TYPES OF INSECTS THAT CAN BE FARMED The number of insects identified as suitable for domestication is increasing. Among thousands of edible insect species, approximately 18 have been identified as suitable for farming and upscaled production for animal feed or direct consumption by humans (table 3.2) (van Huis 2019; Halloran et al. 2018). This section reviews several of these. Large-scale insect farming is still in its infancy and more insect species suitable for farming will likely be identified. Like animal domestication, only insect species with optimal characteristics—such as taste, disease resilience, productivity, manageability, and nutritional composition—are likely to be profitable in farming systems. Moreover, the deliberate domestication of insects can lead to higher growth rates, increased feed efficiency, and increased insect tolerance to human handling and crowded conditions (Lecocq 2019). The ideal insects for mass production have relatively simple life cycles. Insect farming systems are shaped by the life cycles and biological characteristics of the species being produced. The insect species best suited for breeding and production in closed systems have relatively short life cycles and colonizing behavior that thrives in high densities. The species produced in large quantities for food or feed (table 3.2) also have relatively simple life cycles, compared with the two ancient, domesticated insect species, namely the silk moth (for silk) and the honeybee (for honey and pollination). The silk moth (Bombyx mori) feeds only on mulberry leaves, limiting substrate options. In addition, farmers selectively breed silkworms to reduce their wing size so they can no longer fly, making farming simpler. Domesticating honeybees is challenging because of their aggression. Insect production systems are adapted to these biological characteristics. Insects reach maturity faster than most livestock. According to the farmlevel survey, all commonly farmed insect species require fewer than four months to mature from egg to harvestable size. Like livestock, insect growth rates depend on the species, climate, quality of substrates, and form of production, among other factors. Table 3.3 outlines the time it takes for different insect species to reach harvestable size from birth. Houseflies and BSFL have the shortest growth period and can be harvested within one to two weeks—for houseflies within as short as four days and up to 20 production cycles per year. By contrast, house crickets can have the longest growth period of all the insect species surveyed and mopane caterpillars can be harvested only twice per year because of long growth periods and seasonal factors. The farm-level survey revealed that at least 16 different insect species are farmed in 10 of the 13 surveyed African countries (table 3.4). Crickets, mealworms, BSFL, housefly larvae, palm weevil larvae, and mopane caterpillars are the most commonly farmed insects in the surveyed FCV countries. In the Democratic Republic of Congo, the most commonly farmed insect species is the African palm weevil larvae. Insect farming was not reported in Benin and Burundi, and this information was missing from the Tunisia survey. Understanding Insect Farming
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