Multidimensional analyses of physical performance reveal a size‐dependent trade‐off between suites of traits

Machine learning accurately predicts the multivariate performance phenotype from morphology in lizards

Completing the genotype-to-phenotype map requires rigorous measurement of the entire multivariate organismal phenotype. However, phenotyping on a large scale is not feasible for many kinds of traits, resulting in missing data that can also cause problems for comparative analyses and the assessment of evolutionary trends across species. Measuring the multivariate performance phenotype is especially logistically challenging, and our ability to predict several performance traits from a given morphology is consequently poor. We developed a machine learning model to accurately estimate multivariate performance data from morphology alone by training it on a dataset containing performance and morphology data from 68 lizard species. Our final, stacked model predicts missing performance data accurately at the level of the individual from simple morphological measures. This model performed exceptionally well, even for performance traits that were missing values for >90% of the sampled individuals. Furthermore, incorporating phylogeny did not improve model fit, indicating that the phenotypic data alone preserved sufficient information to predict the performance based on morphological information. This approach can both significantly increase our understanding of performance evolution and act as a bridge to incorporate performance into future work on phenomics.

Greater agility increases probability of survival in the endangered northern quoll

Introduced predators combined with habitat loss and modification are threatening biodiversity worldwide, particularly the 'critical weight range' (CWR) mammals of Australia. In order to mitigate the impacts of invasive predators on native species in different landscapes, we must understand how the prey's morphology and performance determine their survival. Here, we evaluated how phenotypic traits related to escape performance predict the probability of survival for an endangered CWR mammal, the northern quoll (Dasyurus hallucatus). We measured mass, body size, body shape, body condition and age, as well as maximum sprint speed, acceleration and agility of female quolls over two consecutive years. Those with higher body condition and agility around a 135 deg corner were more likely to survive their first 21 months of life but were not more likely to survive after this period. No other morphological or performance traits affected survival. Heavier second-year individuals were more agile than first years but second years experienced higher mortality rates throughout the year. Females with higher body condition and agility around a 135 deg corner tended to have shorter limbs and feet but longer heads. Our findings suggest that higher body condition and agility are advantageous for survival in female northern quolls. These results can be used to develop predictive models of predator-prey interactions based on performance capacity and how performance is affected by habitat, aiding conservation efforts to predict and manage the impact of introduced predators on native species.

Correcting for individual quality reveals trade-offs in performance among multiple modes of limbless locomotion in snakes

Trade-offs among performance traits are often difficult to detect despite the physiological and morphological incompatibilities that underlie disparate traits being well understood. However, recent studies that have corrected for individual quality have found trade-offs in human athletes performing various performance tasks. Few studies have found trade-offs among multiple performance tasks after correcting for individual quality in non-human animals because of the difficulty in motivating many animals to perform biomechanically different tasks. We examined potential trade-offs in maximal speeds among ten locomotor conditions that involved the utilization of different locomotor modes in cornsnakes (Pantherophis guttatus). Snakes were assessed during terrestrial lateral undulation, swimming, concertina movements (small and large width) and six conditions of arboreal locomotion (combinations of three perch diameters and two inclines). We found no trade-offs among locomotor conditions when analysing uncorrected speeds or speeds corrected for body condition. However, we found several trade-offs among modes and treatments for speeds corrected for individual quality. Terrestrial lateral undulation speeds were negatively related to speeds of concertina and two of the arboreal locomotion conditions. A trade-off between speeds on large and small perch diameters on a 30° incline was also detected and probably reflects potential conflicts in traits that maximize lateral undulation and concertina.