Combined effects of climate seasonality and the Covid-19 pandemic on the trophic dynamics of the European honey bee in a tropical urban environment.

Abstract

The European honey bee (Apis mellifera Linnaeus, 1758), a cosmopolitan and generalist insect, consumes many trophic resources in urban spaces, including floral resources (i.e., nectar and pollen) and anthropogenic food with high carbohydrate concentrations. Therefore, the foraging activity of A. mellifera in cities may vary over time depending on the availability of these food sources. Seasonal climate and non-seasonal events, such as large-scale changes in human activity, can influence the availability of the honey bee's trophic resources. Given that, this project aims to investigate the combined effects of climate seasonality and the Covid-19 pandemic on the trophic niche of the European honey bee in a tropical urban environment. Despite its devastating effects, the pandemic created a unique opportunity to study the following question: how the lasting removal, followed by the abrupt reintroduction of anthropogenic resources in cities as a consequence of social isolation, affected the seasonal trophic dynamics of A. mellifera? To achieve this, we will perform isotopic analyses to assess the diet of European honey bees on the campus of Unicamp (Barão Geraldo, Campinas, São Paulo) and its urban surroundings in four periods over two years (rainy season, dry season, rainy season during social isolation, and dry season immediately after the end of social isolation). Since floral and anthropogenic resources have distinct carbon isotopic values, we will use the delta 13C values of the honey bee's body tissues to quantify temporal changes in the contribution of natural and human foods to the trophic niche of A. mellifera. We will analyze the delta 13C values using a combination of statistical methods in the R software, such as mixed linear models and Bayesian mixture models.