – decline, and there is an increase in malformed and DNA-damaged sperm.
Lead author Sheri Johnson featured on Our Changing World earlier this year talking about her Marsden-funded work on aging zebrafish fathers. The results of that study showed that although sperm quality declined in older males, who also got fewer matings than younger males, their offspring were getting some survival advantage and more were surviving to adulthood than those fathered by younger males.
Aging Dads: Good or Bad News? ( 12 min 24 sec )
This new study on male fertility was co-authored by Neil Gemmell, who featured on the programme recently talking about mapping platypus and tuatara genomes, and the Trojan Female idea of pest control.
Mapping Unusual Genomes: Platypus and Tuatara ( 16 min 23 sec )
'Trojan Females' - A Novel Idea for Pest Control ( 17 min 22 sec )
Little Spotted Kiwi's Dark Genetic Secret
At first glance numbers of little spotted kiwi at Zealandia Sanctuary in Wellington and on Long Island in the Marlborough Sound seem to be going gang-buster. The population on Long Island is increasing at about 8% a year, as most pairs are producing two clutches of two eggs each year. But this initial good news hides a dark genetic secret: the birds on Long Island are all descended from a single pair of kiwi, and the resulting lack of genetic diversity is having a big impact on the survival of the third generation. The original pair, and the second generation, which comprises pairs of birds that are all brothers or sisters, are breeding well. The problem kicks in for the third generation, when suddenly fertility and egg and chick survival decline markedly.
Little spotted kiwi at Zealandia, on the other hand, are descended from an initial population of 30 birds, and as a result they have the most genetic diversity of any population outside of the founder population on Kapiti Island. Although they produce fewer eggs each year than the Long Island birds these chicks are much more likely to survive to adulthood.
Researcher Helen Taylor, who has just completed her PhD looking at the impact of inbreeding in the two populations, says that kiwi are long-lived birds and if population size along had been used as a measure of success it would have given a very misleading picture. The genetic bottlenecks created when small number of birds were moved to establish new populations builds on a previous genetic bottleneck in little spotted kiwi:every one of the 1700-or-so birds alive today is descended from just five birds that were moved to Kapiti Island.
Helen, who now has a post-doctoral position at the University of Otago, featured on our Changing World in a story about her field work in the Zealandia Sanctuary.
Little Spotted Kiwi and Genetic Research ( 14 min 40 sec )
Spying on Wild Animals with Remote Cameras
By Alison Ballance
Calling all citizen scientists. A wildlife biologist is hoping keen members of the public with a few minutes to spare will be able to help him identify wild animals in photographs taken by remote cameras. The animals include possums, rats, mustelids, as well as the occasional native bird – and a fair number of photos that don’t contain any animals at all.
“That is the blessing and the curse of using this technology,” says Heiko Wittmer. ”We put these cameras out there, which is a lot of work in itself … but they also take a lot of photos. And because they’re motion activated sometimes even just having the wind moving some branches will trigger a photo.”
Victoria University of Wellington’s Heiko Wittmer and research assistant Victor Anton deployed remote cameras at 40 locations around Wellington’s Zealandia sanctuary between March and July 2014. The resulting 65,000 images are now available for identifying by members of the public at www.identifyanimals.co.nz Heiko says that they need every photo checked as many times as possible, and points out that people should ignore the message currently posted on the web site which says that 100% of the photos have been checked. They have only been checked once, and Heiko would like to see them checked many more times. The team will be redeploying the cameras in late February 2015, when more images will be available for identifying.
The project is part of a broader study looking at the potential impact of introduced predators on native wildlife that is moving out of the security of the fenced sanctuary into the surrounding bush and urban areas.
The Polhill community trapping effort is part of the Halo project, which aims to encourage predator trapping around the Zealandia sanctuary, and other Halo project studies have been looking at the possible impact of domestic cats.
Halo Projects in Wellington ( 12 min 39 sec )
Urban Cats and Native Wildlife ( 25 min 32 sec )
Listen to Heiko Wittmer talking about his early work using remote cameras to study pumas in Chile and the United States, as well as the current project around Zealandia sanctuary.
Using Google Balloons to Study the Stratosphere
By Veronika Meduna firstname.lastname@example.org
Google's Loon Project is an initiative to bring high-speed internet to some of the world’s most remote areas via hot-air balloons that act as floating wifi hotspots.
Since the project’s launch and test flights in New Zealand last year, Google has sent more than 170 of the giant balloons high up into the atmosphere from Lake Tekapo. The balloons rise between 15 and 20 kilometres above Earth’s surface, about twice the altitude of a passenger jet, and then get carried with wind currents.
It is this layer of the atmosphere – called the stratosphere – and its often ferocious winds that are of interest to climate scientists. “Changes that occur in the stratosphere can affect our weather and climate”, says Greg Bodeker, of Bodeker Scientific, who received a Marsden Fund grant to use the location data from thousands of the balloons to study the stratosphere.
High-altitude long-lasting balloons are a proven way to study the stratosphere, but campaigns are expensive and have been limited to a small number of events. Greg Bodeker says Google’s Loon project will allow him to study the distribution of various gases, including ozone and methane, in the stratosphere in unprecedented detail.
He says there are several processes that take place in the stratosphere that can affect weather patterns and long-term climate. In winter, a polar vortex of westerly winds forms in the stratosphere above Antarctica, and in late winter and spring, the ozone hole forms chemically in the air within this vortex. Later in the season, around the beginning of summer, the vortex breaks up, leading to ozone-depleted air travelling over New Zealand and increasing sunburn risk.
The processes that control the distribution of various gases within the Antarctic vortex, and how they are likely to respond to a changing climate, are not well simulated in atmosphere-ocean global climate models.
Greg Bodeker says his team will use the balloon’s position and temperature data to improve the understanding of dynamics in the stratosphere, which will in turn improve climate models.