Differences in oxidative status explain variation in thermal acclimation capacity between individual mosquitofish (Gambusia holbrooki)

Abstract

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Water flow and temperature interact to determine oxidative status, swimming performance, and dispersal of mosquitofish (Gambusia holbrooki)

“…Hence, our results indicate that living in flowing water increased ROS production but that there is no increase in oxidative damage because of the increased antioxidant activities in muscle. Similarly, cold (18°C) acclimation in mosquitofish led to increased H 2 O 2 production (Loughland & Seebacher, 2020), but the increased antioxidant activity following cold acclimation prevented increased oxidative damage in our present study. Hence, ROS production and antioxidant defences were balanced in fish from the different environments in our study so that no particular environmental combination of temperature and flow led to an increase in oxidative damage.…”

“…Our aim was to contribute to this challenge by determining the interactive effects of water flow and temperature on oxidative status, swimming performance, and dispersal of mosquitofish ( Gambusia holbrooki ). We conducted a fully factorial experiment with water flow (acclimation to flowing and still water), acclimation temperature (18 and 28°C), and acute test temperatures (18–32°C) as factors to test the hypotheses that: (1) fish living in flowing water have lower oxidative damage, higher swimming performance and, hence, increased rates of dispersal compared to fish from still water (main effect of water flow); (2) oxidative stress is higher at lower acclimation temperatures (main effect of acclimation temperature; Loughland & Seebacher, 2020); but (3) animals acclimate and partially compensate swimming performance for decreasing temperatures (acclimation × acute test temperature interactions) although performance is higher at higher test temperatures (main effect of test temperature); (4) living in flowing water offsets the increased oxidative stress at low acclimation temperatures (water flow × acclimation temperature interaction); and (5) dispersal is correlated with swimming capacity.…”

Oxidative stress mediates rapid compensatory growth and its costs

“…We, however, did not observe any covariation between the superoxide anion concentration or MDA levels and the growth rate at the individual level (Appendix S5; see e.g. also Loughland & Seebacher, 2020). A reason for the lack of covariation at the individual level could be the limited number of replicates per treatment ( N = 15), the relatively low variation within treatment groups and the lethal nature of the physiological analyses, making it impossible to test for several patterns at the individual level, including covariation between the MDA levels at the start of the starvation period and the subsequent growth rate during the starvation period.…”

Effects of temperature on physiological performance and behavioral thermoregulation in an invasive fish, the round goby

“…The abrupt increase in SMR from 25 to 28°C could be caused by an increasing inability to defend membrane integrity at high temperatures: changes in cell membrane phospholipid composition with changing temperature is one of the most profound physiological changes in ectothermic animals ( Hochachka and Somero, 2002 ), and altered membrane phospholipid composition affects energetically demanding processes such as Na + –K + -ATPase activity and restoring the mitochondrial proton gradient in the face of increased leakage across more fluid membranes ( Hulbert and Else, 2005 ). The loss of capacity for thermal compensation of SMR at 28°C could also be due to an onset of other energetically demanding processes to cope with high temperature, such as production of heat shock proteins and anti-oxidant enzymes ( Iwama et al, 1999 ; Sørensen et al, 2003 ; Heise et al, 2006 ; Loughland and Seebacher, 2020 ). Heat shock proteins and anti-oxidant enzymes stabilize altered proteins and alleviate protein degradation in response to thermal stress ( Kiang and Tsokos, 1998 ; Basu et al, 2002 ; Heise et al, 2006 ).…”

“…Phenotypic buffering, that is, maintaining the same level of a trait after a change in the environment, is evolutionary favorable when environmental changes induce stressful conditions at the edge of tolerance ranges (Reusch, 2014). The lack of change in round goby T pref and T avoid with increasing acclimation temperature indicates a high level of phenotypic buffering for acute behavioral thermoregulation, and may give round goby a competitive advantage in fluctuating environments (Loughland and Seebacher, 2020). Interestingly, T pref of the invasive lionfish also did not change with acclimation temperature (Barker et al, 2018), adding to the notion that high levels of phenotypic buffering of behavioral thermoregulation may be advantageous for species introduced to novel environments, and potentially be a common characteristic of invasive species in general.…”