Features

Like the Mitchells in Eastenders, nothing is more important than family for elephants.

Elephants maintain a complex social structure but herds are typically all made up of relatives, from travelling packs of mothers and calves to larger groups that contain aunts and cousins.

New research, published in the Proceedings of the Royal Society B and involving Department of Zoology researchers, has looked at what happens to these family groups when elephant populations are drastically affected by poaching. The researchers studied 900 elephants in the Samburu game reserve in northern Kenya over a five year period.

It turns out that viable social groups are so important that elephants will sometimes bring in unrelated animals into the group.

‘Elephants have historically lived in separate herds and do not mix with others that have no genetic link to them – but for the first time different herds have been seen to be joining together,’ writes Richard Alleyne in the Telegraph.

Iain Douglas-Hamilton of the Department of Zoology and founder of the Kenyan-based charity Save the Elephants took part in this research and sends these fantastic images.

‘This paper builds on the work Save the Elephants has been doing on the social structure of elephants in Samburu, but for the first time brings in genetic evidence to define the extent to which spatial associations of elephants have an underlying genetic basis,’ he told Oxford Science Blog.

ScienceNow, Science magazine’s online news site, helpfully explains how: ‘[The research team] pinpointed the elephants' genetic relationships to each other by sequencing DNA from fresh dung samples.’ 

The Samburu elephant population is thought to have lost three-quarters of its members to ivory poachers in the 1970s. As a result, elephants may be willing to accept non-relatives into their social group to ensure they have the critical mass needed to gather food and protect themselves, the researchers suggest.

‘Among the Samburu elephants, the genetic underpinnings have been eroded by high degrees of illegal killing,’ says lead author, George Wittemyer of Colorado State University. ‘Despite this human-driven pruning of their social tree, these elephants formed novel bonds with non-relatives to rebuild the nested structure of their social relations.’ 

Male red jungle fowl can adjust the quality of sperm they produce, depending on how attractive the female fowl is.

The story, reported last week by Discovery Channel online, goes on to explain that males of many promiscuous species in the animal kingdom – including humans – can mate with many females, but they adjust the quality of their sperm to improve chances of fertilization when the female is more attractive.

The Oxford University research published in Proceedings of the Royal Society B involved red jungle fowl, the ancestor of all modern chicken breeds. The team showed that males transfer seminal fluid to matings with attractive females that boosts sperm swimming velocity.

The results provide crucial evidence of what causes variation in sperm quality, which has important implications for fertility and the evolution of sexual strategies.

I caught up with Dr Charlie Cornwallis of the Edward Grey Institute in the Department of Zoology to learn more.

OxSciBlog: Why might cockerels adjust the quality of their sperm when mating with different females?
Charlie Cornwallis: Females vary in their attractiveness with some hens having large fleshy combs on their heads whereas other females are barely ornamented at all. The size of a female’s comb relates to size of the eggs she lays. So by inseminating higher quality sperm into these females males have a greater chance of fertilising eggs that result in superior offspring.

OSB: How do they do it?
CC: They do this by allocating different amounts of seminal fluid to attractive and unattractive females. Sperm cells are the machines that swim, but to do so they need fuel and seminal fluid provides a crucial energy source. By allocating more seminal fluid to ejaculates males are able to increase the performance of their sperm.

OSB: How were you able to find this out?
CC: Since female attractiveness can easily be determined by measuring the size of the fleshy comb on top of their heads, we fitted attractive and unattractive females with a small harness that enabled us to collect sperm. After males had copulated with females we analysed ejaculates using computer aided sperm analysis software attached to a microscope that was originally designed for IVF programs. This software measures the speed at which sperm swim and this relates to how likely they are to fertilise eggs.

OSB: What are the implications of your findings?
CC: It has previously been shown in a number of species, including humans, that males can adjust the quality of sperm they ejaculate, but how they do this has remained a mystery. Our results show in chickens that cockerels do this by allocating more seminal fluid. This takes us one step further to understanding the factors that determine fertilisation success. We now have to assess what it is in the seminal fluid that makes sperm tick and if this is the case for other species.

