Current Biology最新文献

Knowledge of how animals respond to weather and changes in their physical environment is increasingly important, given the higher frequency of extreme weather recorded in recent years and its forecasted increase globally.^1,2 Even species considered to be highly adapted to extremes of weather, as albatrosses are to strong winds,^3,4,5 may be disadvantaged by shifts in those extremes. Tracked albatrosses were shown recently to avoid storms and the strongest associated winds.⁶ The drivers of this response are so far unknown, though we hypothesize that turbulent storm conditions restrict foraging success, possibly by reducing the detectability or accessibility of food, and albatrosses divert toward more profitable conditions where possible. We tested the impact of the physical environment-wind speed, rainfall, water clarity, and time of day-on feeding activity and success of two species of albatrosses with contrasting foraging strategies. We tracked 33 wandering and 48 black-browed albatrosses from Bird Island (South Georgia) with GPS and immersion loggers, and 19 and 7 individuals, respectively, with stomach-temperature loggers to record ingestions, providing an in-depth picture of foraging behavior. Reduced foraging profitability (probability of prey capture and overall mass) was associated with stormy conditions, specifically strong winds and heavy rain in surface-seizing wandering albatrosses, and the probability of prey capture was reduced in strong winds in black-browed albatrosses. We show that even highly wind-adapted species may frequently encounter conditions that make foraging difficult, giving context to storm avoidance in albatrosses.

Many specialized herbivorous insects sequester single classes of toxic secondary metabolites from their host plants as protection against natural enemies. If and how herbivores can use multiple classes of plant toxins across the large chemical diversity of plants for self-protection is unknown. We show that the polyphagous adults of the beetle Diabrotica virgifera are capable of selectively accumulating benzoxazinoids, cucurbitacins, and glucosinolates but not cyanogenic glycosides. Female beetles transfer the sequestered defense metabolites into their eggs, protecting them against generalist predators. Eggs containing a mixture of toxins are better protected than eggs with individual toxins. This work shows how herbivores can exploit plant chemical diversity to their own benefit as a novel adaptive mechanism that contributes to the structuring of multitrophic interaction networks.

The causes of heterogeneity in evolutionary rates are a key question in macroevolution. Origination and extinction rates are closely related to abiotic factors, such as climate^1,2 and geography,^3,4 as well as biotic factors such as taxonomic richness^5,6 and morphology,⁷ which are influenced by phylogeny.^8,9 Studies on the relationship between morphology and macroevolution have focused on morphological traits, including body size,^6,7,9 shape,¹⁰ color,^11,12 and complexity,^13,14,15 and have proposed biological laws, such as the zero-force evolutionary law¹⁶ and Cope's rule.¹⁷ However, the relationship between morphological complexity and turnover rates remains poorly defined because of the lack of suitable measures for various subjects.^18,19 Here, we establish a quantitative method, the two-dimensional ornamentation index (2D-OI), which allows the description of the ornamental complexity of ammonoids. Ammonoids are one of the most abundant and well-studied fossil groups, with complex conch structures.²⁰ Ammonoids display some similarities with trilobites and mammals^21,22 in terms of their high evolutionary rates; however, the underlying mechanisms remain elusive. Moreover, ammonoids exhibit marked heterogeneity in turnover rates across spatiotemporal scales²³ and clades,^23,24 making them key clades for investigating the relationship between turnover rates and morphological complexity. The results show that morphologically complex genera and species often have higher origination and extinction rates than morphologically simple taxa. Diversity fluctuations of taxa with complex ornamentation generally overimprint and control the overall net diversification rates of ammonoids. This double-edged sword of rapid evolution and increased extinction risk driven by complex morphologies has significant implications for our understanding of how species survive over geological timescales.

