Host-Parasite Interactions in Ecological Communities

Interactions between hosts and their parasitic associates are fundamental to the structure and functioning of ecological communities. Parasites can regulate host population density, alter community composition through trait-mediated effects and influence energy flow across trophic levels. Many hosts support multiple parasite species, giving rise to complex co-infection dynamics in which competition, facilitation and immune modulation shape disease outcomes. At the community scale, parasites contribute to connectance and modularity of food-web networks, acting as hidden nodes that link hosts and non-host species. Environmental change, biodiversity loss and climate warming further modulate host-parasite dynamics by altering host susceptibility, parasite life-cycle completion and transmission pathways. Understanding these processes is critical for predicting the emergence of novel diseases, guiding conservation of both hosts and parasite biodiversity, and managing ecosystem health under global change.

Research from Nature Portfolio

Recent studies have demonstrated that long-evolved host–parasite networks are robust to species loss under historical environmental regimes but may collapse when conditions diverge from those in which they evolved. Digital evolution experiments, coupled with empirical analyses of host–parasite food webs, reveal that historical adaptation confers resilience to primary extinctions, whereas novel stressors associated with rapid environmental change undermine network stability. These findings highlight the vulnerability of natural communities to anthropogenic disturbance and underscore the importance of incorporating evolutionary history into forecasts of disease risk and ecosystem collapse.

Host-Parasite Interactions in Ecological Communities publication trend

The graph below shows the total number of articles in host-parasite interactions in ecological communities across all publications each year (not limited to Nature Index journals).

Technical terms

Bipartite network: A representation of interactions between two distinct groups of nodes (e.g. hosts and parasites) in which edges connect only nodes of different types.

Connectance: The proportion of possible links realised in a network, indicating overall interaction density among species.

Modularity: The degree to which a network is subdivided into relatively independent groups or modules, reflecting clusters of species that interact more frequently among themselves than with others.

Co-infection: Simultaneous infection of a single host by multiple parasite species, often leading to interactions that affect disease severity and transmission.

Host specificity: The range of host species that a parasite can infect, from strict specialists to broad generalists.

References

1. Parasites in food webs: the ultimate missing links. Ecology Letters (2008).
2. An ecosystem approach to understanding and managing within-host parasite community dynamics. Trends in Parasitology (2015).
3. Parasites that change predator or prey behaviour can have keystone effects on community composition. Biology Letters (2014).
4. Environmental change makes robust ecological networks fragile. Nature Communications (2016).
5. Remotely sensed localised primary production anomalies predict the burden and community structure of infection in long‐term rodent datasets. Global Change Biology (2023).
6. A reconstruction of parasite burden reveals one century of climate-associated parasite decline. Proceedings of the National Academy of Sciences of the United States of America (2023).
7. Vegetation cover and biodiversity reduce parasite infection in wild hosts across ecological levels and scales. Ecography (2023).