from a sample of galaxies drawn randomly according to their rate of star formation.

As the Initial Mass Function (IMF) of blue irregular and spiral galaxies are thought to be largely similar [@Bastian], massive stellar progenitors should be just as available per unit star-formation in both galaxy types. However, the much smaller size of blue irregulars would suggest, due to the galaxy mass-metallicity relation [@Tremonti2004], that blue irregular galaxies are typically metal poor in comparison with grand design spirals. Thus [@Fruchter] postulated that LGRB formation is affected by the metallicity of their environments.

[@Stanek2007] showed that the very nearest LGRB hosts all have low metallicity when compared to similar magnitude galaxies in the Sloan Digital Sky Survey (SDSS). Furthermore, [@Kewley2007] found the LGRB host sample to be comparable to extremely metal-poor galaxies in luminosity-metallicity relation, star-formation rate (SFR), and internal extinction. [@Modjaz2008] dramatically strengthened this result by taking advantage of the fact that a broad-lined Type Ic (Ic-bl) supernova has been found underlying the light of nearly [@Thone2014] every LGRB in which a deep spectroscopic search was performed [@Cano2014; @HjorthBloom2012book; @Hjorth2013]. The fact that LGRBs nearly always are associated with a Type Ic-bl SNe would suggest that LGRB progenitors probably 