Do you have a pet tarantula at home and want to add a bit of variety to its diet? Hornworms might have caught your attention because they are easily available at pet feeder stores. But can tarantulas eat hornworms? Let’s find out!
For most people, the idea of a giant poisonous spider brings up only one name – the tarantula. And why not? More than 1,500 species of tarantula are roaming the earth.
But considering their lifecycle and food habits, this arachnid may be just another gentle giant in our ecosystem. And many people love keeping them as pets, and obviously, feeding them the best possible diet becomes a big question for such pet parents.
Today, let us find out about the tarantula’s diet and what kind of food keeps them healthy.
Are Hornworms a Nutritious Diet for Tarantulas?
Tarantulas are natural hunters who feed on small creatures like insects, lizards, pinky mice, moths, and worms. Hornworms are also part of a tarantula’s diet. If you have a tarantula at home, hornworms may be a good idea to give to them.
Yes, hornworms are nutritious. They are high on protein (9%) but low on fat (~3%), with 85% moisture content and a high amount of calcium (nearly 46.4 mg./100 g of body weight).
They are a great water source, obviously, but if you buy them from a good breeder, they can also be a source of antioxidants and carotenoids. This depends on the diet their breeder fed them. These chemicals help in repairing damaged cells and improving immunity.
This makes them good feeder insects for many common household pets, such as geckos, lizards, and of course, tarantulas. These worms are soft, and spiders can digest them easily.
For bigger spiders and pregnant female tarantula, hornworms can be added once a week as part of their diet. This adds both nutrition as well as variety to their meals.
For mature spiders who are refusing other food for some reason, hornworms are a tasty and filling snack that will help them to gain strength.
Do Spiders Eat Hornworms in the Wild?
Yes, they do. In the wild, spiders can hunt for hornworms which are amongst the largest insects on the planet (almost four inches long by the time they are ready to pupate).
Fully-grown hornworms can make up about two days of a tarantula’s diet. The spiders take their time to digest the worms fully.
In captivity, worms are a great source of food for tarantulas since they need live insects to feed on. The best idea is to gut load hornworms, mealworms, and other insects and feed them to your tarantula.
What Are The Negatives of Feeding Hornworms?
Sometimes, hornworms can harm your tarantulas without you even knowing it. Wild hornworms feed on plants of the nightshade family, such as tomatoes, potatoes and eggplants, and tobacco.
Hornworms eat and store within them toxins that come from these plants, and these toxins can harm your spider.
Apart from this, there can be quite a few cons to using hornworms if you buy them from a dealer.
- When you are buying hornworms at a pet store, they can be very expensive
- Finding a reputed supplier can be difficult.
- Hornworms grow very big, very fast, so you need to buy them young and feed them quickly.
- If you aren’t able to feed them in time, hornworm caterpillars will turn into adult moths that are difficult to contain and lay eggs very quickly.
Can You Use Them as a Primary Feeder?
While they enjoy eating hornworms because of their size and softness, you should probably use other food instead of hornworms as their primary food.
Tarantulas are very selective eaters, and there is a chance your spider will not eat any worm you offer them.
Neither are hornworms enough to meet all the nutritional value that tarantulas need. Especially if your tarantula is younger, the best idea is to keep a balanced diet of different protein sources that keep them growing.
Moreover, growing tarantulas need to have a varied diet. A singular food source might not be good for a tarantula since the spiders will get tired of eating it.
A hornworm-exclusive diet can also cause digestive problems because hornworms are nearly 85% water, and too much water can cause diarrhea in your tarantula.
What Type Should You Feed?
If you are considering feeding your tarantula hornworms, feed them container-bred only. This eliminates the chances of your spider eating something toxic.
People with tarantulas always go for larger insects when trying to feed the spider. While this could be helpful for fully-grown spiders, a growing spider needs a little more check on its diet.
The spider should also be fed worms that are smaller in size. Most baby tarantulas will not be able to eat full-grown hornworms and may develop digestive problems.
