Crickets are a rich source of protein and other nutrients. They are popular among herpetologists as a food source for pet reptiles; wildlife rescue and rehabilitation centers also commonly use them to feed various injured and orphaned animals. Because insects are a rich source of protein, some people started farming crickets as a source of human food. The protein content ranges from 56% to 60% of dry matter, depending on diet. They are a good source of fatty acids and minerals such as iron, zinc, and phosphorous.
The most popular species that are farmed is Acheta domesticus (L.), the house cricket. Both larval and adult can be used as animal or pet food, and varying sizes are important in the pet industry, with smaller crickets preferred by some pet owners who need to feed small reptiles. For human food, it makes more sense to process larger individuals, large nymphs, or adults since these insects would have more nutrients present per cricket compared with tiny larvae.
Life cycle stages
Like other farmed insects, crickets are resistant to disease, but females cannibalize males occasionally. Cricket’s life cycle includes an egg, larva, and adult stage. These insects have hemimetabolous or incomplete development, meaning they do not have a pupa stage, and larvae, called nymphs, resemble adults. The length of the life cycle varies and is highly dependent on temperature. More rapid development occurs at temperatures of about 32°C. At this optimal temperature, the total life cycle is about 2 months, while it can take an extra month at cooler temperatures. Adults lay eggs in a moist substrate, and the eggs hatch in one to two weeks if the temperature is about 30 °C. The female lays up to 100 eggs in her lifetime, and the nymphs molt about 8 to 10 times before reaching adulthood. The number of molts and how long development takes depends on temperature, with cooler temperatures resulting in slower development.
Farming crickets for the pet industry is simpler than for human food. Crickets are fed foods to increase nutritional content; for instance, calcium is often added as these insects are usually low in this mineral. This is particularly significant when crickets are used to feed reptiles.
Where crickets are reared for human consumption, other factors come into play, and these insects are fed different human foods to make them as nutritious as possible.
Diet and Water Recommendations for Edible Crickets
Diets for edible crickets can be designed to ensure good levels of palmitic acid, oleic acid, linoleic acid, and α-linolenic acid. The cricket efficiency of conversion of ingested food ranges from 64 to 65 at the 8th week when fed on a diet consisting of rice and pasta, pork and beef meat, bread, cheese skins, fruits and vegetables, and yolk. The feed conversion rate varies from 1.50 to 1.78, depending on diet, with higher values obtained with crickets fed a diet of at least 22% protein.
Crickets do need a source of water, but they readily and easily drown in water containers. Very early stages, recently hatched from eggs, are particularly susceptible to this, which is why watering has to be done with care. It is best to use a moistened sponge as a source of water or a test tube with a piece of cotton. Too much moisture can also lead to mold development; thus, the container needs to be checked and cleaned often.
Optimal Breeding Conditions
Farming outdoors is a viable option only if the farm is established in a country with a warm and humid climate. In cold climates, the development would be too slow, and thus an indoor setup is preferable. Indoor farms have many advantages, including room temperature control, relative humidity, and photoperiod.
Crickets can be farmed in various types of containers; they can be housed in glass containers with screen lids. The density should be no more than 15 crickets per gallon container, and they can be fed a diet of cricket chow, unless being farmed for human consumption, in which case diet may include human foods.
The best way to start a colony is to purchase adults and set up a container containing one or more oviposition chambers that are 10cm in size and hold moist peat or vermiculite for the females to lay eggs in. The substrate should be covered with a screen so that females do not disturb eggs that have been laid. After a week or two, the eggs can be removed and placed elsewhere as the adults could cannibalize the hatchlings. Relative humidity for adults needs to be kept at least 50%, while it needs to be kept higher at about 80% for eggs. Crickets can be housed in aquariums of dimensions 0.50 m × 0.25 m × 0.35 m. A 0.75 mm metal screen can be used as a cover, and, if indoors, a light can be provided using a 25-watt lamp.
Once the eggs hatch, the next step is to remove the young ones and place them in a separate gallon container. They need to be fed and watered often, and the container cleaned regularly. Deceased ones, old food, and feces need to be removed to prevent crickets from becoming ill and dying.
Directly after harvesting, the crickets are frozen in a freezer for at least an hour; the freezer should be kept at -18° C or lower. Crickets are then sent in this frozen form for further processing. To prepare as food, they are first rinsed to clean any feces and other particles off. The next step is blanching, in which the crickets are submerged in boiling water of 100 °C for 4 min and then rinsed off again in cool or cold water. Another option is to place crickets into cans with a brine solution, of 5% sodium chloride, for 16 min at a temperature of120 °C9. These procedures of blanching help destroy any bacteria. Canned and freeze-dried insects are sold to pet owners, along with living ones.
If not canning the crickets, the next step is to dry roast them in an oven for about 3 to 4 hours at 98°C. Some people use a food dehydrator instead, which may be quicker. After dry roasting, they can be eaten or further processed into flour.
To make flour, crickets are milled by placing them into a grinder, running for an initial 10 seconds. Body parts like legs can be sieved out, and the powder ground up once again until very fine; this second part could take another 20 to 30 seconds. In a commercial setting, coarse and fine grinding machines are often used for these processing stages. In the end, powder or flour is made, which can be packaged and sold for people to purchase and use in various recipes.
Managing the Cricket Farm
Collecting, processing, and analyzing production data is essential not only for process optimization but also for minimizing risk. Cogastro solution helps monitor and maintain the most critical production related aspects such as humidity, temperature, feed conversion, cycle speed, and other vital metrics. The software also helps in providing accuracy in feed monitoring, securing traceability, and planning daily work.