School of Science research seminar

Who: Kate DL Umbers School of Science, Western Sydney University

Title: Evolution of praying mantis defensive displays.

Abstract: Startle displays are performances to deter or distract predators, and can include spectacular movements, colours, and sounds. We present the first analyses of the evolutionary history of startle displays using 58 praying mantis species. We found that evolutionary history has a strong effect on display presence and that behavioural traits vary more than body size and shape. Species with many close relatives are more likely to have complex displays, perhaps giving them a survival advantage by appearing different. These results allow us to determine how these defensive displays had evolved through history, and more generally, to better understand predator-prey dynamics.

And:

Who: David G. Harman School of Medicine, Western Sydney University, Australia. Present address: School of Science, Western Sydney University (

Title: Pretty dicey chemistry: An ion trap mass spectrometry study into the reactivity of 1-cubyl radical

Abstract: The reactivity of carbon-centred radicals can be impacted by the geometry of bonds around the radical centre. In polycyclic hydrocarbons the radical centre can be contorted significantly from its preferred trigonal planar geometry. Such bridgehead radicals are expected to have unique properties and are thus attractive targets for gas phase investigations. In this study, distonic radical ions were generated from even-electron precursor ions by collision-induced dissociation within an ion trap mass spectrometer. In this manner a series of charge-tagged bridgehead radical ions were generated including adamantyl and cubyl radicals. Thus formed, bridgehead distonic radical ions were observed to undergo rapid reaction with molecular oxygen present in the ion trap. Interestingly, while adamantyl radicals gave rise to abundant peroxyl radicals (i.e., [M+32]- ions), no analogous products were detected from cubyl radicals despite a similar rate of reaction. Reactions between cubyl and adamantyl radicals were also compared with reagents including chloroform and dimethyldisulfide. This presentation will provide a critical comparison between the reactivities of the two bridgehead radicals with the findings giving insight into the relationship between reactivity and bridgehead radical geometry.

For details about School of Science seminars in Parramatta, please contact Dr Patrice Castignolles, p.castignolles@westernsydney.edu.au .

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