The Latitudinal Biotic Interaction Hypothesis revisited contrasting latitudinal richness gradients in actively vs. passively accumulated interaction partners of honey bees

Abstract

Contrasting hypotheses suggest that the number of biotic interactions per species couldeither increase towards the equator due to the increasing richness of potential interaction partners (Neutral theory),or decrease in the tropics due to increased biotic competition (Latitudinal Biotic Interaction Hypothesis). Empiricaltesting of these hypotheses remains limited due to practical limitations, differences in methodology, and speciesturnover across latitudes. Here, we focus on a single species with a worldwide distribution, the honey bee (Apis mellif-era L.), to assess how the number of different types of interactions vary across latitudes. Foraging honey bees interactwith many organisms in their local environment, including plants they actively select to visit and microbes that theylargely encounter passively (i.e., unintentionally and more or less randomly). Tissue pieces and spores of these organ‑isms are carried to the hive by foraging honey bees and end up preserved within honey, providing a rich recordof the species honey bees encounter in nature.