Breeding Hornworms To Feed Your Tarantula
While you can find hornworms on tomato plants and tobacco leaves, you cannot use those for feeding your pet. Captive-bred hornworms are the best way to ensure there are no toxins in them.
Breeding hornworms is not a simple task, but their rapid growth rate makes them a good option as a feeder. Here are the important things you need to know about breeding hornworms at home.
Feeding the Feeders
Be it tomato hornworms or tobacco hornworms; the insects are very low maintenance. When breeding them, all you need to do is keep them well fed. Most worm cans bought at a pet store will contain a layer of hornworm chow.
Once this layer runs out, you can switch to their usual diet, like leaves from tomato or tobacco plants that will be sufficient for all the worms living inside.
How Much Time Do They Take To Grow?
Hornworms are famous for their rapid growth. A hornworm caterpillar will already be three or four inches long at around three weeks. The length depends on the diet you are providing and what kind of temperatures they are living at.
If you do not want them to grow very big, keep them at a cooler temperature of 45-55 degrees F to stunt their growth.
Frequently Asked Questions
What worms can a tarantula eat?
Tarantulas eat a large number of insects and bugs in the wild as well as in captivity. The common types of worms that a tarantula can eat include mealworms, silkworms, earthworms, and super worms.
You can also offer them the occasional vertebrate like a pinky mouse to fatten them up.
What pets can eat hornworms?
Many pet reptiles and spiders love hornworms. These include geckos, bearded dragons, chameleons, and tarantulas.
Mammals and rodents like hedgehogs and hamsters also enjoy an occasional meal of hornworms. Hornworms are easy to breed, don’t require much food, and their bright green color makes them attractive to most pets.
Can striped knee tarantulas eat hornworms?
The striped knee tarantula has the same diet as an ordinary tarantula. These spiders can also eat hornworms.
It is best only to offer captive-bred hornworms and to gut-load them with a high protein diet to increase their nutritional content before you feed them to your striped knee tarantula.
Do spiders eat hornworms?
Yes, spiders eat hornworms. They are a good source of protein and calcium, low in fat, and can’t move fast, so they are easy prey for spiders.
Moreover, hornworms don’t have an exoskeleton and are squishy to eat. They are easy to digest as well.
Hornworms are a great addition to your tarantula’s diet. These worms are low maintenance, have good nutritional value, and are tasty snacks.
Moreover, they can grow to be quite large, so even a single hornworm can be equal to a whole meal for a growing tarantula. Thank you for reading!
Over the years, our readers have sent us several emails on this topic. Please go through them below.
Letter 1 – Hornworm from Singapore is
February 5, 2012 11:15 am
I found this caterpillar feeding on a leaf of a dieffenbachia (common name dumb cane). It has a voracious appetite consuming almost a leaf approx 35cm x 19cm everyday for about 3-4 days. It has initially a bright green body with a head that resemble a small green snake. It is approx 8-9cm long and its body, the thickness of one’s pinkie (the last finger). The amount of calcium oxalate it consumes would have made it highly toxic to any small animals. From the size of each leaf it eats, it appears the equivalent of a man eating approx more than half a football field of poison and survive! How this little creature knows that it could eat this poison in such quantities and survive, and by doing so becomes a poison chalice for any predator making a meal out of it surely questions the evolution biologists’ premise that creatures like these evolve from some simple cells.
Would appreciate your help in identifying this wonderful creature. Location: urban house garden near the Inland Revenue House Singapore. Tropics.
