Waxworms occupy an interesting spot in the tarantula keeper’s feeder rotation. They are widely available, easy to handle, and most spiders that are the right size for them will take them eagerly. But they also come with a nutritional profile that makes them unsuitable as a primary food source, and understanding where they genuinely fit into your spider’s diet will help you use them properly rather than accidentally doing more harm than good.
What Waxworms Actually Are
Waxworms are not worms in the biological sense. They are the larval stage of the greater wax moth, Galleria mellonella, a species that in the wild lives as a parasite inside beehives, feeding on beeswax, honey, pollen, and shed bee skins. The larvae are soft-bodied, cream-coloured, and typically around 2 to 3 cm in length when fully grown. Their soft exterior and lack of any hard exoskeleton or defensive capability makes them completely harmless to a tarantula at any stage of life, which is one of the reasons they appeal to keepers dealing with slings or newly moulted specimens that are too vulnerable to risk a more active feeder.
The Nutritional Picture
This is where things get interesting, and where most of the debate around waxworms in the hobby originates. According to nutritional data compiled by Dubia.com, waxworms contain approximately 14% protein, nearly 25% fat, and around 58% moisture. Peer-reviewed research comparing commercially raised feeder insects, published in Zoo Biology and summarised via ResearchGate, confirmed that waxworms contain significantly more fat than crickets, mealworms, or superworms, making them the most calorie-dense of the common feeder larvae.
That fat content is both the appeal and the limitation. For a spider that is underweight, recovering from a difficult moult, or simply a sling that needs to put on mass before its next moult, those extra calories are genuinely useful. For a well-fed adult tarantula that is already plump and eating regularly, waxworms offered too frequently could contribute to an overly fat abdomen, which raises the risk of a rupture from a fall. Tarantulas do not store fat the same way vertebrates do, but a consistently high-fat diet still carries risks that justify using waxworms as an occasional treat rather than a regular feeder. Our article on tarantula dehydration covers why your spider’s overall condition matters so much, and body condition is something to keep an eye on whenever you are adjusting feeding routines.
Which Tarantulas Benefit Most
The keeper consensus, backed up by experience shared across communities like Arachnoboards and Tarantula Forum, is that waxworms are genuinely well-suited to larger slings and smaller juveniles. At this stage of life, a tarantula benefits from the additional fat and moisture content, and the soft body of a waxworm is proportionate to what a smaller spider can comfortably handle. Many keepers specifically use waxworms to help a sling plump up and get to its next moult faster, which is particularly valuable during the fragile early stages. Keepers managing small dwarf species also find waxworms useful throughout adulthood for the same reasons.
For most adult tarantulas, waxworms are simply too small to register as a meaningful meal and are often ignored entirely. Larger species are looking for something more substantial, and a waxworm dropped into the enclosure of a well-grown Theraphosa or Lasiodora is unlikely to get a second glance. Smaller arboreals, on the other hand, have been noted by various keepers to take waxworms willingly even at adult size, making them worth trying if your spider falls into that category. See our profile on are tarantulas nocturnal for more context on how feeding behaviour connects to a tarantula’s natural activity patterns.
Waxworms as a Post-Moult Option
One of the most practical uses for waxworms in the hobby is as a first meal after a moult. Following a moult, a tarantula’s fangs need time to fully harden before the spider should be offered live, active prey. The general guidance from experienced keepers at Tom’s Big Spiders is to wait until the fangs have turned fully black before resuming feeding, which signals that they have hardened sufficiently. In the meantime, or as a first gentle meal once that point is reached, waxworms are an excellent choice. Their soft bodies require minimal effort to subdue and consume, and their high moisture content helps with rehydration during a period when the tarantula has been through a physically demanding process. For slings, this approach is particularly common and well-regarded across the hobby.
Gut Loading Waxworms
Waxworms present a unique challenge when it comes to gut loading because their natural diet of beeswax and honey does not lend itself to the same fruit and vegetable loading that works well with crickets or dubia roaches. Their digestive systems are simply not designed to process the same range of foods. That said, some keepers have reported success blending honey, glycerin, and organic oat baby cereal into a mixture and offering it to waxworms for a day or two before feeding them out. This is unlikely to dramatically transform their nutritional profile, but it does ensure the worms have something in their gut when your tarantula consumes them rather than arriving effectively empty. Given that waxworms should only be offered occasionally anyway, it is reasonable to skip elaborate gut loading and simply ensure the worms you offer are fresh and healthy rather than shrunken and depleted from sitting in storage too long.
Storing Waxworms Properly
Waxworms have a reputation for being finicky in storage, but the principles are straightforward once you understand them. According to the care guide at Dubia.com, waxworms should be kept at 55 to 60°F in low humidity conditions. At room temperature they will begin pupating into moths relatively quickly, which renders them useless as feeders. The door shelf of a standard refrigerator is often cited as an ideal storage spot since it tends to sit slightly warmer than the main compartment. At the correct temperature, waxworms can remain viable for several weeks. Remove any that turn black immediately, as dead worms will contaminate the rest of the batch. Good ventilation in the storage container is also essential since waxworms are sensitive to excess moisture and will deteriorate quickly in damp conditions.
How Often to Offer Them
For slings and smaller juveniles where waxworms are most appropriate, offering them every week to ten days as part of a varied rotation works well for most keepers. They should complement, not replace, more nutritionally complete feeders like dubia roaches or crickets. A tarantula that is offered waxworms at every feeding is missing out on the broader nutritional profile that staple feeders provide, regardless of how eagerly it takes them. Rotating waxworms into the mix every few feedings gives your spider the benefit of dietary variety and the occasional caloric boost without tipping the balance too far toward a high-fat diet. Our guide on can tarantulas eat dubia roaches and can tarantulas eat earthworms are good reads for building out a well-rounded feeding rotation that actually serves your spider’s long-term health.
Waxworms are a genuinely useful feeder when used in the right context and with the right spiders, and having a small supply on hand gives you a reliable soft option for post-moult meals and younger animals. To find everything you need to keep your tarantula feeding setup running smoothly, take a look at our best tarantula products page where you will find quality feeding tongs, enclosures, and everything in between.