Chemoreception of cuticular pheromones as prezygotic isolation mechanism

• Applicant: Dr. Jan Büllesbach
• Subject Area: Sensory and Behavioural Biology ; Evolution, Anthropology ; Ecology and Biodiversity of Animals and Ecosystems, Organismic Interactions
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 556847050

A fundamental question in evolutionary biology is understanding how new species originate. The development and maintenance of barriers to interspecific reproduction are considered major driving forces behind speciation. Variations in sexual signaling can greatly contribute to reproductive isolation by enabling species-specific communication and recognition. Cuticular hydrocarbons (CHCs), which are long-chained lipids found on the surface of insects, serve as an excellent example of this. CHCs have been shown to encode species-specific sexual signals across various chemical communication systems. However, there is still limited knowledge about how insects perceive, discriminate, and process the biological information encoded in CHC profiles. This research project aims to address these knowledge gaps by focusing on Nasonia, a species complex of parasitoid wasps that serves as an evolutionary and ecological model system. Previous research by the applicant has demonstrated how CHC-based sexual communication in Nasonia influences behavioral reproductive isolation, how it is genetically controlled, and how it varies between species. Building on this work, the project will investigate the chemoreception networks involved in CHC perception, particularly in the context of prezygotic reproductive isolation within the Nasonia species complex. It is known from ants, which are closely related to wasps, that specific sensilla on their antennae can perceive and distinguish different CHC blends and compounds. By applying this knowledge to Nasonia, the project will focus on N. longicornis, a species known for its behavioral capability to distinguish and prefer conspecific CHC blends over heterospecific ones. For the first time, this research will explore how this behavioral species-specific preference is governed at the chemoreceptive level. The study will identify CHC-sensitive sensilla on the antennae of N. longicornis and stimulate them with both con- and heterospecific CHC blends, as well as CHC profiles gentically manipulated to dratically reduce their sexual attractiveness. Additionally, key CHC compounds hypothesized to act as primary species-specific sexual signals will be investigated according to their individual chemoreceptive impact. The anticipated outcomes of this research will provide novel insights into CHC-based chemoreception, offering a new perspective how these have potentially contributed to reproductive isolation and, ultimately, speciation.

• DFG Programme: Research Grants