Insects have diverse parasitic relationships in which insect parasitize other orders and vice versa, mosquitoes on humans and mites on bees come to mind. This article focusses on the relationships between insects.
1. PARASITIC STRATEGIES
Entomophagous insects are insects that eat other insects. These can be distinguished in two groups:
Predators need one or more prey animals to grow up to adulthood and kill their prey immediately.
Parasites normally use only one host specimen and do not kill or hurt it directly, although the host will suffer from the negative effects the parasite has on it .
There are parasites that kill their host, the parasitoids [2,4]. A parasitoid develops by using the host as food source and kills it directly or indirectly as a consequence of that development .
This group is divided into two sub categories based on the moment when they kill their host [2,4]:
Koinobionts keep their host alive up to a certain stage when they kill it.
Idiobionts kill and consume their host in the state they it is when they attack it.
ECTOPARASITISM AND ENDOPARASITISM
Parasites as well as parasitoids can live outside or inside their host. They are called ectoparasite and ectoparasitoid when living externally, endoparasite and endoparasitoid when internally living.
Hyperparasitism is another form of parasitism that can occur in parasites as well as in parasitoids.
It is called hyperparasitism when a parasite or parasitoid parasitizes another parasite or parasitoid.
Social parasitism is a form of parasitism in which the parasite manipulates the host. Different tactics can be applied for example tricking the host to raise the offspring of the parasite.
SOLITARY vs GREGARIOUS
These parasitic traits can occur for parasites or parasitoids in solitary or gregarious which means that one (solitary) or more offspring (gregarious) can be raised on one host.
Solitary can be regarded as the default.
FACULTATIVE vs OBLIGATE
A facultative parasite is less dependent on a host and can exploit the host to raise its offspring instead of doing it herself .
An obligate parasite is completely dependent on the host in order to raise it’s offspring. She is no longer capable of making a nest and raising the offspring herself .
2. PARASITIC VARIANTS
Parasites and parasitoids can feed on:
Specific terms for these variants are used to depending on the used food sources and/or the stage of the host used.
Parasitism on food collected by the host is called kleptoparasitism  or kleptobiosis . The parasite doing this is called a kleptoparasite or kleptobiont.
In a kleptoparasitic relation it is the host that invested in the collecting and storing food and is negatively impacted when the food is stolen or eaten .
When the larvae of the parasitic species eats the food storage it is also called kleptoparasitism. In this case it is the larva that exhibits the parasitic behaviour, which classifies the species as kleptoparasite as a result.
A parasitoid can kleptoparasitize as well. To gain access to the food source it will kill the host .
The larval behaviour determines whether a species is a kleptoparasite or kleptoparasitoid: when the parasitoid adult stage kills and/or removes the host this is not considered kleptoparasitoidism. In Bloodbees (Sphecodes) for example it is the female that enters the host nest, removes the host larva and then lays an egg. The bloodbee larva that hatches will eat the present food storage and is regarded as a kleptoparasite, not as a kleptoparasitoid.
The host itself can also be parasitic in which case the food storage is a parasitized host.
A host can also be a larva. To differentiate between these situations this is regarded as a form of brood parasitism.
2.2. BROOD PARASITISM
A parasite that is after the host larva or pupa is a brood parasite.
Another type of brood parasitism is nest usurpation in which the parasite does not have its own workers but instead takes over the host nest so the host workers raise its brood [1,6].
A parasitoid that kills the host brood is called a brood parasitoid.
A kleptoparasitoid can also be after the food storage as well as the host larva in which case this is also called a brood parasitoid.
Egg parasitoids consume the eggs of the host . The parasitized egg will produce a new parasite larva instead of a host.
| Braula coeca (adult) |
|Pteromalus puparum |
|Kleptoparasite||food||Xylocopa pubescens (adult) |
Sphecodes (larva) 
Braula coeca (larva) 
|Kleptoparasitoid||food||Cleridae (larva) |
Bombyliidae (larva) 
Chrysis ignita (larva) [8,16]
|Social parasite||nest usurpation||Polistes (adult) |
|Brood ectoparasite||– larva|
| Aulacothrips dictyotus |
|Brood endoparasite||– larva|
|Brood ectoparasitoid||– larva|
|Bombyliidae (larva) |
Anthrax anthrax (larva) 
|Brood endoparasitoid||– larva|
|Ephialtes (larva) |
|Egg ectoparasitoid||egg||Gasteruptidae (larva) |
|Egg endoparasitoid||egg||Mymaridae (larva) [7,9]|
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