As cold-blooded animals, terrarium animals are far more de pendent on light, i.e. the quality and intensity of light, than warm-blooded vertebrates. Activity, feeding, digestion or resting phases are influenced by the alternation of day and night, and especially by the intensity of light. Besides this, many terrarium animals associate light with heat and seek light places in the terrarium in order to „bask in the sun“. These considerations are especially important when choosing heating equipment for desert terrariums.
There are differences in the yield and quality of light, depending on the light source used. Fluorescent tubes, for example, provide a lot of light with little heat production, whereas light bulbs convert a major share of the energy taken up into heat and only a small share into light. The question as to which quality of light is best suited for a specific terrarium is easy to answer if we take a look at nature: For millions of years, plants and animals have been adapting to what the sun sends down to the earth in a long evolutionary process. If we look at the spectrum of sunlight (meaning the part of solar radiation that is visible to us), we recognise a very even distribution of all spectral colours. For this reason, lamps for terrariums should have a spectrum that is as close to being balanced and without gaps as possible. At the same time, all of the plants and animals will be able to exhibit their full natural brilliant colouring.
Metal halide lamps ( daylight with UV-B ) are the top choice for animals requiring sunlight, ultraviolet light (i.e. diurnal animals) and heat. They offer a full spectrum that is sunlight simulating, including UV-A and B radiation, along with heat emission for the terrarium. Accordingly, the temperature in the terrarium decreases after the lamps are switched off, thereby simulating the desired night-time drop in temperature. The JBL L-U-W lamps are available in three different wattages and two versions, depending on whether the animals require a lot of UV ( JBL ReptilDesert L-U-W Light alu ) or less UV ( JBL ReptilJungle L-U-W Light alu ).
UV-light, specifically in the UV-A and UV-B ranges, also plays a significant role in terrarium lighting. Depending on their origin, terrarium animals require more UV light or less for their well-being. UV-B stimulates Vitamin D3 synthesis from the Vitamin D2 precursor. UV-A stimulates pigmentation. It is important to take into account that the glass absorbs around 50 % of the UV radiation, so that the lamps should always be installed inside the terrarium. The distance between the light source and the animal is another important factor: There is information directly on the lamp indicating how much radiation is emitted at which distance from the lamp. If the terrarium is high, the animals can get closer to their UV source if they are provided with something to climb up on.
The following applies to animals that require UV: These animals will not stay healthy if fluorescent tubes are used, even if they emit UV radiation! It is imperative for a UV spot lamp or an L-U-W lamp to be mounted additionally. When using metal halide lamps, one must also bear in mind that they may/can only be operated with special electronic ballasts ( JBL TempSet Unit L-U-W ).