Impacts of a hitchhiking predatory mite on stable fly activity

Pest flies on livestock farms, especially house and stable flies, spread disease, inflict pain on animals, and create major economic losses for farmers. Mites in the Macrochelidae family are a promising biological control agent of pest flies because they feed on fly eggs and larvae and are also phoretic on adult flies. In addition to direct lethal impacts, mites may contribute to pest suppression through unstudied sub-lethal means. Sub-lethal impacts can have significant impacts on pest populations through reduced feeding, activity, reproduction, and pathogen transmission. My research examines how Macrochelidae impact the flight ability of Stomoxys calcitrans. I hypothesize that Macrochelidae that hitch a ride on adult flies will reduce the flies’ ability to disperse and host-seek from the extra burden of carrying these mites and thereby limit time spent feeding on livestock, especially during cooler sub-optimal flight conditions. Field studies captured host-seeking Stomoxys calcitrans on a mixed livestock farm during two field seasons across a range of temperature conditions. Captured flies were inspected for phoretic mites and mite loads were correlated to temperature. Preliminary results indicate that flies with mite loads are less likely to fly and host seek during cooler sub-optimal temperatures. Ongoing laboratory studies are also testing how long and far flies can fly with attached mites compared to unburdened flies. Newly emerged Stomoxys calcitrans are exposed to mites, before tethering the flies and measuring flight longevity.