Reproductive dominance in this group is obtained through worker aggression on potential queens, and there is a tendency towards morphological castes in some but not most species [ 50, 55].
This logic is most likely to apply to taxa lacking strong morphological castes, like Polistes or Bombus, but it might apply in species with castes when females have some control over their own caste fate.
Thus apparent aversion between behavioural or morphological castes [8], [10] resulting in spatial segregation of individuals might arise from indirect spatial exclusion rather than direct repulsion.
Combined with the results presented here, these perspectives suggest that the TOR pathway was one preadaptation that enabled morphological castes – and thus advanced eusocial life – to evolve in insects.
The examples mentioned above have focused on species without morphological castes, in which the decision to help or leave is a behavioral decision made by adults.
The evidence includes apparent morphological caste dimorphism in Polistes olivaceous [22], [23] and Belonogaster petiolata [24], unequivocal morphological caste dimorphism in Ropalidia galimatia [25], and two phenotypes of reproductive development in newly-emerged Ropalidia marginata [26], [27], [28].
Our results present the first evidence for a role of TOR in diphenic development, and suggest that adoption of this ancestral nutrient-sensing cascade is one evolutionary pathway for morphological caste differentiation in social insects.
Here again the decision may be made at the stage of morphological caste determination.
Teachers inflate more for girls, better students, and students from lower castes, but less for Muslim students.
