Periodic Reporting for period 1 - MUSE ('Multisensory Ecology': Understanding adaptive trade-offs between vision and olfaction)
Reporting period: 2016-08-29 to 2018-08-28
Using brain measures, the project established the putative trade-off between vision and olfaction across a range of diurnal insect species, and identified that hunting mode and could help to explain how this trade-off is resolved. I found that predatory insects tend to invest more in vision and less in olfaction compared to insect species foraging by other methods. Using an empirical approach, I also found that living in the dark can reduce not just investment in vision, but also the reduce the size of the brain itself. This empirical approach also provided insights into how natural selection acts on sensory and neural systems, and showed the speed with which changes in the brain occur, and the degree to which these changes are reversible.
Using an empirical approach, I also made observations of this sensory trade-off by examining the brains of the Dark-flies. Using this novel and unique model system, I have demonstrated that individuals have been selected with a relative reduced investment for vision and an increased investment for olfaction. This paper has been submitted to Proc R Soc B (October 2018), and data were also presented at two international conferences (Ento ’17 International Symposium and National Science Meeting at Newcastle University, September 2017; International Congress of Neuroethology (ICN) 2018 in Brisbane (Australia), August 2018).
I also used the Dark-flies to test how quickly selection acts on sensory systems, whether the changes occured simultaneously in visual and olfactory systems, and if changes in investment in sensory systems could be reversible. I found that for Dark-flies put back in the light for 65 generations, investment was shifted towards the visual system becoming relatively more important to the detriment of olfaction (in prep. for Current Biology), confirming our preditions.
Additionally, I also established the genetic basis for the differences in size in areas of the brain that I had observed, and established how it was hereditary (article in preparation for Evolutionary Ecology); and if the differences in brain size between fly strains were related to energy consumption (article in preparation for a special issue in Brain, Behaviour and Evolution).
From our results, we may expect species adopting a nocturnal lifestyle to increase their olfactory capabilities to the detriment of their visual capabilities, and impacts on species becoming nocturnal may be more far-reaching than previously thought.