Memory not being what it once was, it took me a few days to find the reference to worker larvae being subjected to nutritional stress which veers them down a different developmental pathway than queen larvae.
> Initially, not only the queen-destined larvae, but also worker larvae receive a certain amount of nutritious jelly, although the worker jelly appears to have lower concentration of sugars and some other ingredients compared to the queen food. However, after 3 days of growth only queen-destined individuals will continue to get unrestricted quantities of a special multifactorial food, produced in head glands of nurse bees, known as royal jelly or bee milk. In contrast, worker larvae switch to a simpler diet consisting of pollen and sugars, which ensures that they will become functionally sterile helpers.
> It has been argued that nutritional stress during development to which worker larvae are subjected after 3 days on rich royal jelly-like diet is a critical factor enforcing major reshaping of the worker’s organismal outcome in particular ovarian function and behavioural physiology. Such nutritional stress associated with differential feeding may have been a driver of evolutionary inventions associated with division of labour and insect sociality.
Maleszka, R. (2018). Beyond Royalactin and a master inducer explanation of phenotypic plasticity in honey bees. Communications biology, 1(1), 1-7.
This builds upon previous work:
> Our findings that larval food restriction reduced worker ovariole number and gustatory response are consistent with the associations found in the previous studies (Page, 2013; Tsuruda et al., 2008), suggesting that the linkage between developmental nutritional stress, responses of ovarian function, and behavioral physiology may have been co-opted during the evolution of sociality and used to affect division of labor.
Wang, Y., Kaftanoglu, O., Brent, C. S., Page, R. E., & Amdam, G. V. (2016). Starvation stress during larval development facilitates an adaptive response in adult worker honey bees (Apis mellifera L.). Journal of Experimental Biology, 219(7), 949-959.
More recent work states:
> Queen-destined larvae have abundant nutrition, and organ growth is only limited by the intrinsic program. Worker-destined larvae have a shortage of nutrition that restricts growth and influences metabolic parameters accordingly.
Roth, A., Vleurinck, C., Netschitailo, O., Bauer, V., Otte, M., Kaftanoglu, O., ... & Beye, M. (2019). A genetic switch for worker nutrition-mediated traits in honeybees. PLoS biology, 17(3), e3000171.
Commenting on the above:
> Annika Roth, Dr. Martin Beye, and their colleagues at the Heinrich-Heine University, Germany, have elegantly shown that this particular nature versus nurture debate is far from settled [16]. We know that queens and drones both have sugar-rich diets, and both have large gonads, whereas workers have a more limited diet and have underdeveloped gonads.
> In a sweltering 33°C room, Roth and colleagues painstakingly injected thousands of delicate, freshly laid, genetically female eggs with the Cas9 machinery and guide RNA. Roth and colleagues found that when they disrupted fem, the genetically female embryos completely switched to males and even grew large male sex organs. This was despite being reared on a nutrient-restricted worker diet. Fem is therefore a master regulator and is necessary for restricting the development of sex organs.
McAfee, A., Pettis, J. S., Tarpy, D. R., & Foster, L. J. (2019). Feminizer and doublesex knock-outs cause honey bees to switch sexes. PLoS biology, 17(5), e3000256.
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