What diet and environment, squirts and flies, can tell us about male fertility

A young scientist who discovered that sperm from male mice swim faster when fed sugar, and that when male sea squirts compete to produce sperm the resulting eggs are less likely to hatch, has won the Young Tall Poppy Science award.

Evolutionary ecologist Dr Angela Crean, from the University of Sydney, won for her discoveries showing a male's diet and environment affect the quality of his sperm and offspring.

In addition to her work on mice and sea squirts, she also found a female neriid fly's first partner can influence the size of offspring sired by her future partners and that the diet of the father affected the size of the fly's offspring.

Dr Crean said she was shocked when her team discovered a new form of non-genetic inheritance, the Herald reported.

"We did a lot of follow-up studies to check our results," she told the Herald's Nicky Phillips.

The ancient idea that offspring can inherit characteristics from their mother's previous mate - known as telegony - was once discredited when scientists established more than a century ago that genes were the dominant way traits passed from parent to offspring.

But her research found that when a large male neriid fly (Telostylinus angusticollis) mated with a female before she was fertile he would pass along his seminal fluid, while her eggs remained unfertilised.

"Something other than sperm in the ejaculate (we do not know what is it yet), from a previous partner can penetrate a developing egg, influencing its growth despite being sired by another male," she said.

"We are only just beginning to realise that a father's lifestyle can have at least as much influence as a mother's on the health of their children. We do not yet fully understand how these environmentally-acquired traits are transmitted across generations," Dr Crean said at the time.

With about 50 per cent of human infertility cases resulting from less fertile sperm, Dr Crean, 36, hoped her discoveries offered potential for new reproductive strategies across the spectrum, from agriculture to humans.

The other winner of the young Tall Poppy award was University of Sydney's Dr Ivan Kassal who has pioneered the
application of quantum computing to chemistry and leads research into quantum effects in light harvesting to design better solar cells.

This story What diet and environment, squirts and flies, can tell us about male fertility first appeared on The Sydney Morning Herald.