Please don't be alarmed by the title! The bugs we are discussing don't deliver nasty bites or even have teeth but they are the champions of collective binging. Let’s start from the beginning…
Although they may be an unremarkable fly in many ways – segmented body, two wings, two huge compound eyes, two antennae – black solider flies are somewhat simpler versions of the flies that we normally think of. They don't have mouth, so they don’t spit and contaminate our food. They are not the most accomplished flyers, so instead of buzzing around they are sedentary for most of time, preferring to bask in the warming rays of the sun. For the rest of their life, they copulate, with the male flies exerting themselves to win female partners through an airborne and whirlwind like courtship ritual. After the former fertilises a fecund female, she will later lay hundreds of eggs and then their lives’ mission is accomplished.
The eggs are far too minuscule (well below 1mm in length, as pictured) to be seen well without a magnifier. They hatch within 2 to 3 days and gradually acclimate to the world for another couple of days before their feasting starts. The larvae feed quickly; their size can expand dramatically in both length and width in a week, growing from less than 3mg up to 300mg. Each larva consumes approximately 20% of their bodyweight per day. Not impressive? That’s equivalent to a 60kg human being binging more than 12kg of food each day!
Black solider fly larvae are excellent team workers. When watching videos of larvae finishing a huge pizza, a whole fish or massive mound of food in a blink of the eye, you might think that they simply keep eating nonstop day and night. In fact, one larva only gulps for about 5 minutes then takes a break for another 5 before resuming their dégustation. Therefore, while some larvae adjourn from devouring, other eager ones jump back in game, pushing from behind and lifting the gluttons up to get access to food. This continuous moving of the crowd forms a ‘living fountain’ against the cliff-face of the food mountain.
This collective binging makes black soldier fly larvae a perfect key to solve the global issue of food waste and can help to close the loop of the human food chain.