Fine Structure and Function of Capture Threads

Abstract

Capture threads may be defined as threads whose peculiar properties cause prey to adhere to them. With respect to these properties two types of capture threads may be distinguished:

• 1. Capture threads whose suitability for holding prey is based upon a covering that consists of a viscous glue. These threads are sometimes called sticky or adhesive threads. However, these characteristics can also be attributed to the other type of capture threads. Therefore, capture threads belonging to this first type will be called gluey capture threads in this review.

• 2. Capture threads whose suitability for holding prey is based upon a covering that consists of innumerable, extremely fine fibrils. They are often called hackled bands or hackled silk because of their characteristic appearance. Since the fibrils originate from the cribellum, these capture threads are also spoken of as cribellate threads or cribellar silk. However, these terms are ambiguous: cribellate spiders produce a variety of threads, which are not at all capture threads, and cribellar silk denominates only a component of these capture threads. Therefore, the threads in question will be called cribellar capture threads in this review.