Data from: Little evidence for morphological change in a resilient endemic species following the introduction of a novel predator

Human activities, such as species introductions, are dramatically and rapidly altering natural ecological processes, and often result in novel selection regimes. To date, we still have a limited understanding of the extent to which such anthropogenic selection may be driving contemporary phenotypic change in natural populations. Here we test whether the introduction of the piscivorous Nile perch, Lates niloticus, into East Africa's Lake Victoria and nearby lakes coincided with morphological change in one resilient native prey species, the cyprinid fish Rastrineobola argentea. Drawing on prior eco-morphological research, we predicted that this novel predator would select for increased allocation to the caudal region in R. argentea to enhance burst-swimming performance, and hence escape ability. To test this prediction, we compared body morphology of R. argentea across space (nine Ugandan lakes differing in Nile perch invasion history) and through time (before and after establishment of Nile perch in Lake Victoria). Spatial comparisons of contemporary populations only partially supported our predictions, with R. argentea from some invaded lakes having larger caudal regions and smaller heads compared to R. argentea from uninvaded lakes. There was no clear evidence of predator-associated change in body shape over time in Lake Victoria. We conclude that R. argentea have not responded to the presence of Nile perch with consistent morphological changes, and that other factors are driving observed patterns of body shape variation in R. argentea.Shape variation across lakesThis file contains basic biometric data (length, weight, sex, maturity) and raw shape data (partial warps, uniform components, and relative warps) for R. argentea collected from Ugandan lakes in 2010.Sharpe_mukene shape across lakes_Dryad.csvShape variation across timeThis file contains basic biometric data (length) and raw shape data (partial warps, uniform components, and relative warps) for R. argentea collected from Lake Victoria from 1966 to 2010.Sharpe_mukene shape across time_Dryad.cs