Characterization of pheromones and courtship behaviour of desert dwelling drosophilids (mulleri complex).

• Main Author: Koh, Qi Ling.
• Other Authors: School of Biological Sciences
• Format: Final Year Project
• Language: English
• Published: 2012
• Subjects: DRNTU::Science::Biological sciences::Evolution
• Online Access: http://hdl.handle.net/10356/48695
• Institution: Nanyang Technological University

Pheromones are chemical compounds that mediate social behaviour and are believed to play an important role in speciation. The species from the Drosophila mulleri complex provide excellent models to study speciation because their populations are widely distributed and exist in sympatry and allopatry. This study aims to characterize the pheromone profiles of these closely-related drosophilids using ultraviolet laser desorption ionization mass spectrometry (UV-LDI MS) and to assess the differences in courtship behaviour of the desert drosophilid males toward recently-mated females and virgin females. Results showed qualitative and quantitative differences in the pheromone profiles between males and females and between different drosophilid populations. Furthermore, there is a general lack of interest from Drosophila mojavensis (PO09 and SC05) and arizonae (PO09) males to initiate courtship and copulate with recently-mated females of Drosophila mojavensis (PO09 and SC05) and arizonae (PO09). The lack of interest may be accounted for by the presence of transferred compounds, triacylglycerides (TGs) and acetates, from males to females during copulation. Results from the assays indicated that virgin females perfumed with male-specific TGs and acetates elicited less courtship from males, and may suggest that males differentiated virgin females from recently-mated females through these compounds, thus allowing for mate discrimination.