Predators weaken prey intraspecific competition through phenotypic selection
- Resource Type
- Authors
- Simon P. Tye; Koby Strayhorn; Adam M. Siepielski; Mabel Serrano; Adam Z. Hasik; Taylor Ping
- Source
- Ecology Letters. 23:951-961
- Subject
- 0106 biological sciences
Food Chain
Odonata
Ecology
010604 marine biology & hydrobiology
media_common.quotation_subject
Fishes
Biology
biology.organism_classification
010603 evolutionary biology
01 natural sciences
Food web
Intraspecific competition
Competition (biology)
Predation
Mesocosm
Phenotype
Density dependence
Damselfly
Predatory Behavior
Animals
Adaptation
Ecology, Evolution, Behavior and Systematics
media_common
- Language
- ISSN
- 1461-0248
1461-023X
Predators have a key role shaping competitor dynamics in food webs. Perhaps the most obvious way this occurs is when predators reduce competitor densities. However, consumption could also generate phenotypic selection on prey that determines the strength of competition, thus coupling consumptive and trait-based effects of predators. In a mesocosm experiment simulating fish predation on damselflies, we found that selection against high damselfly activity rates - a phenotype mediating predation and competition - weakened the strength of density dependence in damselfly growth rates. A field experiment corroborated this finding and showed that increasing damselfly densities in lakes with high fish densities had limited effects on damselfly growth rates but generated a precipitous growth rate decline where fish densities were lower - a pattern expected because of spatial variation in selection imposed by predation. These results suggest that accounting for both consumption and selection is necessary to determine how predators regulate prey competitive interactions.