Optional food preparation

Prior to supplementation and offering of insects to lizards, many specialized hobbyists do the following:

Crickets are caught individually and the "thighs" pinched, either with tweezers or by hand, which causes the crickets to drop their hindlegs. These crickets cannot jump out of the feeding dishes or move around as actively, thus slowing the rate at which vitaminl mineral supplement coatíng is lost.

Mealworms are pinched hard atmidbodywith fine tweezers or between thumb and forefinger. The result is partíal paralysis of the back half of the mealworm. Here again, escape from a feeding dish is prevented. Another consideration is thatpinched and injured mealworms that escape do not usually survive. In the case of king mealworms in particular, this would be desirable in a vivarium where lizards are breeding.

One technique used with lizards that recognize prey by scent is to crush the heads of mealworms with tweezers. The result is a mealworm that "smells" right but doesn't move. This works well with lizards like baby monitors or Indonesian blue-tongue skinks (Tiliqua gigas). These animals can spend so much time thrashing and eatíng a single active mealworm that by the time they retum to the dish, the others may have all escaped.

AlI of this may sound cruel to insects, but what a lizard does is not going to be any better. We're dealing with predators and we must decide between the welfare of predator lizards and that of insect prey.

111. Vitamin/Mineral Supplementation

When you don't have the time to nutrient 10ad insects, the very least you should do is this next step.

With proper gutloading ofinseds and with the opportunity for exposure to natural sunlight, minimal supplementation will be required when feeding your lizards. Most of the cornmercial lizards breeders that keep their lizards outdoors and feed their inseds a high quality diet use little or no supplementation. Under the above conditions, suppleinentation once a week with powdered calcium carbonate is usually all that is required. Recent research seems to indica te that it is probably best to avoid vitamin D3 supplementation if lizards are regulady exposed to sunlight (Dr. Gary Ferguson, pers. cornm.).

For lizards kept indoors with no exposure to sunlight, vitamin/mineral supplementation will have to be adjusted to one's procedures, with regards to gut loading of insects and maintenance systems. If you use a strong UV-A- or UV-Bgenerating bulb (UV -generating bulbs are due to appear on the market in the near future for use with reptiles), then with a proper gut loading regimen, calcium supplementation once or twice a week should be all that is necessary. There is still some question as to whether BL-type blacklights, which generate relatively high levels of UV-A, yet low levels of UV-B, may actually enable lizards to absorb calcium. The distance from the bulb to the animal is probably a critical factor. Unfortunately, we do not know enough about calcium metabolism in lizards (which appears to vary from species to species) to have pat answers to questions about the best feeding procedures.

If there is no exposure to high UV-A- and UV-B-generating bulbs, then calcium/vitamin 03 supplementation once a week is recornmended with most species of lizards, as long they are fed high quality, gut-Ioaded insects. With hatchlings and subadults, calcium/vitamin 03 supplementation twice a week is recornmended.

Without proper gut loading of insects, it will be necessary to resort to cornmercial vitamin/mineral supplements to correct deficiendes associated with nutrient-poor food insects. This is not without risk, because most cornmercial reptile vitamin/ mineral supplements are based on modified bird formulations that have not been supported with research. As a result, many of the cornmercial vitamin/mineral supplements tend to be high in vitamin A and, in some cases, vitamin 03. Other vitamins are also probably not present in the right proportions. Ideally, a formulation should be developed that allows for regular dusting without the risk of overdosing; thus, it should be a very dilute vitamin/mineral supplement. A mixture of one part cornmercial vitamin/ mineral reptile supplementwith two or three parts calcium carbonate, used to dust food insects once a week, will be adequate for most adult insect-eating lizards. For irnmature animal s, a twice-a-week supplementation schedule is recornmended. Oepending upon the species, this will have to be adjusted. Obviously, an adjustment will be necessary if an animal shows signs of metabolic bone disease. It is worth noting that because most lizard buyers will not provide the right kind of lighting and very unfortunately will not feed their food insects a varied diet. vitamin/mineral supplementation will probably be critical for most lizards sold in the pet trade to fare welllong termo One of the most COmInon diseases in captive lizards, metabolic bone disease, will be easily prevented with proper suppplementation.

In spite of some of the recently uncovered problems with current cornmercial vitamin/ mineral supplements, there is no doubt that the practice of vitamin/mineral supplementation by hobbyists has contributed significantly to the successful captive breeding and rearing of many lizard species.