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The episodic production of large seed crops by some perennial plants (masting) is known to increase seed escape by alternately starving and swamping seed predators. These pulses of resources might also act as an agent of selection on the life histories of seed predators, which could indirectly enhance seed escape by inducing an evolutionary load on seed predator populations. We measured natural selection on litter size of female North American red squirrels (Tamiasciurus hudsonicus) across 28 years and five white spruce (Picea glauca) masting events. Observed litter sizes were similar to optimum litter sizes during nonmast years but were well below optimum litter sizes during mast years. Mast events therefore caused selection for larger litters (𝛽' = 0.25) and a lag load (𝐿 = 0.25) on red squirrels during mast years. Reduced juvenile recruitment associated with this lag load increased the number of spruce cones escaping squirrel predation. Although offspring and parents often experienced opposite environments with respect to the mast, we found no effect of environmental mismatches across generations on either offspring survival or population growth. Instead, squirrels plastically increased litter sizes in anticipation of mast events, which partially, although not completely, reduced the lag load resulting from this change in food availability. These results therefore suggest that in addition to ecological and behavioral effects on seed predators, mast seed production can further enhance seed escape by inducing maladaptation in seed predators through fluctuations in optimal trait values.

Evolutionary biologists have long trained their sights on adaptation, focusing on the power of natural selection to produce relative fitness advantages while often ignoring changes in absolute fitness. Ecologists generally have taken a different tack, focusing on changes in abundance and ranges that reflect absolute fitness while often ignoring relative fitness. Uniting these perspectives, we articulate various causes of relative and absolute maladaptation and review numerous examples of their occurrence. This review indicates that maladaptation is reasonably common from both perspectives, yet often in contrasting ways. That is, maladaptation can appear strong from a relative fitness perspective, yet populations can be growing in abundance. Conversely, resident individuals can appear locally adapted (relative to nonresident individuals) yet be declining in abundance. Understanding and interpreting these disconnects between relative and absolute maladaptation, as well as the cases of agreement, is increasingly critical in the face of accelerating human-mediated environmental change. We therefore present a framework for studying maladaptation, focusing in particular on the relationship between absolute and relative fitness, thereby drawing together evolutionary and ecological perspectives. The unification of these ecological and evolutionary perspectives has the potential to bring together previously disjunct research areas while addressing key conceptual issues and specific practical problems.

Many species facing climate change have complex life cycles, with individuals in different stages differing in their sensitivity to a changing climate and their contribution to population growth. We use a quantitative genetics model to predict the dynamics of adaptation in a stage-structured population confronted with a steadily changing environment. Our model assumes that different optimal phenotypic values maximize different fitness components, consistent with many empirical observations. In a constant environment, the population evolves toward an equilibrium phenotype, which represents the best compromise given the trade-off between vital rates. In a changing environment, however, the mean phenotype in the population will lag behind this optimal compromise. We show that this lag may result in a shift along the trade-off between vital rates, with negative consequences for some fitness components but, less intuitively, improvements in some others. Complex eco-evolutionary dynamics can emerge in our model due to feedbacks between population demography and adaptation. Because of such feedback loops, selection may favor further shifts in life history in the same direction as those caused by maladaptive lags. These shifts in life history could be wrongly interpreted as adaptations to the new environment, while in reality they only reflect the inability of the population to adapt fast enough.

In this paper we look at the manifestation of different psychopathologies and propose that the disorders are on a continuum with normal behavior which, when exaggerated, becomes maladaptive. The basic paradigm of adaptation consists of cognition, affect, motivation, and behavior. Maladaptation occurs when there are errors in cognition involving the four domains of gain, loss, threat, or offense, thus triggering positive or negative affect, motivation, and subsequent behavior. Behavior is traditionally focused upon when we evaluate and treat psychopathology, but the root of disorders is the exaggeration of commonplace thoughts. We argue that treating the exaggerated expectation of pleasure or apprehension of pain will result in the return of the normal processes as the superordinate monitors discrepancies between maladaptive beliefs and reality.

