Nature teaches engineers new tricks

To help solve design problems, we should look to nature. For example, ants could help with traffic patterns, bees could provide insights on aerodynamics, and skunk cabbage may reveal new ways to regulate temperature.

Through millions of years of evolution, many species have come up with elegant solutions to problems that crop up today in various engineering fields. We should learn from this biological wisdom, says Francis Ratnieks at the University of Sheffield in England.

The biologist cited the foraging strategy of pharaoh's ants to illustrate this point in the July 28 issue of Nature. How these foragers move efficiently to and from a food supply provides an answer to what Dr. Ratnieks calls one of those "simple to state but hard to solve problems" that confront designers of traffic flow, electronic messaging, electricity transmission, and other network systems.

How do pharaoh's ants know which way to go? By laying out a chemical trail in a pattern in which the junction of three trails forms a Y. The stem of the Y leads to or away from the nest. It also intersects the two arms at a wide angle while the arms form a smaller interior angle of about 60 degrees. The ants have enough geometrical instinct to sense the difference in angles and follow the right trail.

Insects probably have evolved a variety of solutions to the foraging problem, Ratnieks notes. We should care about them "because human life depends more and more on engineering systems that must solve similar problems to function efficiently," he explains.

In the field of aerodynamics, honey bees and bumble bees have some wisdom to share, according to research published this week in the Proceedings of the National Academy of Sciences. The flapping flight of these small insects carries aerodynamics into a region where conventional theory fails. These bees have evolved a flight system different from that of most small flying insects, find Michael Dickinson at the California Institute of Technology in Pasadena and colleagues. While some insects fly by swinging their wings in large arcs, the bees' wings move in much shorter arcs while flapping at a relatively high frequency. This short-arc high-speed wing motion gives the bees a much wider power range than other insects enjoy.

Then there's the mystery of skunk cabbage temperature control. The plant's internal temperature remains around 20 degrees C. even when it's freezing - 0 degrees C. or below - outside. How the plant does it is still unknown. But research suggests that the regulation operates in accord with an algorithm based on mathematical chaos theory, explain Japanese scientists Takanori Ito and Kikukatsu Ito in the November Physical Review E.

New Scientist magazine reports that the two scientists have now built and are testing a temperature control that incorporates the algorithm.

One of the most important lessons we can learn from highly evolved biological systems is how to make our own engineered systems stronger, Ratnieks notes. "If there's one thing natural selection is good at, it is eliminating solutions that are not robust," he says.

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