Few events involving animals are more dramatic than when they band together and head out on the march cross-country. Among examples are the many thousands of wildebeests and other hoofed mammals that form herds and migrate across the African plains.

Countless millions of Mormon crickets and young locusts also sometimes unite with their own kind and form teeming, hungry islands of life that devour everything in their path that's edible. Some spectacular marching packs stretch several miles wide and extend 10 miles or so in length. And they can travel a mile or so a day.

Why such groups of insects form has mystified humans for thousands of years. One firmly held belief was that God was punishing men and women for their sins. A more recent, scientific theory has been the "safety-in-numbers" idea -- that the small animals congregate periodically as a way of protecting themselves from predators such as birds and rodents.

Now, a trio of insect experts has developed what they believe is strong new evidence that the latter theory is correct. By gluing radio transmitters -- each weighing less than half a gram -- to the backs of Mormon crickets in northeastern Utah and northwestern Colorado, Drs. Gregory A. Sword, Patrick D. Lorch and Darryl T. Gwynne showed experimentally that band formation indeed boosted insect survival.

Dartmouth Medical School geneticists have found links in the cell death machinery of worms and mammals, opening new avenues for studying and targeting a process vital to development and implicated in cancer and autoimmune diseases.

The work, reported in the February 17 issue of Nature, demonstrates the role of mitochondria, the cellular power plant, in prompting worm cells to self destruct. These results unify cell death models along the evolutionary spectrum, from simple animal systems to humans.

Parrots, long a favorite pet animal, are attractive to owners because of their vibrant colors. But those colors may mean more to parrots than what meets the eye.

For more than a century, biochemists have known that parrots use an unusual set of pigments to produce their rainbow of plumage colors, but their biochemical identity has remained elusive. Now, an Arizona State University researcher has uncovered the chemistry behind the colors of parrots, describing on a molecular level what is responsible for their bright red feathers.

Dutch researcher Corine Visser investigated a new way of transporting medicines into the brain. Her approach made use of an iron transport system located on the blood-brain barrier. The smaller the medicine, the more easily it penetrates the brain.

A special barrier between the blood and the brain, the so-called blood-brain barrier (BBB), protects the brain from toxic substances. It only lets through important nutrients for the brain such as iron, glucose and oxygen. Visser allowed larger molecules, such as medicines, to pass through the blood-brain barrier by attaching these to the iron-containing protein transferrin. This technique allowed the medicines to 'hitch a lift' and pass unnoticed though the BBB. How much medicine reaches the brain depends on the size of the molecule attached to the transferrin.

The labs of the future will be "labs-on-a-chip", i.e., integrated chemical and biochemical laboratories shrunk down to the size of a computer chip. An essential prerequisite for such labs are appropriate microcompartments for the confinement of very small amounts of liquids and chemical reagents. Directly accessible surface channels, which can be fabricated by available photolithographic methods, represent an appealing design principle for such microcompartments and, thus, provide a new route towards open microfluidic and nanofluidic systems. Scientists from the Max Planck Institute of Colloids and Interfaces, the Max Planck Institute of Dynamics and Selforganization and the University of California in Santa Barbara have shown that such open systems are possible in general but only if the geometry of the surface channels is carefully matched with their wettability (PNAS 102, 1848-1852 (2005).

Yale scientists report in the journal Nature that the "missing" genes for tRNA in an ancient parasite are made up by splicing together sequences in distant parts of the DNA genome.

The research led by Professor Dieter Söll in the Department of Molecular Biophysics and Biochemistry at Yale focuses on the most ancient organism with a known genome sequence. Nanoarchaeum equitans, is a member of a new phylogenetic kingdom in the Archaea containing organisms that are primitive, parasitic and extremophile, or notable for living in the most extreme environments.

Surprisingly, Söll's team found that, although the genome of Nanoarchaeum lacks several intact tRNA genes, functional forms of those tRNAs can be made by copying from two distant DNA sequences -- and joining them.

The fascinating interactions between flowers and their pollinators have resulted in a spectacular diversity of plants. In order to entice pollinators such as bees, flies or butterflies to visit and successfully pollinate their flowers, plants have evolved intriguing mechanisms and attractants, of which nectar is best known.

Thirty years ago, researchers discovered that nectars of flowers pollinated by butterflies contain substantial amounts of amino acids. Recent experiments have shown that butterflies actually prefer nectars with a high amino acid content. These findings led to speculations about the significance of nectar amino acids for butterfly fitness and insinuated that butterflies have acted as agents of natural selection on nectar composition.