Phenological shifts are the most commonly reported ecological responses to climate change and can be produced rapidly by phenotypic plasticity. However, both the limits of plasticity and whether it will be sufficient to maintain local adaptation (or even lead to maladaptation) are less clear. Increased winter precipitation has been shown to lead to phenological delays and corresponding annual decreases in fitness in Columbian ground squirrels (Urocitellus columbianus).Wetook advantage of natural phenological variation (across elevations) in this species to better assess the extent of phenotypic plasticity in emergence dates and the relationships between emergence dates and individual annual fitness. We coupled a reciprocal translocation experiment with natural monitoring across two populations separated by ∼500 m in elevation. Individuals in both populations responded plastically to both spring temperature and winter precipitation. Translocated individuals adjusted their emergence dates to approach those of individuals in their adoptive populations but did differ significantly in their emergence dates fromresidents. There were no differences in annual fitness among treatment groups nor selection on emergence date within a year. Phenotypic plasticity is thus sufficient to allow individuals to respond to broad environmental gradients, but the influence of variation in emergence dates on annual fitness requires further investigation.

Alterations in the immune system with aging are considered to underlie many age-related diseases. However, many elderly individuals remain healthy until even a very advanced age. There is also an increase in numbers of centenarians and their apparent fitness. We should therefore change our unilaterally detrimental consideration of age-related immune changes. Recent data taking into consideration the immunobiography concept may allow for meaningful distinctions among various aging trajectories. This implies that the aging immune system has a homeodynamic characteristic balanced between adaptive and maladaptive aspects. The survival and health of an individual depends from the equilibrium of this balance. In this article, we highlight which parts of the aging of the immune system may be considered adaptive in contrast to those that may be maladaptive.

Evolutionary biologists tend to approach the study of the natural world within a framework of adaptation, inspired perhaps by the power of natural selection to produce fitness advantages that drive population persistence and biological diversity. In contrast, evolution has rarely been studied through the lens of adaptation's complement, maladaptation. This contrast is surprising because maladaptation is a prevalent feature of evolution: population trait values are rarely distributed optimally; local populations often have lower fitness than imported ones; populations decline; and local and global extinctions are common. Yet we lack a general framework for understanding maladaptation; for instance in terms of distribution, severity, and dynamics. Similar uncertainties apply to the causes of maladaptation. We suggest that incorporating maladaptation‐based perspectives into evolutionary biology would facilitate better understanding of the natural world. Approaches within a maladaptation framework might be especially profitable in applied evolution contexts – where reductions in fitness are common. Toward advancing a more balanced study of evolution, here we present a conceptual framework describing causes of maladaptation. As the introductory article for a Special Feature on maladaptation, we also summarize the studies in this Issue, highlighting the causes of maladaptation in each study. We hope that our framework and the papers in this Special Issue will help catalyze the study of maladaptation in applied evolution, supporting greater understanding of evolutionary dynamics in our rapidly changing world.

Adaptation to climate change can have trade-offs and unintended outcomes that may add to climate impacts. Identifying how these consequences arise in local contexts is an important step in climate adaptation planning, but the tools for doing so are still evolving. We demonstrate how social-ecological qualitative network models (QNMs) can be used to explore the consequences of climate adaptation in fisheries. Drawing on the dynamics of the U.S. West Coast Dungeness crab fishery, we simulate a climate-intensified harmful algal bloom in a model fishing community and compare outcomes for human well-being, with and without climate adaptation. We consider a range of climate adaptations, from coping mechanisms to transformational adaptation, based on actions identified during participatory scenario planning. We first use QNMs to identify how common trade-offs arise across adaptation strategies, specifically highlighting how diverse strategies focusing on material loss result in persistent negative outcomes for community relationships and culture. We then explore alternative configurations of model structure to understand how plausible diversity in a social-ecological system can contribute to unintended, inequitable outcomes from climate adaptation. In our QNMs, altering in-season flexibility (fishers’ capacity to increase effort in alternative fisheries not affected by a harmful algal bloom) greatly influenced the degree to which climate adaptation reduced or intensified harmful algal bloom impacts on well-being. We demonstrate that QNMs are a useful tool for climate adaptation planning because they can be used to explore common trade-offs across adaptation options; highlight potentially inequitable outcomes associated with system complexity and uncertainties; and direct future research and monitoring priorities to help early identification of unintended consequences.

