Abbreviated Science Round-up: Traveling bees, crocs vs Lucy, inevitable inequality
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Bees tackle a seriously tough math problem At some point in your life, whether you know it or not, you’ve tried to solve “the traveling salesman problem.” In fact, you’ve tried many, many times. The classic version of the problem postulates a salesAbbreviated Science Round-up: Traveling bees, crocs vs Lucy, inevitable inequality
Bees tackle a seriously tough math problem At some point in your life, whether you know it or not, you’ve tried to solve “the traveling salesman problem.” In fact, you’ve tried many, many times. The classic version of the problem postulates a salesman out on the road, facing many stops ahead and looking for the optimal route that will reduce the distance traveled to the minimum. If the route is simple enough, intuition is generally enough to develop a near-optimal approach. But add a few more stops, some more options in routing, and this falls under that big group we discussed a few weeks ago — NP-C problems. That nasty class of issues where there seems no neat way to find the best solution except by testing them all. Keep that in mind as you ponder the best way to grab those last minute gifts. You’re not going to come up with the best route to the book store, the cheese shop, and that place with the quirky jewelry. Just drive. The good news is that real life rarely penalizes a less-than-perfect solution to this issue. Real world human beings may be years discovering all the potential shortcuts and side routes that can be taken to squeeze in that one last stop for the day, and unless the pressure for best route is “getting back to the cave ahead of something whose name includes the word ‘saber,’” it’s rarely fatal. Good enough is generally … good enough. But better is still better. Every mile saved is gas in that salesperson’s tank or, in the case of bees, more calories returned for calories expended. As it turns out, bees confronted with multiple sources of food do improve their routes over time … but their number-crunching isn’t all that hard core: On our array, bees did not settle on visit sequences that gave the shortest overall path, but prioritised movements to nearby feeders. Nonetheless, flight distance and duration reduced with experience. This increased efficiency was attributable mainly to experienced bees reducing exploration beyond the feeder array and flights becoming straighter with experience, rather than improvements in the sequence of feeder visits. Flight paths of all legs of a flight stabilised at similar rates, whereas the first few feeder visits became fixed early while bees continued to experiment with the order of later visits. Stabilising early sections of a route and prioritising travel between nearby destinations may reduce the search space, allowing rapid adoption of efficient routes. So the routes got shorter over time because the first parts of the route became straighter, though bees did continue to experiment with different orders for later stops on the route … which isn’t a bad approach, especially if the initial positions are already near-optimal. Actually, what makes this study impressive isn’t just the test of insect-path-solving, but the technology that let the researchers tag and continuously track six bees closely enough to map their paths in very fine detail. Okay, let’s take a direct path to more research ... Read more