Catterpillars of Bombyx mori, strangely called silkworm in English, are notoriously known for the the production of silk. They are moths, insects of the family Bombycidae. The species has been so genetically altered by humans that it can no longer survive independently in nature, particularly since the adults have lost the ability to fly. They have been domesticated in China about 5000years ago.

The trivial terminology is really weird, as the Silkworm is actually no worm but it is the larval stage, a caterpillar of the adult Silkworm Moth, luckily also called Silkmoth.

Since the captive care for silkworms has been established on artificial substrates, they became also widely available as a food for insectivorous reptiles.

Commercial reeders have of course a deep interest in selling them, so they promote them as much as they can. And no one speaks about the downside and risks and annoyances, which are tied with feeding with silkworms. Let us open now the can of worms and see what is in there?

First, let us see, what is the COMPOSITION of the silk worms

The overall composition of a silkworm would be as follows:

- Water: 80%

- Dry matter: 20%

The approximate breakdown of the dry matter composition of a silkworm is as follows:

- Proteins: 55-60%

- Fats: 30-35%

- Carbohydrates: 5-10%

- Minerals, vitamins, and other compounds: 5%

If you compare this with the values for crickets, you get:

- Water: 60%

- Dry matter: 40%

And within the dry part

- Proteins: 60-70%

- Fats: 15-25%

- Carbohydrates: 5-10%

- Minerals, vitamins, and other compounds: 5-10%

We simply see

Excess water

Much higher percentage of fats

Lower percentage of protein

There are several serious constraints, which can cool down the enthusiasm in feeding these now widely available feeder.


Silkworms have 80% and more water content and it is what I call "merely water" for good reasons.

Its weight is about 3-5g when fully grown. It means, their body is made up from 4ml of water. This is double to quadruple daily dosis of liquid water for panther and veiled in case they do not go with nighttime fogger and the humidity at night is under 80%. If they are fogged properly, the water dosis is much more times what they need! It means that even one big silkworm causes overhydration of the chameleon. The result is: their body liquids get dissolved under the optimal level and do not work well. Therefore, the proteins and fats contained in the silkworm will not be fully digested, moreover the excess water is a challenge for the kidneys and intestinal tract to get rid of. You can see it on the white overhydrated urate and light brown, sluggish, amorphous, watery (and often even liquid - diarrhea), smelly poop - typical result of feeding silk-moths. If regularly overhydrated, chameleons develop chronical inflammation of the intestines, caused by osmotic ruptures of the enterocytes (epithelial cells that line the inner surface of small and large intestines) that are then attacked by bacteria.


All commercial breeders of silkworms block any questions about the food composition they provide to the silkworms. So, we have no clue, how they have been fed. If the food contains mulberry leaves or someone even smartly feeds them exclusively with the natural food (mulberry leaves), beware the sap contained in the leaves is toxic! The contained toxins (pyrrolidizine alkaloids) cause digestion problems, diarrhea, are hepatotoxic (cause damage of the liver), stimulate nervous system which causes failure of its function, hallucinations etc. So, nothing desirable. Toxic sap is contained in the whole tree except for ripe fruits, which can be consumed.

So, what is the result?

No enthusiasm concerning nutritive value of the silkworms in their larval stage:

- Too fatty

- Potentially dangerous

- Too much water

- Bad digestion

- Unknown content

- Potentially toxic.

Is it really that disastrous? Not really…

Do chameleons eat silkworms in the wild? No, they do not, there are no silkworms in the wild. But, they eat other caterpillars. They eat them predominantly in the young-hood, as they usually hatch in the rainy season where most diurnal insects hatch from eggs and pass the larval stage to puppate. They do not feed on them in general too much when adult, because most of the caterpillars will

already transform to pupae.

The toxins have never been reported to cause harm in chameleons. Their amounts in the bodies can be quite low and they can be detoxicated or tolerated by the silkworms… We do not know, nobody ever did research on that. The poisons may be harmless or in low concentration or absent but can also be of cumulative action - it means, they can seemingly not work up to some threshold. And then cause big problems. We have also no way hot to discretely separate the bad influence of these toxins on the wellness and longevity - so we do not know in what extent the toxins contributed to shortened lifetime in comparison/combination e.g. with exposure to toxic fumes of plastics, stress, wrong hydration, lighting etc.

So, what are the conclusions?


I in person never feed my chameleons with silkworms. The risk is too high for me and I respect the ancient rule: in dubio abstine (in case of doubt, abscond).


I can recommend doing the same or use them just as a rare and occasional treat.

I would merely go for the adult moths, which, during the metamorphosis, lose most of the fat, add lots of roughage and contain a break amount of water of the catterpillars.

They di not bring any tangible benefit other than variety, they are wayery and fatty and on the volume, they ovehydrate and have rather low nutritive value if compared to body mass. There is no need to feed with them, we have good alternatives.

But, it is up-to you

Do your decision wisely and do it now informed way

Author: Petr Nečas