Frank and Linsenmair (2017) - Division of labor is a key characteristic in social insects, with the most obvious example being the queen focusing on reproduction while the workers focus on nest tasks and foraging (Holldobler and Wilson 1990). Worker division of labor can arise from combinations of worker age, morphology, frequency distribution and dominance interactions (Holldobler and Wilson 2008). Within behavioral castes, such as brood care or foraging, further task partitioning can occur (like brood care focused on grooming or feeding). This behavioral caste membership can have a physiological or developmental basis (Holldobler and Wilson 2008). There is a variety of evidence and debate about how fluid movement between behavioral castes is (i.e., foragers returning to brood care work) (Korczynska et al. 2014, Herb et al. 2012), but it is well established that the partitioning of tasks during foraging, nest maintenance or brood care have a higher degree of flexibility (i.e., brood care workers may groom, feed or move larvae depending on current demands but are not recruitable for foraging) (Robinson et al. 2009). Work division in monomorphic species is generally believed to be regulated on the basis of age polyethism, with younger workers conducting nest tasks and later on performing tasks outside the nest, such as foraging (Holldobler and Wilson 2008). In addition to age polyethism, worker division of labor may also have a morphological basis.
Also see Chapter 8 of The Ants: Caste and Division of Labor.