Cleptoparasitic: Hosts; Epeolus variegatus is undoubtedly a cleptoparasite of several species of Colletes. In most cases proof (based on reared specimens from reliably identified host cells) is necessary, as for E. cruciger. The following is a list of hosts based on the literature: Colletes daviesanus (Blair, 1920 (specimen reared); Carr, 1916; Chambers, 1949; Nielsen, 1903; Richards, 1937, 1979; Boreham, 1956b); C. fodiens (Chambers, 1949; Hallett, 1928; R.C.L. Perkins, 1920, 1923; Richards, 1937, 1979); C. halophilus (Guichard, 1974) and C. succinctus (Clark, 1924; Butterfield & Fordham, 1932; O'Toole & Raw, 1991). A.B. Duncan (pers. comm.) observed specimens of this Epeolus at Torrs Warren (the Scottish site referred to above) entering the nest burrows of C. floralis. However, on examination of his entire Colletes collection, a few misidentified C. fodiens were found amongst his C. floralis from the same locality as his observations on this Epeolus. It seems likely, therefore, that the C. fodiens was nesting amongst an aggregation of C. floralis and that the former was the real host of this Epeolus (pers. obs.). Further investigation to confirm C. floralis as a host of this species is thus necessary (Else & Edwards, 2018).
C. similis is cited as a host by Söderman & Leinonen (2003) and C. fodiens and C. daviesanus by Celary (1990). Westrich (1990) and Bogusch (2003). The full situation is summarised by Bogusch & Hadrava (2018).