Biological Reviews最新文献

Understanding how human activity impacts natural systems is crucial for maintaining ecosystem health and the services these provide for societies. Phenotypic plasticity - the regulated expression of different phenotypes by a single genotype - is the most effective response to increase resistance or resilience of phenotypes to rapidly changing environments. Here, we review the mechanisms that underlie phenotypic plasticity in animals. Understanding the regulatory mechanisms is important because these determine the time course of establishment and persistence of alternative phenotypes. We propose that regulation of trans- and intergenerational plasticity, developmental plasticity and reversible acclimation involves (i) environmental information acquisition, (ii) signal integration, and (iii) translation of environmental information to alter phenotypes. We provide a high-level overview of each of these stages with the aim of summarising current knowledge and making it accessible to a broader audience who are not necessarily expert in neuroendocrine and molecular biology. Information acquisition occurs primarily by sensors that transduce environmental information (e.g. temperature, light, chemicals, etc.) to the central nervous system. An exception is AMP-activated protein kinase (AMPK) that senses cellular energy levels and interacts locally and with neuroendocrine systems to adjust anabolic and catabolic metabolism. Signal integration is achieved primarily by neural and endocrine mechanisms. The major players are the autonomic nervous system, the hypothalamus-pituitary-adrenal/interrenal (HPA/I), the hypothalamus-pituitary-thyroid (HPT), and the hypothalamus-pituitary-somatotrophic (HPS) axes, which receive environmental information from the brain and transmit it via hormone signalling. Phenotypic effects of these major axes can be directly to the target tissues, or via epigenetically modified gene expression programs. DNA methylation, histone modifications, and microRNAs are the principal epigenetic processes, of which the first two are regulated by neuroendocrine signalling. Importantly, all of these processes (AMPK, neuroendocrine, epigenetic) interact with each other so that regulation occurs in a network-like manner rather than by individual regulators alone. Nonetheless, an appreciation of individual mechanisms is an essential starting point that can guide future research into more complex interactions to advance understanding of the evolution and ecological importance of plasticity.

For the vast majority of the evolutionary history of Homo sapiens, a range of natural environments defined the parameters within which selection shaped human biology. Although human-induced alterations to the terrestrial biosphere have been evident for over 10,000 years, the pace and scale of change has accelerated dramatically since the onset of the Industrial Revolution in the late 18th century. Industrialisation has profoundly transformed our various natural habitats, driving rapid urban expansion, increasing reliance on fossil fuel energy and causing environmental contamination, ecosystem degradation and biodiversity loss. Today, most of the world's population resides in highly industrialised urban areas. These new primary human habitats differ fundamentally from our ancestral natural habitats, creating novel environmental challenges while, simultaneously, lacking key natural features linked to health and function. Although the adaptive capacity of humans has enabled survival in diverse and fluctuating environmental conditions, this capacity is limited. It is possible that the rapid industrialisation of our habitat is outpacing our adaptive capacity and is imposing selective pressures that threaten our evolutionary fitness. A growing body of observational and experimental evidence suggests that industrialisation negatively impacts key biological functions essential for survival and reproduction and, therefore, evolutionary fitness. Specifically, environmental contamination arising directly from industrial activities (e.g. air, noise and light pollution, microplastic accumulation) is linked to impaired reproductive, immune, cognitive and physical function. Chronic activation of the stress response systems, which further impairs these biological functions, also appears more pronounced in industrialised areas. Here, we consider whether the rapid and extensive environmental shifts of the Anthropocene have compromised the fitness of Homo sapiens. We begin by contrasting contemporary and ancestral human habitats before assessing the effects of these changes on core biological functions that underpin evolutionary fitness. We then ask whether industrialisation has created a mismatch between our primarily nature-adapted biology and the novel challenges imposed by contemporary industrialised environments - a possibility that we frame through the lens of the Environmental Mismatch Hypothesis. Finally, we explore experimental approaches to test this hypothesis and discuss the broader implications of such a mismatch.

