Bastin Florian, Savarit Fabrice, Lafon Grégory, Sandoz Jean-Christophe
Evolution, Genomes, Behaviour and Ecology, CNRS (UMR 9191), Univ Paris-Sud, IRD, Université Paris-Saclay, Gif-sur-Yvette, France.
Laboratoire d'Ethologie Expérimentale et Comparée, Université Paris 13, Sorbonne Paris Cité, Villetaneuse, France.
PLoS One. 2017 Oct 4;12(10):e0185949. doi: 10.1371/journal.pone.0185949. eCollection 2017.
During the mating season, drones (males) of the Western honey bee (Apis mellifera) form congregations numbering thousands high in the air. Virgin queens arrive at these congregations after they have formed and mate on the fly with 15-20 drones. To explain the formation of drone congregations, a drone-produced aggregation pheromone has been proposed many years ago but due to the low accessibility of natural mating sites in bees, its study has progressed slowly. Recently, we used a walking simulator in controlled laboratory conditions to show that drones are indeed attracted by groups of other drones. Since these previous experiments were carried out with drones captured when flying out of the hive, it is currently unclear if this olfactory attraction behaviour is related to the drones' sexual maturity (usually reached between 9 and 12 days) and may thus be indicative of a possible role in congregation formation, or if it is observed at any age and may represent in-hive aggregation. We thus assessed here the dependency of drone olfactory attraction on their age. First, we performed behavioural experiments in the walking simulator to measure olfactory preferences of drones in three age groups from 2-3 to 12-15 days. Then, we performed chemical analyses in the same age groups to evaluate whether chemical substances produced by the drones may explain age differences in olfactory attraction. We show that honey bee drones are attracted by conspecifics of the same age when they are sexually mature (12-15 days old) but not when they are younger (2-3 and 7-8 days old). In parallel, our data show that drones' chemical profile changes with age, including its most volatile fraction. These results are discussed in the context of drone mutual attraction both within the hive and at drone congregations.
在交配季节，西方蜜蜂（Apis mellifera）的雄蜂会在空中形成数千只的蜂群。处女蜂王在蜂群形成后到达这些蜂群，并在空中与15 - 20只雄蜂交配。为了解释雄蜂蜂群的形成，多年前就有人提出雄蜂会产生聚集信息素，但由于蜜蜂自然交配地点难以接近，对其研究进展缓慢。最近，我们在可控的实验室条件下使用步行模拟器表明，雄蜂确实会被其他雄蜂群体所吸引。由于之前的这些实验是用从蜂巢飞出时捕获的雄蜂进行的，目前尚不清楚这种嗅觉吸引行为是否与雄蜂的性成熟（通常在9至12天之间达到）有关，因此可能表明其在蜂群形成中可能发挥的作用，或者这种行为在任何年龄都能观察到，可能代表蜂巢内的聚集行为。因此，我们在此评估了雄蜂嗅觉吸引对其年龄的依赖性。首先，我们在步行模拟器中进行行为实验，以测量2 - 3天至12 - 15天三个年龄组雄蜂的嗅觉偏好。然后，我们对相同年龄组进行化学分析，以评估雄蜂产生的化学物质是否可以解释嗅觉吸引的年龄差异。我们发现，当西方蜜蜂雄蜂性成熟（12 - 15日龄）时，它们会被同龄的同种个体所吸引，但在较年轻（2 - 3日龄和7 - 8日龄）时则不会。同时，我们的数据表明，雄蜂的化学特征会随年龄变化，包括其最易挥发的部分。我们将在蜂巢内和雄蜂蜂群中雄蜂相互吸引的背景下讨论这些结果。
