Are Silkworms Safe for Leopard Geckos? A Feeding Guide
- Role
- Rotation supplement
- Protein
- ~11%
- Fat
- ~2%
- Moisture
- ~80%
- Chitin
- very low
- Ca:P
- ~1:2
- Calcium-rich
- No (dust it)
- Best for
- Soft-bodied protein for picky or recovering animals
I've fed silkworms to leopard geckos for years, and they're one of the few feeders I'll recommend without hesitation, with one rule attached. Yes, silkworms are safe. They're soft-bodied, low in fat, easy to digest, and carry the best natural calcium-to-phosphorus ratio of any commonly bred feeder. The catch is that they're a supplement, not a staple, and feeding them well means understanding what they bring and what they can't replace.
The nutritional case for silkworms
Silkworms (Bombyx mori) eat nothing but mulberry leaves, and they concentrate that diet into a feeder profile few others match. By dry weight, a fresh silkworm runs roughly:
- ~64% protein — high but not excessive
- ~10% fat — low next to mealworms (~28%) and superworms (~17%)
- Calcium around 177 mg per 100g, phosphorus around 250 mg — a Ca:P ratio near 1:1.4
- ~76% moisture — meaningful hydration
For leopard geckos the low-fat number is the headline. Geckos store fat in their tails, and they store it easily, gaining weight fast on rich feeders like waxworms. Silkworms let you offer real volume without pushing a gecko toward obesity.
Why the calcium ratio matters
Leopard geckos in captivity are vulnerable to metabolic bone disease (MBD), which develops when dietary phosphorus consistently outweighs calcium. Most feeder insects sit around 1:8 to 1:20 Ca:P, far short of the roughly 2:1 a gecko's metabolism wants, which is exactly why keepers dust feeders with calcium powder.
Here's the honest version: silkworms get you closer to the target, around 1:1.4, but they're still not at 2:1. So on a silkworm day the calcium dust does less heavy lifting, but silkworms don't eliminate dusting on your other feeders. The Merck Veterinary Manual's section on metabolic bone disease lays out why calcium balance is the central nutritional issue in captive lizards.
Sizing and life stage
Silkworms grow from 3 mm hatchlings to 7 cm pre-cocoon larvae over about 28 days, so you can buy them at almost any size. Match them to the gecko:
| Gecko stage | Total length | Silkworm size | Per feeding |
|---|---|---|---|
| Hatchling | under 4 in | small, ~1.5-2 cm | 1-2 |
| Juvenile | 4-7 in | medium, ~3 cm | 2-3 |
| Adult | 7+ in | medium-large, ~4-6 cm | 2-4 |
The general feeder rule still 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 a refused meal.
You can source any of these stages from the silkworm collection at All Angles Creatures, which is where I buy mine.
How often to feed silkworms
Treat silkworms as 20-30% of the protein rotation, not the whole diet. 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 don't need to appear in every meal, but once or twice a week meaningfully supports long-term bone health and clean sheds.
Practical handling and storage
Silkworms are more delicate than most feeders, and this is where keepers lose batches.
- Keep them in their shipping container at 72-82°F. Never refrigerate them, cold kills silkworms outright.
- Feed fresh mulberry chow (a paste of dried mulberry leaves and water) every other day.
- Don't let the chow dry out or grow mold, both are the usual causes of die-off in storage.
With proper feeding a batch keeps 2-4 weeks before the worms begin to pupate.
What silkworms can't do
Silkworms can't be the only feeder. A single-feeder diet, even an excellent one, leaves gaps:
- Low chitin. Silkworms exercise the digestive system less than crickets or roaches. A little chitin in the overall diet is healthy.
- Ratio still isn't 2:1. Calcium dusting on staple feeders stays essential.
- Cost. Silkworms are expensive per gram compared to roaches, so an all-silkworm diet is impractical anyway.
Signs the rotation is working
A leopard gecko on a varied 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 eyes and an active hunting response when feeders enter the enclosure
- Consistent, firm fecal pellets with no undigested food
If feedings get refused, the most common culprit isn't the feeder, it's temperature. Leopard geckos need a warm-side surface temperature of 88-92°F to digest properly, and a too-cool enclosure shuts the feeding response down before any specific worm gets blamed.
Bottom line
Silkworms are among the safest, most nutritionally valuable feeders you can give a leopard gecko. They cut down on calcium dusting, add real hydration, and slot cleanly into a varied rotation alongside roaches, hornworms, and BSFL. The only hard rule is the one that applies to every feeder: variety beats any single staple, no matter how good that staple is.
For the full feeding picture see my leopard gecko feeder notes on silkworms vs other crested-gecko options, and browse every care guide on the exotic animals hub.