Turning workers into false queens– the role of exogenous pheromones in regulating reproduction in worker honey bees

Abstract

One of the responses that honey bee workers can make in the event of queen loss is to develop into false queens. False queens are workers that exhibit both behavioural and physiological traits similar to those of a true queen. However, the presence of more than one false queen in a colony distorts the established hierarchies. As transformation into a false queen occurs after emergence as an adult, we tested the effect of worker mobile pheromone carriers (PCs) treated with exogenously supplied pheromones on their nestmates. The PCs carried either synthetic mandibular gland pheromones or pheromones extracted from parasitic workers. Only the PCs attracted retinues of workers, increased pheromone production and activated their ovaries, becoming false queens. Pheromones from workers were more effective than extracts of commercially available synthetic queen pheromones in eliciting these effects. Using this simple mobile pheromone delivery system, we have shown that carrying amounts of exogenous pheromone can induce pheromone production in the carrier, resulting in the production of false queens within experimental groups. Possible implications of using this technique to modify and regulate worker reproduction in colonies are discussed.

Cross-activity of honeybee queen mandibular pheromone in bumblebees provides evidence for sensory exploitation

“…Our key result -that the non-native honeybee QMP also inhibits egg-laying in both worker and queen bumblebees -adds to the evidence for a route of sensory exploitation. We argue that such exploitation could allow social insect queens to produce compounds that manipulate the workers to remain sterile, but that a major hurdle would be that the queens themselves also have to be immune to such compounds (Holman et al, 2013;Yusuf et al, 2018). At the same time, other queen pheromones, such as hydrocarbon queen pheromones, are most likely derived from ancestral fertility cues and thus have probably evolved via a sender-precursor route (Oi et al, 2015;Van Oystaeyen et al, 2014).…”

“…At the same time, our data shows that QMP not only inhibited the reproduction of bumblebee workers but also the reproduction of queens, which illustrates a major hurdle for such a scenario. That is, for queen control to be possible, the queens themselves should be immune to the manipulative substances they emit (Holman et al, 2013;Yusuf et al, 2018). In the specific case of honeybee QMP administered to bumblebees, this does not appear to be case.…”

“…However, queens might well be less sensitive to the sterility-inducing effects of manipulative pheromones than workers, for example due to the queens' much greater fecundity, which could translate in them having a higher threshold at which their reproduction would be inhibited (Holman et al, 2013). Hence, chemical manipulation might -over limited evolutionary time -be possible as part of an evolutionary arms race, at least until workers would evolve resistance mechanisms (Foster et al, 2000;Keller, 2009;Kocher and Grozinger, 2011;Oi et al, 2015;Peso et al, 2014;Yusuf et al, 2018).…”

“…In fruit flies though, mainly the hydroxy-acids, and not HVA, induced the most pronounced antiovarian response (Galang et al, 2019;. Furthermore, possible evidence for arms races is found in anarchistic and socially parasitic honeybees, where reproductive workers mimic the glandular secretions of the queens (Katzav-Gozansky et al, 2003;Martin et al, 2004;Moritz et al, 2002;Niu et al, 2016;Okosun et al, 2017;Okosun et al, 2019;Sole et al, 2002), thereby escaping egg policing and controlling other workers while they themselves appear insensitive to the compounds (Yusuf et al, 2018). Generally though, research suggests that in honeybees worker reproduction is largely made unprofitable by the presence of worker policing, which results in the selective elimination of most worker-laid eggs (Oi et al, 2015;Wenseleers et al, 2004a;Wenseleers and Ratnieks, 2006a).…”

Identification of royal jelly as a potential new drug to protect the ovarian reserve and uterus against cyclophosphamide in rats

“…Unlike the sterile worker bees with the same genetic makeup, the spawn of the queen bee depends on it being fed with RJ. In addition, when there is no queen bee in a colony, one of the worker bees consumes RJ and turns into a “false queen,” regaining its ovulatory functions [ 8 ]. Therefore, RJ appears to be very important for ovulatory function.…”