Genotypic richness and phenotypic dissimilarity enhance population performance

Area of Science:

• Ecology
• Evolutionary Biology
• Population Genetics

Background:

• Biodiversity increases can stem from species richness or genetic diversity within species.
• Intraspecific genetic diversity (genotype number) can enhance primary productivity and cascade to higher trophic levels.
• Interactions among genotypes (e.g., facilitation, inhibition) influence population performance beyond additive effects.

Purpose of the Study:

• To investigate if phenotypic dissimilarity among genotypes explains the effect of genotype number on population performance.
• To determine the relative contributions of genotype number and phenotypic dissimilarity to the population performance of Orchesella cincta.

Main Methods:

• Created nearly homogeneous genotypes from inbred isofemale lines of Orchesella cincta.
• Assessed phenotypic dissimilarity based on life-history traits: egg size, egg development time, and juvenile growth rate.
• Conducted a microcosm experiment using genotype mixtures of one, two, four, and eight genotypes.

Main Results:

• Genotypic richness significantly increased population size and biomass production.
• Greater net diversity effects were associated with higher genotypic richness.
• A positive log-linear relationship was observed between phenotypic dissimilarity and net diversity effects for juvenile population size and total biomass.

Conclusions:

• The magnitude of the genotypic richness effect on population performance is determined by the degree of phenotypic dissimilarity among genotypes.
• This relationship plateaus at higher levels of phenotypic dissimilarity.
• Both genotype number and phenotypic dissimilarity are crucial for understanding population performance, similar to trait dissimilarity observed among species.