Edible Insects Diversity and Their Importance in Cameroon

Insects are known to be part of Sub-Saharan African region. Entomophagy is a common practice in Cameroon food systems. The current chapter is based on both original research and major literature review in the domain. A variety of insects species and consumable stages, as well as preference and their spatial distribution are presented in this chapter. Insects are described according to the recent taxonomy features and their bioecology is provided. Some consumption patterns, preferences and determinants are described. The role of insects consumption is also highlighted as well as some prospective investigation targeting edible insects preservation and sustainability in Cameroon. The paper points out some policy gaps that need to be addressed to harness the potentials of edible insects in Cameroon food systems.


Introduction
Most of sustainable development goals are food related and should be addressed properly. Particularly in Africa, food and nutrition insecurity is coupled to a growing demand of animal source proteins that could be solved by a different conception of food systems [1]. The ideas about considering insect production as part of livestock have been a long run scholar discussion in the West [1,2] and emerged as a consistent topic in Africa of recent [3,4]. Insect consumption also called entomophagy is then widely accepted as a palliative to food scarcity not only for today but also for the future [1,5,6]. Insect consumption is part of cultural heritage in tropics and beyond [6][7][8]. Insects at different stages are nutritive food sources made cheaper by their availability and sustainable by their nature [5,7,9]. Cameroon has been regularly cited for its richness of edible insects and related practices [3,4]. The objective of this review is to summarize the major features concerning edible insects, few constraints and opportunities for the country in a globalized and changing environment.

Distribution of entomophagy in Cameroon
Cameroon is an elongated country stretching from Congo Basin (humid tropics) to Lake Chad (Sahel). The country is also described as Africa in miniature by its diversity and position. The entomophagy is present everywhere from Sahelian to humid forest regions [3][4][5]. There is a variety of beliefs attached to insect consumption all over the country [5,10]. Some communities have a larger panel of edible insects throughout the year than other [11]. The differences observed concerning practices and recipes among communities are based on preferences, ability to harvest and process as well as the social importance attached to insect consumption [11,12]. There is a large number of insects consumed in Cameroon.

Diversity of edible insects
Compared to other food sources, there are little taboos in insects' consumption in most of Sub-Saharan countries [3]. About 1700 insects' species are consumed around the world with majority from tropical world [1]. Some are widely identified and few less known in the context of recent interest by research in Cameroon.

Major groups
Caterpillars (order Lepidoptera) are the most populated group of edible insects in Cameroon concerning the number of species [10,11,13]. About 200 species have been reported and many are still unveiled. Some are used by limited communities, making their identification a real challenge [5,11]. Forests provide shelter and perfect milieu for numerous of them [5,7,9]. Populations have developed a great knowledge about the bioecology of the most marketed species. In savannah and less woody forests, there are less diversity like in Adamawa and northern regions [10]. Figure 1 below displays the naturel gathering nest (in a tree) and fresh and dried caterpillars found in Cameroon.
The second group of most consumed insects is made up of termites (order Blattodea) with two species, Macrotermes sp., being the most exploited [10][11][12]14]. Termites are widely exploited all over the country [10]. The common recipe is to grill them after removing wings with onions, raw or not, as shown in Figure 2 [14].
Besides "soft" species, crunchy and crispy are very regarded as a delicacy, mainly of Coleoptera order [15]. Adult Palm weevils are known as pest but "domesticated" by raffia palm harvesters (adults and grubs) [10,11]. Various adults' species are the most collected in Cetonia sp. (Figure 3) [13], larvae are the most demanded is palm weevil, particularly the yellowish skin which is grown in raffia palm (see Figure 4) in Cameroon household [11]. Some tree, shrubs or humus grubs are also exploited in particular communities and need to be properly identified [10,13].
The acridians or grasshoppers (Orthoptera), Locusta migratoria (also Schistocerca gregaria) known as migratory locusts are commonly exploited in drier regions of Cameroon (Figure 5), whereas Ruspolia differens, Tettigonia viridissima and Zonocerus variegatus are exploited in humid environments in southern Cameroon [10,14]. Zonocerus sp. is treated with care because of toxins if not well prepared before ingestion.     Field crickets and cricket-like species (order Orthoptera) are also exploited in Cameroon humid regions [10,11]. Giant cricket also called tobacco cricket (Brachytrupes membranaceus) is widely harvested. Some species are believed to have particular uses in pharmacopoeia beside being considered as food.

Specialties
Insects have played important roles in some national communities. For instance, some forest groups like Baka people praise the taste, flavors, contents and properties of some insects at particular stages [5,11]. Honey bees larvae are considered as a powerful detoxification agent and then prescribed to some recovering patients in those communities [11]. In the same line, red ants (Oecophylla longinoda) are used by some forest communities in Centre region to cure manhood impotency. These biting red ants are collected, grilled and mixed with some other local herbs and fruits before consumption [11].

