Since crickets, roaches and mealworms are the typical go-to meal items for most tarantula owners, you may be wondering if it’s also safe to them feed hornworms. After all, hornworms are large and they have a threatening looking growth on their back end!
Along with the standard feeders, captive-bred hornworms make an excellent addition to a varied diet for a tarantula, especially if you have large adult spiders. They are a low-fat, high-calcium prey option that has a soft exoskeleton – including the horn – making them not only a meal that most spiders will readily accept, but one that can quickly put weight onto a specimen with a thin abdomen.
Can you catch wild hornworms and feed them to tarantulas?
Wild hornworms are not safe to give to your tarantulas or other creepy-crawlies. These caterpillars naturally feed on plants in the nightshade family, such as leaves of tobacco and tomato plants, which contain toxins that would be poisonous to other critters in the quantities that hawkmoth caterpillars consume. Each species of hornworm has a specific host that that it specializes in eating.
Although most of the toxins that a hornworm would ingest are excreted through their feces, part of their defense system is storing a small amount of the poison in their body. This helps deter spiders and other creatures from eating them.
For example, when a hornworm eats the leaves from a tobacco plant, they route a tiny amount of the nicotine into the haemolymph. Once in the haemolymph, it’s excreted through tiny openings on the side of the caterpillar and through their skin pores. This effectively creates their own cloud of homemade spider repellant.
The process of doing this is referred to as “defensive halitosis” by researchers, and it’s works on more than spiders. The toxic cloud hornworms create can also keep other would-be predators away, such as ants and parasitic wasps.
Your tarantulas should always be fed hornworms that were bred in captivity specifically so they could be safe feeders for pet reptiles, amphibians, and various creepy-crawly creatures.
Will a hornworms horn kill a tarantula?
The horn on a hornworm poses absolutely no threat to your tarantula, it’s completely harmless, flexible, and cannot stab your spider. You do not need to remove it before offering the caterpillar as a feeder.
Why are hornworms good for tarantulas?
Hornworms make an excellent feeder for all sizes of tarantulas because they’re soft, high in moisture, and usually taken with gusto. When offered occasionally, they are a healthy way to keep a tarantula’s diet as varied as it would be in the wild. They make a massive meal for most tarantulas (unless you’re feeding them off when the caterpillars are still tiny), which stretches out how frequently the tarantula needs to be fed.
Hornworms can be offered to larger spiderlings and adults alike. For example, tiny hornworms are an awesome way to entice stubborn spiderlings to eat if they’re reluctant to take crickets and you don’t feel like chopping up mealworms. You can buy cups of them when they are super tiny caterpillars.
The larger, older hornworms are perfect for bigger spiders that are looking too thin, such as a female that may have recently laid an egg sac or a specimen that has recently molted. You can also try offering one to mature males that are refusing food and getting too skinny (although, it’s likely they will still refuse the caterpillar).
Are there any cons to hornworms as feeders?
The cost of buying cups of hornworms, coupled with their insanely fast growth rate, can definitely be considered downsides. Offering hornworms as feeders can quickly become cost prohibitive for large collections of tarantulas, and they grow so rapidly that they may become too large for many of your spiders to eat.
Aside from the cost and quick growth, keep in mind that hornworms are a very messy food item. You will have cage maintenance to do after offering them because their bodily fluids often shoot everywhere when a tarantula bites them.
Is it hard to keep feeder hornworms alive?
Feeder hornworms are not difficult to care for. All you have to do is offer them enough food to withstand their constant eating and keep them at an acceptable temperature range. If you’re buying a cup of them at the pet store, they will come with a thick layer of worm chow that will be sufficient as long as you don’t allow all of the caterpillars to grow large.
Do I have to feed my feeder hornworms worm chow?
You don’t have to feed hornworms premade worm chow if you’d rather avoid commercial feed. Some people like to make their own food blend using ingredients like non-toasted wheat germ, nonfat dry milk, agar-agar, linseed oil, nutritional yeast, various vitamins, sugar, and water (here’s a recipe). That being said, homemade chow most likely isn’t worth the effort and cost if you’re only keeping a small amount of hornworms.
It’s pretty common for people on various reptile forums to suggest feeding them veggies, such as red bell peppers (only the pepper, not the leaves), carrots, and leafy greens, like kale, collards, dandelion greens, grapevine leaves, mulberry leaves and sweet potato leaves.
One homemade worm chow recipe I found on a chameleon forum consisted of dandelion greens, grape leaves, arugula, mustard greens, basil, sweet potato, carrot, wheat germ, some spirulina, and a bit of brewer’s yeast. All of the ingredients were pulverized into a paste.
Another DIY worm food recipe I found used mustard greens, turnip greens, kale, alfalfa, bee pollen, carrots, apples, orange slices, strawberries, blueberries, blackberries, grapes, and sweet potatoes. Again, all the ingredients were blended into a paste for the caterpillars.
When will tiny hornworms be large enough to feed to tarantulas?
If you keep the caterpillars at room temperature, or slightly above room temperature, then they will grow incredibly quickly. A cup of tiny hornworms will become giant feeders by the end of the week assuming that you don’t move them to a cooler temperature to slow their growth down.
When I pick out cups of hornworms at the pet store, I always look for ones that have super tiny caterpillars because they go from the perfect size to behemoths in what feels like a single day.
Is it possibly to slow the growth of hornworms for a small collection?
Kept at room temperature (68°F-72°), a cup of hornworms will grow moderately quickly. If you keep them between 81°F- 90°F, they will grow insanely fast. If you need to extend how long the caterpillars live, then you can keep them at a cooler temperature briefly.
Is it okay to only feed my tarantula a diet of hornworms?
Rather than offer a singular source of food, the best way to increase the chances that you’re meeting all of your tarantula’s dietary needs is to offer them a varied diet that consists of different types of prey items. Although I can’t find anyone that definitely knows how a hornworm exclusive diet would affect a tarantula in the long-term, it’s not something that I would personally do for my own collection.
Is it okay to feed hawkmoths to tarantulas?
You’re not out of luck you’ve kept a cup of hornworms for so long that they the caterpillars have turned into moths! Please do not release them outside. The adult hawkmoths still make excellent feeds for adult tarantulas, especially if you have large arboreals.
Final Thoughts on Giving Tarantulas Hornworms
I think hornworms make an excellent feeder option for my collection of tarantulas, even for the spiderlings and juveniles. I just make sure the prey item offered is reasonably sized for the spider. However, I don’t exclusively give my spiders hornworms. Instead, they are offered occasionally as part of a varied diet that also consists of crickets, mealworms and roaches. I also use them as a tool to put weight onto females I’m trying to breed and scrawny individuals that look a bit haggard after a molt.