Superfetation, the ability to simultaneously carry multiple litters of different developmental stages in utero, is a reproductive strategy that evolved repeatedly in viviparous animal lineages. The evolution of superfetation is hypothesized to reduce the reproductive burden and, consequently, improve the locomotor performance of the female during pregnancy. Here, we apply new computer-vision based techniques to study changes in body shape and three-dimensional fast-start escape performance during pregnancy in three livebearing fishes (family Poeciliidae) that exhibit different levels of superfetation. We found that superfetation correlates with a reduced abdominal distension and a more slender female body shape just before parturition. We further found that body slenderness positively correlates with maximal speeds, curvature amplitude and curvature rate, implying that superfetation improves the fast-start escape performance. Collectively, our study suggests that superfetation may have evolved in performance-demanding (e.g. high flow or high predation) environments to reduce the locomotor cost of pregnancy.
Fast-start_MATLAB_data_part1
MATLAB File Archive containing tracking data for individual fast-start manoeuvres. See README.txt for definitions of variables.
dryad_small.7z.001
Fast-start_MATLAB_data_part2
MATLAB File Archive containing tracking data for individual fast-start manoeuvres. See README.txt for definitions of variables.
dryad_small.7z.002
Fast-start_MATLAB_data_part3
MATLAB File Archive containing tracking data for individual fast-start manoeuvres. See README.txt for definitions of variables.
dryad_small.7z.003
Fast-start_MATLAB_data_part4
MATLAB File Archive containing tracking data for individual fast-start manoeuvres. See README.txt for definitions of variables.
dryad_small.7z.004
Fast-start_MATLAB_data_part5
MATLAB File Archive containing tracking data for individual fast-start manoeuvres. See README.txt for definitions of variables.
dryad_small.7z.005
Fast-start_MATLAB_data_part6
MATLAB File Archive containing tracking data for individual fast-start manoeuvres. See README.txt for definitions of variables.
dryad_small.7z.006
Fast-start_MATLAB_data_part7
MATLAB File Archive containing tracking data for individual fast-start manoeuvres. See README.txt for definitions of variables.
dryad_small.7z.007
Fast-start_MATLAB_data_part8
MATLAB File Archive containing tracking data for individual fast-start manoeuvres. See README.txt for definitions of variables.
dryad_small.7z.008
Fast-start_MATLAB_data_part9
MATLAB File Archive containing tracking data for individual fast-start manoeuvres. See README.txt for definitions of variables.
dryad_small.7z.009
Fast-start_MATLAB_data_part10
MATLAB File Archive containing tracking data for individual fast-start manoeuvres. See README.txt for definitions of variables.
dryad_small.7z.010
Fast-start_MATLAB_data_part11
MATLAB File Archive containing tracking data for individual fast-start manoeuvres. See README.txt for definitions of variables.
dryad_small.7z.011
Fast-start_MATLAB_data_part12
MATLAB File Archive containing tracking data for individual fast-start manoeuvres. See README.txt for definitions of variables.
dryad_small.7z.012
Fast-start_MATLAB_data_part13
MATLAB File Archive containing tracking data for individual fast-start manoeuvres. See README.txt for definitions of variables.
dryad_small.7z.013
Fast-start_MATLAB_data_part14
MATLAB File Archive containing tracking data for individual fast-start manoeuvres. See README.txt for definitions of variables.
dryad_small.7z.014
Fast-start_MATLAB_data_part15
MATLAB File Archive containing tracking data for individual fast-start manoeuvres. See README.txt for definitions of variables.
dryad_small.7z.015
Morphology_Fast-start_final-data
The file 'Morphology_Fast-start_final-data.xls' is used for all the statistical analyses in our manuscript. See the accompanying README_Morphology_Fast-start_final-data.txt file for a specific content description.