Mealworms

🔤 Taxonomy

Tenebrio molitor is the accepted scientific name used for this feeder guide.

Common names used in the feeder trade:

Mealworm
Yellow mealworm

📌 Description

Mealworms are the larvae of a darkling beetle and are useful, quiet, easy-to-store feeders for many reptiles, amphibians, birds, fish, tarantulas, and mantids. They are less active than crickets and easier to contain, but their chitin and phosphorus-heavy profile mean they should be rotated with other feeders rather than used as the only staple.

Feed a clean dry base plus fresh plant foods. Gut-load for 24-48 hours before feeding, then dust according to the predator species supplement schedule. No feeder species is a complete diet by itself.

🌍 Distribution

This species is associated with stored grain and human food stores and is now cosmopolitan through trade and storage environments.

For keeper practice, biosecurity matters more than a precise range map: commercial feeder insects are moved far outside their natural ranges, and escaped animals should never be released or treated as harmless.

⚖️ Regulations and safety

Tenebrio molitor is not listed in the CITES Appendices in the official CITES checklist reviewed for this guide. No specific EU wildlife trade Annex listing was found for the species.

The EU Invasive Alien Species Regulation restricts species on the Union list; this guide does not treat Tenebrio molitor as a Union-list species. Local and national rules can still restrict live insect imports, transport, breeding, sale, use in schools or workplaces, and disposal.

The Bern Convention is not normally relevant because this is not a European native protected-species care issue. Keep cultures secure, never release live feeders, and freeze surplus or unwanted insects before disposal where local rules allow.

🤌 Husbandry

A practical culture needs correct temperature, airflow, clean food, controlled moisture, and a container that prevents escapes. Keep feeder cultures away from pesticides, aerosols, cleaning fumes, and wild insects. Do not mix fresh shop tubs into a long-term colony without quarantine.

Good setup:

Smooth-sided plastic tub or ventilated culture cup
Fine mesh or fabric ventilation that the feeder cannot pass through
Dry food area separated from wet food or moist medium
Sorting container for feeding and cleaning
Clear date labels for cultures and purchased batches

💡 Lighting

Feeder insects do not need UVB. A normal room day-night rhythm is enough. Keep cultures out of direct sun because small containers overheat quickly.

🌡 Heating and temperature

Recommended ranges:

Holding and breeding: 22-28°C
Fast growth: 26-28°C
Cool slowdown: 10-15°C
Avoid damp heat and condensation

💧 Humidity and water

Moisture should come from safe foods or controlled moisture areas, not from stagnant wet substrate. Remove moldy food quickly and keep dry foods dry.

🌿 Enclosure and decoration

Use enough surface area and ventilation to prevent crowding, condensation, and odor. Keep cultures simple so dead insects, spoiled food, and mites can be spotted quickly. Clean small holding tubs between batches and refresh long-term cultures before they collapse.

🪳 Feeding

Useful foods:

Wheat bran, oats, or insect gut-load as the dry base
Carrot, squash, sweet potato, apple, or leafy greens for moisture
Small, frequent fresh food portions to avoid mold

Feed a clean dry base plus fresh plant foods. Gut-load for 24-48 hours before feeding, then dust according to the predator species supplement schedule. No feeder species is a complete diet by itself.

🥚 Breeding

Adults lay eggs in the dry food and fine substrate. Keep beetles and larvae warm, provide a constant dry food base, and sieve or split colonies periodically so eggs, young larvae, and adults are not all crowded together.

Do not let breeding goals override feeder quality. Cultures that smell sour, contain many dead insects, or show heavy mites should not be used for sensitive animals.

🩺 Common problems

Common problems:

Mold from excess moisture or stale food
Mites from damp waste and old cultures
Escape through poor lids or oversized ventilation mesh
Nutritional imbalance when one feeder is used alone
Predator injury or impaction risk when feeders are oversized
Culture crashes from heat, crowding, pesticides, or contamination

📌 Conclusion

Use this feeder as part of a varied rotation, keep the culture clean, and match feeder size to the animal eating it. Culture hygiene is part of nutrition and safety.