Brenninger, F. A., Zug, R. & Kokko, H. (2025), Infection dynamics of endosymbionts that manipulate arthropod reproduction. Biological Reviews 100, 1787–1812. https://doi.org/10.1111/brv.70024

The following funding statement has been added to the article: Open access publishing facilitated by Universitat Zurich, as part of the Wiley - Universitat Zurich agreement via the Consortium Of Swiss Academic Libraries.

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Extant snakes (Serpentes) are a highly diverse group of squamate reptiles, which have independently evolved key morphological adaptations to consume a large variety of vertebrate and invertebrate prey. While these predator-prey interactions have been widely addressed by several studies, little is known regarding the occurrence of cannibal behaviour in snakes, with scattered reports restricted mostly to natural history notes or incidental records. Here we provide an extensive review of cannibalism in extant snakes, with 503 case events available from the literature, that encompass at least 207 species in 15 families, in both captivity and the wild. For all case events, including those with and without location data, cannibal incidents occurred mostly within the Colubridae (29.0%), Viperidae (21.2%), and Elapidae (18.9%). As cannibalism in snakes has been hypothesized to be a random event, we test whether theories of foraging and feeding strategies apply to cannibal behaviour, finding that prey and predator body size are positively correlated (R = 0.81). Furthermore, we explore the evolution of cannibal behaviour in extant snakes, inferring a maximum-likelihood ancestral character estimation of cannibalism over a family-level phylogenetic tree, which revealed independent evolution of this behaviour at least 11 times during the evolutionary history of snakes. Cannibalism also appears to be correlated with macrostomate mandibular morphotypes, occurring only in Alethinophidia, and being absent in most snakes that possess mandibular morphotypes with reduced mobility. We conclude that cannibal behaviour appears to be widespread in extant snakes, and possibly represents an opportunistic behaviour that can be related to their evolutionary history, dietary and morphological specialization, environment, and other ecological correlates.

Sheep and deer calcanei are important models for studying cortical (compact) and trabecular (cancellous) bone adaptation because they are amenable to direct strain measurement (due to lack of surrounding muscles), experience relatively simple/unidirectional bending, exhibit osteon remodelling, and have the most pronounced regional variations in mineralization and other histological characteristics reported in any bone. This simple loading environment is characterized by bending that produces prevalent/predominant tension on the plantar side and predominant compression on the dorsal side of the cantilevered, beam-like shaft of these bones. Histocompositional differences are clear between these opposing cortices, optimizing their mechanical properties for these regional differences in loading environment. This keeps the fracture risk low by enhancing the safety factor of the entire bone. Understanding how mechanosensitive cells within bone accomplish this is fundamentally important for advancing core concepts in bone biology and functional adaptation, and for clinical applications. However, an uncontested 1995 study used qualitative histological observations from a small sample (two sub-adults; three adults) of domesticated sheep calcanei and in vivo strain data from Lanyon's seminal study of sheep calcanei to reject the idea that this bone is simply loaded. That study argued that reversals of bending during the swing phase of gait negate the ‘tension/compression (plantar/dorsal)’ concept, thus invalidating much of the basic and translational value of the model. Their opinion is important because many investigators consider it valid despite contrary conclusions of subsequent biomechanical/histomorphological studies. This review critically evaluates the foundations of the main conclusion of that 1995 study, because their refutation of the simplicity of the artiodactyl calcaneus model has been favourably cited nearly 60 times in the peer-reviewed literature. After exposing and correcting errors and reconciling contradictory observations in that study, this review explores the strengths, limitations, and potential applications of the artiodactyl calcaneus model for advancing understanding of mechanisms and consequences of bone adaptation. Studies reviewed herein support viewing artiodactyl calcanei as simply loaded ‘tension/compression bones’, validating their continued use in this context in a broad spectrum of studies of cortical and trabecular bone adaptation. A particularly promising application of this model is that it can serve as a ‘control bone’ for studies of other presumably simply loaded bone regions, such as the human femoral neck, especially regarding the relationship of its load history, structural and material organization, and propensity to fracture.

