Two black soldier flies feeding on a paper towel previously soaked in 5% sugar solution

Adult black soldier flies do not feed. This common misconception originated from early publications on soldier fly biology that reported adults reproducing in the absence of feeding. Also, non-feeding adults are not unusual among insects: nutrient accumulation takes place at a larval stage while adults focus on reproduction (think mayflies). In fact, adult black soldier flies feed on various liquid substances, which are often substituted by sugar or honey solutions in captivity. It is true that they do not need to feed and can utilize resources accumulated at a larval stage. However, they are better off when fed as adults. A human also can survive without food for about 30 days, but such a starvation period is not likely to be the happiest and most productive period in a person’s life.

Black soldier flies can be used to recycle any organic waste. It is true that black soldier fly larvae are omnivorous saprophages, which is a fancy way to say that they can eat a wide variety of dead and decaying organic matter. This ranges from manure to animal carcasses to processed grains. However, such a wide range of food substrates still does not mean that any rotting junk is equally suitable for them. Some items may be lacking in nutrients; other items may have toxins or be difficult to digest. Overall, black soldier flies do best on a balanced diet that has an array of nutrients. They generally lean towards preferring substrates of plant origin, although by no means are they strict vegetarians. Having said that, plant residues rich in cellulose and lignin, such as dead leaves or sawdust, are not suitable for larval development. Black soldier flies also do not like high concentrations of fat and / or protein.

Fully grown black soldier fly larvae harvest themselves. Once fully grown, black soldier fly larvae turn dark in color, stop feeding, and start wondering around in search of a dry and protected place to pupate. In theory, migrating larvae can be directed into a collecting vessel of some kind and harvested this way. This eliminates the need to sift them out of substrate. However, there several problems with this approach that make its use impractical in most cases. First, not all larvae necessarily leave the substrate; instead, some of them stay put and pupate at the place where they developed. Second, not all larvae leave at once. As a result, it may be necessary to wait for a number of days for them to vacate the premises. This wastes time and space that can be used to grow the next batch of larvae. Third, the larvae that do not feed and move over considerable (for their size) distances use up energy reserves and lose weight.

Insect meal is equivalent to fishmeal. Black soldier flies can be used as a sustainable alternative to wild caught fishes when formulating animal feeds. However, it does not mean that they are equivalent and fish products can be simply replaced by insect products at a one-to-one ratio. Chemical composition of the two is different. Therefore, feeds need to be formulated anew. For some species of domestic animals, feed ingredients derived from black soldier flies may be superior to that derived from fishes. For other species, they may be inferior or even unsuitable. In some cases, using both in the same feed formulation may be the best approach. All this needs to be tested experimentally.

Farming black soldier flies and other insects will save the world. While it is a valuable technology contributing to the development of a circular economy, growing black soldier flies will not save the world by themselves. Our world is a complicated place that faces many complex problems. Complex problems, in turn, require complex solutions. Recycling wastes using insects contributes to developing such solutions, but there are many other components. Furthermore, these components need to be integrated into comprehensive and customizable approaches. Unfortunately, there is no silver bullet solution.

Evil ruling classes want ordinary people to eat bugs while they eat steaks and caviar. Black soldier flies are meant for animal feed, not for human food. This may change in the future, but there are also more established species of edible insects (crickets, for example). Many animals love eating black soldier fly larvae because insects are an essential component of their natural diet (think chickens, for example). So, consumer acceptance is not much of an issue for them. Furthermore, insect farming is neither easy, nor particularly cheap. Therefore, insect protein is not a cheap substitute for other animal proteins. It has many advantages, but the current price is not one of them.