Fig. 2

Morphological changes of the workers developing into neotenic reproductives (NRs). a The primary reproductives with darkened pigmentation. Scale bar =1.0 mm. b Neotenic reproductives in colony. Scale bar =1.0 mm. c A female workers. Scale bar =1.0 mm. d The neotenic reproductives derived from female workers had brown pigmentation on their heads. Scale bar =1.0 mm. e The ovary of neotenic reproductives. Scale bar = 100 μm. f Each oocyte in workers was surrounded by degenerated follicle cells. Scale bar = 20 μm. g Each oocyte in the neotenic reproductives was surrounded by a thick layer of cube-shaped follicle cells. Scale bar = 25 μm