heterotrophs
Figure 15.2 All animals that derive energy from food are heterotrophs. The a black bear is an omnivore, eating both plants and animals. The b heartworm Dirofilaria immitis is a parasite that derives energy from its hosts. It spends its larval stage in mosquitos and its adult stage infesting the hearts of dogs and other mammals, as shown here. credit a: modification of work by USDA Forest Service; credit b: modification of work by Clyde Robinson .