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Chemical signals are known to play an important part in the organisation of insect societies, but the mode of action of these signals is still a subject of controversy. While some researchers propose that pheromones produced by the queen are honest signals of her quality informing worker behaviour, others suggest that they are means of manipulation not necessarily beneficial to workers' fitness. The honeybee (Apis mellifera) is sometimes cited as an example of the latter possibility. Our study aimed to test the extent to which queen quality predicts worker behaviour, the relation of queen-produced chemicals to her quality and the interplay between queen signalling and worker behaviour. We decided to test worker attitude towards different queens in the most direct way by presenting groups of workers simultaneously with two different queens of differential reproductive capacity, and analysing worker behaviour towards each of them in terms of attendance, retinue and aggression. Our results indicate that workers show preference for queens with higher reproductive potential, that queen's reproductive potential was honestly reflected in queen-produced signals and that these signals indeed guide worker behaviour. Thus, our findings overall support the honest queen signal theory and contribute to understanding of mechanisms underlying different phenomena in bee sociality. [ABSTRACT FROM AUTHOR]

To test the hypothesis that exposure to queen mandibular pheromone (QMP) modulates ecdysteroid production in adult worker honey bees, ecdysteroids were measured in hemolymph and other tissues of individual adult worker honey bees reared with or without QMP in cages and field colonies. Ecdysteroid titers were higher in caged workers exposed to QMP continuously from the first day of adult life than in workers reared without QMP. Statistical cluster analysis suggested the possibility that a subgroup of workers (“responders”) is more sensitive to QMP in this regard than other workers. In 12-day-old workers, ecdysteroid titers in workers reared in queenright (QR) colonies were similar to those observed in cages with QMP, but lower than those in queenless (QL) colonies. Differences in number of ovarioles or degree of ovarian activation did not correlate with hemolymph ecdysteroids. Previous studies have demonstrated ecdysteroids in hemolymph in very young adult workers and in workers in QL colonies; the present study indicates that production of ecdysteroids occurs in older adult worker honey bees in the absence of morphological signs of ovarian activation, with cage studies revealing a modulatory role for QMP masked in the complex environment of the hive. [ABSTRACT FROM AUTHOR]

The discovery of 'queen substance', and the subsequent identification and synthesis of key components of queen mandibular pheromone, has been of significant importance to beekeepers and to the beekeeping industry. Fifty years on, there is greater appreciation of the importance and complexity of queen pheromones, but many mysteries remain about the mechanisms through which pheromones operate. The discovery of sex pheromone communication in moths occurred within the same time period, but in this case, intense pressure to find better means of pest management resulted in a remarkable focusing of research activity on understanding pheromone detection mechanisms and the central processing of pheromone signals in the moth. We can benefit from this work and here, studies on moths are used to highlight some of the gaps in our knowledge of pheromone communication in bees. A better understanding of pheromone communication in honey bees promises improved strategies for the successful management of these extraordinary animals. [ABSTRACT FROM AUTHOR]