Page 2 of 3 | © 2005-2010 text by Michael Jacobi
The beetle larvae marketed as mealworms and superworms offer the arachnoculturist an easy to keep alternative to crickets. The biggest problem in their use is that they are burrowing and if they are not attacked immediately they may disappear into the substrate and metamorphose into beetles, which arachnids tend to avoid eating due to their chemical defenses.
The small mealworms (Tenebrio molitor larvae) and their larger form marketed as "giant" mealworms are used by a small percentage of keepers. Recently a smaller species (Tenebrio obscurus) has entered the pet trade under the name "mini mealworm". Since these beetle larvae can be kept alive and in the larval stage for some time in a refrigerator, they are convenient and of some use in arachnoculture.
However, the beetle larva that is most popular with arachnoculturists is Zophobas morio, better known as the superworm. This is a much larger and softer "grub" that is an eager eater and can be gut-loaded with a nutritious diet to provide an excellent meal for captive animals.
Superworms will die in a refrigerator and should be kept in a warm and dry container with a substrate of bran, which they will also feed on. A small ventilated storage tub is an ideal container. I provide moisture by offering slices of zucchini squash and leafy greens and also feed them the roach dry diet.
Superworms are approximately 2 in [5 cm] in length and are suitable for large arachnids. To obtain a variety of sizes so that they can be offered to smaller arachnids, the keeper must breed them. When superworms are kept in a large group they do not pupate and will remain as larva. In order to cause them to pupate and eventually become adults (beetles), it is necessary to separate them into small individual containers. Small condiment cups, Dixieª cups or film canisters work well, and about one hundred superworms should be individually place in these containers. Within a short time they will pupate and eventually become adult beetles, which can then be placed together in a container similar to that used to house groups of superworms. Some keepers place the pupae together before they become beetles, but this usually results in some of the pupae being eaten by the beetles that have metamorphosed earlier. Adult beetles are fed a diet similar to that of the larval superworms, with apple and orange added for variety and additional moisture. The beetles have a very unique and strong odor and it is best to avoid touching them when possible. Once numerous tiny larvae are seen in the container, wait about one more week and then discard the adult beetles by releasing them outdoors. Because of their stench, I personally choose to get rid of the beetles as soon as possible and donÕt offer them as food to my arachnids or reptiles. The beetles lay eggs over a period of time and as weeks pass there should be a wide variety of sizes of larvae available, which make excellent prey items for captive arachnids.
Arachnids that have a strong feeding response and are out in the open in the cage are easy to offer superworms to. When dropped directly in front of the arachnid the superworm is usually eagerly pounced upon. Arboreal tarantulas or other arachnids can often be fed superworms by holding the larva gently with rubber-tipped forceps and allowing it to wiggle in front of the spider. However, it is difficult to use superworms for arachnids that live in burrows or beneath rocks. If a superworm is not attacked immediately, it will burrow into the substrate and may not be found by either predator or keeper. Eventually it will often pupate and reappear as a beetle, which can be removed if not eaten.
This is another insect larva (the Silk Moth, Bombyx mori) that is being sold as food for reptiles and can be offered to arachnids. However, they are more difficult to maintain than other feeders. They are very sensitive to bacteria and breeders recommend that you sterilize your hands or wear surgical gloves when handling or performing their daily cage cleaning. They feed solely on mulberry leaves or a commercial diet that requires time and effort to prepare. But if you're willing to spend the time raising silkworms you may be rewarded with some large moths that are likely to be relished by some arachnids.
Waxworms are Greater Wax Moth (Galleria mellonella) larvae that are readily available in pet and bait shops. They are accepted as food by many arachnids and, if allowed to pupate, the adult moths are eagerly accepted by arboreal tarantulas and wandering, huntsman and widow spiders. They are often sold in containers filled with wheat bran or sawdust-like bedding. Better bedding can be made by mixing the wheat bran with honey and adding some grated bee's wax. The finished product should be dry yet sticky to the touch. However, this mixture is so good that it allows the waxworms to create the silken tubes they would pupate in, which makes it time-consuming to extract them. To prevent this and store waxworms for an extended time they can be refrigerated. Many suppliers on the Internet offer waxworms, some in a variety of sizes.