Are Silkworms Safe for Leopard Geckos?

Yes — silkworms are not just safe for leopard geckos, they are one of the most nutritionally valuable feeders you can offer. They are soft-bodied, low in fat, easy to digest, and carry the highest natural calcium-to-phosphorus ratio of any commonly bred feeder insect. The catch is that they are a supplement, not a staple, and using them well means understanding what they bring to the diet, what they cannot replace, and how to feed them in the right rotation.

The nutritional case for silkworms

Silkworms (Bombyx mori) feed exclusively on mulberry leaves and concentrate the nutrients in a way few other feeders match. A typical fresh silkworm provides, by dry weight, roughly:

• ~64% protein — high but not excessive
• ~10% fat — low compared to mealworms (28%) and superworms (~17%)
• Calcium 177 mg per 100g, phosphorus ~250 mg — a Ca:P ratio close to 1:1.4
• ~76% moisture — substantial hydration

For leopard geckos specifically, the low-fat profile is the headline. Leopard geckos store fat in their tails, but they store it easily and gain weight on rich feeders like waxworms or unmodulated superworms. Silkworms let you offer real volume without driving the gecko toward obesity.

Why the calcium ratio matters

Leopard geckos in captivity are vulnerable to metabolic bone disease (MBD), which develops when dietary calcium is consistently outweighed by phosphorus. Most feeder insects have a Ca:P ratio of roughly 1:8 to 1:20 — far short of the 2:1 the gecko's metabolism needs. Keepers compensate by dusting feeders with a calcium powder. Silkworms get you closer to the target naturally, so the calcium dust does less heavy lifting on a silkworm-feeding day.

Sizing and life-stage considerations

Silkworms grow from 3 mm hatchlings to 7 cm pre-cocoon larvae over roughly 28 days. The right size depends on the gecko:

• Hatchling leopard geckos (under 4 in total length): small silkworms, ~1.5–2 cm, fed 1–2 at a time during their main meal
• Juveniles (4–7 in): medium silkworms, ~3–4 cm, 2–3 per feeding
• Adults (7+ in): medium-to-large silkworms, ~4–6 cm, 2–4 per feeding

The general feeder rule applies: prey should be no wider than the space between the gecko's eyes. Silkworms are softer than crickets or roaches and forgive a slightly larger size, but oversized prey still risks impaction or refused feedings.

How often to feed silkworms

Treat silkworms as 20–30% of the protein rotation, not the whole thing. A workable weekly cycle for an adult leopard gecko:

• 2 staple meals: appropriately sized discoid roaches or crickets, dusted with calcium
• 1 silkworm meal: 2–3 silkworms, no dust needed
• 1 supplemental meal: small hornworms for hydration, or a couple of BSFL for an extra calcium hit

Hatchlings and juveniles eat daily; adults settle into every other day. Silkworms do not need to appear in every meal, but their inclusion once or twice a week meaningfully improves long-term bone and shell health.

Practical handling and storage

Silkworms are more delicate than most feeders. Keep them in their shipping container at 72–82°F, never refrigerated (cold kills them outright). Provide fresh mulberry chow every other day — a paste mixture of dried mulberry leaves and water that is sold alongside the worms. Do not let the chow dry out or grow mold; both are common reasons silkworms die in storage. With proper feeding, a batch keeps for 2–4 weeks before pupation.

What silkworms cannot do

Silkworms cannot be the only feeder. Leopard geckos benefit from variety, and a single-feeder diet — even an excellent one — leaves nutritional gaps. Specifically:

• Silkworms are relatively low in chitin, which means they exercise the gecko's digestive system less than crickets or roaches. Some chitin in the diet is healthy.
• The Ca:P ratio is good but still not 2:1 — calcium dusting on staple feeders remains essential.
• Silkworms are an expensive feeder per gram compared to roaches, so building a 100% silkworm diet is impractical for most keepers anyway.

Signs that silkworm feeding is working

A leopard gecko on a well-rotated diet that includes silkworms shows:

• Tail width roughly equal to neck width — the visual marker of healthy fat reserves
• Smooth, complete sheds with no retained skin
• Bright, alert eyes and active hunting response when feeders enter the enclosure
• Consistent fecal output (firm pellets, no undigested food)

If feedings are refused, the most common cause is temperature — leopard geckos need a warm-side surface temperature of 88–92°F to digest properly, and a too-cool enclosure shuts feeding response down before any specific feeder gets blamed.

Bottom line

Silkworms are one of the safest, most nutritionally valuable feeders available to leopard gecko keepers. They reduce reliance on calcium dusting, deliver substantial hydration, and fit cleanly into a varied feeding rotation alongside roaches, hornworms, and BSFL. The only hard rule is the same one that applies to every feeder: variety beats any single staple, no matter how good the staple is. For more on building a complete leopard gecko feeding rotation, see our care-guide library.