plat-de-fos-rotis

Appelées foss au Cameroun, les larves de charançons constituent un mets très apprécié.

© IRD/Joseph Fumtim

Larvae on the menu

Summary

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According to an FAO report, there will be 9.7 billion human beings on the planet in 2050. Food production must increase by 70% to feed everyone. In this context, insects appear to be a possible source of alternative food. But what is their nutritional value? We focus on that of palm weevil larvae.

“Would you care for more palm weevil larvae?” This could be your host’s question during a meal in the future. Which larvae are we talking about? The yellow ones or the white ones, the ones we harvest or the ones we breed? And do they all have the same nutritional value? The latest research conducted in Cameroon by a team involving Inra, the university of Yaoundé 1 and IRD, answers these questions and shows that wild or farmed plump larvae are equally beneficial to those who eat them(1). In the scenario of food insecurity in 30 years’ time raised by the FAO, they could become a source of alternative and complementary food… 

Top 3 consumable insects

“We examined the case of palm weevil larvae as they are already eaten in the entire intertropical zone: America, Africa, Asia or Indonesia, recounts Philippe Le Gall from the Evolution, genomes, behaviour and ecology unit. Along with termites and moth caterpillars, they form the top 3 most popular insects”. They have an undeniable advantage: they are available all year round, unlike other insects whose reproductive cycle is not continuous.

“Larvae are traditionally harvested by looking for dead or live raffia palms where weevils have laid eggs. In some areas of Cameroon, the villagers have come up with a semi-farming method: they cut down raffia palms to encourage weevils to breed”, explains the entomologist. The environmental cost is huge… To develop a lower-impact larvae production project, IRD, CIFOR?Center for International Forestry Research  and a Cameroonian association, LIFT?Living Forest Trus, joined forces and established a larvae breeding farm! A raffia stem in a box can produce 276 larvae, i.e. 8 times more than the traditional collection method!

In this context, Philippe Le Gall and John Muafor, founder of the LIFT NGO, have just determined the nutritional composition of the caterpillars. Not only by comparing farmed larvae with wild larvae but also by distinguishing between white and yellow ones. “These two morphotypes occur naturally and, although they are sold at different prices and under different names, are the same species, the researcher concludes, as demonstrated by the DNA sequence analysis”. Apart from their difference in colour, the skin of yellow larvae is harder and they live on different types of raffia palms than white larvae.

As many proteins

Une dodue larve de charançon, source nutritive de qualité.

© IRD - Joseph Fumtim

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Are these differences reflected in their nutritional value? Not in all domains. Firstly, wild larvae are larger, heavier and contain more lipids than farmed larvae. Secondly, yellow larvae contain more lipids and vitamin A precursors than white ones. They also provide more energy. “However, the lipid profile is the same in all three groups studied: omega-3 and linoleic acid, unsaturated fatty acids, recommended by nutritionists!”, Philippe le Gall points out. Thirdly, “even though variations occur, in terms of proteins, the amino acid composition is similar for all larvae”.

In conjunction with LIFT, Philippe Le Gall continues his research to explore the possibilities of using weevils as a food resource for Humans or Animals: development of half maize flour-half crushed insects flour patties; larvae flour study for fish farming… Some of these promising avenues may soon become a reality: a pilot processing plant is being set up in Yaoundé.


Documentary on the larvae breeding farm in Cameroon


Note :
1. Aymar Rodrigue Fogang Mba, Germain Kansci, Michèle Viau, Lucie Ribourg, John Fogoh Muafor, Nordine Hafnaoui, Philippe Le Gall, Claude Genot, Journal of Food Composition and Analysis,   Growing conditions and morphotypes of African palm weevil (Rhynchophorus phoenicis) larvae influence their lipophilic nutrient but not their amino acid compositions, 19 février 2018


Contacts :
philippe.le-gall@ird.fr / claude.genot@inra.fr / gkansci2000@yahoo.fr (Université de Yaoundé 1)