Context : The favoured progenitors of long-duration gamma-ray bursts ( GRBs ) are rapidly rotating Wolf-Rayet ( WR ) stars .
However , most Galactic WR stars are slow rotators , as stellar winds are thought to remove angular momentum .
This poses a serious challenge to the collapsar model .
Recent observations indicate that GRBs occur predominately in low metallicity ( Z ) environments , which may resolve the problem : lower Z leads to less mass loss , which may inhibit angular momentum removal , allowing WR stars to remain rotating rapidly until collapse .

Aims : We wish to determine whether low Z WR stars rotate on average more rapidly than Galactic WR stars .

Methods : We perform a Very Large Telescope ( VLT ) linear spectropolarimetry survey of WR stars in the low Z environment of the Large Magellanic Cloud ( LMC ) and compare our results with the Galactic sample of Harries et al .
( 1998 ) .

Results : We find that only 2 out of 13 ( i.e .
15 % ) of LMC WR stars show line polarization effects , compared to a similarly low fraction of \sim 15-20 % for Galactic WR stars .

Conclusions : The low incidence of line polarization effects in LMC WR stars suggests that the threshold metallicity where significant differences in WR rotational properties occur is below that of the LMC ( Z \sim 0.5 Z _ { \odot } ) , possibly constraining GRB progenitor channels to this upper metallicity .