Ontogenetic niche shift is an ecological phenomenon where an organism changes its diet or habitat during its ontogeny (development). During the ontogenetic niche shifting an ecological niche of an individual changes its breadth and position. The best known representatives of taxa that exhibit some kind of the ontogenetic niche shift are fish, insects and amphibians. A niche shift is thought to be determined genetically, while also being irreversible. Important aspect of the ONS is the fact, that individuals of different stages of a population utilize different kind of resources and habitats. The term was introduced in a 1984 paper by biologists Earl E. Werner and James F. Gilliam.
The ONS, which divides a population of the same species into distinct life-history stages, can affect food web of a community.
The extreme ONS can be seen among insects. On the picture above are shown a pupa and an imago of Rhopalomyia solidaginis.
Pacific salmon (Oncorhynchus) is an anadromous fish species that exhibits a drastic habitat niche shift.
Skull of a juvenile Tyrannosaurus. Juveniles of megatheropods proposedly occupied mesocarnivoran ecological niche.
In ecology, a niche is the match of a species to a specific environmental condition. It describes how an organism or population responds to the distribution of resources and competitors and how it in turn alters those same factors. "The type and number of variables comprising the dimensions of an environmental niche vary from one species to another [and] the relative importance of particular environmental variables for a species may vary according to the geographic and biotic contexts".
The flightless dung beetle occupies an ecological niche: exploiting animal droppings as a food source.
The Grinnellian niche can be described as the "needs" niche, or an area that meets the environmental requirements for an organism's survival. Most succulents are native in dry, arid regions like deserts and require large quantities of sun exposure.
Beaver dam in Hesse, Germany. By exploiting the resource of available wood, beavers are affecting biotic conditions for other species that live within their habitat.
The shape of the bill of this purple-throated carib is complementary to the shape of the flower and coevolved with it, enabling it to exploit the nectar as a resource.