Thank you for writing back to us after getting your automatic response that your letter was received. Out small staff does not have the ability to post every letter or even to respond to every submission. When we originally read your inquiry, we were unable to provide a quick identification without research, and then we never returned to your request. A second reminder is always helpful, but we greatly appreciate when readers attach the images again. We needed to go through our unanswered mail to try to locate your original submission. Our first thought was that this caterpillar had a head like a remora fish. Though its markings seem distinctive, we were unable to make out details because of the poor resolution of the photo. The fact that it had a caudal horn escaped our notice upon the first viewing. That single bit of information would have at least allowed us to provide you with the family name Sphingidae and that the common name of caterpillars from the family is Hornworms. We decided to do a web search of a few key words, and “caterpillar, Singapore, diffenbachia” immediately led us to the Common Butterflies of Singapore website and a match with the Hawkmoth Eupanacra elegantulus. The Common Butterflies of Singapore website states: “This hawkmoth is quite commonly found in urban gardens. The caterpillar host plants appear to be species from the aroid family like varieties of Dieffenbachia, Syngonium and Monstera deliciosa which are all commonly cultivated in Singapore gardens. The young caterpillars are slender, pale green with a straight pale pink spine at the end of their bodies.They have poorly developed false eyespots at this stage. They feed while on the underside of leaves to conceal themselves from predators. When they are not feeding the caterpillars rest near the base of the stems of the hostplant, blending in well as can be seen above.” Butterfly Pals has some wonderful photographs of the entire life cycle.
Letter 2 – Hornworm from South Africa
Subject: Fuschia munching catetpillar
Location: Johannesburg South Africa
November 10, 2015 1:11 am
Hi – this magnificent bug was found devouring my fuschia. I live in Jhb, South Africa and would love to know what it is. Regards
Signature: Debbie Vieira
This is a Hornworm, the caterpillar of a Hawkmoth in the family Sphingidae. We glanced through iSpot with no luck, but carefully searching through all of the entries may lead you to a species name. Perhaps one of our readers will have better luck with a conclusive identification.
After your response my kids made it their challenge to find the species. They eventually found it under Hippotion Celerio.
Thanks for putting us on the right track.
Update: Theretra capensis
Thanks to a comment from Bostjan Dvorak, we now know that this is the caterpillar of Theretra capensis, a species pictured on African Moths where the food plants are listed as: “Vigna, Ampelopsis, Cissus, Rhocissus digitata, Rhocissus tridentata, Rhocissus tomentosa, Vitis vinifera” but there is no mention of Fuschia.
Letter 3 – Hornworm from Crete
Scary 5inch long caterpillar!!
Location: Crete Greece
October 26, 2010 11:30 am
Again I need your expert help to identify this very large caterpillar which arrived on my patio under the Bouganvillia after strong winds in the night. At first I thought it was a snake! Hawk moth again maybe? Five inches long, a horn at the rear and cream colour underneath. I live on the island of Crete. Thanks for all you do to enlighten us amateur nature lovers!
Signature: Cathy P
You are correct. This is a Hornworm as the caterpillars of the Hawkmoths are frequently called. Alas, we do not know the species and a cursory search of the internet did not turn up any matches. Perhaps one of our readers will have better luck identifying the species.
Hi Daniel and Cathy:
It looks like a brown color variant of the Death’s-head Hawkmoth, Acherontia atropos, which is widespread throughout Europe and Africa. As with many hawkmoth (Sphingidae) caterpillars, it comes in a large variety of body colors and patterns. Wikipedia provides lots of interesting information about the species. Regards. Karl
Letter 4 – Hornworm from South Africa probably Theretra cajus
Subject: our caterpillar
Location: Pringle Bay, W. Cape, South Africa
January 29, 2014 12:28 am
Please help us identify our caterpillar! What will it become?