Insect farming is frequently promoted as a sustainable food solution, yet current evidence challenges many environmental benefits claimed by industry proponents. This review critically examines the scientific foundation for assessing the environmental impacts of insect farming in both human food and animal feed applications. Our analysis reveals substantial limitations in existing research. Most studies have been conducted in small-scale settings, which may not accurately reflect real-world, industrial conditions. There are significant uncertainties, with many authors highlighting the fact that the future environmental impact of large-scale insect production is unknown. This is especially true given claims that insects can be fed on food waste and that insect frass can be used as fertiliser, both of which have considerable challenges to overcome at scale. Furthermore, insect-based foods predominantly substitute for plant products with limited environmental impact rather than meat, while evidence indicates that insect feed and pet food applications, when not utilising genuine food waste, generate greater environmental impacts than conventional alternatives. By providing a comprehensive overview, this review highlights key areas for further research and ensures policymakers have a clearer picture of the remaining uncertainties surrounding this emerging industry.

In plants, sexual selection is argued to operate through reproduction to shape plant traits. Pollen size and style length are two traits that potentially reflect male-male competition and female choice. Adaptations in one trait may elicit an evolutionary response in the other, leading to correlated evolution at higher taxonomic levels. Many studies have examined their correlation across diverse taxonomic groups, with inconsistent results that limit our understanding of the selective forces and processes affecting these traits. To address this, we conducted a comprehensive meta-analysis on 51 studies from 43 published articles. The results uncovered a significant positive correlation between pollen size and style length across studies. To validate this finding further, we compiled a data set comprising 1041 species from 421 genera in 89 families, with measurements of both pollen size and style length. Phylogenetically controlled analyses confirmed a consistent positive correlation between these traits. Furthermore, our analysis revealed a significant effect of pollination vector on pollen size variation. Specifically, mammal-pollinated species produced substantially larger pollen grains, while wind-pollinated species showed no significant difference in size relative to those pollinated by Diptera, Hymenoptera, or Aves. Pollen size also exhibited a negative correlation with pollen number at macroevolutionary scales. Overall, this study underscores a correlated evolutionary pattern between pollen size and style length across angiosperms, calling for more in-depth investigations on the mechanisms by which sexual selection shapes traits that convey male competitive ability and female preference.

A series of terminological, technical, conceptual, and statistical challenges present themselves when trying to study correlations between measures of performance abilities (what an animal can do) and behavioural traits (what an animal chooses to do). We attempt to synthesise literature on this topic, with a specific focus on locomotor performance and behavioural traits measured with standardised tests. We argue that measures of forced performance (e.g. endurance on a motorised treadmill) and voluntary behaviour (e.g. wheel running) often fall along a continuum, sometimes grading into each other. On the performance end of the continuum, tests should measure what an animal can do when motivation is maximal and/or it is given no choice but to exert itself maximally. On the behavioural end of the continuum, tests should capture what animals choose to do of their own free volition, with no experimental attempt to affect motivation. Hence, performance tests attempt to eliminate variation in motivation by forcing all individuals to be maximally motivated, whereas variation in motivation is an inherent component of all behavioural tests. In some cases, however, differentiating between measures of performance versus behaviour can seem almost arbitrary. Moreover, individuals may consistently differ in how willing they are to ‘perform’ even when ‘forced’ to do so. We compiled studies reporting any association (covariation, correlation or linear regression) between putative measures of locomotor performance and behaviour in various taxa. The vast majority of those studies report phenotypic correlations, and only a handful have reported genetic correlations or explored potential correlated responses to selection on performance or behaviour. To our knowledge, this is the first global overview of how locomotor performance and behaviour covary in animals, and we believe that our synthesis will be useful to guide future research on locomotor performance and its relationship with other ecologically relevant traits. For example, we argue that a multi-level (co)variance partitioning approach is necessary to gain insights into the importance of how motivation differs across levels (e.g. among- versus within-individual variation, genetic versus environmental variation). Finally, we outline a multitude of compensation and co-specialisation mechanisms that may occur between performance and behaviour, and propose future avenues for research that include selection and manipulative studies to help identify the role of correlational selection, individual experience, and predation detectability on the relationships between behaviour and performance.