NEW PAPER: Costs of running differ for egg-laying and live-bearing females

A new paper from Hans Recknagel (during his PhD/postdoc) and Robbie Hussain (while an intern with us) uses the common lizard oviparous - viviparous hybrid zone as an experimental system to measure the cost of running.

Published in Ecology and Evolution open access 

Abstract 

Pregnancy is a physiological cost of reproduction for animals that rely on fleeing to avoid predators. Costs of reproduction are predicted to differ between alternative reproductive strategies or modes, such as egg-laying (oviparity) or live-bearing (viviparity). However, disentangling the factors that comprise this cost and how it differs for oviparous or viviparous females is challenging due to myriad environmental, biological, and evolutionary confounds. Here, we tested the hypothesis that costs of pregnancy differ between oviparous and viviparous common lizards (Zootoca vivipara). We predicted that the degree of locomotor impairment during pregnancy and therefore the cost of reproduction would be higher in viviparous females. We conducted our experiment in a hybrid zone containing oviparous and viviparous common lizards. Due to the common environment and inclusion of hybrid individuals, we could infer whether differences were inherent to parity mode. We found that the average and maximum running speed of pregnant females was slower than after they had given birth or laid eggs. Viviparous females experienced an additional pregnancy weight burden and for a longer time period, but were not slower at running than pregnant oviparous females. In addition, we found a parity mode-specific effect of reproductive investment; producing larger clutches was costlier for the locomotor performance of viviparous females for reasons other than the mass increase. Locomotor costs were found to be intermediate in hybrid females, indicating that they are specific to each reproductive mode. Our study shows that viviparous females experience an additional physical and physiological cost of pregnancy and reproductive investment. This two-fold cost implies that viviparous females modulate resource allocation decisions and/or adjust their behavioural responses that result from locomotor impairment.

Popular posts from this blog

NEW PAPER: Genomics of head and body shape parallelism in Arctic charr

Image
Published today as free open access in Molecular Ecology :  Genomic underpinnings of head and body shape in Arctic charr ecomorph pairs Sam Fenton, Arne Jacobs, Colin Bean, Colin Adams & Kathryn Elmer The appearance of repeated phenotypes across replicates in similar environments have been described as examples of parallel evolution. However, the genomic bases of these similar phenotypes is rarely elucidated and so whether the same genomic pathways are used to achieve these similar phenotypes across replicates is rarely known. Here we used the repeated divergence of benthivorous-planktivorous ecomorph pairs of Arctic charr to investigate the genomic underpinnings of head and body shape morphology across replicates. We found that only a small number of associated SNPs for each phenotype were shared across all four ecomorph pairs we investigated with selection on associated SNPs varying considerably across replicates. Overall, these results suggest that the genomic underpinnings ...
Read more