Praz (2017) reports that Megachile minutissima is probably polylectic with a preference for Fabaceae
From March to October 2011, males and females of M. minutissima have been found visiting flowers of 11 plant species of 10 families, although most females were captured on P. farcta.
Alqarni et al (2014) report the following plants in Saudi Arabia: Coriandrum sativum (Apiaceae); Pulicaria undulata (Asteraceae); Calotropis procera (Asclepiadaceae); Heliotropium ramosissimum (Boraginaceae); P. farcta (Fabaceae); Mentha longifolia (Lamiaceae); Peganum harmala (Nitrariaceae); Ochradenus baccatus, Reseda alba (Resedaceae); Tamarix spp, (Tamaricaceae); Zygophyllum coccineum (Zygophyllaceae).
Rozen and Kamel (2007) indicated that M. minutissima regularly visits Trifolium alexandrinum, as well as alfafa (Medicago sativa)(Fabaceae) for pollen.