There are 2 elements that make “crowding” interesting—mechanism (causality) and manifestation (effect). In our companion paper, Larry Roberts addresses mechanisms. Here, we focus on manifestation.
As ecologists, it is difficult to get too excited about Clark Read's paper on the “crowding effect” in cestodes, at least initially. The paper acknowledges clearly that the phenomenon has been observed repeatedly, is mostly a discussion of appropriate techniques, and concludes with a brief overture to causality. Recalling a popular television commercial from several years ago, “Where's the beef?”
The answer lies in the implication of crowding. Simply stated, crowding means too many of something. In the case of worms in the gut of a host, it is obvious that there exists a finite number of individuals that can physically fit into a gut. Crowding is a common phenomenon, certainly not restricted to tapeworms in the small intestine of a rat. It is very,...