Evaluating Functional Dispersal in a Nest Ectoparasite and Its Eco-Epidemiological Implications

Area of Science:

• Ecology
• Parasitology
• Vector-borne diseases

Background:

• Functional dispersal is crucial for species' ecological and evolutionary paths, impacting communities.
• Quantifying dispersal is challenging, especially for small organisms like parasites.
• Understanding parasite dispersal aids in identifying population dynamics drivers and infectious agent circulation in vectors.

Purpose of the Study:

• To quantify the functional dispersal of the soft tick Ornithodoros maritimus within yellow-legged gull colonies.
• To investigate the influence of nest success and tick sex on dispersal rates.
• To reconcile observed infectious agent distribution with tick dispersal behavior.

Main Methods:

• An experimental field study manipulating nest success and tick origin.
• Capture-Mark-Recapture modeling to estimate dispersal rates.
• Accounting for tick capture probability, survival, and sex in dispersal estimations.

Main Results:

• Tick survival was higher in successful nests with available hosts but capture probability was lower.
• Overall tick dispersal between nests was low, irrespective of nest status or sex.
• No evidence of homing behavior was observed; foreign ticks did not disperse more.

Conclusions:

• The study confirms the strong endophilic nature of Ornithodoros maritimus, demonstrating life cycle plasticity.
• Low dispersal challenges previous assumptions about infectious agent distribution within colonies.
• Dispersal may occur over longer timescales, or host movements outside the breeding season may explain agent distribution.