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Related Concept Videos

Competition

Competition

When organisms require the same limited resources within an environment, they may have to compete for them. Competition is a net-negative interaction. Even if two competing individuals or populations do not interact directly, the overall fitness of both competitors is lowered as a result of not having full access to the limited resource.

Predator-Prey Interactions

Predator-Prey Interactions

Predators consume prey for energy. Predators that acquire prey and prey that avoid predation both increase their chances of survival and reproduction (i.e., fitness). Routine predator-prey interactions elicit mutual adaptations that improve predator offenses, such as claws, teeth, and speed, as well as prey defenses, including crypsis, aposematism, and mimicry. Thus, predator-prey interactions resemble an evolutionary arms race.

Limits to Natural Selection

Limits to Natural Selection

Organisms that are well-adapted to their environment are more likely to survive and reproduce. However, natural selection does not lead to perfectly adapted organisms. Several factors constrain natural selection.

Conservation of Small Populations

Conservation of Small Populations

Small population sizes put a species at extreme risk of extinction due to a lack of variation, and a consequent decrease in adaptability. This weakens the chances of survival under pressures such as climate change, competition from other species, or new diseases. Large populations are more likely to survive pressures such as these, as such populations are more likely to harbor individuals that have genetic variants that are adaptive under new stresses. Small populations are much less...

Symbiosis

Symbiosis

Symbiotic relationships are long-term, close interactions between individuals of different species that affect the distribution and abundance of those species. When a relationship is beneficial to both species, this is called mutualism. When the relationship is beneficial to one species but neither beneficial nor harmful to the other species, this is called commensalism. When one organism is harmed to benefit another, the relationship is known as parasitism. These types of relationships often...

Frequency-dependent Selection

Frequency-dependent Selection

When the fitness of a trait is influenced by how common it is (i.e., its frequency) relative to different traits within a population, this is referred to as frequency-dependent selection. Frequency-dependent selection may occur between species or within a single species. This type of selection can either be positive—with more common phenotypes having higher fitness—or negative, with rarer phenotypes conferring increased fitness.

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Related Experiment Video

Updated: Sep 18, 2025

Protocol for Assessing the Relative Effects of Environment and Genetics on Antler and Body Growth for a Long-lived Cervid

Protocol for Assessing the Relative Effects of Environment and Genetics on Antler and Body Growth for a Long-lived Cervid

Published on: August 8, 2017

Parasite-Mediated Competition Limits Dominant Cervid Competitor.

Jennifer A Grauer¹, Joshua P Twining², Manigandan Lejeune³

¹New York Cooperative Fish and Wildlife Research Unit, Department of Natural Resources and the Environment, Cornell University, Ithaca, New York, USA.

Ecology Letters

|June 25, 2025

Summary

This summary is machine-generated.

Parasites critically impact wildlife communities. This study found parasite-mediated competition, not direct competition, limits moose (Alces alces) populations, highlighting indirect interactions

Keywords:

competition giant liver fluke meningeal worm moose parasite parasite‐mediated competition white‐tailed deer

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Last Updated: Sep 18, 2025

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Area of Science:

Ecology
Wildlife Conservation
Parasitology

Background:

Species interactions shape ecological communities through direct and indirect pathways.
Empirical evidence for the importance of indirect interactions, particularly parasite-mediated competition, is limited.
Understanding these interactions is crucial for managing wildlife populations and biodiversity.

Purpose of the Study:

To investigate the role of parasite-mediated competition in structuring interactions between moose (Alces alces) and white-tailed deer (Odocoileus virginianus).
To determine if direct or indirect interactions limit moose occupancy in a shared habitat.
To provide empirical evidence for the significance of indirect interactions in community ecology.

Main Methods:

Utilized 2 years of detection/non-detection data for moose and white-tailed deer.
Analyzed parasite loads in fecal samples (Parelaphostrongylus tenuis, Fascioloides magna).
Employed a hierarchical abundance-mediated interaction model to assess interspecific competition.

Main Results:

Moose occupancy was significantly limited by parasite-mediated competition.
No evidence of population-level effects from direct competitive interactions between moose and white-tailed deer was found.
Parasites play a critical role in shaping cervid community structure.

Conclusions:

Indirect interactions, specifically parasite-mediated competition, are a key driver of community outcomes.
Conservation and management strategies must consider the impact of parasites on species interactions.
Findings are vital for addressing challenges like habitat loss, disease, and climate change affecting wildlife.