OSB: What do we know about humans? Do men use similar strategies to chickens and is it even possible to do experiments to find out?
CC: The ability of males to adjust the quality of sperm they allocate to ejaculates has been shown to be extremely widespread. In fact it has been demonstrated in insects, fish, birds and mammals, including humans. However, it is not possible to tell whether males across all these species adjust their sperm quality using seminal fluid without conducting experiments specifically tailored to each species. I know that some colleagues are carrying out some experiments on humans at the moment so hopefully they will be able to answer part of this question soon.

Before OxSciBlog packs its bags and heads off on holiday for the summer there's just time to highlight the work of Oxford geology student David Ferguson.

David is writing regular updates for The Guardian's Science Blog about his mission to the Afar region of Ethiopia.

As he explains, it's a place of awesome seismic and volcanic activity, where the earth is literally tearing itself apart as tectonic plates pull away from each other.

This makes it a fascinating location for earth scientists to study.

In this first post David explains how a satellite image of a plume of gas led to him leaping on a plane for Addis Ababa within 24 hours and once there trying to persuade the Ethiopian military to fly him out of one of the remotest places on Earth.

He'll be posting further updates on the expedition over the following days so be sure to check back with The Guardian Science Blog for news on his progress.

A lot of the time, the tables, figures and graphs included in scientific papers can be pretty impenetrable for those outside that particular area of research. But just occasionally there are figures that can stand alone from a paper, illustrating clearly what the raw data show.

This figure comes close to that ideal. It is very clear that the overall death rate among adults aged 15–54 in Russia is much higher than in Western Europe. The reason? Alcohol.

Most, if not all, of the four-fold difference in risk of death now seen in this age range can be put down to alcohol, and to a lesser extent tobacco.

And while overall death rates in Western Europe have been decreasing, largely as people stop smoking, Russian death rates have fluctuated wildly as alcohol use has altered in the face of political and economic change.

The proportion of deaths in adulthood that can be put down to alcohol in Russia is staggering. A study published in The Lancet and led by the Clinical Trial Service Unit [CTSU] at Oxford University and the Russian Cancer Research Centre in Moscow has found that over half of deaths among people in their 20s, 30s and 40s in Russia are caused by alcohol. This can be from alcohol poisoning, accidents, violence, or through diseases strongly related to alcohol, such as TB, pneumonia, pancreatitis or liver disease.

Professor Sir Richard Peto, who led the statistical analysis of the data at CTSU, said: ‘If current Russian death rates continue, then about 5 per cent of all young women and 2 per cent of all young men will die before age 55 years from the direct or indirect effects of drinking.’

The graph shows Russian death rates dropping when alcohol consumption fell by a quarter in 1985 under President Gorbachev’s 1985–8 anti-alcohol laws. They doubled between 1988 and 1994 when they reached a peak before the Russian economy collapsed. Since then, the death rates have varied but remained high.

There is some hope in these observations. As Professor Peto says, ‘This shows that when people who are at high risk of death from alcohol do change their habits, they immediately avoid most of the risk.’ 

Final preparations are underway for our 3 July event for visitors from the World Conference of Science Journalists (WCSJ 2009).

As our previous post explains the event gives international and UK journalists the chance to meet some of Oxford's top scientists and enjoy drinks and food in the lovely riverside surroundings of Magdalen College.

We've been bowled over by the response from all quarters and the final guest list is bursting at the seams with the sort of people who make Oxford University such an exciting place to do/write about science.

As previously reported Professor Sir Richard Peto, Professor Lionel Tarassenko, Professor Fred Taylor and Dr Ian Goldin are among those attending but the guest list now also includes Professor Sir David Weatherall, Professor Valerie Beral, and Professor Steve Davies - and we also hope to see Lord May.

I'd like to give a special mention to the friends of OxSciBlog who will be there: these include engineer and roboticist Dr Paul Newman, and podcast contributors Professor Irene Tracey and Professor Frances Ashcroft.

Thanks in advance to everyone helping to make this happen.