1 The kidneys are used to remove excess water and ions from the blood. 2  These are then expelled as urine. 3  The kidneys perform a vital role in homeostatic regulation in mammals, removing excess water, salt, and urea from the blood.
Ectoparasites Parasites that live on the outside of the host, either on the skin or the outgrowths of the skin, are called ectoparasites. They are directly transmitted between hosts.
Parasitoid wasp. Females of the parasitoid wasp Neoneurus vesculus ovipositing in workers of the ant Formica cunicularia. The term parasitoid wasp refers to a large evolutionary grade of hymenopteran superfamilies, mainly in the Apocrita. The parasitic or parasitoidal Apocrita are divided into some dozens of families. They are parasitoids of various animals, mainly other arthropods.