Insects are central in horse production systems: they transmit pathogens, cause skin and behavioral disorders, and indicate environmental quality. Current responses often rely on individual protection (blankets, repellents, short-lived insecticides), addressing symptoms rather than environmental drivers, and are increasingly ineffective and pose ecological risks. Preventive ecosystem-level interventions are therefore needed. We propose a multi-scalar approach integrating entomological knowledge into ecological biocontrol for equine health.
A targeted review identified the key pest species (Simulium spp., Tabanus spp., Stomoxys spp., Musca domestica). Field observations (2024–2025) in a semi-arid horse farm in central Spain (“La Nebulosa”) showed that late-spring to early-autumn biting activity was exacerbated by high temperatures, low humidity, and sweat interacting with dusty haircoats, amplifying irritation and host chemical cues. Horses also differ in susceptibility due to variation in skin integrity, sweating, and reactivity, requiring strategies that balance environmental and individual needs.
Our preliminary multi-scalar interventions included the following: (i) micro-scale actions on host-linked microhabitats using biocontrol and stage-specific traps, together with systematic fly-mask use to prevent ocular irritation; (ii) meso-scale adaptation of stables and paddocks to reduce soil moisture; and (iii) macro-scale enhancement of insectivorous biodiversity and aromatic plant deterrence.
Qualitative improvements included reduced fly pressure, fewer skin lesions in susceptible individuals, calmer behavior, and no conjunctivitis cases this year (vs. two in the previous year). These findings support the development of a Bayesian model integrating environmental drivers and individual susceptibility to quantify responses in future seasons. We conclude that insects can transition from indicators of degradation to co-managers of ecological resilience, enabling preventive biocontrol with welfare and ecological co-benefits.
