Ecological speciation appears to contribute to the diversification of insect herbivores and other parasites, which together comprise a major component of Earth's biodiversity. Host shifts are likely an important step in ecological speciation, and understanding how such shifts occur is critical to forming and testing hypotheses explaining parasite diversity. In this article, I argue that phenotypic variation in hosts arising from environmental variation (phenotypic plasticity) can promote shifts in parasites by bridging both spatiotemporal and phenotypic gaps between ancestral and novel hosts. This hypothesis, which I call the 'plastic-bridge hypothesis', is conceptually distinct from those invoking genetic variation in bridging these gaps. I describe the mechanistic basis of plastic bridges, review circumstantial evidence in support of the hypothesis and suggest strategies for testing it. I use herbivorous insects and their host plants as a model, but the proposed ideas apply to any system fitting a broad definition of a host-parasite relationship. The plastic-bridge perspective suggests that parasite diversity is not only due to divergent selection provided by hosts, but also to the intraspecific variation that facilitates shifts between them. This view is timely, as biological invasion and range shifts associated with climate change foster novel interactions between parasites and hosts.
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Trends Ecol Evol
January 2025
Department of Environmental Science and Policy, University of California, One Shields Ave, Davis, CA 95616, USA.
Transgenerational plasticity (TGP) has largely focused on how parental exposure to ecological conditions shapes the phenotypes of future generations. However, organisms acquire information about their ecological environment via social learning, which can also shape TGP in profound ways. We demonstrate that non-parents alter how parents detect and respond to environmental cues in ways that spillover to affect offspring, non-parents influence offspring even without direct physical interactions, and parental cues received by offspring can alter the phenotypes of other juveniles.
View Article and Find Full Text PDFNeurosci Biobehav Rev
January 2025
Department of Psychiatry and Psychotherapy, Philipps University Marburg, Rudolf-Bultmann-Str. 8, 35039 Marburg, Germany; Center for Mind, Brain and Behaviour, Philipps University Marburg, Hans-Meerwein-Str. 6, 35032 Marburg, Germany. Electronic address:
Recurrent psychosocial stress poses a significant health challenge, prompting research into mechanisms of successful adaptation. Physiological habituation, defined as decreased reactivity to repeated stressors, is pivotal in protecting the organism from allostatic load. Here, we systematically review and meta-analyze data from studies investigating the capacity of central stress systems to habituate when repeatedly exposed to a standardized psychosocial stressor, the Trier Social Stress Test (k=47).
View Article and Find Full Text PDFMol Ecol
January 2025
Department of Biology, Colorado State University, Fort Collins, Colorado, USA.
Genomic projections of (mal)adaptation under future climate change, known as genomic offset, faces limited application due to challenges in validating model predictions. Individuals inhabiting regions with high genomic offset are expected to experience increased levels of physiological stress as a result of climate change, but documenting such stress can be challenging in systems where experimental manipulations are not possible. One increasingly common method for documenting physiological costs associated with stress in individuals is to measure the relative length of telomeres-the repetitive regions on the caps of chromosomes that are known to shorten at faster rates in more adverse conditions.
View Article and Find Full Text PDFNat Commun
January 2025
Hopp Children's Cancer Center (KiTZ), Heidelberg, Germany.
Human cancer cell lines are the mainstay of cancer research. Recent reports showed that highly mutated adult carcinoma cell lines (mainly HeLa and MCF-7) present striking diversity across laboratories and that long-term continuous culturing results in genomic/transcriptomic heterogeneity with strong phenotypical implications. Here, we hypothesize that oligomutated pediatric sarcoma cell lines mainly driven by a fusion transcription factor, such as Ewing sarcoma (EwS), are genetically and phenotypically more stable than the previously investigated adult carcinoma cell lines.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
The University of Arizona - Tucson, Tucson, AZ, USA.
Background: Host commensal gut microbes are shown to be crucial for microglial maturation, and functions that involve innate immune responses to maintain brain homeostasis. Sex has a crucial role in the incidence of neurological diseases with females showing higher progression of AD compared with males. Transcriptomics has been a powerful tool for the characterization of microglial phenotypes however, there is a large gap in relating to their functional protein abundances.
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