How to Feed Silkworms to Reptiles: Practical Guide to Nutrition, Care, and Sourcing

Silkworms are a high-quality feeder insect with exceptional protein:fat ratios and soft bodies. This guide covers nutrition, feeding, sourcing, safety and storage.

Why silkworms are worth the effort

Silkworms (Bombyx mori) are a premium feeder insect prized by reptile keepers because they are soft-bodied, highly digestible and typically offer a superior protein:fat ratio compared with common feeders. They are especially useful for juveniles, growing reptiles and skittish eaters that prefer slow, non-jumping prey.

Silkworms do have husbandry quirks — most strains are traditionally fed mulberry leaves and many hobbyists find them harder to source year‑round than crickets or mealworms. This guide covers practical feeding, safety, storage and which species benefit most.

Nutritional profile

Nutrient analyses vary by life stage (larvae vs pupae), diet (mulberry vs artificial feed) and moisture content (fresh vs freeze‑dried). Below are representative values from published analyses and breeder data presented on a dry‑matter basis (DM):

• Protein: 45–60% DM (typical = ~55% DM)
• Fat: 15–30% DM (typical = ~20–25% DM)
• Ash (minerals): 3–6% DM
• Calcium: ~0.1–0.5% DM (fresh values lower)
• Phosphorus: ~0.8–1.5% DM
• Typical Ca:P ratio: ~0.05–0.6:1 (often well below ideal for reptiles)

• Silkworms are protein‑rich and often lower in fat than waxworms or superworms, making them excellent for growth phases and weight control.
• The calcium:phosphorus ratio is usually low (less than the ideal ~1.5–2:1 for growing reptiles), so calcium supplementation is required.
• Nutrient content improves when silkworms are fed high‑quality mulberry or appropriately formulated gut‑load.

How mulberry feeding affects nutrition

Bombyx mori is a domesticated species that historically is raised on mulberry (Morus spp.). Mulberry leaves are nutrient‑dense and contribute to a more desirable nutrient profile in the larvae:

• Mulberry‑fed silkworms often have higher protein, better vitamin content and improved palatability.
• Silkworms reared on poor or off‑label diets may be fattier or nutrient‑deficient and can pass those deficiencies to the reptile eating them.

Feeding guidelines

Frequency and portioning

• Juveniles (growing reptiles): Offer silkworms daily or every other day, depending on species and metabolic needs. For fast‑growing species (e.g., juvenile bearded dragons, monitors), feed daily as part of a varied diet.
• Adults: 2–4 times per week as part of a mixed diet. Use silkworms to reduce dietary fat load and promote lean growth.
• Hatchlings and neonates: Use pinhead/small silkworms sized no larger than the animal’s head. Soft bodied silkworms are excellent first prey items for many hatchlings.

• Prey should be no wider than the reptile’s head width. Match silkworm size (pinhead, small, medium, large) to the animal.
• Offer short sessions and remove uneaten live prey after 15–30 minutes to avoid stress or accidental bites.

Preparation and supplementation

• Gut‑load: For live silkworms, feed a calcium‑rich gut‑load for 24–48 hours prior to offering them to your reptile. Good gut‑load choices include collard greens, dandelion greens, or commercially formulated gut‑loads fortified with calcium.
• Dusting: Because silkworms generally have a low Ca:P ratio, dust feeders with calcium powder (calcium carbonate without vitamin D3) at most feedings for juveniles. For adults, dust 2–3× per week. Use a multivitamin dust (with vitamin D3) once weekly unless your vet advises otherwise.
• Frozen/thawed: Many keepers use frozen silkworms for convenience. Thaw fully to room temperature and lightly dust with calcium before feeding. Avoid microwaving; thaw in a sealed bag in warm water or overnight in the fridge then bring to room temp.

Special notes

• Avoid over‑relying on silkworms as the sole prey item for omnivorous species (e.g., bearded dragons) — combine with greens, vegetables and other feeder insects to meet micronutrient needs.
• Do not offer pupae to small gape reptiles — pupae are denser/fattier and may be choking hazards for very small animals.

Which species benefit most

Silkworms are beneficial for a wide range of insectivorous and omnivorous reptiles and amphibians. Typical best matches:

• Small to medium geckos: leopard geckos, crested geckos (occasionally), mourning geckos — excellent for juveniles.
• Day geckos and anoles — soft, easy to capture prey.
• Chameleons — non‑jumping, visible prey item reduces stress for shy eaters.
• Small to medium arboreal lizards — green anoles, house geckos.
• Juvenile bearded dragons and blue tongued skinks — as part of a varied feeder rotation.
• Amphibians and small snakes (e.g., young corn snakes occasionally) may accept silkworms, especially if size matched.

