Fun with Science Club®


			Spiders make their webs invisible to catch insects. Beth Tyler 05.03.01 Spiders weave silk webs for catching insects to eat. An unfortunate insect flying by might get caught in a web, becoming the spider's next meal. The spiders that make the most invisible webs catch the most insects (the insect can not see the web, so it flies straight into it and gets tangled up). Spiders who can't make their webs invisible are more likely to starve. The spiders who starve don't have as many babies as the spiders who live into old age. A baby spider will grow up and make a web like the one its parents made. Since the parents who make invisible webs will have the most babies, every generation there will be more spiders making invisible webs. Some spiders have become very good at making their webs hard to see. Scientists Todd A. Blackledge and John W. Wenzel wanted to find out if the silk Argiope aurantia spiders make is more invisible to honeybees than the kind of silk Pterinochilus sp. (tarantulas) make. Because honeybees like flowers, they tested their hypothesis by setting up some places with flowers for the honeybees to fly around in. Then they divided the honeybees into two groups. One group could fly around in the place that had some flowers with tarantula webs around them. The other group could fly around in the place that had some flowers with Argiope webs around them. Then the scientists watched the bees to see how often they got caught in the webs. They discovered that the Argiope webs caught more insects. The scientists concluded that the Argiope spiders are better than the Pterinochilus spiders at making their webs invisible to insects.


			Blackledge, Todd A., and John W. Wenzel. 2000. The evolution of cryptic spider silk: a behavioral test. Behavioral Ecology 11(2): 142-145.