If you want maintain a self-sustaining mealworm farm, it is best to let some of the mealworms grow into darkling beetles so they can reproduce. This is critical for the success of your farm, so I will walk you through the basics of caring for adult beetles.
Darkling beetles prefer dark, cool places. Provide them with grains, fruits or vegetables for optimum health. A female darkling beetle lays eggs to begin the life cycle again.
Where to Raise Darkling Beetles
Darkling beetles don’t require a large container. A plastic bin with a secure lid is ideal. Drill some small ventilation holes in the lid to provide airflow. Line the bottom with a substrate like coconut fiber or peat moss, which retains moisture without becoming soggy. A depth of 1-2 inches should be sufficient for burrowing.
You can also use a mesh to cover the container. It is easier to set up compared to drilling. Just make sure the holes are not too big as the mealworms might crawl out. As long as the container is at least 6 inches tall it should not be an issue.
Temperature and humidity: Darkling beetles are adaptable but prefer a temperature range of 70-85°F (21-29°C). Keep their enclosure in a warm room that doesn’t experience extreme temperature fluctuations. Maintain a humidity level of around 50-60%. Mist the bedding if necessary to keep it from drying out. The container shouldn’t be too damp as too much moisture can lead to mold or mite infestations.
Darkling beetles need bedding or substrate to burrow and forage. I use a mixture of soil, sand and leaf litter because it mimics their natural environment. You can add pieces of bark and make cardboard tunnels to serve as hiding spots. Darkling beetles like to feel secure so it’s a good idea to provide several hiding places.
For more information you can check out this guide on mealworm bedding.
Maintenance and Cleaning
Regular maintenance is needed to keep darkling beetles healthy. Remove any moldy or decaying food before they attract pests and lead to infections.
I sift through the substrate weekly to remove waste or dead beetles. Replace the bedding at least every few months or more often if needed. You can use different materials as long as it is deep enough for the beetles to burrow.
Diet and Nutrition
Beetles are not that picky when it comes to food. For the best results however, you should provide them with the most nutritious options. Here is a general guideline on what to feed them.
Darkling beetles mainly consume grains and plant-based materials. A diet consisting of wheat bran, oats, or cornmeal should be their staple food. You can use just one type or mix and match.
They can also benefit from fresh fruits and vegetables. Carrots, apples, oranges, and potatoes all provide nutrients and hydration, which are essential for their growth.
Lettuce, spinach, kale, or any other leafy greens can be added to their diet too. These vegetables contain vitamins and minerals that darkling beetles need.
Moisture and Nutrients
Darkling beetles require some form of moisture in their diet. You can provide moisture through the food (fruits for instance). Or you can put small pieces of damp sponge or paper towel in the container. Don’t make the sponge too damp because it might lead to mold growth.
Darkling beetles also need calcium for their exoskeleton and egg development. Crushed eggshells, cuttlebone and calcium-enriched reptile pellets are my favorite options.
They require protein for growth and reproduction. Fish flakes, dog food and cat food are excellent protein sources. Don’t give it to beetles daily though, every few days is fine.
Beetles don’t need expensive food, but nutritious ones are a must. Remember that your goal is to make them as healthy as possible for breeding purposes.
Health Reminders
Darkling beetles can become prone to obesity if given high-fat foods regularly. It is best to avoid fatty items like nuts, seeds, or oily food scraps.
Check their food supply regularly and remove anything that has been spoiled. Mold can harm the beetles and contribute to the growth of harmful bacteria and parasites.
Aside from moist fruits, I also provide my beetle with water. Use a shallow dish so the water doesn’t make a mess if it gets toppled over. Replace the water regularly.
Breeding and Reproduction
Breeding usually occurs during the warmer months as conditions are optimal for survival. The process begins with courtship where males compete for the attention of females. This can involve intricate displays such as antennal tapping, jostling, or circling each other.
Mating takes place after courtship. Some male species have developed spines or hooks to ensure successful fertilization.
Laying Eggs
After mating, the female lays her eggs in the substrate. The number of eggs laid varies depending on the species but can range from a few dozen to several hundred. Darkling beetle eggs are small, oval-shaped and whitish or yellowish in color.
The eggs incubate anywhere from a few days to several weeks. The incubation period depends on factors such as temperature, moisture, how healthy the beetle is, etc. When the eggs hatch, tiny darkling beetle larvae emerge.
These larvae, commonly referred to as “mealworms” look like worms hence the name. They have a voracious appetite and feed on a variety of organic materials including decaying plants, fungi, or even other insects.
The Beetle Life Cycle
As the larvae grow, they undergo a series of molt. During the molting stage, mealworms shed their exoskeleton to accommodate their increasing size. The number of molts varies depending on the species, but 4-6 times is the average. Each molt is followed by a brief period of rest or pupation.
The pupal stage is the last phase before the larvae turns into a beetle, completing the cycle. The pupal period can last from a few days to weeks depending on the environment and species.
The newly emerged beetle is soft and pale, but it hardens and darkens within a few hours. The adult beetles have fully formed wings and are capable of flight, though their capabilities can vary among species.
Lifespan
Darkling beetles can live for three months to more than a year. It depends on their health, diet, habitat and other factors. A year may not seem like a long time, but beetles will have laid plenty of eggs by then.
Conclusion
Darkling beetles require care and attention, but they are the keys to a profitable mealworm farming business. Once you learn to raise beetles, you will have a constant supply of mealworms, pupa and beetles at your disposal.
