Published May 3, 2022 | Version v1
Dataset Open

Multigenerational exposure to increased temperature reduces metabolic rate but increases boldness in Gambusia affinis

  • 1. University of Auckland

Description

Acute exposure to warming temperatures increases minimum energetic requirements in ectotherms. However, over and within multiple generations, increased temperatures may cause plastic and evolved changes that modify the temperature sensitivity of energy demand and alter individual behaviours. Here, we aimed to test whether populations recently exposed to geothermally elevated temperatures express an altered temperature sensitivity of metabolism and behaviour. We expected that long-term exposure to warming would moderate metabolic rate, reducing the temperature sensitivity of metabolism, with concomitant reductions in boldness and activity. We compared the temperature sensitivity of metabolic rate (acclimation at 20 versus 30°C) and allometric slopes of routine, standard, and maximum metabolic rates, in addition to boldness and activity behaviours, across eight recently divergent populations of a widespread fish species (Gambusia affinis). Our data reveal that warm-source populations express a reduced temperature sensitivity of metabolism, with relatively high metabolic rates at cool acclimation temperatures and relatively low metabolic rates at warm acclimation temperatures compared to ambient-source populations. Allometric scaling of metabolism did not differ with thermal history. Across individuals from all populations combined, higher metabolic rates were associated with higher activity rates at 20°C and bolder behaviour at 30°C. However, warm-source populations displayed relatively bolder behaviour at both acclimation temperatures compared to ambient-source populations, despite their relatively low metabolic rates at warm acclimation temperatures. Overall, our data suggest that in response to warming, multigenerational exposure (e.g., plasticity, adaptation) may not result in trait change directed along a simple "pace-of-life syndrome" axis, instead causing relative decreases in metabolism and increases in boldness. Ultimately, our data suggest that multigenerational warming may produce a novel combination of physiological and behavioural traits, with consequences for animal performance in a warming world. 

Notes

        • Males have no data in the pregnancy column
  • Individuals that did not leave the refuge were not measured for activity and have no data in the "Time_spent_exploring_s" column
  • NA's in dataset indicate missing data

Column descriptions/  units:

  • Site refers to the location where Gambusia were collected
  • Geothermal refers to the designation of sites as geothermal or ambient, geothermal sites received warm water inputs and ambient sites experience daily and seasonal changes in environmental temperature.
  • Source_Temp refers to the temperature of the site at the time of fish collection in degrees Celcius.
  • Temp_lab refers to the temperature that fish were acclimated in the laboratory in degrees Celcius
  • Run refers to the order in which metabolic rate was measured on fish
  • Fish_ID is a unique identifier for each fish in this study.
  • Sex refers to the sex of the fish measurements were done on (M = male, F = female).
  • Pregnancy describes if the fish was visibly pregnant at the time of metabolic rate measurement, where Y indicates yes or that the fish was pregnant and N indicates no or that the fish was not pregnant.
  • length: fish length (mm)
  • dry_mass_mg: fish dry mass (mg)
  • dry_mass_g: fish dry mass (g)
  • Excretion_rate: Fish excretion rate (ammonium and NOX) measured immediately following RMR (µg N min-1 fish-1)
  • Time_to_leave_s: Time the fish took to leave the refuge, maximum latency was 600 seconds (seconds)
  • Time_spent_exploring_s: Time the fish spent exploring after leaving the refuge (seconds)
  • SMR_rate_fish: standard metabolic rate of each fish (µg min-1 fish-1)
  • RMR_rate_fish: routine metabolic rate of each fish (µg min-1 fish-1)
  • MMR_rate_fish: maximum metabolic rate of each fish (µg min-1 fish-1)

Funding provided by: Royal Society of New Zealand Marsden Fund
Crossref Funder Registry ID: http://dx.doi.org/10.13039/501100009193
Award Number: 16-UOA-23

Funding provided by: The Kate Edger Educational Charitable Trust*
Crossref Funder Registry ID:
Award Number:

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