Theory predicts that performance-based habitat choice^1,2,3-where individuals select environments based on their local performance-should be widespread in nature and significantly influence ecological and evolutionary processes, including local adaptation, population divergence, reproductive isolation, and speciation.^{2,4,5,6,7,8,9} However, experimental evidence supporting these predictions has been largely lacking. In this study, we addressed this by inducing performance-based habitat choice in wild tree sparrows (Passer montanus) through the manipulation of differential access to transponder-operated feeders in two adjacent woodland areas. Sparrows overwhelmingly chose to move to and breed in the area where their feeding performance was highest, leading to local adaptation and increased reproductive success. Moreover, this non-random movement led to a high degree of assortative mating for transponder type and to reproductive isolation with respect to this ecological trait-all within a single generation. Our findings provide an empirical proof of principle that performance-based habitat choice can drive adaptive population divergence, even in the absence of divergent natural selection, underscoring its potential role as a key mechanism in ecological and evolutionary dynamics. This highlights the importance of integrating performance-based habitat choice into broader frameworks of adaptation and speciation, especially in the context of rapidly changing environments.

Concepts describe how instances of the same kind are related, enabling the categorization and interpretation of new information.^1,2 How concepts are represented is a longstanding question. Category boundaries have been considered defining features of concept representations, which can guide categorical inference,³ with fMRI evidence showing category-boundary signals in the hippocampus.^4,5 The underlying neural mechanism remains unclear. The hippocampal-entorhinal system, known for its spatially tuned neurons that form cognitive maps of space,^6,7 may support conceptual knowledge formation, with place cells encoding locations in conceptual space.^4,8,9,10,11 Physical boundaries anchor spatial representations and boundary shifts affect place and grid fields,^{12,13,14,15,16} as well as human spatial memory,^17,18,19 along manipulated dimensions. These place cell responses are likely driven by boundary vector cells, which respond to boundaries at specific allocentric distances and directions,^20,21,22,23 the neural correlates of which have been identified in the subiculum and entorhinal cortex^20,24,25. We hypothesize similar patterns of memory adaptations in response to shifting category boundaries. Our findings show that after category boundary shifts, participants' memory for category exemplars distorts along the changed dimension, mirroring place field deformations. We demonstrate that the boundary vector cell model of place cell firing best accounts for these distortions compared with alternative geometric explanations. Our study highlights a role of category boundaries in human cognition and establishes a new complementary link between hippocampal coding properties with respect to boundaries and human concept representation, bridging spatial and conceptual domains.

The "short-great-appendage" arthropods (Megacheira), such as Leanchoilia, have featured heavily in discussions of arthropod evolution, particularly related to the head and its appendages.^1,2,3,4 Megacheirans are subject to competing interpretations, either as a clade⁴ or a grade,⁵ in the stem group of Euarthropoda⁶ or, alternatively, Chelicerata.⁴ They are most diverse in Cambrian Burgess-Shale-type deposits, where the family Leanchoiliidae is represented by six genera,^{7,8,9,10,11,12} characterized by the presence of three distal flagella on the great appendage with a presumed sensory function. We describe the first post-Cambrian member of this family, Lomankus edgecombei gen. et sp. nov, from the Upper Ordovician (Katian) Beecher's Trilobite Bed site of New York State-the first post-Cambrian megacheiran with the exception of the Silurian and Devonian Enaliktidae. Micro-computed tomography (micro-CT) scanning reveals the morphology of the short great appendage with elongate flagella, four biramous cephalic limbs, 11 trunk segments with biramous limbs and dorsal tergites, and an elongate telson unique within Leanchoiliidae. The great appendage is also unique: the long endites that bear the flagella in other leanchoiliids are absent (or at least greatly reduced) and each flagellum appears to attach directly to an individual podomere, suggesting a sensory rather than a raptorial function. The remarkable preservation of a well-developed ventral plate (epistome-labrum complex) anterior of the mouth reinforces a deutocerebral origin^2,13 of the short great appendages. Lomankus edgecombei unveils the three-dimensional (3D) head morphology of leanchoiliids in unparalleled detail and demonstrates that these iconic fossil arthropods ranged into dysaerobic environments in the Ordovician, where Lomankus occupied a deposit-feeding niche.

