Many animals possess protective markings to avoid predation, including patterns to reduce the risk of detection (camouflage), to indicate that the animal is toxic or inedible (‘warning colours’), or to mimic another animal or object (‘mimicry’ and ‘masquerade’). In addition, many creatures such as butterflies, moths, and fish possess two or more pairs of circular markings, often referred to as ‘eyespots’. Many eyespots are effective in startling or intimidating predators, and can help to prevent or stop an attack. For the past 150 years it has been assumed that this is because they mimic the eyes of the predator’s own enemies.
However, recent work by University of Cambridge zoologists, Martin Stevens, Chloe Hardman, and Claire Stubbins, indicates that this widely-held hypothesis has no experimental support.
Stevens, Hardman, and Stubbins tested the response of wild avian predators to artificial moths, created from waterproof paper. Specific patterns, such as intimidating eyespots of different shapes, sizes and number, and with different levels of eye mimicry, were printed on to the paper using a high quality printer. These ‘moths’ were then pinned to trees of various species at a height of one to three metres in the mixed deciduous Madingley Woods in Cambridgeshire, UK. Attached to each of the artificial moths was an edible mealworm as a temptation for woodland birds such as the blue tits, great tits, blackbirds, and house sparrows.
The zoologists discovered that artificial moths with circular markings survived no better than those with other conspicuous features and that the features of eyespots which most encouraged predators to avoid them are large size, a high number of spots, and conspicuousness in general.
As Dr Stevens explains, ‘the birds were equally likely to avoid artificial moths with markings such as bars and squares as they were to avoid those with two eye-like markings. This leads us to conclude that eyespots work because they are highly conspicuous features, not because they mimic the eyes of the predators’ own enemies. This suggests that circular markings on many real animals need not necessarily, as most accounts claim, mimic the eyes of other animals.’
 Conspicuousness, not eye mimicry, makes ‘‘eyespots’’ effective antipredator signals (Martin Stevens, Chloe J. Hardman, and Claire L. Stubbins) Behavioral Ecology doi:10.1093/beheco/arm162
Dr Martin Stevens | alfa
Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
29.03.2017 | Materials Sciences
29.03.2017 | Physics and Astronomy
29.03.2017 | Earth Sciences