Sex‐specific genetic differences in endurance swimming of Trinidadian guppies

Abstract

Swim performance is considered a main fitness‐determining trait in many aquatic organisms. Swimming is generally the only way most aquatic prey can escape predation, and swimming capacity is directly linked to food capture, habitat shifts, and reproduction. Therefore, evolutionary studies of swim performance are important to understand adaptation to aquatic environments. Most studies, however, concentrate on the importance of burst‐swim responses to predators, and little is known about its effect on endurance. Even fewer studies associate differences in organism swim capabilities to key gender‐specific responses. In this experiment, we assess the gender‐specific genetic basis of swimming endurance among four different populations of Trinidadian guppies adapted to different predation regimes. Our results show that second‐generation common‐garden females adapted to a low‐predation environment show longer swim endurance than fish adapted to a high‐predation environment. We also find an expected effect of lowered swimming endurance during pregnancy, but interestingly, it did not matter whether the females were in advanced stages of pregnancy, which severely changes body morphology, versus mid‐pregnancy. Males did not show the same trends across populations, and overall had lower swim endurances than female fish combined even when accounting for size differences. Populations recently transplanted from high‐ to low‐predation environments showed similar endurance to natural low‐predation environments in one population but not the other. This study highlights the importance of endurance in the adaptation of aquatic organisms to different predation regimes.

Intent matters: how flow and forms of information impact collective navigation

“…Animal groups are, of course, typically far from homogeneous. Heterogeneity could enter the group in numerous ways: genetic variation affecting, say, swimming or flight speed, [ 49 ]; pre-migration history leading to navigators with differing fitness or energy reserves [ 50 ]; social structures within groups, e.g. based on age, maturity or experience [ 51 , 52 ].…”

Intent matters: how flow & forms of information impact collective navigation

“…Animal groups are, of course, typically far from homogeneous. Heterogeneity could enter the group through numerous ways: genetic variation affecting, say, swimming or flight speed, [36]; pre-migration history leading to navigators with differing fitness or energy reserves [37]; social structures within groups, e.g., based on age, maturity or experience [38,39]. Incorporating such heterogeneity, of course, would require careful consideration: for example, more mature individuals may have access to higher levels of inherent information, and could also have a greater weighting in the collective information process of others; fitter individuals could have differing swim speeds, and so on.…”

Reproducing in hot water: Experimental heatwaves deteriorate multiple reproductive traits in a freshwater ectotherm

“…The total swimming time, the highest water velocity and the time the fish spent swimming at the highest velocity were recorded, from which its critical swimming speed was calculated after Brett (1964). Critical swimming speed is defined as the maximum speed that a fish can sustain for a set period (Brett, 1964), that is, how fast a fish can swim, and is a proxy for endurance (Gordon et al, 2015). Swimming performance tests were conducted in the afternoon.…”