Insects: Small Creatures, Big Impact

Beneficial Insects: Small Creatures With Big Impacts

Biodiversity in Africa

Africa is among the most biodiverse regions in the world, home to more than 25 percent of global biodiversity and eight of the 25 biodiversity hotspots. Regions such as the Congo-basin, South Africa, and Madagascar are considered megadiverse. Ecosystem services from this rich biodiversity have enormous potential to contribute to better livelihoods. The continent hosts nearly 7 million different insect species that provide pollination, pest control, decomposition, and maintenance of overall biodiversity.

Insects: Pests and Protectors

While insects are generally viewed as pests, only a small subset are pests of crops or carry diseases affecting humans and livestock in Africa. Pest populations are kept under check by natural factors, such as parasitoids, predators, and microbes. For instance, a small native micro wasp, Cotesia icipe, can specifically target armyworms and parasitize over 120 invasive fall armyworm larvae, effectively killing them. Other natural enemies like dragonflies, damsel flies, predatory bugs, maggots of hoverflies, or rove beetles aid in controlling a wide variety of insect pests. However, unsustainable and intensive farming practices such as misuse of pesticides, monocultures, and land use changes can significantly disrupt this natural balance. Additionally, invasion by pests not native to Africa and changing climates can result in catastrophic outbreaks of crop pests, affecting food security, human, animal, and environmental health.

Conservation and Sustainable Farming

Conservation of natural enemies through sustainable farming practices can offer effective management of insect pests with positive economic and health impacts. For instance, the release and conservation of a small parasitic wasp, Anagyrus lopezi, resulted in effective control of the invasive cassava mealybug, Phenacoccus manihoti, in over 27 sub-Saharan African countries, with estimated benefits of over 9.4 billion US dollars. In East Africa, the release and conservation of parasitoids, Diadegma semiclausum and Cotesia vestalis, resulted in successful management of Plutella xylostella, a pesticide-resistant pest of crucifers, with significant economic impacts. Similarly, invasive fruit flies, Bactrocera dorsalis, are biologically controlled with parasitoids, Fopius arisanus and Diachasmimorpha tryoni, in Africa. To ensure that countries continue to benefit from these biological control efforts, sustainable and compatible farming practices need to be promoted and scaled.

Beneficial Insects and Pollination

Beneficial insects not only protect crops from pests but also aid in pollination. Several crops grown in Africa, such as avocado, cucurbits, African nightshades, cocoa, spider plants, and others, depend on insect pollinators to improve crop yields and quality. Beyond crops, pollinators contribute to maintaining plant biodiversity in natural vegetation. When we think of insect pollinators, most of us are reminded of honeybees, Apis mellifera, a major pollinator in the ecosystem. However, there are over 2,600 other species of bees in Africa that contribute to pollination. Some of them, such as stingless bees, also offer diverse and unique honey and honey-related products, like bee wax, to improve the income and livelihood of farmers. Other insects such as moths, wasps, flies, beetles, and ants also contribute to pollination. Close interaction of pollinators with cultivated crops makes them vulnerable to unsustainable crop management practices such as pesticide misuse.

Organic Fertilizers and Insect Biomass

Organic fertilizers are a key resource in sustainable agriculture, the availability of which is scarce in Africa. Several insects such as house flies, blow flies, soldier flies, dung beetles, and flower chafer beetles thrive on organic waste and recycle them to high-value biofertilizers for improved soil health and crop yields. In addition, the insect biomass generated also presents a rich source of protein, fats, minerals, vitamins, well-balanced amino acids, and other essential elements, which can be used as high-quality ingredients in animal feeds to substitute or replace the expensive and scarce fish and soya bean meals. These insects are an excellent source of oil with their potential use as biodiesel, additives in soap and cosmetic production, as well as immunity enhancers.

Insects as a Food Source

The emergence of starch-rich crops and domesticated livestock and birds has eroded the cultural acceptance of insects as a food option globally. However, in Africa, insects continue to be a traditional food with over 500 insect species consumed. Termites, locusts, long-horned grasshoppers, ants, saturniid caterpillars, and crickets, among others, contribute to much-needed proteins, fats, and essential minerals. Currently, these insects are accessed from the wild during seasonal outbreaks which are increasingly affected by climate change. Wild-harvested insects risk contamination from microbes, heavy metals, and pesticides. Recent research efforts in Africa led by the International Centre of Insect Physiology and Ecology (icipe) are focused on science-based mainstreaming of edible insects, through sustainable mass rearing for their year-round availability. The focus is also to improve the nutrient profiles of edible insects for health and nutrition.