Pesticides: Easier Detection of Pollution and Impact in Rivers Made Possible

Researchers from the Helmholtz Centre for Environmental Research (UFZ) have developed a tool that can easily estimate the harmful effect of pesticides on living organisms in rivers and on water quality. This can be done in minutes.

Pesticides cause characteristic changes to the composition of the life community that is affected. What is required is to find out which living creatures, e.g. insects and crabs, are found at a certain point along the river and in what numbers. The scientists have now set up a Web application where this data can be entered and evaluated to show immediately the level of pollution.

Regional data is currently available for Germany, France, Finland and Western Siberia, but the system has also been tested in the UK and in Australia. There is no charge for using the service. The advantage of the new tool is that in many cases, complex, expensive chemical analyses will no longer be necessary.

Journal reference:

Beketov M.A., Foit K., Schäfer R.B., Schriever C.A., Sacchi A., Capri E., Biggs J., Wells C., Liess, M. SPEAR indicates pesticide effects in streams - comparative use of species- and family-level biomonitoring data. Environmental Pollution, 157(6), June 2009

Light as an Aid for Bird Migration

Latest research on European Robins is making established facts about migration of birds on its head. Scientists have discovered that In European Robins, a visual center in the brain and light-sensing cells in the eye and not magnetic sensing cells in the beak allow the songbirds to sense which direction is north and migrate correctly.

Researchers have known that built-in biological compasses tell migrating birds which way to fly, but the details of how birds detect magnetic fields has been unclear.

Special proteins called cryptochromes in the birds’ eyes may mediate this light-dependent magnetic sensing according to the scientists. Light hitting the proteins produces a pair of free radicals, highly reactive molecules with unpaired electrons. These electrons have a property called spin which may be sensitive to Earth’s magnetic field. Signals from the free radicals may then move to nerve cells in cluster N, ultimately telling the birds where north is.

To find the location that houses the magnetic compass the scientists caught 36 migratory European robins and made sure that the birds could all orient correctly under natural and induced magnetic fields. Next, the researchers performed surgeries on the birds to deactivate one of the two systems. The team either severed the nerve that connects the beak cells to the brain, or damaged the brain cells in cluster N that receive light signals from cells in the eye.

Birds with the severed beak-to-brain nerve, called the trigeminal nerve, still oriented perfectly. On the other hand, birds with damaged cluster N regions could no longer sense and orient to magnetic fields. These robins failed to pick up both the Earth’s natural magnetic field and the artificial fields created by the researchers.

Details of the study appear in Nature dated October 29^th.

Tiger Moth Uses Ultrasonic Clicks to Jam Bat's Sonar and Escape Death.

Tiger Moth (Bertholdia trigona ) make up to 450 ultrasonic clicks in a tenth of a second to jam bat's sonar and escape death. This discovery was made by Aaron Corcoran, a Wake Forest University graduate student, and William Conner, professor of biology at Wake Forest. High-speed infrared video cameras were used to record the interactions between predator and prey. The researchers also recorded the high-frequency sounds made by both the bats and the moths during each interaction.

The moth clicks back using a paired set of structures called "tymbals. This disrupt the bat's echolocation cycle. The researchers are yet to discover exactly how the jamming works.

Sonar jamming extends the defensive repertoire available to prey in the long-standing evolutionary arms race between bats and insects.

Details of the research appears in Science magazine

Eyes of Mantis Shrimp Could Inspire Design of Sophisticated DVD and CD players

The Mantis Shrimp research conducted at the University of Bristol's School of Biological Sciences in collaboration with colleagues at UMBC, USA and the University of Queensland, Australia is likely to inspire a new generation of highly sophisticated CD and DVD players.

The Mantis Shrimps is found on the Great Barrier Reef in Australia. These shrimps have the most complex vision systems known to science. They can see in twelve colours . Humans see in only three colors. Mantis Shrimp can also distinguish between different forms of polarized light.

Artificial devices only tend to work well for one colour of light while the natural mechanism in the mantis shrimp's eyes works perfectly across the whole visible spectrum of light. This natural mechanism, comprised of cell membranes rolled into tubes outperforms synthetic designs by all counts. Scientists believe that it could help us make better optical devices in the future using liquid crystals that have been chemically engineered to mimic the properties of the cells in the mantis shrimp's eye.

Details of the research appear in the latest issue of the journal Nature Photonics.