Background and Hypothesis Although studies have identified social fragmentation as an important risk factor for schizophrenia and other psychotic disorders, it is unknown whether it may impact social functioning. This study investigates whether social fragmentation during childhood predicts maladaptation to school as well as social functioning during childhood and adulthood. Study Design Data were collected from the North American Prodrome Longitudinal Study. Participants included adults at clinical high risk for psychosis (CHR-P) and healthy comparisons (HC). Maladaptation to school and social functioning during childhood were assessed retrospectively and social functioning in adulthood was assessed at baseline. Study Results Greater social fragmentation during childhood was associated with greater maladaptation to school (adjusted β = 0.21; 95% CI: 0.02 to 0.40). Social fragmentation was not associated with social functioning during childhood (unadjusted β = −0.08; 95% CI: −0.31 to 0.15). However, greater social fragmentation during childhood predicted poorer social functioning in adulthood (adjusted β = −0.43; 95% CI: −0.79 to −0.07). Maladaptation to school mediated 15.7% of the association between social fragmentation and social functioning. The association between social fragmentation and social functioning was stronger among adults at CHR-P compared to HC (adjusted β = −0.42; 95% CI: −0.82 to −0.02). Conclusions This study finds that social fragmentation during childhood is associated with greater maladaptation to school during childhood, which in turn predicts poorer social functioning in adulthood. Further research is needed to disentangle aspects of social fragmentation that may contribute to social deficits, which would have implications for the development of effective interventions at the individual and community levels.

Since agricultural productivity is weather and climate-related and fundamentally depends on climate stability, climate change poses many diverse challenges to agricultural activities. The objective of this study is to review adaptation strategies and interventions in countries around the world proposed for implementation to reduce the impact of climate change on agricultural development and production at various spatial scales. A literature search was conducted in June–August 2023 using electronic databases Google Scholar and Scientific Electronic Library eLibrary.RU, seeking the key words “climate”, “climate change”, and “agriculture adaptation”. Sixty-five studies were identified and selected for the review. The negative impacts of climate change are expressed in terms of reduced crop yields and crop area, impacts on biotic and abiotic factors, economic losses, increased labor, and equipment costs. Strategies and actions for agricultural adaptation that can be emphasized at local and regional levels are: crop varieties and management, including land use change and innovative breeding techniques; water and soil management, including agronomic practices; farmer training and knowledge transfer; at regional and national levels: financial schemes, insurance, migration, and culture; agricultural and meteorological services; and R&D, including the development of early warning systems. Adaptation strategies depend on the local context, region, or country; limiting the discussion of options and measures to only one type of approach—\"top-down” or “bottom-up”—may lead to unsatisfactory solutions for those areas most affected by climate change but with few resources to adapt to it. Biodiversity-based, or “ecologically intensive” agriculture, and climate-smart agriculture are low-impact strategies with strong ecological modernization of agriculture, aiming to sustainably increase agricultural productivity and incomes while addressing the interrelated challenges of climate change and food security. Some adaptation measures taken in response to climate change may not be sufficient and may even increase vulnerability to climate change. Future research should focus on adaptation options to explore the readiness of farmers and society to adopt new adaptation strategies and the constraints they face, as well as the main factors affecting them, in order to detect maladaptation before it occurs.