They may only be 1.5mm in size, but the tiny wasps that pollinate fig trees can travel over 160km in less than 48 hours, according to research from scientists at the University of Leeds. The fig wasps are transporting pollen ten times further than previously recorded for any insect.
The fig wasps travel these distances in search of trees to lay their eggs, which offers hope that trees pollinated by similar creatures have a good chance of surviving if they become isolated through deforestation.
"Fig trees provide very important food for vertebrates," explains Dr Stephen Compton of the University's Faculty of Biological Sciences. "More birds and animals feed on fig trees than on any other plant in the rainforest. Our research shows that trees pollinated by this type of insect should be very resistant to forest fragmentation."
"Fig wasps are weak flyers," added Dr Compton. "They fly up in an air column and are then carried by wind until they sense host figs at which point they drop close to the ground and hunt out the scent of the tree which is specific to them.
"As adult wasps live for just 48 hours, they must have travelled these distances incredibly fast. It took our field scientists and volunteers nearly two weeks to walk 250km and map the fig trees used in the research."
Using a unique mix of field work and genetic tests, the researchers tracked the movement of pollen between trees and used this as the marker for insect movement.
The trees were DNA tested and seedlings grown from their fruit. Genetic tests on the seedlings enabled the researchers to identify which trees had cross-pollinated. As the trees are only pollinated by the fig wasp Ceratosolen arabicus, the scientists were able to map the distances travelled by the insects.
"This is the first research to identify each individual tree, rather than extrapolate the genetic mix from a sample," said Professor Philip Gilmartin, formerly from Leeds and now at the University of Durham. "We were basically paternity testing trees: we knew which tree was the 'mother' and because we already had the DNA results for the other trees, it was easy to identify the 'father'. It meant we were tracking the route of an individual grain of pollen."
The shortest distance recorded for cross-pollination was 14km and the furthest 164km. Trees were not necessarily pollinated by their nearest neighbour, and some pollen came from unidentified trees, indicating that some insects were travelling even longer distances than those recorded.
The research was part of a PhD studentship carried out by Sophia Ahmed and funded through the Biotechnology and Biological Sciences Research Council (BBSRC) with additional support from the Natural Environment Research Council (NERC). The findings are published this week in the Proceedings of the National Academy of Sciences (PNAS).
Graham Askew, Simon Walker, BBSRC (Jan 2018), £699,781
Jennifer Tomlinson, Royal Society (Jan 2018), £512,801
Carrie Ferguson, Bryan Taylor, Harry Rossiter, The Physiological Society (Dec 2017), £7,392
Ralf Richter, Royal Society (Dec 2017), £6,000
Christine Foyer, British Council Newton Fund (Dec 2017), £49,840
Adrian Whitehouse and colleagues in School of Chemistry and University of Liverpool, MRC (Nov 2017), £622,319
Michelle Peckham, Neil Ransom, MRC (Nov 2017), £495,159
Dave Lewis, British Council India (Nov 2017), £22,540
Hannah Dugdale, Royal Society (Nov 2017), £15,000
Elton Zeqiraj, Royal Society (Nov 2017), £15,000
Shaunna Burke, Cancer Research UK Innovation Grant (Nov 2017), £20,000
Alex O'Neill and colleagues in Chemistry, BBSRC (Nov 2017), £431,865
Jessica Kwok, Wings for Life (Nov 2017), £87,365
Tom Bennett, BBSRC (Oct 2017), £523,679
Neil Ranson, Darren Tomlinson, BBSRC (Oct 2017), £494,318
Nikita Gamper, BBSRC (Oct 2017), £490,426
Amanda Bretman and colleagues from UEA, NERC (Oct 2017), £430,886
Juan Fontana, Rosetrees Trust consumables grant (Oct 2017), £22,500
Helen Miller, DSM Nutritional Products AG (Sep 2017), £69,988
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Jamie Johnston, Physiological Society (Sep 2017), £10,000
Frank Sobott, Adrian Goldman, Mark Harris, Andrew Macdonald, Stephen Muench, Sheena Radford and colleagues in FMH and MAPS, Wellcome Trust Equipment Call (Aug 2017), £415,000
Ralf Richter, David Brockwell, Eric Hewitt, Jessica Kwok, Emanuele Paci and MAPS/FMH, BBSRC (Jun 2017), £600,000
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Stefan Kepinski, Yoselin Benitez-Alfonso, Tom Bennett, Michelle Peckham, BBSRC (Jun 2017), £331,000
Roman Tuma, Lars Jeuken, Paul Millner, Sheena Radford, Peter Stockley and MAPS/FMH, BBSRC (Jun 2017), £222,000
Vas Ponnambalam, Darren Tomlinson, Stephen Wheatcroft, BHF (May 2017), £107,878
Graham Askew in collaboration with Bangor University, BBSRC (Mar 2017), £477,383
Stephen Muench, BBSRC (Mar 2017), £132,945
Nic Stonehouse, MRC (Mar 2017), £906,341
Bill Kunin, Steve Sait, BBSRC (Mar 2017), £602,831
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Sheena Radford, Wellcome Trust (Mar 2017), £1,836,482
Beatrice Filippi, Royal Society (Mar 2017), £15,000
Jamie Johnston, Royal Society (Mar 2017), £15,000
Tom Bennett, Royal Society (Mar 2017), £15,000
Ryan Seipke, BBSRC (Feb 2017), £52,116
Mary O'Connell, BBSRC (Feb 2017), £46,986
Hannah Dugdale, NERC (Feb 2017), £504,138
Anastasia Zhuravleva, EPSRC (Jan 2017), £100,792
Richard Bayliss, Cancer Research UK (Jan 2017), £1,600,000
John Barr, EU (Jan 2017), £339,000
Mark Harris, Royal Society (Jan 2017), £250,000
Alison Dunn, NERC (Jan 2017), £105,000
Alex Breeze, Pancreatic Cancer Research Fund (Jan 2017), £180,000
Alison Dunn, NERC (Dec 2016), £18,000