Biotype

Definition

A genetically or physiologically distinct population within a species, distinguished by a specific trait, host association, or ecological preference rather than by morphology alone. Biotypes often reflect local adaptation, host-race formation, or cryptic genetic divergence, and may be recognized before formal subspecies or species status is established. The term is commonly applied to insect populations that differ in host-plant use, pesticide resistance, or vector competence.

Etymology

From Greek bios (life) + typos (impression, model).

Example

In the green peach aphid Myzus persicae, distinct biotypes are recognized based on their ability to colonize specific host plants; one biotype thrives on tobacco, while another specializes on Brassica crops, despite minimal morphological differences.

Synonyms

• Ecotype
• physiological race
• host race

Related Terms

• Subspecies
• strain
• morph
• host race
• Ecotype
• cryptic species
• population genetics

Usage Notes

Biotype is often used provisionally when the taxonomic status of a divergent population remains unresolved; it carries no formal rank. In medical and agricultural entomology, biotypes frequently denote vector populations or pest strains that differ in disease transmission or insecticide resistance. Contrast with morph (morphological variant) and ecotype (ecologically adapted population), though these categories overlap in practice.