Ultimate Guide to Raising Mealworms at Home: 10 Key Things You Must Know!

Friends who are raising mealworms have a variety of options for their breeding containers. Cardboard boxes, paper boxes, and various types of containers can serve as suitable breeding boxes. It’s crucial to ensure that there are no gaps around the bottom of these containers to prevent small insects from crawling out. To further prevent escapes, it’s advisable to affix tape to the edges of the breeding boxes.

Inside the breeding box, it’s essential to place a regular thermometer and a standard hygrometer. Mealworms are sensitive to light, and during the summer, even a few minutes of direct sunlight can be fatal to them. Therefore, it’s prudent for home breeders to cover windows with fabric to block direct sunlight from reaching the insects. Additionally, avoid situating the breeding containers near heat sources as this can lead to dehydration among the insects.

Hatching conditions vary based on temperature and humidity:

• For temperatures around 25 to 30 degrees Celsius with humidity levels of 50 to 70%, it typically takes about 7 to 10 days for hatching.
• At temperatures of 15 to 20 degrees Celsius with humidity levels between 40% to 60%, hatching takes approximately 30 days.
• In environments with temperatures between 0 to 10 degrees Celsius and humidity of 40% to 60%, the insects enter a period of dormancy and generally do not hatch.

Once you’ve acquired the eggs, they require minimal attention if the temperature and humidity are appropriate; they will naturally hatch. When you observe the insect skin, it’s time to bury some hard vegetables like carrots or apples in the breeding box every 3 to 5 days, as these foods do not dry out easily. Leafy vegetables such as cabbage are not recommended, as they tend to dry out quickly.

The amount of food you provide should align with the consumption rate of the mealworms. Add food when they have finished the previous supply, and ensure some bran is present in the box. While you can provide vegetables whenever they consume them, reduce the quantity of vegetables when the mealworms reach a size of approximately 1.5 centimeters, as larger mealworms benefit from drier food. For mealworms exceeding 2.5 centimeters in size, feeding them vegetables every 5 days is sufficient; excessive feeding can be detrimental.

Monitoring the temperature in boxes containing dry bran is crucial since the bran generates heat, and larger mealworms produce more heat.

Regarding living conditions:

• Mealworms thrive at temperatures between 26°C and 32°C, with the fastest growth occurring at 35°C. Temperatures exceeding 35°C can lead to reduced growth, and at 38°C, mealworms may die from heat. However, they exhibit some cold resistance, with older larvae tolerating temperatures as low as -4°C.
• While mealworms are relatively tolerant of dry conditions and can survive with moisture levels below 10%, excessively low humidity can result in slower growth, reduced weight, and decreased feed efficiency. The ideal moisture content in feed is approximately 15%, and indoor air humidity should be around 70%. When feed moisture content reaches 18% and indoor humidity reaches 85%, it can hinder growth and make the insects susceptible to diseases, especially adult mealworms.

Dietary considerations:

• Mealworms are omnivorous and consume various grains, oilseeds, and by-products of grain processing such as bran and cornmeal. They also consume various vegetable leaves.
• Young larvae have a broader diet range and can feed on dried mulberry leaves, leguminous plant leaves, and even other insect carcasses when food is scarce. They may also nibble on the paper used for bedding.
• When raising mealworms artificially, it’s crucial to provide a diverse diet that includes a mix of feeds to meet their nutritional requirements. A typical mixture might consist of 80% bran, 10% cornmeal, 9% peanut cake, and 1% other supplements, including various vitamins, mineral powder, and antibiotics. Alternatively, a mix of 60% bran, 20% crushed rice bran, 10% cornmeal, 9% soybean cake, and 1% other supplements could be used. Adjust the proportions based on local conditions and economic factors.

Behavioral traits of mealworms:

• Photophobia: Adult mealworms prefer dark corners or shelter under leaves, grass, or debris to avoid direct sunlight. Young larvae tend to stay near the surface of grains, flour, or bran, typically about 1 to 3 centimeters below. Therefore, it’s vital to provide dim lighting conditions when raising mealworms or use containers with lids to shield them from direct sunlight.
• Aggregation: Both young larvae and adult mealworms have a tendency to aggregate. However, overcrowding should be avoided as it can raise temperatures within the group, leading to heat-related deaths among young larvae. Overcrowding also reduces their living space and can result in food shortages, causing adults and larvae to consume eggs and pupae. Conversely, keeping the population too small leads to wasted space and decreased productivity. Therefore, it’s important to carefully control population density when raising mealworms artificially.