We can tell you for certain that this is a Hornworm, the caterpillar of a Sphinx Moth or Hawkmoth in the family Sphingidae, but we are having a bit of difficulty narrowing the identification down to a species. Your caterpillar bears a striking resemblance to the Hornworms in the genus Hippotion that are pictured on ISpot, however, we cannot find an example that is a perfect match that is identified to the species. This individual on ISpot looks identical to your caterpillar, and it is identified as an Arum Sphinx. We dug a bit more and found many photos of a green variation on this caterpillar, also on ISpot, and it is identified as probably Hippotion eson. This image on Inmagine supports that identification, but we would like confirmation on a website with more scientific credibility. The adult Hippotion eson is pictured on African Moths, and the distribution includes South Africa. We would not rule out the possibility that this is Hippotion celerio, the Silver-Striped Hawkmoth, based on this image on ISpot. We are relatively confident that the genus Hippotion is correct, but do to variability within the species and similarities between species, we cannot be certain of an exact identification.
Update: November 4, 2016
We just received a comment identifying this Hornworm as Theretra cajus.
Letter 5 – Hornworm from Australia
Funky Orange Caterpillar
Location: Sydney, Australia
January 26, 2012 6:19 am
We found this little guy roving around our back deck, celebrating Australia day in style. It was a slightly brighter orange colour than the photo shows. Just wondering what it might be? Obviously some kind of hornworm but I couldn’t see any entries already on your site depicting something that looked the same.
Signature: Many thanks, Bridget.
We quickly identified your caterpillar as a Hornworm in the family Sphingidae, but we had to expend some effort to properly identify it. There are many possibilities of Sphingidae on the Butterfly House website, and the thumbnails are often so small that we need to visit the individual pages. At first we thought we had identified your caterpillar as Hippontion celerio, but the Butterfly House images show a much more delicate caudal horn. A much better match is Theretra latreillii on Butterfly House, which states: “Normally the eyespot is hidden by a fold in the skin of the first abdominal segment, and the spot is only displayed when the animal is disturbed. Indeed when the skin is folded, the head and prothorax look like the upper jaw, and the first set of legs like the lower jaw, of some much larger beast, which may deter predators.” The Brisbane Insect website identifies the adult as the Pale Brown Hawk Moth.
Letter 6 – Hornworm of a Privet Hawk Moth from Hawaii
Subject: Caterpillar Found
Location: Kaneohe, Hawaii
November 2, 2015 4:45 pm
Hi. I’m a preschool teacher in Kaneohe, Hawaii. It rains often here and it a tropical savannah climate. We found this little guy crawling on our sidewalk. I think it probably was eating a hibiscus plant. It was about 6 inches at its longest, has a little tail, and no hair.
Signature: Ms. Lee’s Class
Dear Ms. Lee’s Class,
We believe we have correctly identified this Hornworm from the family Sphingidae as the larval form of the Privet Hawk Moth, Psilogramma menephron, based on images posted to the Sphingidae of the Americas site where it states: “The Caterpillar is an agricultural pest on Olive trees (Olea europaea, OLEACEAE), but is perhaps most often found in suburbia on Privet (Ligustrum vulgare, OLEACEAE ), Jasmine (Jasminum officinale, OLEACEAE ), and Australian Native Olive (Olea paniculata, OLEACEAE), but also feeds on other plants in the families: OLEACEAE and BIGNONIACEAE.” The site also states: “Many Sphingidae larvae will darken (reddish brown to brown) considerably when they are ready to pupate, especially if they are going into a diapausing state” and finding it on the ground indicates it was probably getting ready to dig beneath the surface and pupate, so it will likely emerge in the spring. You can try keeping it in a terrarium with some dirt and if you are lucky, your class will be treated to the metamorphosis process.
Thank you so much for your response. We placed out hornworm in a large jar with dirt last Monday and it immediately dug itself underground. Because we are in a tropical climate, and we do not have a real winter, when do you think we can expect it to emerge, and what steps can we take to take good care of it?
Hello again Ms. Lee,
You should get that Privet Hornworm out of the jar. A more open container, like a cage or a terrarium with a screen top would be much better as a pupal habitat. You can spray the top of the soil with water if it appears to be drying out. A crammed jar is not the best place for the adult Privet Hawkmoth to emerge, especially if you do not notice it shortly after digging to the surface. We would guess an emergence in about six weeks.