• Large adult monitors (insufficient caloric density alone), very large carnivorous snakes (which prefer larger, fatter prey), and obligate omnivores where variety of plant matter is required.

Safety considerations

• Parasites/disease: Domesticated silkworm strains raised in clean facilities have a relatively low parasite risk compared with wild‑caught insects. Still, buy from reputable suppliers with food‑safety practices. If buying from an unknown source, consider freezing the insects for 48–72 hours (to kill parasites) and then thawing prior to feeding.
• Bacterial contamination: Keep insects clean; remove frass and spoiled gut‑load. Wash hands after handling.
• Pesticides: Never feed wild‑harvested silkworms or insects from unknown environments — pesticide residues can be fatal to reptiles.
• Over‑supplementation: Be cautious with Vitamin D3 — routine use of calcium without D3 is safer for frequent feedings; use D3‑containing powders per vet guidance to avoid hypervitaminosis D.

Sourcing and availability challenges

• Seasonality and supply: Silkworms are less commonly mass‑produced for the U.S. pet trade than crickets or mealworms. Expect seasonal availability from specialist breeders and higher cost per insect.
• Live vs frozen: Many vendors sell both live and frozen options. Frozen is more convenient and safer for long travel, while live often elicits stronger feeding responses.
• Legal/import issues: Check local regulations — some places restrict import of live insects.

Storage and maintenance (keeping silkworms alive)

If you choose to keep live silkworms, basic husbandry will keep them healthy and maximize their nutrition:

• Housing: Ventilated plastic containers or rearing trays with smooth sides to prevent injury.
• Temperature: Keep near typical room temperature (around 70–80°F / 21–27°C) for active feeding and growth. Avoid extreme heat or cold. (Some breeders short‑term chill to slow development; do this only following supplier recommendations.)
• Food: Provide fresh mulberry leaves when available. If mulberry is not available, many breeders use high‑quality leafy greens or commercial silkworm diets — ask supplier for specifics.
• Hygiene: Remove frass daily and replace soiled bedding. Good hygiene reduces fungal/bacterial problems.
• Life stage management: Silkworms will pupate. Larvae are preferred as feeders; pupae are fattier and best used frozen/thawed or as a treat.

Alternatives

If silkworms are unavailable or impractical, consider these feeders:

• Dubia roaches — excellent protein and calcium profile, hardy and easy to breed.
• Black soldier fly (BSF) larvae / phoenix worms — high calcium and good for insectivores, especially calcium‑sensitive species.
• Crickets — versatile and widely available; gut‑load and dust as usual.
• Mealworms/superworms — calorically dense (watch fat content), good occasional item but harder chitin for small hatchlings.
• Butterworms/waxworms — high fat, use as occasional treats for weight gain.

Practical comparison: silkworms vs common feeders

• Protein: silkworms ≈ mealworms/dubia on a dry matter basis but often are more digestible and palatable for juveniles.
• Fat: silkworms are lower in fat than waxworms and many superworms, making them better for lean growth.
• Calcium: most feeder insects (including silkworms) are low in calcium relative to phosphorus — supplementation remains necessary unless using high‑calcium alternatives like BSF larvae.

Key takeaways

• Silkworms are a nutritionally valuable feeder: high protein, relatively low fat, soft bodied and very digestible.
• Mulberry‑fed silkworms typically have better nutrient profiles; ask your supplier about diet.
• The Ca:P ratio in silkworms is usually low — always dust or gut‑load with calcium (regular dusting for juveniles, intermittent for adults) and follow vet guidance for vitamin supplementation.
• Use silkworms as part of a varied diet and match prey size to the animal’s head width.
• Source from reputable breeders; frozen silkworms are convenient and safe when properly thawed.

• Reptiles Magazine – feeder insect articles and husbandry tips. https://www.reptilesmagazine.com/
• Mader, D.R. (Ed.). Reptile Medicine and Surgery (standard veterinary reference for reptile nutrition and husbandry).
• Selected insect nutrition studies comparing Bombyx mori composition (see peer‑reviewed journals on insect composition and silkworm pupae analysis).

Frequently Asked Questions