On Sat, 10 Apr 1999, Alexander Haber wrote:
> Russell Farris schrieb:
>> > What is the definition of a parasite? I tend to think of worms, or
> > the leeches that I pulled off of my legs as a kid swimming in Indiana. But I
> > often see Chamydiae referred to as parasites. Thanks for your attention.
>> For me a parasite is a living thing just taking something from another living
> thing, without giving something back or asking.
I think the important thing about parasitism is not the trophic
interaction, but rather the use of a living organism as habitat. Most
blood feeders like leeches and hematophagous arthropods (with the
exception of the hard ticks) have traits that minimize their association
with their meal, i.e., feed and get out as soon as possible, and are
probably best considered as predators. Parasites, on the other hand,
require traits that allow them to maximize their association with the
host, such as evading or manipulating the immune response.