for including a SN Ia rate that varies with stellar metallicity. We propose that this arises from the effect of metallicity on the white dwarf produced. In general, it is expected that, for the same initial stellar mass, the white dwarf from a star of lower metallicity should be more massive. This may be due to decreased mass loss and/or opacity resulting in hotter burning over the lifetime of the star (e.g., @Umeda:1998ij [@Willson:2000kb; @Marigo:2007xq; @Meng:2007ni]). The simplest interpretation of this is that it should be easier to reach the requisite Chandrasekhar mass for explosion through the addition of mass via binary evolution or a double white dwarf merger.

To obtain a semi-quantitative estimate of the resulting change in the SN Ia rate with metallicity, we must consider the effect of a varying WD mass over the range of metallicities for the galaxies in the LOSS sample. One may hope for guidance from the initial-final WD mass relation determined from young star clusters. However, the clusters in which detailed studies are possible are nearby and formed recently, which necessarily limits them to single, $\sim\,$solar metallicity stars (e.g., @Kalirai:2007tq [@Williams:2008ms]). We utilize the theoretical results of @Umeda:1998ij in combination with the 