feeder-insects

Can Lizards Eat Black Soldier Flies?

November 19, 2020

can lizards eat black soldier flies - picture of close-up view of adult black soldier fly

Black soldier flies are the adult form of Hermetia illucens. Their larvae have made a big splash as feeders in the reptile world, but what about after they pupate? Can lizards eat black soldier flies?

Can Black Soldier Flies Be Used as Feeders?

Yes!

Although they may look like wasps, black soldier flies don’t have any stinging or biting parts, and are unable to harm your reptile. And when the larvae are raised in hygienic, disease-free facilities, the flies should be disease-free as well.

Black soldier flies also make for a great enrichment activity for your pet lizard. They make your lizard work for their food, encouraging them to exercise wild-like behaviors and get some exercise in the process, helping keep your pet entertained as well as healthier. 

Of course, some lizards appreciate flying feeders more than others. Chameleons in particular are known to be fond of and very capable of capturing flying insects for their dinner. Some other lizards, such as bearded dragons, are also known to be able to occasionally catch them. Fortunately, black soldier flies are relatively lazy and easy to catch, as far as flies go.

Black Soldier Fly Nutritional Value

The adult black soldier fly’s nutritional value is comparable to that of the larvae. According to this study, when fed chicken feed as larvae, adult black soldier flies offered the following nutritional value  (this data is on a dry matter basis and can’t be compared with as-fed values):

Male Adult Black Soldier Flies

  • 44.0% protein
  • 32.2% fat
  • 3.0% ash

Female Adult Black Soldier Flies

  • 43.8% protein
  • 30.6% fat
  • 2.8% ash

For comparison, large black soldier fly larvae harvested at 14 days (just before pupation) were measured at the following nutritional value:

  • 39.2% protein
  • 28.4% fat
  • 8.3% ash

Calcium-to-phosphorus ratio in adult black soldier flies was not discussed in the abovementioned study, but due to the reduction in ash content after pupation, it’s possible that adult black soldier flies are lower in calcium than their larval counterparts. For this reason, it’s important to source well-gutloaded, high-calcium black soldier fly larvae for raising into flies, and to only offer them alongside a variety of other, calcium-dusted, feeder insects.

How to Raise Black Soldier Flies

Adult black soldier flies live for just 5-8 days, so it’s not very practical to buy them in their adult form. This means that if you want to use the flies as feeders, you will need to raise them yourself. 

The good news is that this is pretty easy! Just buy some large black soldier fly larvae and wait for them to pupate. Once they turn into pupae (stiff and black), you can sprinkle them on the floor of your lizard’s terrarium, and they will hatch inside the terrarium, no fly-catching skills required.

Alternatively, you can put the pupae in a cup of moistened dirt inside a mesh screen enclosure (like a 12” butterfly cage), and keep them between 77-86°F. Once they turn into flies, you can use the door of the cage to introduce them into your reptile’s enclosure. To help them last longer, you may be able to extend their lifespan by offering a small, shallow bowl of sugar water for them to drink.