Biology of Reproduction, Vol 21, 235-239, Copyright © 1979 by Society for the Study of Reproduction

Light Intensity and Reproduction in Wild and Domestic House Mice

¹ The Institute of Reproductive Biology, Department of Zoology, University of Texas, Austin, Texas 78712

Wild caught house mice and laboratory raised CF-1 stocks each were bred under low light intensities. The first litters of these 2 stocks were paired as adults in constant darkness, or on a 14L:10D cycle with the light phase maintained at either 10-20 lux or at >1000 lux. Reproduction over a 75 day period was normal for both stocks in constant darkness. Productivity, particularly litter size, was markedly depressed in wild Mus at >1000 lux but was unaffected by lighting condition in the domestic stock. These results suggest that normal animal room lighting will depress productivity in wild Mus and that selection against this response must have occurred during domestication. The present results also support the ecological literature which indicates that seasonal breeding in wild Mus, where it occurs, is not photoperiodically-induced and, indeed, that this species can breed well in the absence of any light cycle.