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Heteropogon sp. for sure :)

The species is much trickier as I cannot see very important details. And I am not sure you don't have two different species there. See that the solitary male doesn't have white bold flecks on the fore tarsi (very important feature) or white pollinose marks on the abdomen, which the male of the first one does have. Might be an optical effect though...

Anyway, it/they should be in the group lehri/pyrinus/scoparius, in case it is something already recorded for Iran.