DOI: 10.5061/dryad.0gb5mkm0d
title: Thermal evolution ameliorates the long-term plastic effects of warming, temperature fluctuations and heat waves on predator-prey interaction strength

description: How thermal evolution may affect trophic interactions and its implications
 for trophic system stability remains unstudied. To advance insights in how
 global warming shapes trophic interactions, we need to consider besides
 increases in mean temperatures, also daily thermal fluctuations (DTF) and
 heat waves (HW), and how their effects are modulated by thermal evolution.
 Using a common-garden approach we tested how each thermal factor affected
 predator metabolic rate and functional response parameters, and used these
 responses to predict long-term predator-prey interaction strength between
 larvae of the damselfly Ischnura elegans and the water flea Daphnia magna.
 By using high- and low-latitude predator populations with the latter being
 exposed to higher mean temperatures, higher DTF and more frequent HW, we
 assessed the potential impact of thermal evolution at the high latitude
 using a space-for-time substitution. In line with thermal adaptation,
 growth rates were faster and handling times shorter in low-latitude
 compared to high-latitude larvae at 24°C, while the opposite was true at
 20°C. Warming weakened the long-term interaction strength, except for the
 high-latitude trophic system at DTF and HW where plastic responses
 therefore may not stabilize the high-latitude system. This extends the
 emerging insight that temperature variation may make ectotherms more
 vulnerable to warming. The contributions of metabolic rate, search rate
 and handling time in shaping thermal effects on interaction strength often
 differed between latitudes. A key finding was that thermal evolution may
 further weaken the long-term interaction strength of the high-latitude
 trophic system under increases in mean temperatures, even at DTF and
 potentially also at HW. Our results underscore the importance of daily
 thermal fluctuations and heat waves in shaping predator-prey interactions,
 and may suggest an overall stabilizing contribution of predator thermal
 evolution ameliorating thermal plastic effects on food web stability.
description: This dataset contains the growth rates, functional responses,
 metabolic rates of the damselfly <em>I. elegans </em>larvae
 from low- and high- latitudes at 20 and 24°C under different thermal
 variation scenarios (constant, 10°C daily temperature fluctuations, and a
 32°C heat wave).
description: For datasheet "growth_rate": ID = damsefly
 individual IDl; F0 date = date the larva reached final larval
 instar; origin = damselfly origin (s = south, n = north);  population =
 damslefly population ID; mother = mother damsefly ID; treatment = thermal
 variation (cte = constand, dtv = daily temperature variation, hw =
 heatwave) + mean temperautre (20 = 20°C, 24 = 24°C) treatment; ori_temp =
 local mean summer temperature; m_dev_temp = mean developmental
 temperature; vtype = thermal variation type; replicate_FR = replicate ID
 of the functional response mesurement; initial_mass = fresh weight at day
 3 at final larval instar (mg),;final_mass = fresh weight at day 8 at final
 larval instar (mg). For datasheet "functional
 response": ID = damsefly individual IDl; F0 date = date the
 larva reached final larval instar; origin = damselfly origin (s = south, n
 = north);  population = damslefly population ID; mother = mother damsefly
 ID; treatment = thermal variation (cte = constand, dtv = daily temperature
 variation, hw = heatwave) + mean temperautre (20 = 20°C, 24 = 24°C)
 treatment; m_dev_temp = mean developmental temperature; replicate_FR =
 replicate ID of the functional response mesurement; final_mass = fresh
 weight at day 8 at final larval instar (mg); prey_num = initial
 <em>D. magna</em> density; consumed = <em>D.
 magna </em>consumed after 24 h. For datasheet
 "metabolic rate": ID = damsefly individual IDl; origin =
 damselfly origin (s = south, n = north);  population = damslefly
 population ID; fr_type = thermal variation (cte = constand, dtv = daily
 temperature variation, hw = heatwave) treatment;  treatment = thermal
 variation (cte = constand, dtv = daily temperature variation, hw =
 heatwave) + mean temperautre (20 = 20°C, 24 = 24°C) treatment;
 replicate_MR = replicate ID of the metabolic rate mesurement. adj_d_ppm =
 damselfly oxeygen concentration depletion after 24 h, adjusted by control
 (damsefly-free) measurements; final_mass = fresh weight at day 8 at final
 larval instar (mg).