Host-Parasite Interactions

Host–parasite interactions are fundamental ecological processes in which parasites exploit host resources for their own survival, growth and reproduction, often to the detriment of host fitness. These relationships range from transient infestations on external surfaces (ectoparasitism) to complex internal infections (endoparasitism), and they drive co-evolutionary arms races in which hosts evolve detection and defence mechanisms while parasites evolve immune-evasion and transmission strategies. Across terrestrial, freshwater and marine environments, parasites can influence host behaviour, population dynamics and ecosystem functions. For example, behavioural manipulations by parasitoid insects can alter host web-building or foraging, while microbial pathogens may trigger shifts in host immune gene expression or symbiotic associations. Understanding these interactions is crucial not only for fundamental biology but also for managing human and animal diseases, conserving wildlife and controlling agricultural pests.

Research from Nature Portfolio

Recent studies have revealed how warming-induced stress exacerbates coral disease outbreaks. Comparative transcriptomic analyses in reef-building corals show that lethal tissue-loss syndrome triggers symbiont-degradation pathways and shifts in algal photosystem gene expression, linking host immunity with symbiont identity during infection under thermal anomaly. In colonial seabirds, experimental tick removal demonstrates a direct causal link between high ectoparasite loads and reduced chick growth, bill development and fledging success. Treated chicks exhibit higher body mass, accelerated growth rates and greater survival than controls, underlining the fitness cost of sublethal parasitic burdens and the potential benefit of targeted parasite management. Field observations of temperate songbirds under varying rainfall and temperature regimes have shown that ambient weather conditions modulate the probability and abundance of nest-dwelling blowflies, but that ant presence can mitigate parasitic effects on nestling growth, highlighting the context-dependent nature of multi-host arthropod interactions.

Research from all publishers

Work on the blue mussel Mytilus edulis demonstrates that prior exposure to trematode larvae induces a learned, rapid filtration-reduction response, lowering infection rates at the cost of feeding time. This phenomenon illustrates non-consumptive effects of parasites on ecosystem engineers through a gut–brain axis. In vertebrates, the evolutionarily conserved disgust system, which integrates sensory, cognitive and physiological cues, underlies widespread avoidance of pathogen-rich substrates; studies in wild mammals reveal that sensory cues can trigger spatial ‘landscapes of disgust’ that reduce disease risk and may be harnessed in wildlife conservation and zoonotic spill-over prevention.

Host-Parasite Interactions publication trend

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

Technical terms

Ectoparasite: A parasite living on the host’s external surfaces, such as ticks or lice.

Endoparasite: A parasite inhabiting the interior of host tissues or organs, including protozoans and helminths.

Immune evasion: Parasite strategies that subvert or inhibit host immune responses, enabling persistence.

Behavioural manipulation: Parasite-induced alteration of host behaviour to enhance parasite transmission or survival.

Non-consumptive effect: Parasite influence on host traits (e.g. foraging, movement) without direct consumption.

Arms race: Reciprocal evolutionary adaptations in hosts and parasites driven by mutual selective pressures.

References

1. Proximate mechanism of behavioral manipulation of an orb-weaver spider host by a parasitoid wasp. PLOS ONE (2017).
2. Spider manipulation by a wasp larva. Nature (2000).
3. Stony coral tissue loss disease induces transcriptional signatures of in situ degradation of dysfunctional Symbiodiniaceae. Nature Communications (2023).
4. Weather impacts on interactions between nesting birds, nest-dwelling ectoparasites and ants. Scientific Reports (2022).
5. Mussel memory: can bivalves learn to fear parasites?. Royal Society Open Science (2022).
6. Disgust in animals and the application of disease avoidance to wildlife management and conservation. Journal of Animal Ecology (2023).