Tommi Nyman of the University of Joensuu in Finland together with colleagues from Sweden and Germany uncovered a food web involving willow trees, sawflies, and the parasites feeding on sawfly larvae. Sawflies (a group of insects related to bees and wasps) lay their larvae in willows creating galls, which are protruding growths of plant tissue. Nyman's group used data from galls collected from willows over an 18-year period. They classified 43 sawfly species using genetic analysis and assessed the degree of parasitism to which these insects had been subjected by 72 different parasites.
Their statistical analysis showed that parasitism promotes the insects' ecological divergence in a co-evolutionary arms race. The sawflies develop new gall-types and, in doing so, can escape the attentions of the parasites without having to switch host plant. Some parasites, however, have in turn adapted to the divergence in gall-types, driving further speciation. These processes partly explain the unusual diversity of herbivorous insects and their parasitoids.
This study is the first time that key co-evolutionary hypotheses such as the classic Escape-And-Radiate (EAR) hypothesis have been tested in a phylogenetic framework. EAR suggests that hyper diverse communities result from co-evolutionary arms races featuring cycles of enemy escape, radiation, and colonization by new enemy lineages. The results show that the EAR hypothesis is too simplistic to be applied to complex species-rich food webs.
"Our results indicate that niche-dependent parasitism is a major force promoting ecological divergence in herbivorous insects," says Nyman. "Diversification seems to be spurred by a continuous stepwise process, in which ecological and phenotypic shifts in prey lineages are followed by a lagged evolutionary response by some of the associated enemies."
Lauren Hillman | alfa
Complete skin regeneration system of fish unraveled
24.04.2018 | Tokyo Institute of Technology
Scientists generate an atlas of the human genome using stem cells
24.04.2018 | The Hebrew University of Jerusalem
At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.
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Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.
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University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
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Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
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