Classification of Parasitoids on the Basis of Parasitoid – Host and Parasitoid – Parasitoid Relationships
I) Number of Individuals/hosts:
a) Solitary Parasitoids:
One progeny alone is capable of competing the development in or its host e.g. Chelonus blackdurni on PTM.
b) Gregarious Parasitoid:
Several progeny are capable of completing their development in or on a single host e.g. Copidosoma koehleri on PTM. This may includes the parasitoid that deposits one or very few eggs in their host from which develops hundreads or thousands of progeny. These are polymbryonic species e.g. Braconid, Macrocentrus gifuensis on European corn borer.
II) Site of Attacks on Host Body:
An insect parasite which feed externally on the host body and complete their development externally on its host e.g. Bracon brevicorni.
Parasitoids which complete their development within or inside their host body e.g. Chelonus blackburni. Endoparasitoid of aphids frequently emerge through a flap cut in the host abdomen.
III) Food Web Relationships:
a. Primary Parasitoids:
The form of parasitism in which the attacking organism that develop itself in or upon the host which is non-parasitic e.g. on introduced pine saw fly 24 parasitoids of a primary nature from hypmenoptrous and Dipterous species.
b. Secondary Parasitoids:
The parasitoids develop itself in or on the host that are primary parasitoid.
c. Tertiary Parasitoids:
The parasitoid develops itself in or on the host which is already secondary parasitoid. e.g. The parasitoid Tetrastichus coerulescens parasitic on secondary parasitoid Hybrocytus spp. and the primary saw fly parasitoid Itoplectis conquisitor.
d. Quaternary Parasitoids:
Form of hyperprasitism in which the parasitic establish itself in/or the tertiary parasitoid.
IV) No. of Hosts Attacked:
The parasitoids which are specific to one particular host e.g. The icheumonid parasitoid, Mesolicus tenthredinis is a specific for saw fly.
b) Oligophagous or Stenophagous:
Those parasitoids that restrict themselves to vary few and often closely related hosts, e.g. Exerterus amictoriius is an ichneumonid parasitoid of saw fly in the genera Diprion and Neodiprion.
Those parasitoids that maintain themselves on a multiple of hosts, e.g. Compsilura concinnata a tachinid introduced against gypsy moth has been recorded from close to 20 hosts.
V) No. of Host individuals Essential for Attack:
Many of oligo and polyphagous parasitoid species requiring alternating of hosts to complete several generations each year, e.g. The tachinid, Ceromasla auricaudata which over winters in a host pupa of fall webworm normally attacks univoltine spruce budworm in the spring in Canada.
The parasitoids those require only one host species for development, e.g. Exenterus amictorius a parasitoid on the introduced pine saw fly and the Drino bohemica, a lachinid parasitoid of European spruce sawfly.