The study shows for the first time that the nutritional quality of plant food sources for herbivores has a far-reaching impact on an ecosystem as a whole, potentially impeding important functions that the ecosystem performs, such as the natural predation and control of agricultural pests.
The scientists compared aphids living on sprouts to aphids living on wild cabbages in a field experiment which took place on a farm in theNetherlands. They could see that the sprouts were of a lower nutritional value for aphids than the cabbages, because the aphids feeding on them were smaller in size, and the number of aphids living on them was fewer.
They then traced the effects up through the food chain to discover that the implications of poor nutritional quality in plants spread throughout the extended network of feeding relationships in an ecosystem known as a food web. This means that the sprouts affect not only the herbivore aphids that eat them, but also the primary parasitoid wasp predators that mummify and eat the aphids, and the secondary parasitoid wasps that in turn eat the primary parasitoid wasps.
The scientific team made this discovery by analysing the food webs associated with both types of plants. They found that food webs based on sprout-eating aphids are less complex and involve a less diverse network of predators than those food webs based on higher quality plants like wild cabbage.
This is because larger, cabbage-eating aphids produce larger primary parasitoid predators, which in turn attract more of the opportunistic generalist feeders among the secondary parasitoids, leading to a greater diversity of species and complexity in the ecosystem. This shows that plant quality indirectly influences the foraging decisions taken by individuals higher up the food chain which ultimately determines the structure of the food web.
One of the paper's authors, Dr Frank Van Veen from Imperial College London's NERC Centre for Population Biology, explains why this is important:
"The diversity and complexity of food webs have long been seen as good indicators of how well an ecosystem is functioning, and how stable it is, but until now we had very little idea of the processes that determine diversity and complexity. Our study has shown that changing just one element, in this case plant quality, leads to a cascade of effects that impact on predators across the food web.
"If we are to predict how environmental change is going to affect ecosystems and the functions they perform, an important part of the puzzle is to understand the mechanisms by which an effect on one species propagates through the complex network of interacting species that make up an ecosystem."
Dr Van Veen adds that their research has no implications for human sprout consumption: "Our aphid study certainly does not mean sprouts aren't good for humans to eat - our nutritional requirements differ enormously from those of insects."
The research was jointly led by scientists at Wageningen University in the Netherlands and Imperial College London, and was funded by the Netherlands Organisation for Scientific Research (NWO) and the UK Natural Environment Research Council.
Danielle Reeves | alfa
New study shows producers where and how to grow cellulosic biofuel crops
17.01.2018 | University of Illinois College of Agricultural, Consumer and Environmental Sciences
Robotic weeders: to a farm near you?
10.01.2018 | American Society of Agronomy
On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.
We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
19.01.2018 | Materials Sciences
19.01.2018 | Health and Medicine
19.01.2018 | Physics and Astronomy