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Abstract Much research has shown that environmental stress can induce adaptive and maladaptive phenotypic changes in organisms that persist for multiple generations. Such transgenerational phenotypic plasticity shrouds our understanding of the long‐term consequences of ongoing anthropogenic pressures.Here, we evaluated within‐ and transgenerational phenotypic responses to food stress in the freshwater crustacean,Daphnia. We reared 45 clones ofDaphnia pulicariaeach on high‐qualityScenedesmusand low‐quality (but also non‐toxic) cyanobacteria (generation 1). Offspring produced by generation 1 adults were then reared onScenedesmus(generation 2), and life‐history traits were measured across both generations.The results show thatDaphniain generation 1 exhibited reduced fitness (i.e., delayed maturation, lower reproductive output, increased clutch interval) when reared in the presence of cyanobacteria as opposed to high‐quality food. However, maternal stress had no clear influence on the fitness of offspring. That is,Daphniain the second experimental generation had similar mean trait values, irrespective of whether their mothers were reared on cyanobacteria or high‐quality food.Signals of transgenerational life‐history effects were obscured, in part, by extensive clonal variation amongDaphniain the direction of transgenerational responses to cyanobacteria (i.e., adaptive and maladaptive plasticity). Further analyses demonstrated that such individual variance in plasticity might be open to selection and potentially offer a means of contemporary adaptation to cyanobacteria. Taken together, our results denote a link between the overall strength of transgenerational responses to the environment and the potential for rapid evolution in populations. A freePlain Language Summarycan be found within the Supporting Information of this article.
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Decoupling the effects of food and density on life‐history plasticity of wild animals using field experiments: Insights from the steward who sits in the shadow of its tail, the North American red squirrel
Abstract Long‐term studies of wild animals provide the opportunity to investigate how phenotypic plasticity is used to cope with environmental fluctuations and how the relationships between phenotypes and fitness can be dependent upon the ecological context.Many previous studies have only investigated life‐history plasticity in response to changes in temperature, yet wild animals often experience multiple environmental fluctuations simultaneously. This requires field experiments to decouple which ecological factor induces plasticity in fitness‐relevant traits to better understand their population‐level responses to those environmental fluctuations.For the past 32 years, we have conducted a long‐term integrative study of individually marked North American red squirrelsTamiasciurus hudsonicusErxleben in the Yukon, Canada. We have used multi‐year field experiments to examine the physiological and life‐history responses of individual red squirrels to fluctuations in food abundance and conspecific density.Our long‐term observational study and field experiments show that squirrels can anticipate increases in food availability and density, thereby decoupling the usual pattern where animals respond to, rather than anticipate, an ecological change.As in many other study systems, ecological factors that can induce plasticity (such as food and density) covary. However, our field experiments that manipulate food availability and social cues of density (frequency of territorial vocalizations) indicate that increases in social (acoustic) cues of density in the absence of additional food can induce similar life‐history plasticity, as does experimental food supplementation.Changes in the levels of metabolic hormones (glucocorticoids) in response to variation in food and density are one mechanism that seems to induce this adaptive life‐history plasticity.Although we have not yet investigated the energetic response of squirrels to elevated density or its association with life‐history plasticity, energetics research in red squirrels has overturned several standard pillars of knowledge in physiological ecology.We show how a tractable model species combined with integrative studies can reveal how animals cope with resource fluctuations through life‐history plasticity.
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- Award ID(s):
- 1749627
- PAR ID:
- 10455906
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Journal of Animal Ecology
- Volume:
- 89
- Issue:
- 11
- ISSN:
- 0021-8790
- Format(s):
- Medium: X Size: p. 2397-2414
- Size(s):
- p. 2397-2414
- Sponsoring Org:
- National Science Foundation
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