GENERAL PART 



GENERAL REFERENCES 



Braun, '06; Kuchenmeister, '57; Law, '03; Leuckart, '86; Linstow, '78; 

 Manson, '07; Neumann, '92; Neveu-Lemaire, '08, '12; Perroncito, 'oi; Rail- 

 liet, '95; Stiles, '07; Wagner, '02. 



Definition of the term "parasite" — Not easily limited. Often 

 defined as "An organism which lives at the expense of another." 

 This definition applicable to a predatory species or, in its broadest 

 sense, to, aZZ organisms. Parasitism not an isolated phenomenon. 

 For the purpose of this course we may say: 



A parasite is an organism which, during the whole or a part of its 

 life, lives on or in the body of another organism, from which it obtains 

 its sustenance. 



The infested organism is known as the host. 



Parasites distinguished from saprophytes, which live on decaying 

 organic matter. Impossibility of draiwing a sharp line between this 

 method of life and that of true parasites. 



Distinguished from predatory species, which typically live on 

 organisms smaller than themselves, and which immediately kill their 

 prey. Inter grading. 



Parasitism a form of symbiosis. 



Symbiosis defined — Symbiosis (s^/n = together, bios = liie) is the 

 living together or two dissimilar organisms. Parasitism contrasted 

 with mutualism (typical symbiosis) and with commensalism. 



Forms of parasitism — In considering the forms of parasitism one 

 may distinguish : 



Ectoparasites, those which live on the exterior of their host or, 

 more rarely, in cavities which communicate freely with the surface. 

 Also known as epizoa. 



Endoparasites, those which live within the internal organs. 



Temporary parasites, those which visit the host only at intervals, 

 contrasted with stationary parasites. Of the latter we may have 

 periodic parasites, such as bot-flies, or ichneumon flies, parasitic in 

 only a stage of the life cycle; and permanent parasites, parasitic for 

 life. 



