280 days of Urbpandemonium #168
Sep. 7th, 2015 10:29 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png)

This fly and many others like it were in an indoor zoo exhibit. This exhibit has a soil substrate with a stream water feature in it. The exhibit animals are omnivores and their diets consist of live earthworms, some raw ground meat, moistened pelleted food, and chopped fruits and vegetables. The flies were in big enough numbers that they were a nuisance, and some keepers were concerned for the health of the collection animals.

Control for flies should proceed in this order: 1. remove food and breeding habitat, if possible 2. exclude flies from the area using screen or other barriers 3. trap flies mechanically, with glue-based traps 4. If levels of flies are still intolerable, apply pesticide. Actually, I skipped an even earlier step in this sequence: Identify the pest. Without a proper identification, you may not know what the flies are using as a food source or breeding habitat, and you may not know what kinds of things may attract them to sticky traps (light, odor, color).

Over at bugguide.net I got an identification to the family level: Heliomyzidae or "sun flies." Bug guide's page on the family says "Habitat: Usually in shaded areas, typically near rotting matter (compost, dung, carrion etc.) or fungi; some associated with caves or bird/mammal nests." This exhibit resembles a cave, contains several bird/mammal nests (the collection animals' nest boxes), is always a shaded area, contains dung and carrion, and probably the wet soil is growing a fair amount of fungi. My recommendation is going to be to increase the frequency of cleaning, reduce the amount of time the food is on exhibit, and possibly improve and increase ventilation to disturb the flies' activity and keep the soil somewhat drier. With reduced food and habitat, the flies will reduce in numbers, ideally to a tolerable if not undetectable level.