The “risk allocation hypothesis” can predict how prey species will respond to predation risk, balancing vigilance with potentially risky behaviours. In order to maximize fitness, an optimal behavioural repertoire can evolve to respond to predation threat to allow for both survival and future fitness gains. High locomotor activity and time spent engaging in mating behaviours are expected to put Drosophila melanogaster at a greater risk to predation. With direct predator exposure, Drosophila are predicted to reduce activity and mating, which over years of exposure, will be reflected in evolved behavioural traits and evolved changes in the genome. Predation as a selective force shows alterations in flies genomes of experimentally evolved populations. Locomotor activity was found to be reduced in the presence of zebra jumping spiders (Salticus scenicus), presumably due to these spiders as visual hunters, using movement to detect prey. This behaviour is reflected in populations of Drosophila that have been constantly under selection by predators. Flies evolved with spider predators or mantid predators (Tenodera aridifolia sinensis) showed reduced locomotor activity when no predators are present. Interestingly, while alterations are seen for locomotory activity, the presumed risky behaviours of courtship and mating did not show an evolved response. Wild caught populations under threat from spiders, as well as the evolved populations when no predators were present showed no alterations in courtship or copulation behaviour. It appears that although there may be potential risks associated with mating behaviours, the benefits to future fitness when mating outweigh the potential costs from predation risks in Drosophila. / Thesis / Master of Science (MSc) / Predation is a profound selective force, with many anti-predator adaptations seen throughout the diversity of life. Antipredatory behavioural adaptations must balance immediate and future fitness effects, to maximize overall fitness. In Drosophila melanogaster, research into natural ecology and role of predation is generally lacking for behavioural & evolutionary studies. I will discuss research on the influence of predator exposure on Drosophila behaviours, as well as the evolution of Drosophila behaviours and genomes through experimentally evolved populations of Drosophila. While predation risk has resulted in changes in Drosophila locomotory activity, predation has not altered mating behaviours.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/22140 |
| Date | 11 1900 |
| Creators | Knoops, Paul |
| Contributors | Dworkin, Ian, Biology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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