For the identification of insects and other fauna and flora of South Africa.

Sunday, April 17, 2011

Spider and moth - Hairy Field Spider (Neoscona blondeli) Araneidae

This beautiful spider had just caught the moth and had started to spin a web around it so that it could not fly off. During the course of my browsing around trying to find out more about spider eating habits, I came across this article published in 2008 by Patricia A. Michaels and thought it might be of interest. What do spiders eat Spiders, long considered carnivores, (although there might be exceptions to that rule), traditionally choose insects and other arachnids as their primary source of food. Arachnologists, scientists who study spiders, have long been intrigued by spider diets. One question they consider, "Are Spiders Picky Eaters", has been the subject of both observation and scientific experimentation. Like all scientists, when arachnologists conduct experiments on spider diets, they are trying to stay as objective as possible with respect to the potential answers. Objectivity in scientific experimentation often loosely translates into scientists trying to prove their thinking is wrong, rather than prove their thinking is correct. Scientifically, the process is known as testing the null hypothesis. A pair of arachnologists conducting experiments on the pickiness of spider eating habits, started with the hypothesis that spiders eat any insects that come their way. They conducted an experiment with an Araneidae species, an orb weaving spider (Micrathena Gracilis). Over an extended period of time, they counted the number and size of insects that flew into the web. They also recorded the number and size of the insects that the spider captured for dinner. Testing the null hypothesis meant that the researchers thought that the spider would eat all the insects that landed in the web, regardless of insect size. At the end of their experiment, they concluded that when given the choice between large and small insects caught in the web, the spider preferred larger insects. In scientific terms, they concluded there was a statistically significant relationship between spider diet and insect size. The hypothesis that spiders are picky eaters still stands. Information supplied by: http://greennature.com/article120.html

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