How these maggots efficiently demolish a pizza | Science News for Students

How these maggots efficiently demolish a pizza

Masses of the larvae create a living fountain that knocks slowpokes up and away
Apr 1, 2019 — 6:45 am EST
an animation showing black solder fly larvae eating a pizza

Thousands of fly maggots can demolish an entire pizza in about two hours.

Sean Warner

It all started with the can’t-tear-your-eyes-away video of maggots devouring a pizza. The black soldier fly larvae downed the 41-centimeter (16-inch) pie in just two hours. Watching sped-up action of the writhing mass inspired Olga Shishkov in Atlanta. The Georgia Tech mechanical engineer wondered what made these insects such champions of collective feeding.

What she discovered: They make a living fountain.

A Hermetia illucens larva doesn’t eat steadily, Shishkov found. It feeds for about five minutes, then may rest for another five. But it can be one of thousands of such larvae. And there will always be some in that group pushing forward. They will shove the resting larvae upward. These will then fall back like water in a fountain. This motion keeps the non-eaters from slowing down the feast.

a photo of black fly larvae surrounding and devouring an orange, and a diagram showing how the flies create a whirling fountain while eating
A surge of black soldier fly larvae (left) surrounds a piece of an orange. At the center, the larvae create a living fountain (schematic cross section at right). The incoming larvae toward the bottom shove those closer in (ones that have paused to rest) up and out of the way. The motion spins the food (curling arrow at top) as the maggots jostle one another.
O. Shishkov et al/J. of the R. Soc. Interface 2019

Shishkov and her colleagues described the behavior February 6 in the Journal of the Royal Society Interface

Shishkov borrowed her analytical techniques from the study of fluids. For instance, she treated larvae as particles moving with a current. Then she looked for overall patterns of flow in the writhing mass of up to 10,000 insects. As she tracked the directions larvae wriggled, she saw that a fountainlike flow develops around a chunk of food.

As larvae took a break from binging, the hungry crowds behind shoved them upward. Those at the top then fell away from the cliff-face of food. This up-and-out push let a larva eager to feed replace one that’s taking a break.

The frantic feeding of black-soldier-fly larvae isn’t just fun to watch. The maggots define “food” broadly. Pizza, garbage, animal waste — it’s all good. So people hoping to cut food waste may consider whether pushy maggots are the answer. Maybe they will gorge on what humans consider garbage. Later, those larval clean-up crews could be fed to chickens or other animals that people eat.

That’s certainly one reason to embrace a species that not only eats garbage but can handily murder a pizza. Also, Shiskov says, “They’re the cutest maggots I’ve ever seen.”

This pizza doesn’t stand a chance against a horde of black soldier fly larvae. Thousands of maggots demolish the pie in about two hours, as seen in this high-speed video.
Science News/YouTube

Power Words

(more about Power Words)

average     (in science) A term for the arithmetic mean, which is the sum of a group of numbers that is then divided by the size of the group.

black soldier fly     Hermetia illucens. As adults, these flies have long bodies and may be mistaken for wasps (although they have no stinger). The adults live a short time and have no mouth parts. Their larvae, though, are insatiable eaters. Scientists are studying those larvae to determine if they can reduce farm and food waste.

colleague     Someone who works with another; a co-worker or team member.

current     A fluid — such as of water or air — that moves in a recognizable direction. 

develop     To emerge or come into being, either naturally or through human intervention, such as by manufacturing. (in biology) To grow as an organism from conception through adulthood, often undergoing changes in chemistry, size and sometimes even shape.

engineer     A person who uses science to solve problems. As a verb, to engineer means to design a device, material or process that will solve some problem or unmet need.

insect     A type of arthropod that as an adult will have six segmented legs and three body parts: a head, thorax and abdomen. There are hundreds of thousands of insects, which include bees, beetles, flies and moths.

journal     (in science) A publication in which scientists share their research findings with experts (and sometimes even the public). Some journals publish papers from all fields of science, technology, engineering and math, while others are specific to a single subject. The best journals are peer-reviewed: They send all submitted articles to outside experts to be read and critiqued. The goal, here, is to prevent the publication of mistakes, fraud or sloppy work.

larva     (plural: larvae) An immature life stage of an insect, which often has a distinctly different form as an adult. (Sometimes used to describe such a stage in the development of fish, frogs and other animals.)

maggot     The larva of a fly.

mechanical engineer     Someone trained in a research field that uses physics to study motion and the properties of materials to design, build and/or test devices.

particle     A minute amount of something.

species     A group of similar organisms capable of producing offspring that can survive and reproduce.

sustainable     An adjective to describe the use of resources in a such a way that they will continue to be available long into the future.

waste     Any materials that are left over from biological or other systems that have no value, so they can be disposed of as trash or recycled for some new use.

Citation

Journal:​ O. Shishkov et al. Black soldier fly larvae feed by forming a fountain around food. Journal of the Royal Society Interface. Published online February 6, 2019. doi: 10.1098/rsif.2018.0735.