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Predator‐ and competitor‐induced responses in amphibian populations that evolved different levels of pesticide tolerance
Author(s) -
Jones Devin K.,
Hua Jessica,
Mattes Brian M.,
Cothran Rickey D.,
Hoverman Jason T.,
Relyea Rick A.
Publication year - 2021
Publication title -
ecological applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.864
H-Index - 213
eISSN - 1939-5582
pISSN - 1051-0761
DOI - 10.1002/eap.2305
Subject(s) - biology , amphibian , phenotypic plasticity , tadpole (physics) , ecology , population , predator , edaphic , mesocosm , pesticide , hylidae , predation , zoology , ecosystem , physics , demography , particle physics , sociology , soil water
Exposure to agrochemicals can drive rapid phenotypic and genetic changes in exposed populations. For instance, amphibian populations living far from agriculture (a proxy for agrochemical exposure) exhibit low pesticide tolerance, but they can be induced to possess high tolerance following a sublethal pesticide exposure. In contrast, amphibian populations close to agriculture exhibit high, constitutive tolerance to pesticides. A recent study has demonstrated that induced pesticide tolerance appears to have arisen from plastic responses to predator cues. As a result, we might expect that selection for constitutive pesticide tolerance in populations near agriculture (i.e., genetic assimilation) will lead to the evolution of constitutive responses to natural stressors. Using 15 wood frog ( Rana sylvatica ) populations from across an agricultural gradient, we conducted an outdoor mesocosm experiment to examine morphological (mass, body length, and tail depth) and behavioral responses (number of tadpoles observed and overall activity) of tadpoles exposed to three stressor environments (no‐stressor, competitors, or predator cues). We discovered widespread differences in tadpole traits among populations and stressor environments, but no population‐by‐environment interaction. Subsequent linear models revealed that population distance to agriculture (DTA) was occasionally correlated with tadpole traits in a given environment and with magnitudes of plasticity, but none of the correlations were significant after Bonferroni adjustment. The magnitudes of predator and competitor plasticity were never correlated with the magnitude of pesticide‐induced plasticity that we documented in a companion study. These results suggest that while predator‐induced plasticity appears to have laid the foundation for the evolution of pesticide‐induced plasticity and its subsequent genetic assimilation, inspection of population‐level differences in plastic responses show that the evolution of pesticide‐induced plasticity has not had a reciprocal effect on the evolved plastic responses to natural stressors.