Although we call them a ‘worm’, mealworms are actually the larvae stage of the Tenebrio molitor beetle. Most of us either breed or purchase these little fellows to feed to a variety of finches, softbills and some parrots. They also provide the most asked questions at General Meetings, finding their way on a regular basis to the question box.
Having consulted the Adelaide Museum, S.A. Mealworm Breeders and other keepers of this worm I hope the following information will answer some of the questions most frequently asked.
Firstly we have only 2 species of worm, the main one that we all keep plus a sub-species, often referred to as racehorses. These are usually found in aviaries hustling about in spent seed on the aviary floor. They have harder skin casings than the normal worm and are harder for birds to handle. Professional worm Breeders tell me they are extremely difficult to colonise in boxes and are best left in the aviary.
Now we come to super-worms and mini-worms. Same as the normal worm, but one is fed on a growth hormone, the other on a retardant designed to increase the size of the worm or the latter to remain as a mini-worm. In the case of super-worms they become sterile and just continue to grow until they die. They don’t chrysalise and turn to beetles so they are useless as a breeding medium.
One could also question the wisdom of feeding these worms to your birds. S.A. Mealworm Breeders and other S.A. producers do not adopt this practice, with the super and mini-worms coming from Interstate.
While temperature is an important factor in breeding worms, 24 to 26 degrees celsius is recommended, humidity is an even greater factor. At 20 percent humidity the beetle lays only 2 or 3 eggs. Take the humidity to 70 percent and up to 600 eggs are laid. This is most probably why populations drop off in the summer if your box becomes dry. Of course nothing ever runs smoothly. A mite, which can multiply enormously in a very short time, can appear. The best way to get rid of mite, along with weevils, is to place some wormwood in the box. This will get rid of these pests within 24 hours. One user of this method tells me that as the wormwood dries out and breaks up he places it in a piece of stocking. Does the job, but keeps the box cleaner.
One method of raising humidity is to place greaseproof paper in the centre of the box on your top layer of hessian or material that covers your final layer of bran. Lettuce leaves and some soaked and squeezed bread can be placed on the paper to supply moisture.
Professional breeders in the main use a culture of bran and pollard, with pollard representing 20 percent of the mixture. They feed carrots only as the other source of food.
If you wish to improve the calcium content of the worms, put a generous layer of chicken meal. More expensive but improves the food value. Two final items – firstly, don’t disturb the brood too often. Take a quantity sufficient for a weeks supply and at the same time tidy up the box changing lettuce leaves and bread. Secondly, after the first harvesting fresh bran can be added and with the medium containing eggs another cycle will develop. Continued use of the culture will see it break down and become putrefied with urine. It is best not to use the medium more than twice.