Edible insects' trade
Insects contribute also to income generation in rural and peri urban households [5,11]. Local and transboundary trade involving Cameroon has been mentioned in some studies [5,14]. Insects' harvesting requires some abilities acquired by empirical experiences which made some people experts and providing livelihoods means. This is for instance the case of Guizigua and Mofu men reputed to master termites' ethology [16]. The rapid urbanization is African towns is also promoting agro-industries, with impact on insects' consumption [17]. There is a growing economy of edible insects though the primary objective of insects' collection is own consumption [10,11,14]. As shown by Figure 6, there are many reasons attracting consumers to insects' utilization as food sources, with varying weight.

Marketing channels, actors and benefits
Edible insects have become a more or less "normal" item or commodity in local trading spaces, even in big cities [17,18]. The main categories of actors involved in collection are youths (irrespective of sex) for seasonal insects, women and youths for crickets and locusts, men for grubs and termites [5,10,11,18]. Intermediate categories are made mainly by women or youths (street vendors) and exclusively women for urban markets. In Mofu and Baka communities some insects are exclusively harvested by men under specific conditions [12,16]. Benefits are determined by the quality of products (freshness, color, origin and presentation), particularly in town markets [5,11,18].

New trends
With the influence of the mainstream food systems, processing and labeling edible insects are sectors for new food ventures [15,17]. The type and flavors of spices make the difference for some conserved or already processed items [10]. Fast communication is now harnessing the pickup of technologies and making edible insects' as a potential popularized food item [1,2,6].

From harvesting to farming
Insect production for human consumption started very humbly under a group of researchers from Gembloux-Belgium [2]. Preliminary findings in artificial production of palm weevil larvae are promising [19]. Massive palm grub production is in pilot stages with some important success [19][20][21][22][23]. Substrates and microclimate conditions have been mastered and trials already done under farmers' conditions [22]. The investment for edible insects' production is balanced with substantial income attached and also to environmental health.

Some aspects of nutrition and food safety
If supposed nutritional factors with food habits have factored much entomophagy in Cameroon like in other places, some field experiences are giving evidence [1,6,19,24]. Science communication and access are making consumers more attracted by appealing presentation of edible insects' nutrition facts. Palm weevil larvae has been largely studies [25] and results are opening avenues for other larvae consumption [26]. Entomophagy is then no more a fancy or traditional habit, but a real response to nutritional insecurity [27,28]. Food safety in edible insects encompasses both endogenous and environmental factors. Chemical analyses have shown that some insects need special care before their consumption, like Zonocerus variegatus, because of its gut contents [29]. Under agrochemical pollution, natural harvesting is no safer as highlighted by some consumers in Cameroon suffering of indigestion [11,24]. Pesticides are contaminants becoming a potential problem for consumers of in Cameroon western highlands [30].

Perspectives about policies and research gaps
Insects' consumption even popular or popularized is not yet legal in Cameroon context [30] because of insufficient policies. Most of gathered food in nature in Cameroon is not yet under strict safety regulation which may bring Edible Insects serious public health issues in case of hazardous products. While insects' farming and trade are gaining population attention, research and other influencers should in connivance with other international bodies invest in the domain. Vocational and higher education systems should also embrace genuinely the trends by crafting appropriate curricula and learn from learning by doing experiences. Mofu community has a wide range of knowledge on insects in their environment [31]. Indigenous knowledge built for centuries could speak a lot to research and policy today for better future of better human nutrition security, adapted to the context of biodiversity depletion [32]. From old, new can grow, new roads from within to many other places where collaboration are opened. The International Centre of Insect Physiology and Ecology (ICIPE) is already theorizing interesting and promising channels, and some in Cameroon about insects' domestication.

Conclusion
Insects' consumption in Cameroon is a reality for ages. Its biodiversity is very rich and massively exploited diversely. There are large numbers of species, exploited for food and other reasons. Urbanization and communication facilities coupled to food systems unification are favoring the migration of habits across generations and regions. Besides nutritive values at home level, edible insects provide income, jobs and potential enterprises, both for economic, scientific and cultural impacts in Cameroon society. There are gaps that make excellent avenues for innovative approaches in insects research. On the food safety aspects, risks analyses regarding natural or secondary toxicity of consumed insects should be undertaken. Edible insects' value chain could be made also stronger is legal framework is well designed and implemented. There are needs to train Veterinarians and others on harvesting methods as well as processing and packaging, which could yield norms. These could mainstream numerous affordable insects within animal proteins food systems and improve nutrition security and income generation at many extents. Some indigenous habits and skills (related to products' properties and bioecology) should be well studied and not regarded as lower knowledge. Many communities practices could be excellent avenues for future, wider than food security alone. Edible insects' research and policy need to be strengthened locally with the existing findings already uncovered.