We tend to think that anything that looks like a maggot must be a flesh-eating monster. Instead, larvae eat a variety of materials. There are those that eat carcasses and those that eat only dead vegetable matter and contribute to the composting process.
Until last summer, I’d never even heard of a black solider fly (BSF, Hermetia illucens), but when I noticed maggots in my YOLO Compost Tumbler shell for the first time, I turned to Google to identify them.
The winged BSF adult is not a fly that irritatingly buzzes around the home, landing on dog poop outside and food inside. The BSF adult lives only for a few days, does not bite nor sting and neither does it feed. Like silkworm moths, its purpose is to mate, lay eggs and then die. Importantly, it does not transfer disease either. These are harmless, beneficial insects that you are unlikely to even notice as they do not come into your home and they won’t buzz around your YOLO Compost Tumbler.
While the adult female fly may sneak into your YOLO to lay her eggs, she most likely lays them on the organic material that you’re collecting to put into your YOLO. BSF winged adults, while not a pest that you’ll notice, are around and they are widespread. What you may first notice is a really tiny translucent-white larvae and then, later, a brown, torpedo-shaped and flattened grub, with tough-looking skin.
Larvae can live for several weeks and in this time they consume huge quantities of organic waste, including livestock manure, as they grow. They do not eat living plants or fresh vegetables. They also do not eat high cellulose items like grass, leaves and paper. This is why you’ll see them in kitchen-waste compost and not in your garden compost. Interestingly, they do eat meats, dairy, oils, onions and citrus, and they love coffee grounds and tea bags (we do not recommend putting meats, dairy or oils in your YOLO).
BSF grubs have even more uses. They are bred as feed for pets like chickens, fish, birds, reptiles and amphibians. Protein and calcium-rich, they are also farmed for aquaculture, animal feed and are processed into dog food. They also make for good bait for fishing. (Yes, they are good for human food too – apparently when you cook them, they smell a bit like cooked potatoes, are harder on the outside with soft meat on the inside and they taste nutty and a bit meaty.)
BSF larvae contribute to your compost by rapidly breaking down organic matter. Depending on how many arise, you can literally toss in a tub of material and it will be substantially gobbled by the next day.
You won’t see the larvae in winter – it gets too cold for them; they reappear in summer. To attract egg-laying females, just leave the lid of your YOLO Compost Tumbler open for a few hours. They are attracted more by wet materials than dry; to discourage them from being in your compost, make sure you have sufficient dry materials like crushed leaves, torn-up cardboard and the like in your mix.
Instead of shuddering when you see maggots in your compost, see them instead for what they are: a beneficial insect that contributes to the recycling of your organic kitchen waste.
Read this funny and informative article written by Maria Gaura, “Yucky but useful: Maggots make compost” (July 2008)