DOI: 10.5061/dryad.ks2j1
title: Data from: Behavioural and physiological adaptations to low-temperature environments in the common frog, Rana temporaria

description: Background: Extreme environments can impose strong ecological and
 evolutionary pressures at a local level. Ectotherms are particularly
 sensitive to low-temperature environments, which can result in a reduced
 activity period, slowed physiological processes and increased exposure to
 sub-zero temperatures. The aim of this study was to assess the behavioural
 and physiological responses that facilitate survival in low-temperature
 environments. In particular, we asked: 1) do high-altitude common frog
 (Rana temporaria) adults extend the time available for larval growth by
 breeding at lower temperatures than low-altitude individuals?; and 2) do
 tadpoles sampled from high-altitude sites differ physiologically from
 those from low-altitude sites, in terms of routine metabolic rate (RMR)
 and freeze tolerance? Breeding date was assessed as the first day of spawn
 observation and local temperature recorded for five, paired high- and
 low-altitude R. temporaria breeding sites in Scotland. Spawn was collected
 and tadpoles raised in a common laboratory environment, where RMR was
 measured as oxygen consumed using a closed respiratory tube system. Freeze
 tolerance was measured as survival following slow cooling to the point
 when all container water had frozen.Results: We found that breeding did
 not occur below 5°C at any site and there was no significant relationship
 between breeding temperature and altitude, leading to a delay in spawning
 of five days for every 100 m increase in altitude. The relationship
 between altitude and RMR varied by mountain but was lower for individuals
 sampled from high- than low-altitude sites within the three mountains with
 the highest high-altitude sites (≥900 m). In contrast, individuals sampled
 from low-altitudes survived freezing significantly better than those from
 high-altitudes, across all mountains. Conclusions: Our results suggest
 that adults at high-altitude do not show behavioural adaptations in terms
 of breeding at lower temperatures. However, tadpoles appear to have the
 potential to adapt physiologically to surviving at high-altitude via
 reduced RMR but without an increase in freeze tolerance. Therefore,
 survival at high-altitude may be facilitated by physiological mechanisms
 that permit faster growth rates, allowing completion of larval development
 within a shorter time period, alleviating the need for adaptations that
 extend the time available for larval growth.
description: Temperature
 dataTemperature data: Air
 temperature data collected every two hours, by site. Date, Time: when air
 temperature was recorded. Temperature in degrees centigrade by
 site.Study
 sitesStudy sites: Site name
 (abbreviation), location (latitude and longitude) and altitude (metres
 above sea level).Routine metabolic
 rateRoutine metabolic rate:
 Individual ID, Family, Mountain of origin (abbreviation), Altitude of
 origin (Low or High) and Routine_metabolic_rate (ml O2 g-1
 h-1).Freeze
 toleranceFreeze tolerance:
 Individual ID, Mountain of origin (abbreviation), Altitude of origin (Low
 or High), Weight (g) and Survival (1=survived, 0=died).