Coevolution

Definition

The process of reciprocal evolutionary change between two or more interacting species, wherein each exerts selective pressure on the other, driving adaptations that influence fitness in both lineages. The term also extends to trait–trait interactions within a species and gene–culture dynamics.

Etymology

co- (Latin, 'together') + evolution

Example

The coevolution of fig wasps (family Agaonidae) and their host fig trees (Ficus): each fig species typically relies on a specific pollinating wasp for pollination, while the wasp depends on the fig's enclosed inflorescence for oviposition and larval development, with reciprocal morphological and behavioral adaptations maintaining this obligate mutualism.

Related Terms

• arms race
• mutualism
• Parasitism
• pollination syndrome
• host–parasite dynamics
• evolutionary escalation

Usage Notes

Distinguish from simple adaptation to a static environment; coevolution requires evidence of reciprocal selection. The term is sometimes applied loosely to any correlated evolutionary change, but strict usage demands demonstrated feedback between evolving lineages. Contrast with 'coadaptation,' which describes complementary traits without implying ongoing reciprocal selection. In entomology, classic examples include butterfly–host plant chemical arms races and ant–aphid defensive mutualisms.