We should be eating more insects and using their waste to grow crops,
says plant ecologist

Date:
March 2, 2022
Source:
Cell Press
Summary:
Researchers already knew that insects are an excellent source of
protein for humans, but they didn't expect to learn that they have
such a positive impact on plants. Researchers discuss the benefits
of using the waste from insect-as-food-and-feed production to
promote sustainable crops.



FULL STORY ========================================================================== Marcel Dicke already knew that insects are an excellent source of protein
for humans, but he didn't expect to learn that they have such a positive
impact on plants. In an Opinion paper published on March 2 in the journal Trends in Plant Science, Dicke, a researcher at Wageningen University
in the Netherlands, and colleagues discuss the benefits of using the
waste from insect-as-food-and-feed production to promote sustainable
crops. The authors argue this approach could enhance plant growth,
health, pollination, and resilience.


==========================================================================
The leftovers from insect production come in two main forms: exuviae,
the exoskeletons left behind after molting, and frass, named for the
German word for eating. Frass is "basically insect poop and unconsumed
food," says Dicke.

When added to soil, the exuviae and frass promote both plant growth
and health.

Insect feces are rich in nitrogen, a nutrient that is pivotal to plant
growth but is scarce in most soils; therefore, it is often added to crops
in synthetic fertilizer. The insect exoskeletons are rich in chitin,
a polymer that is difficult for most organisms to digest.

"There is, however, a set of bacteria that can metabolize chitin, and
those microbes help plants to be more resilient to diseases and pests,"
says Dicke.

"When exuviae are added to soil, the populations of those beneficial
bacteria increase." Dicke and his team see the application of
insect-rearing byproducts to crops as a novel step towards a circular
food system in which there is very little waste. The insects are fed
waste streams from crop farming or food production, and the insects then provide humans with food. Using the leftovers from insect production to
bolster crop growth could close this circle. Now, he just needs to get
people on board.

Insects, which Dicke refers to as "mini-livestock," are already efficient
to farm, especially when compared to more traditional livestock. It takes roughly 25 kilograms of grass to produce one kilogram of beef. The same
amount of grass can produce ten times as much edible insect protein. This
is due to the higher conversion rate of insects and because up to 90%
of an insect's body mass is edible, as opposed to only 40% of a cow.

"I have eaten crickets, mealworms, and locusts," says Dicke. "Many
people in in our part of the world need to get used to eating insects,
but I can tell you that I've eaten many other insect species around the
globe, and I've always had a wonderful meal on them." The researchers
plan to continue to investigate the potential for exuviae to work as
a pest control. When a plant is attacked by an insect, its leaves can
produce volatiles that attract the predators of the pest. "I call it
the plant's cry for help," says Dicke. "They are recruiting bodyguards."
Dicke thinks that a similar process might be happening through the plants' roots and that the microbes that are digesting the chitin in the insect
waste might also be acting as security for the plants by breaking down pathogenic fungi and making the plant resilient to pests. "Studies have
already shown that microbes associated with the roots help plants by
protecting against diseases," says Dicke. "Now we're investigating whether plant roots recruit microbes that help them in defending against pests." ========================================================================== Story Source: Materials provided by Cell_Press. Note: Content may be
edited for style and length.


========================================================================== Journal Reference:
1. Katherine Y. Barraga'n-Fonseca, Azkia Nurfikari, Els M. van de
Zande, Max
Wantulla, Joop J.A. van Loon, Wietse de Boer, Marcel Dicke. Insect
frass and exuviae to promote plant growth and health. Trends in
Plant Science, 2022; DOI: 10.1016/j.tplants.2022.01.007 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220302110558.htm

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