A crayfishs urine scares off its enemies.
The left-hand crayfish fans green urine at its opponent
© T. Breithaupt
A well-timed blast of urine is the key to winning a crayfish fight, say researchers. The chemical aggression intimidates opponents into backing down.
Ecologist Thomas Breithaupt injected freshwater crayfish with a dye that made their urine glow green. He and his colleague Petra Eger staged fights between blindfolded crayfish (Astacus leptodactylus), to replicate the animals nocturnal habits1.
Freshwater crayfish fight a lot. They live in dense groups of up to 20 individuals per square metre, and squabble over food, shelter and mates.
Brawls involve a ritualized escalation of violence - from posturing, to gripping, arm wrestling and finally attempting to wrench each others limbs off. Urination increases as the animals become more aggressive, the researchers found.
Chemical signals in the urine tell each party how likely it is to win, reducing the number of extreme fights. If urine release is blocked, fights are longer and more violent.
Crayfish waft the glowing urine towards opponents with their gills. "As far as I know, this is the first time that anyones seen chemical communication underwater," says Breithaupt, although the water probably hums with such messages.
But chemical posturing still needs something to back it up, says Atema, and most encounters do get physical. "Violence is always the reinforcer."
JOHN WHITFIELD | © Nature News Service
New photocatalyst speeds up the conversion of carbon dioxide into chemical resources
29.05.2017 | DGIST (Daegu Gyeongbuk Institute of Science and Technology)
Copper hydroxide nanoparticles provide protection against toxic oxygen radicals in cigarette smoke
29.05.2017 | Johannes Gutenberg-Universität Mainz
The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.
The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
29.05.2017 | Earth Sciences
29.05.2017 | Life Sciences
29.05.2017 | Physics and Astronomy