Sabine Nooten
University of Würzburg, Biocenter, Department of Animal Ecology and Tropical Biology
Germany
The role of environmental features in shaping insect traits
Insects are an essential part of global biodiversity. They stand at the relative base of the food chain and play important roles in ecological processes. They are also sensitive to environmental change. I am using social Hymenoptera (ants and wild bees) as model organisms to tackle questions related to global patterns, species traits, and key ecological processes. On the global scale, my research shows that there is a huge variety of the sheer numbers and densities across biomes, regions and habitats. On smaller scales, regional communities are related to land use types and habitat features. In climatically challenging environments, only species with a specific suite of traits persevere. Given the current loss of insect biodiversity in terms of species richness and abundances, it is paramount to understand relationships between insect species, their traits and the environment. In other words – why are insects where they are and which key features are important to persist in the future?
The influence of environmental stressors and associated landscapes on diet diversity, body traits, and reproduction in wild bees
Wild bees are crucial pollinators, guaranteeing the reproduction of many flowering plants and their production of diverse nuts, fruits and seeds. Despite their vital ecosystem service of pollination which is tightly linked to food production, generating billions of dollars every year, wild bee populations are declining in response to anthropogenic stressors. Deforestation and the depletion of floral resources are key challenges, reducing nesting opportunities and food availability for wild bees. Sublethal doses of pesticide disrupt the behaviour and physiology of solitary bees, including their chemical communication, in the case of the latter, affecting their own reproduction.
In this talk, I will present two case studies: one in the Neotropical region and another in the Temperate region, addressing these stressors and how they impact wild bees. The first study focuses on the primitively eusocial orchid bee, Euglossa cordata (Apidae: Euglossini), for which I examine diet diversity and brood production in Neotropical areas. First, we assess the impact of deforestation on pollen diversity in E. cordata nests, finding that forested areas in São Paulo (Brazil) support higher pollen diversity and greater brood production. Moreover, published studies across the Neotropical region corroborate the idea that forest cover predicts higher pollen diversity in Euglossa bees.
The second study investigates the influence of conventional and organic farming systems on the nesting occupancy rate and body traits of Osmia bicornis (Megachilidae: Osmiini), an essential crop pollinator in Germany. Our findings reveal that sustainable agriculture enhances nesting and brood cell production, and local farming practices affect body size and cuticular hydrocarbons. These cuticular hydrocarbons are sex pheromones that influence mating behavior, potentially mediating the effect of pesticide on bee populations.
Our results highlight the need for collaboration among scientists, farmers, and policymakers to protect wild bees, emphasizing that landscape and resource management, along with greater attention to sustainable pest management, are key to wild bee conservation.
Funding:
Aurelia Stiftung and SAGST
