Wasps key to survival of 1,200 species

Global warming may kill pollinators of figs, food for many animals: Study
David Ee Straits Times 6 Apr 13;

IF WASPS that pollinate fig trees die out due to global warming, it could lead to a "massive loss of animal species", Singaporean researchers have found.

A worldwide temperature rise of 3 deg C - which scientists predict could happen by 2050 as greenhouse gases warm the planet - could kill the wasps that the 750 known fig varieties rely on to reproduce.

This would reduce fig numbers, which could in turn lead to the decline of up to 1,200 species that rely on it as a food source - including orang utans, fruit bats and hornbills.

The claims come from a two-year study into wasps led by Singaporean ecologist Nanthinee Jevanandam, who was a PhD researcher at the National University of Singapore when it started.

She had been studying fig trees in Kent Ridge during a hot spell in 2010 when she noticed unusual pollination patterns.

The study's results, published last month in Biology Letters - the journal of the Royal Society, the United Kingdom's national academy of science - could have far-reaching implications.

"Because of their ecological importance, any loss of fig species or reduction in their abundance would be of major conservation concern," the paper concludes.

A knock-on effect would result, said Ms Javanandam, affecting not only species that feed on figs, but also others further up the food chain.

Figs are widespread globally and can be found in both temperate and tropical regions, including Japan and Australia.

The researchers exposed more than 4,000 wasps of four species to increasing temperatures in a laboratory, starting from 25 degC.

They found that an average temperature rise of 3 deg C led to declines of up to 25 per cent in the lifespans of three of the species.

These tiny fig wasps typically live for just one to two days.

With a shorter time to live, they would have less time to locate figs to pollinate.

But Ms Javanandam cautioned against sounding alarm bells. There is the possibility, she said, that the wasps could genetically adapt to higher real-world temperatures as the planet warms.

She added that she hoped her team's findings would encourage more research in the area.

She said: "I wouldn't go so far as to say it's a crisis. We cannot predict these things absolutely. But the importance of figs is clear - this cannot be disputed."