Can You Feed Crested Geckos Hornworms?
By: Jason
Last Updated: January 25, 2023
Crested geckos eat many insects, but not all insects are good for them. What about hornworms? Can crested geckos eat hornworms safely?
Crested geckos can eat captive-bred hornworms as a treat once or twice a month. Hornworms are high in moisture, low in fat, and easy to digest because they have no hard outer shell (chitin). Never feed your pet wild hornworms- they can be toxic.
There is more to learn about buying and storing the bright green bugs and how to get them ready to feed to your crested gecko. Keep reading to get all your questions answered!
Species Overview
Hornworms (Manduca sexta), sometimes called tobacco hornworms, are the young of the Manduca genus hawk moth. They get their name from the small, pointed ‘horn’ on their posterior end. Despite its appearance, the horn is soft.
They have a striking appearance in addition to the horn. Their bright blue-green bodies lined with white diagonal stripes cause them to stand out, which helps ward off predators.
Life cycle
The hornworm is the larvae stage of this insect. They begin as an egg and hatch within a few days of being laid.
The hornworm has a short life cycle, lasting 30-50 days. After that, most pupate or begin the change into a moth.
Hornworms grow fast, especially when kept at the right temperature (80 degrees Fahrenheit). They can even double in size in a day! Cooler temperatures will slow down their growth and extend how long they remain as larvae.
At the end of this phase, the insect builds a cocoon to change into a moth.
Diet
In the wild, tobacco hornworms prefer to eat plants in the nightshade family, which includes tomatoes and tobacco plants.
These plants share contain toxins that build up in their bodies over time. That chemical is what makes wild hornworms potentially toxic to pets. Because of this, only feed captive-bred hornworms to your crested gecko.
Commercially-raised hornworms eat a special diet that does not have the same toxins, making them safe as live feeders.
Other Notes
Their colorful appearance stimulates picky eaters. Hornworms are a great way to get pet lizards who haven’t eaten to start eating again.
Hornworms are agricultural pests. Do not release them (put them outside) at any stage. If you need to dispose of them, place them in a plastic bag in the freezer for 24 hours. Then, throw away the (sealed) bag.
Nutritional Value
It is vital to consider the nutritional value of any food you feed to your pet.
The size of an insect and how it was fed and cared for will change its nutritional composition. If you look around, you will find a range of results online. Below is an average of their nutrients.
Tobacco Hornworm
- Protein – 10%
- Fat – 2.5%
- Fiber – 1.5%
- Moisture – 85%
- Minerals – 1%
- Calcium – 464 mg/kg
- Phosphorous – 1394 mg/kg
Hornworms have no hard outer shell (chitin), which makes them easier to digest than many other feeder insects. It is also part of why their water content is so high. The flip side is that they are low in protein. Since protein helps young crested geckos grow fast, hornworms aren’t the ideal ‘every week’ food.
Like almost all feeder insects, they have too little calcium (Ca) for their phosphorous (P) content.
So when are they good to use? Feed them to dehydrated crested geckos and those who are not eating. Their bright colors make them hard to resist.
Feeding Instructions
Size
Crested geckos can eat insects shorter than the distance between their eyes.
When first born (first instar), hornworms are about 1/4 of an inch long (7 mm). Fully grown hornworms are 3-4 inches long (7-10 cm). That’s huge!
Hornworms start small but get big fast. It only takes them 2-3 weeks to grow ten times their original size.
Fully grown hornworms are too long for crested geckos to eat live. Large adult cresties grow to 16 inches long (40 cm) but usually have less than 2 inches (5 cm) width between their eyes.
Because of how fast they grow and how big they get, many keepers focus on slowing down their growth. Temperature and limiting access to food is the key.
Gut loading
Unlike dubia roaches and crickets, you do not need to gut-load hornworms.
The containers that hornworms come in have food made for them, which is all they need to eat before you give them to your pet.
Dusting
Immediately before serving up the hornworms to your crestie, you’ll need to add supplements. The most crucial dietary mineral they have is calcium, but many also include other vitamins and minerals.
Find an ultrafine powder. The powder doesn’t always stick well to the skin of hornworms, but the most refined ones do a better job of sticking.
To coat, first, place the worms in a small container. Then, sprinkle some powder on them. Gently swirl the cup to get the dust to coat them evenly. Now they are ready to give to your pet!
Don’t apply powder to any insects you are not offering up right away. It is easy to dust another hornworm if your crestie eats up its first serving and is looking for more!
Where do I feed the hornworms to my crestie?
There are a few options for how and where to give the hornworms to your crested gecko.
Many keepers will put insects directly into the enclosure with their crestie.
This method is simple and direct. It makes the best hunting experience for your pet. Hornworms, unlike some insects, won’t hurt your crested gecko if left uneaten. The only drawback of this approach is that you don’t know how many your crested gecko ate.
