Science - March 6, 2018

Young scientist given stage during dies natalis

Tessa Louwerens

On 9 March, during WUR’s one-hundredth dies natalis, three young WUR scientists will speak about the way their research contributes to the unravelling of life. Natural ways of fighting harmful insects, migration patterns after a hurricane and dancing molecules will be at the centre of attention.

©Margreet Bruins
©Margreet Bruins

Assistant Professor Nina Fatouros in the Biosystematics group studies how plants in the cabbage family defend against insects that lay eggs on their leaves. ‘From prior research, we already know that eggs of various butterfly species trigger a kind of hypersensitivity reaction in some plants. The plant’s tissue dies off, with the insect eggs often also perishing as a consequence.’ The eggs of the cabbage white, a species of butterfly, seem to induce a similar reaction in black mustard, a wild species of cabbage. Fatouros: ‘Not every plant has an equally strong reaction; it varies between various species, but even between individual plants. We also saw that the reaction was accompanied by the excretion of a substance that attracts parasitic insects, such as parasitic wasps, which destroy the eggs. With this process, the plant creates a double line of defence, making it an interesting mechanism to defend crops against pests. If we can unravel which genes in the cabbage are involved, we could use plant breeding to cross these genes into other crops to help the latter to better withstand harmful insects, such as caterpillars. We must reduce the use of pesticides as much as we can. Nature often has already found a solution for every problem we encounter.’

Assistant Professor in Environmental Policy Ingrid Boas studies the relation between climate change and human migration. ‘When we think of environmental and climate changes, we usually get this Apocalyptic vision, with millions homeless and on the run. We think of tensions, chaos, sometimes even war.’ But Boas’ analysis paints a very different picture. She travelled to Bangladesh for her research. The country suffers ongoing erosion and is regularly hit by hurricanes. Mobility patterns around the country had already been mapped using anonymous mobile data, Boas says. ‘In those data, you see many people move during and after a hurricane. But contrarily to what is often thought, these people are not fleeing.’ Boas travelled to the area and investigated what was going on. ‘The problem with big data is that you don’t know what the patterns truly mean, unless you take a closer look at the local circumstances. By talking to the people in the area affected, we discovered that they were not looking for a safe haven; most of them could stay home. And if they did flee their homes, they never went far.’ But then what was the explanation for the large flows found in the big data? ‘Eventually, we discovered those were the fishermen who went to the harbours to save their boats from the storm.’ According to Boas, the image of climate change leading to mass migrations of panicked people leaving their homes and coming our way is mistaken. ‘On the contrary, we see that people prefer to stay put, move to a close-by location or scatter very slowly. However, it is in the places where we see no movement that the people are in the greatest danger, as they have no way of fleeing in case of a disaster.

Joris Sprakel, Associate Professor in the Physical Chemistry and Soft Matter group, explains how he and his group work on the visualisation of what he calls ‘the dance of the molecules’. ‘We are developing new methods and techniques to understand what the foundation of various phenomena in daily life is at the molecular level.’ He compares it with the migration of a murmuration of starlings: the individual birds fly in a swarm that moves almost organically and continuously changes form, speed and direction. ‘The dance that arises from this cannot be explained by describing the movement of a single animal; it is the effect of the collective.’ In the 1950’s, mathematician Alan Turing devised a way to describe this pattern forming based on a few simple rules of physics. But although these rules are simple, finding them is extremely challenging. They were only discovered about twenty years ago for the swarms of birds. Sprakel: ‘Molecules also exhibit this kind of complex dance. But to fathom these rules, we must first be able to visualise this dance. We are working on that. We are developing new equipment, theoretical models and computer simulations.’ In a select few cases, they have already managed to unravel these rules. For example, for the material used in spacecraft. ‘Delft University of Technology creates self-healing materials for spacecraft that work similarly to human skin when damaged. And although this group was able to create several of these materials over the past years, the underlying mechanisms were unclear. We have managed to map the process, and based on these rules, researchers will now work on further improving the materials for the next generation of spacecraft.’

Further reading (partly in Dutch):