et al. 2005), a theoretical prediction for metallicity dependent WR winds is currently unavailable, nor is there a well-established observational relationship for it. Consequently, stellar evolution theorists need to opt for one of two rather drastic assumptions in dealing with this issue: either, ([*i)*]{} they extrapolate the mass loss - $Z$ dependence of O stars to WR stars (e.g. Heger & Woosley 2002, Heger et al. 2003, Eldridge & Tout 2004), or ([*ii)*]{} they assume a mass loss that is independent of $Z$ at low metallicity (e.g. Schaller et al. 1992, Maeder & Meynet 1994, Meynet & Maeder 2005).

The first assumption is based on the idea that O and WR stars share similar properties: both are hot, luminous, and generate high-speed outflows. Therefore, one might expect the winds to be driven by the same physical mechanism, i.e. that of radiation pressure on millions of spectral lines (Lucy & Solomon 1970; Castor et al. 1975, hereafter CAK). The second assumption arises from the fact that WR stars produce copious amounts of carbon and oxygen through self-enrichment, so that the radiation-driven wind may not depend on the initial metallicity of the host galaxy.

That WR winds could at all be driven 