Orb-web building as an instinct: the first part of an argument

Abstract

Orb-web building is usually interpreted as a stereotyped, resistant-to-learning performance. In order to detect eventual effects of experience on web building, groups of adult orb-web spiders Argiope argentata (Fabricius) were kept for an extended period in frames of different dimensions, spinning different sized webs. They were then tested in a frame of an intermediate size. It was hypothesized that previous experience of building in larger or smaller contexts would have effects on the size or internal proportions of the test webs. Data did not corroborate such an expectation: results may be taken as reinforcing an instinctivist point of view: I prefer to interpret them as showing that some aspects of past experience do not affect the basic features of the web-building program. The question of the role learning may play in the spider's spinning skills remains open.