Apparently most fruits and veggies. The wetter the better, probably.
They like, in no particular order,

Watermellon and rinds
Honeydew and rinds
Canteloupe and rinds
rotten strawberries
Bananas in all stages, the riper the better, most likely
Pineapple, (but the tough skin stays around and the green leafy top that looks like aloe vera doesn't seem to interest them)
Avocado (but the peel sticks around and doesn't break down quickly)

It looks like they also like most bread type products, including:

muffins
tortillas
breads
pretzels
chips

And also potatos, and potato chips and also french fries.

Used coffee grounds (UCG) are reported to be a favorite too.

The much shorter list would be what they won't, or more accurately, can't eat. But I think this thread is a good idea because it's a common question.

A few things I've fed to BSF:

jelly beans
beef
empty gelatin capsules
M&Ms
dog poo
grass seed
whole fish
cockroach (dead)
frog (dead)

As merkurmaniac pointed out; they can't consume the most outer peel of most things. In the case of tomatoes the inedible part is so thin it's almost transparent. Watermelon rind is also consumed except for a very thin layer. I don't think there is a fruit or vegetable that they can't eat. I also don't think there any animals they couldn't eat, but I would be careful about limiting flesh to what they can consume quickly. Grains and dairy products of of all types can also be consumed. I've read that they can break down soft bone eventually but I can't say from personal experience.

They don't break down the high cellulose parts of plants such as the peels mentioned above, grass, leaves, etc.

I'm not sure what they do with oils like processed vegetable oil.

I was reading an article in Renewable Energy called, "Double the biodiesel yield: Rearing black soldier fly larvae, Hermetia illucens, on solid residual fraction of restaurant waste after grease extraction for biodiesel production" and apparently they will eat the sludge that is left over after cooking grease is filtered for use as biodiesel. As an added bonus, then the oil from the BSFL can be can be used to make biofuel as well.

You wouldn't think there would be much nutritional value in fryer sludge, but of course there can't be much in old coffee grounds either and we know how much BSF like them.

Add to the list: dead rats, snakes and anole lizards.

The larvae seem to like any type of old grain too.

The discussion posts have be split off to " BSFL Feed Discussion"(link).

I threw in leftovers from fried chicken and they were gone in three days. I still have a problem with fruit flies but I heard they would eventually go away. I've only had my BSF for a week.

Blake, you might want to hold off on feeding animal protein until you have a dense colony. I get nervous when warm meat sits around too long.

My neighbor was pruning and gave me a grocery bag of rhubarb stalks and leaves. I know the leaves are toxic, the stalks less so, but would you feed them to the larvae?

From Wikipedia:
"Rhubarb leaves contain poisonous substances, including oxalic acid which is a nephrotoxic and corrosive acid that is present in many plants... In the petioles (stalks), the amount of oxalic acid is much lower, only about 2-2.5% of the total acidity, which is dominated by malic acid."

I'm thinking that rhubarb may fall into the "better safe than sorry" category of food for larvae. Whatcha think?

Sue

I'd agree at least for the leaves.

I've been allowing fibrous plants to rot for while before feeding them to my colony. I typically tie them up in plastic bag and let them sit in the sun for a few days. I wonder if a process like that would alter any toxins in the rhubarb.

I don't suggest that you risk an entire colony by feeding something that is reportedly toxic, but I doubt it would have adverse effects on BSF larvae.

Oxalic acid is also found in cabbage, spinach, and starfruit, though perhaps not to the levels in rhubarb leaves. The median lethal dose for humans of rhubarb leaves is 5 kilograms (11 pounds). That's the point at which you could expect half the sample population that ate 11 pounds of it to die from it. Given that BSF eat a MUCH higher percentage of their body weight than humans do, the leaves might cause them problems. I wouldn't hesitate to feed them the stalks though. (None of my BSF have suffered from the occasional rotten starfruit or leftover spinach or cabbage they've been fed.

Okay, thanks. But after thinking about it, and remembering how much trouble I've had with BSF (bad luck + stupidity), I think I'll err on the side of caution and just compost the rhubarb. The little squirmers are doing well, and I would hate to ruin that.

Sue

I think I'll avoid giving the larvae yogurt in the future... I think that was a mistake. I washed them off, put them in a fresh tub with cooked squash and some yogurt. After a week or so, the smell coming from the grub tub was getting really vinegary. I didn't want to get the mix too acidic, as I didn't know how that would affect them over time, and they've been doing really well.

I've just had to wash them off again, and put them in a fresh tub with new food. No yogurt. Just more cooked squash and a couple of cantaloupe halves like dome homes -- they like those.

They seem to be happier now.

Sue

My BSF absolutely LOVE yogurt! They also chow down on curdled milk, cottage cheese and stale sour cream. About the only things that concern me as far as feeding them are raw onions and garlic. Naturally, you should not maintain any feeds that you find offensive in odor - ESPECIALLY if you are maintaining an indoor colony.

I haven't noticed any issues with garlic or onions, but I don't think I've ever put a lot in at once.

Tarvus, I threw a whole raw onion into one of my units to see how aggressively the larvae might go after it.