Abstract: | Having previously documented experimentally the need for ultraviolet B (UVB) irradiation (290–315 nm) in the light environment of captive female panther chameleons (Furcifer pardalis) to ensure hatching success of their eggs, we investigated optimal UVB irradiation levels. From 1996–1998 28 hatchling female panther chameleons were raised to maturity and bred (using vitamin and mineral‐fortified insect diets low in vitamin D) in nine different artificial UVB light environments. Seven of the environments included long (12 hr/day) low irradia‐tion exposures ranging from 1.7 to 22 μW/cm2 UVB, with a corresponding conversion of provitamin D3 to photoproducts in in vitro models of 0.18 to 1.52% in 2 hr. Two environments included short (0.5 and 1.0 hr/day), high irradiation exposures of 55 and 49 μW/cm2 UVB, respectively, with a corres‐ponding conversion of provitamin D3 to photoproducts in in vitro models of 8.3% to 14.6% in the respective 0.5‐ and 1.0‐hr time periods. Females raised with the mid‐level long/low exposures (5–15 μW/cm2 UVB; 0.52–1.32% conversion to photoproducts in in vitro models) produced viable eggs with a significantly higher percentage of hatching compared to those with the extreme (highest or lowest) long/low exposures. Those raised with the short‐/high‐exposure environments produced viable eggs with a generally high percentage of hatching, but success was variable. The results and techniques for light quality assessment are interpreted, with recommendations for practical application by the herpetoculturist desiring to successfully breed panther chameleons in captivity. Zoo Biol 21:525–537, 2002. © 2002 Wiley‐Liss, Inc. |