Another option is to give them to the crested gecko in a separate enclosure. This secondary feeding space can be an empty plastic container or glass tank without a natural substrate or decor.
Doing it this way makes hunting very easy. The hornworms have nowhere to hide, and you know how many they ate in 15 minutes.
The third option is to hand-feed them with tongs. You pinch the hornworm with the long pincers and put it near the mouth of the crested gecko. They will notice it for sure!
You probably don’t need to hand-feed hornworms to your crested gecko. Even reluctant eaters may be more inclined to try and take a bite out of these vibrant worms.
How often can I serve them?
Limit hornworms to twice a month. They should not be the only live feeder insect fed to a crested gecko.
Ideally, your pet should mostly eat powdered gecko food with some live feeder insects and occasional fruit. This mix will give them all the vitamins and minerals they need.
Too many hornworms can result in runny poop. The high water content might be causing your gecko to excrete that extra water in its stool. Feed your crested gecko hornworms with another less moist, protein-heavy insect (like dubia roaches) for a more balanced meal.
Hornworms are a tasty treat!
How many should I give?
The general guide is to feed as many insects as a crested gecko can eat in fifteen minutes.
Hornworms are more of a treat, so start by giving your pet only one or two (depending on their size), along with another insect.
The size of the lizard and the size of the worms will make a real difference in the count.
Dead or alive?
Most crested geckos prefer eating live insects over dead, freeze-dried, or canned ones. Hornworms aren’t readily for sale dried or in cans, so that isn’t a problem.
Because hornworms keep growing, they may get too big for your crestie. You can kill them (humanely), cut them, and serve the smaller pieces to your crested gecko instead. If you do this, the sooner you offer them up, the better.
Buying & Storing
Price range
You can purchase medium hornworms for $0.85 each when you buy 12 or $0.60 each when you buy 24.
Since most large chain pet stores do not carry hornworms, most keepers who use them shop online. Stores usually sell these insects in packs of 12 or 24.
When you buy hornworms, much of what you are paying for is their food. Their food is made just for them, and the weight adds to shipping costs.
Where can I buy the best hornworms?
Several great companies sell hornworms.
How do I keep them?
Hornworms come in plastic cups made to be their home until you feed them to your pet.
Follow the setup instructions, as each seller might use a different method. For most, you place the cup with food on the top and the lid facing down. The worms crawl to the food, and their dropping falls for easy removal.
Notice where the vent holes are on the cup. Keep them open to make sure the worms get enough fresh air.
The temperature you keep them at will determine how fast they grow, so decide how much bigger you want them to get. To grow them faster, keep them at 82 degrees Fahrenheit. Once they get to the size you need, keep them at 50-55 degrees Fahrenheit to slow down their growth. At this temperature, they eat less food, too. They do not do well in the refrigerator or a wine cooler.
There is no need to add more food.
Remove the waste daily and any worms if they die.
Mold might form in the cup from too much humidity and not enough light. It also occurs when a cup isn’t stored upside down, and the worm’s waste touches the food. If you find mold, scoop it out with a spoon.
How long do they live?
Hornworms live for about 30 days before transforming into a moth. Keeping them cooler can extend this to 50 days.
Most keepers don’t have a problem with them dying too quickly. The issue is that they get too big, too fast. You don’t want to offer them to a crested gecko too often to ‘use them up’ because it isn’t healthy for the lizard.
Why are they changing colors?
If you notice your hornworms have begun to turn red, they are entering the pre-pupa stage.
If you can, feed them off within the next two days before they turn into moths.
Do All Crested Geckos Like Hornworms?
Just like with humans, each crested gecko has preferences. Not every person likes the same foods, nor does every crestie.
Can you think back to a time you tried a new food? Maybe you took only a little taste and then stopped and tried again later. Just like humans, crested geckos need to warm up to new things.
If you’ve offered hornworms to your pet and they weren’t interested the first time, don’t worry. Try offering the worms with tongs to help them give it a try.
Your crested gecko isn’t interested in eating hornworms? No problem! There are plenty of other live feeder insects to try instead.
Conclusion
Hornworms are healthy feeder insects that you can feed your crested geckos every two weeks as a treat.
For many keepers, though, there is a mismatch with hornworms. They don’t live for long and can outgrow the pet lizard. They aren’t a good staple food, so you can’t feed them all to your crestie at once.
So what is the solution? Only order a few and buy the smallest ones you can. Offer several of them to your pet right once you get them, and then again every two weeks. Store them in cool temperatures as they get larger.
This approach exposes your pet to a new thing to eat and has the least amount of food waste.
What about other insects? Can Crested Geckos Eat Mealworms?