"The victim can allow the enemy to remain and instead try to live with the consequences", explains Erik Svensson, Professor of Animal Ecology at Lund University.
There are many examples of 'coevolution', i.e. where the enemy and the victim influence each other's development in close interaction. In several plant studies it is for instance a relationship between a parasite (the enemy) and its host plant (the victim). Erik Svensson and his colleague Lars Råberg have recently published an article in the journal Trends in Ecology & Evolution, in which they discuss the evolution of enemy-victim relations in animals.
The cuckoo's brood parasitism is a classic example. The great spotted cuckoo lays its eggs in the nest of the European magpie and lets the magpie pair raise its young. The magpie can in turn respond by trying to recognise alien eggs and reject them; this is a form of resistance. However, there is a risk that the magpie may accidently reject one of its own eggs. In addition, the magpies that reject cuckoos' eggs run a higher risk of having their nests destroyed by adult cuckoos. There is evidence that magpies that live in close proximity to great spotted cuckoos actually compensate for this by laying more eggs than magpies that breed in areas where cuckoos are not present. One reason for this could be that it is a way to compensate for the eggs that risk being destroyed. This defence tactic is classified as tolerance, rather than resisistance. It means that the victim tries to live with the presence of the enemy instead of resisting.
Erik Svensson conducts research on damselflies. He has shown that enemy-victim relationships can also occur within the same species. When damselflies mate, the male clasps the female's thorax. Immediately after fertilisation, the female begins laying eggs. Yet females are constantly subject to mating attempts and harassment from other males, which incur costs in the form of a reduced number of eggs. However, some females have developed a higher tolerance to this mating harassment, which means that they are able to partly buffer the negative effects of mating harassment on their egg laying.
Lars Råberg has studied tolerance in mice. He has performed an experiment in which he infected different mouse strains with malaria. It was apparent that the different mice did not become ill to the same extent, despite the fact that they had the same number of parasites in their bodies. Thus tolerance can also reflect itself in how sensitive a victim is to an enemy.
"This is a new way of viewing the evolution of enemy-victim interactions in animals. The role of tolerance in suchinteractions have previously been discussed primarily in the context of the plant world. We believe that tolerance could be at least as important as resistance in animal co-evolution between enemies and their victims", says Erik Svensson.
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21.11.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
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