Drosophila Melanogaster Oviposition and Toxicity Studies on a Chip

Oviposition or egg-laying is an important behaviour used to assess the biological processes in Drosophila melanogaster. This behaviour is affected by physical and chemical properties of the substrate, which have not been investigated precisely and parametrically with existing manual approaches. Current oviposition-based chemical screening studies using agar plates are inaccurate, labor-intensive, and inflexible due to the manual chemical doping of agar. In this thesis, we have devised a miniaturization method to precisely and repeatedly manipulate agar stiffness and exposure area to quantitatively study their effects on oviposition in Drosophila. Using this method, we have also developed agar-polydimethylsiloxane microfluidic devices for single- and multi-concentration chemical (zinc and acetic acid) dosing and on-chip oviposition screening of Drosophila. A 1% exposure area was found to provide pure agar-like oviposition, and our microfluidic devices demonstrated chemical concentration dependency in oviposition responses. These devices may be further used for assaying fundamental oviposition questions, learning, and decision-making phenomena in Drosophila and other egg-laying insects.