Peripheral modulation of worker bee responses to queen mandibular pheromone

Abstract

It is generally accepted that young worker bees (Apis mellifera L.) are highly attracted to queen mandibular pheromone (QMP). Our results challenge this widely held view. We have found that unless young workers are exposed to QMP early in adult life, they, like foragers, avoid contact with this pheromone. Our data indicate that responses to QMP are regulated peripherally, at the level of the antennal sensory neurons, and that a window of opportunity exists in which QMP can alter a young bee's response to this critically important pheromone. Exposing young bees to QMP from the time of adult emergence reduces expression in the antennae of the D1-like dopamine receptor gene, Amdop1. Levels of Amdop3 transcript, on the other hand, and of the octopamine receptor gene Amoa1, are significantly higher in the antennae of bees strongly attracted to QMP than in bees showing no attraction to this pheromone. A decline in QMP attraction with age is accompanied by a fall in expression in worker antennae of the D2-like dopamine receptor, AmDOP3, a receptor that is selectively activated by QMP. Taken together, our findings suggest that QMP's actions peripherally not only suppress avoidance behavior, but also enhance attraction to QMP, thereby facilitating attendance of the queen.dopamine ͉ honeybee ͉ olfaction ͉ pheromone

Queen mandibular pheromone modulates hemolymph ecdysteroid titers in adult Apis mellifera workers

“…We suggest that responders (defined as individuals that show elevated ecdysteroid titers in the presence of QMP) and non-responders (individuals that do not show elevated titers in the presence of QMP) possibly represent different genotypes but may also reflect differences in epigenetic factors. The pheromone response threshold has been previously shown to be influenced by individual differences such as ovary size, social behavior, and age of exposure (Amdam et al 2009;Pankiw and Page Jr 1999;Traynor et al 2014;Vergoz et al 2009). A study in which responses to QMP presentation were observed in caged workers on the first 8 days of adult life revealed colony-level and individual differences in performance of the QMP-evoked retinue response, as well as differences in QMP-evoked brain gene expression profile (Kocher et al 2010).…”

“…Other responses of workers to QMP also display age dependency. For example, attractiveness of QMP wanes as workers age: young workers are attracted to QMP while older workers are repelled (Vergoz et al 2009). Using microarrays and mRNA quantification by qRT-PCR, Grozinger (2003) showed that exposure to QMP differentially regulated expression of several hundred genes in young nurse bees vs. older foragers.…”

Experience-dependent modulation of antennal sensitivity and input to antennal lobes in male moths (Spodoptera littoralis) pre-exposed to sex pheromone

“…Contrasting with this view, many recent studies have shown that, like mammals, insects also display a high degree of plasticity (Menzel and Giurfa, 2006;Giurfa, 2007;Groh and Meinertzhagen, 2010). This is particularly well illustrated by the numerous examples of how previous experience of odorants with strong biological significance may lead to adaptive behavioural and neural changes Vergoz et al, 2009;Arenas et al, 2009;Beggs et al, 2007;Iyengar et al, 2010;Urlacher et al, 2010). Many insect species are capable of olfactory learning, and their olfactory pathways exhibit high degrees of neural plasticity.…”

Queen mandibular pheromone: questions that remain to be resolved

“…If HVA targets AmDOP3 receptors in vivo, AmDOP3 receptor activation could potentially contribute to effects of QMP on the behaviour and physiology of young worker bees. All three of these DA receptors are expressed in the antennae (Vergoz et al 2009) as well as in the brain of the bee (Beggs et al 2005;Kurshan et al 2003;Humphries et al 2003;Blenau et al 1998). HVA activation of AmDOP3 at the level of the antennae could potentially alter signals conveyed from the antennae to ALs of the brain.…”

“…Interestingly, bees exposed to QMP early in adult life tend to have lower levels of Amdop1 expression in the antennae and brain than bees that have never been exposed to this pheromone (Beggs et al 2007;Vergoz et al 2009). Moreover, young workers showing strong attraction to QMP have been found to have higher Amdop3 transcript levels, and levels of transcript for the octopamine receptor, Amoa1, than bees not strongly attracted to this pheromone.…”