Breeding methods:

• Mealworms are typically raised in containers.
• Adult breeding involves encouraging them to lay numerous eggs. After emerging from pupae and before their body color darkens, adult beetles should be transferred to breeding containers. These containers are typically 60 cm in length, 40 cm in width, and 15 cm in height, constructed from wood, with a 2-3 mm iron wire mesh at the bottom. Ensure that the mesh doesn’t have large holes, which could allow adults to escape.
• The recommended male-to-female ratio for introducing adults is usually 1:1. Before placing adults in the breeding container, place a wooden board at the bottom and cover it with paper for egg-laying. Add a 1 cm thick layer of feed on top of the paper to encourage egg-laying on the paper rather than in the feed. Leafy vegetables like mulberry leaves or leguminous plant leaves can be added to provide hiding spots for adults and maintain a stable temperature.
• Regularly cover the top with cabbage, adjusting the amount based on temperature and humidity. These vegetables provide moisture and additional vitamins. Adults can freely access the feed on the surface, and most eggs are laid between the paper and the feed through the wire mesh, preventing the adults from consuming the eggs.
• After approximately three months of continuous egg-laying, females will gradually die due to aging, and the egg-laying rate will significantly decrease. Consequently, after three months, it’s advisable to remove all adults to prevent wasted feed and space and to improve production efficiency.

Breeding and raising young larvae (continued):

• Young larvae are raised from hatched eggs. After hatching, these tiny larvae will move about, and it’s essential to gently separate them from the eggs and place them in a container with proper ventilation to maintain airflow.
• In the early stages, young larvae are more sensitive to environmental changes, so avoid exposing them to strong light or drafts.
• Maintain suitable temperature and humidity levels, with young larvae thriving at around 30°C and humidity between 50% and 70%.
• Initially, feed young larvae with finely ground feed, using bran mixed with water or milk as their primary food source. Gradually introduce powdered feed that is rich in protein and vitamins as they grow.
• As young larvae continue to develop, you can provide coarser feed, such as bran and chopped vegetables.
• It’s crucial to keep the bedding materials clean and dry to prevent the growth of harmful microorganisms.
• Maintain proper spacing among the larvae to avoid overcrowding, which can lead to stress, cannibalism, and reduced growth rates.
• Regularly monitor their development and growth, as young larvae undergo several molting stages as they grow. Be prepared to adjust their diet and living conditions accordingly.
• Once they reach a suitable size, larvae can be transferred to larger containers or separated based on their growth stage.

Harvesting mealworms:

• Mealworms are typically harvested at different stages of development, depending on their intended use.
• For small mealworms suitable for feeding reptiles and birds, harvesting can be done when they reach a length of approximately 1.5 centimeters.
• To obtain larger mealworms, often used for human consumption or as fishing bait, allow them to grow to a size of approximately 2.5 centimeters or more.
• Harvesting is usually accomplished by sieving the mealworms out of their substrate using a mesh or sieve. Gently shake or tap the container to separate the mealworms from the bedding.
• It’s essential to clean and sort the harvested mealworms, removing any dead or unhealthy individuals.
• Store the harvested mealworms in a suitable container with ventilation holes and provide them with a small amount of bran or feed to keep them nourished.
• Maintain the storage container at an appropriate temperature, typically around 10-15°C, to slow down the mealworms’ metabolism and extend their shelf life.

Additional tips:

• Maintain excellent hygiene in the breeding and rearing areas to prevent the spread of diseases.
• Regularly clean and replace bedding materials to prevent the buildup of waste and harmful microorganisms.
• Use containers with secure lids to prevent escapes and contamination.
• Keep detailed records of breeding and feeding schedules to track the progress of your mealworm colony.
• Experiment with different feed sources and supplements to optimize the nutritional content of your mealworms.

Remember that successful mealworm breeding requires careful attention to environmental conditions, hygiene practices, and feeding strategies. With patience and consistent care, you can establish a thriving mealworm colony for various purposes, including pet food, human consumption, or bait.