Cichlids provide textbook examples of speciation driven by dietary specialisation. The link between diversity and trophic niche partitioning should mean that periods of environmental change, colonization events, and introductions of invasive fish species have a significant impact on the dietary ecology of cichlids. Rapid diversification in feeding habits, for example, is predicted by models that link adaptive radiations to relaxed competition and expansion into vacant ecospace. Shifts in dietary niche, potentially associated with character displacement, would be expected to result from introductions of invasive competitor species.
Skeletal remains and teeth of cichlids from African lake sediments are starting to be used to test evolutionary and ecological hypotheses (1, 2) but direct testing requires analysis of dietary preferences in historical and sub-fossil specimens. This is difficult to do based on morphological data, because analysis of functional morphology is hampered by the mismatch between apparent specialization in trophic morphology and actual diet (3, 4), particularly in fishes.
Recently, we developed a new approach to dietary analysis based on the application of quantitative dental microwear texture analysis (DMT; (5)) to cichlids and other fishes (6, 7). DMT analysis of worn surfaces of fish teeth provides a powerful new tool for dietary discrimination and investigation of trophic resource exploitation in fishes. It is particularly useful because the dietary signal accumulates over several days/weeks and therefore avoids the ‘snapshot’ problem inherent in stomach contents analysis. Significantly, DMT analysis can detect subtle dietary differences between individuals and populations in historical, sub-fossil and fossil specimens, and where stomach contents or isotopic data are lacking, but it has yet to be applied to a broad range of cichlids with diverse feeding habits.
This project will develop and apply DMT analysis of cichlids to determine the sensitivity and degree to which DMT can capture the range of diets among cichlids. The outcome of this analysis will allow direct testing of hypotheses of ecological and evolutionary diversification and displacement linked to environmental change over historical and longer timescales.
UK Bachelor Degree with at least 2:1 in a relevant subject or overseas equivalent.
Available for UK and EU applicants only.
Applicants must meet requirements for both academic qualifications and residential eligibility: http://www.nerc.ac.uk/skills/postgrad/
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1. Dieleman J, Van Bocxlaer B, Nyingi WD, Lyaruu A, Verschuren D. Recurrent changes in cichlid dentition linked to climate-driven lake-level fluctuations. Ecosphere. 2019;10(4):e02664.
2. Muschick M, Russell JM, Jemmi E, Walker J, Stewart KM, Murray AM, et al. Arrival order and release from competition does not explain why haplochromine cichlids radiated in Lake Victoria. Proc Biol Sci. 2018;285(1878).
3. Robinson BW, Wilson DS. Optimal foraging, specialization, and a solution to Liem’s paradox. Am Nat. 1998;151:223-35.
4. Bellwood DR, Wainwright PC, Fulton CJ, Hoey AS. Functional versatility supports coral reef biodiversity. Proceedings of the Royal Society B-Biological Sciences. 2006;273(1582):101-7.
5. Scott RS, Ungar PS, Bergstrom TS, Brown CA, Grine FE, Teaford MF, et al. Dental microwear texture analysis shows within-species diet variability in fossil hominins. Nature. 2005;436(7051):693-5.
6. Purnell MA, Darras LPG. 3D tooth microwear texture analysis in fishes as a test of dietary hypotheses of durophagy. Surf Topogr. 2015;4(1):014006.
7. Purnell MA, Seehausen O, Galis F. Quantitative three-dimensional microtextural analyses of tooth wear as a tool for dietary discrimination in fishes. J R Soc Interface. 2012;9(74):2225-33.