Identifying a suitable mating partner is an ancient and critical biological problem. How a fruit fly distinguishes a fly of the same species from flies of innumerable related species remains unclear. We analyze the Ir52 receptors, expressed in taste neurons on the fly legs and encoded by a cluster of genes. We find that the cluster shows dynamic evolution, rapidly expanding and contracting over evolutionary time. We develop a novel in vivo expression system and find that Ir52 receptors respond differently to pheromone extracts of different fly species. The receptors are activated by some compounds and inhibited by others, with different receptors showing distinct response profiles. Circuit mapping shows that Ir52 neurons are pre-synaptic to sexually dimorphic neurons that overlap with neurons acting in courtship behavior. Our results support a model in which Ir52 receptors detect information about the species of a potential mating partner.

Residues of plant protection products (PPPs) are frequently detected in bee matrices^1,2,3,4,5,6 due to foraging bees collecting contaminated nectar and pollen, which they bring back to their hive. The collected material is further used by nurse bees to produce glandular secretions for feeding their larvae.⁷ Potential exposure to PPPs occurs through direct oral ingestion, contact during foraging, or interaction with contaminated hive material.^8,9 Contaminants can pose health risks to adult worker bees,^10,11 queens,^12,13 drones (males),¹⁴ or larvae,^15,16 potentially impacting colony health and productivity. However, residue concentrations can vary significantly between analyzed matrices, and potential accumulation or dilution steps have not been widely investigated. Although research has provided valuable insights into contamination risks, there remain gaps in our understanding of the entire pathway from field, via foragers, stored products, nurse bees, and finally to food jelly, i.e., royal, worker, and drone jelly, and the larvae, including all possible processing steps.¹⁷ We collected samples of bee-relevant matrices following the in-field spray application of the product Pictor Active, containing the fungicides boscalid and pyraclostrobin. The samples were analyzed for residues along this entire pathway. Fungicide residues were reduced by a factor of 8-80 from stored product to nurse bees' heads, suggesting a filtering function of nurse bees. Furthermore, detected residues in larval food jelly resulted from added pollen and not from nurse bee secretions. Calculated risk quotients were at least twice as low as the threshold values, suggesting a low risk to honey bee colonies from these fungicides at the tested application rate.

Nuclear positioning is a crucial aspect of cell and developmental biology. One example is the apical movement of nuclei in neuroepithelia before mitosis, which is essential for proper tissue formation. While the cytoskeletal mechanisms that drive nuclei to the apical side have been explored, the influence of nuclear properties on apical nuclear migration is less understood. Nuclear properties, such as deformability, can be linked to lamin A/C expression levels, as shown in various in vitro studies. Interestingly, many nuclei in early development, including neuroepithelial nuclei, express only low levels of lamin A/C. Therefore, we investigated whether increased lamin A expression in the densely packed zebrafish retinal neuroepithelium affects nuclear deformability and, consequently, migration phenomena. We found that overexpressing lamin A in retinal nuclei increases nuclear stiffness, which in turn indeed impairs apical nuclear migration. Interestingly, nuclei that do not overexpress lamin A but are embedded in a stiffer lamin A-overexpressing environment also exhibit impaired apical nuclear migration, indicating that these effects can be cell non-autonomous. Additionally, in the less crowded hindbrain neuroepithelium, only minor effects on apical nuclear migration are observed. Together, this suggests that the material properties of the nucleus influence nuclear movements in a tissue-dependent manner.

Efficient elimination of apoptotic cells within epithelial cell sheets is crucial for preserving epithelial barrier integrity.¹ It is well established that immediate neighbors of an apoptotic cell actively participate in its removal by enclosing it within a wall of actomyosin, pushing it out in a purse-string manner in a process called apical extrusion.^2,3,4,5,6,7 Here, we found that sustained elevation of calcium ions in neighboring epithelial cells is necessary to generate the contractility required for apoptotic cell elimination. This phenomenon, which we call calcium response in effectors of apical extrusion (CaRE), highlights the disparate calcium dynamics within the epithelial sheet. Furthermore, we elucidate the essential role of desmosomes in CaRE. Specifically, we identify a subset of IP3 receptors within the endoplasmic reticulum that is recruited to the desmosome by K-Ras-induced actin-binding protein as the core component of this process. The interplay between these cellular structures heightens actomyosin contractility to drive apoptotic cell removal. Our findings underscore the physiological significance of integrating desmosomes with the endoplasmic reticulum in epithelial sheet homeostasis, shedding new light on cell-cell communication and tissue maintenance.