Due to their limited ranges and inherent isolation, island species have long been recognized as crucial systems for tackling a range of evolutionary questions, including in the early study of speciation.1,2 Such species have been less studied in the understanding of the evolutionary forces driving DNA sequence evolution. Island species usually have lower census population sizes (N) than continental

The mushroom body (MB) of Drosophila melanogaster has multiple functions in controlling memory and behavior.1, 2, 3, 4, 5, 6, 7, 8, 9 However, circuit mechanisms that generate this functional diversity are largely unclear. Here, we systematically probed the behavioral contribution of each type of MB output neuron (MBON) by blocking during acquisition, retention, or retrieval of reward or punishment

The Frankfurt specimen of Psittacosaurus sp. (SMF R 4970) from the Early Cretaceous Jehol deposits of Liaoning (Figure S1) exhibits the best preservation of scale-clad integument in any non-avian dinosaur yet described1. Preservation of colour patterns and countershading allowed a detailed reconstruction of this individual’s physical appearance suggesting it was camouflaged for life in a shaded lighting

Risk denialism and “alternative facts” as championed by the outgoing US president have cost many lives in the COVID-19 pandemic and are on track to cost many more in the climate catastrophe. After years of growing disconnect between public discourse and reality, how can societies return to a consensual view of established truth? Michael Gross investigates.

The diverse ways and environments in which animals move are correlated with morphology1, but morphology is not sufficient to predict how animals move because behavioral innovations can create new capacities. We document a new mode of snake locomotion — ‘lasso locomotion’ — that allows the brown treesnake (Boiga irregularis) to ascend much larger smooth cylinders than any previously known behavior.

A new study of the macaque visual cortex has revealed that visual area V4 performs substantial analysis of solid shape structure. The findings draw new attention to the embedding of local three-dimensional shape analysis into the early cortical stages of visual processing.

In species with intense male competition, reproducing at the wrong time can have dire consequences for females. A new study of wild gelada monkeys finds that females delay or accelerate puberty to moderate the risks of inbreeding and infanticide.

Faces are complex objects of great variety, which the visual brain somehow manages to organize by similarity. Two such orderings in fact exist and one, a new study finds, is transformed into the other over time, enhancing a face’s distinctiveness.

The replication band in the macronucleus of ciliated protozoa has fascinated microscopists since the 19th Century. It migrates through the nucleus, corresponding to a region of DNA replication and nascent chromatin assembly. A new study shows that calcium and actin filaments may participate in the formation and migration of the replication band.

When flowers provide nectar, they can count on visits, and potential pollen transport, by many kinds of nectar-drinking animals. Yet, some flowers instead offer fatty oils that certain specialized bees gather with their forelegs. A recent study reveals how such a switch occurred and may have contributed to the formation of a new species.

New work shows that the glycocalyx meshwork on the surface of macrophages prevents phagocytic receptors from binding their ligands by two means — electrostatic charge and steric hindrance. Components of this barrier are present on pathogenic and malignant targets that elude phagocytosis.

We build models of the world around us to guide perception and learning in the face of uncertainty. New evidence reveals a neurocomputational mechanism that links predictive processes across cognitive domains.

A new study has identified genes that protect Caenorhabditis elegans from hypoxic stress. Genomic approaches and whole-organism proteomics reveal a regulatory interaction between a threonyl-tRNA synthetase and ribosome biogenesis that modulates global translation and hypoxic sensitivity.

Calcium signalling in astrocytes modulates sleep, yet how astrocytes communicate with neural circuits that control sleep is unclear. A new study now uncovers a calcium-dependent relay between astrocytes and neurons that promotes sleep homeostasis in fruit flies.

Animals display a diversity of life cycles, including larvae in some lineages but not in others. A new study reveals a shared genetic toolkit in many animals that regulates the transition to the juvenile form, from an embryo or a larva.

Norepinephrine and acetylcholine regulate brain activity during changes in arousal and attention that are also reflected in fluctuations of the pupil. New research suggests that during goal-directed behavior, serotonin is also associated with pupil dilation.

Centromeres, the chromosomal loci that ensure chromosome segregation by directing kinetochore assembly, are typically marked by the histone CENP-A. A study in CENP-A-deficient insects finds that virtually any chromosomal region with low nucleosome turnover can assemble kinetochores, highlighting the extraordinary plasticity of holocentromeres.

Sleep is critical for diverse aspects of brain function in animals ranging from invertebrates to humans. Powerful genetic tools in the fruit fly Drosophila melanogaster have identified — at an unprecedented level of detail — genes and neural circuits that regulate sleep. This research has revealed that the functions and neural principles of sleep regulation are largely conserved from flies to mammals

The timing of behavior under natural light-dark conditions is a function of circadian clocks and photic input pathways, but a mechanistic understanding of how these pathways collaborate in animals is lacking. Here we demonstrate in Drosophila that the Phosphatase of Regenerating Liver-1 (PRL-1) sets period length and behavioral phase gated by photic signals. PRL-1 knockdown in PDF clock neurons dramatically

Sleep is under homeostatic control, whereby increasing wakefulness generates sleep need and triggers sleep drive. However, the molecular and cellular pathways by which sleep need is encoded are poorly understood. In addition, the mechanisms underlying both how and when sleep need is transformed to sleep drive are unknown. Here, using ex vivo and in vivo imaging, we show in Drosophila that astroglial

The ability to represent and respond to uncertainty is fundamental to human cognition and decision-making. Noradrenaline (NA) is hypothesized to play a key role in coordinating the sensory, learning, and physiological states necessary to adapt to a changing world, but direct evidence for this is lacking in humans. Here, we tested the effects of attenuating noradrenergic neurotransmission on learning

The timing of female maturation in wild mammals is often constrained by ecological variables that relate to food acquisition. However, maturational timing in female mammals can also respond to social variables. Specifically, the arrival of novel males can accelerate maturation while the presence of related males can inhibit it. Despite studies on more than two dozen mammalian taxa in captivity, evidence

The transition from the Late Neolithic to the Bronze Age has witnessed important population and societal changes in western Europe.1 These include massive genomic contributions of pastoralist herders originating from the Pontic-Caspian steppes2,3 into local populations, resulting from complex interactions between collapsing hunter-gatherers and expanding farmers of Anatolian ancestry.4, 5, 6, 7, 8

The insect sex determination and the intimately linked dosage compensation pathways represent a challenging evolutionary puzzle that has been solved only in Drosophila melanogaster. Analyses of orthologs of the Drosophila genes identified in non-drosophilid taxa1,2 revealed that evolution of sex determination pathways is consistent with a bottom-up mode,3 where only the terminal genes within the pathway

As writing systems are a relatively novel invention (slightly over 5 kya),1 they could not have influenced the evolution of our species. Instead, reading might recycle evolutionary older mechanisms that originally supported other tasks2,3 and preceded the emergence of written language. Accordingly, it has been shown that baboons and pigeons can be trained to distinguish words from nonwords based on

Organismal phenotypes usually have a quantitative distribution, and their genetic architecture can be studied by genome-wide association (GWA) mapping approaches. In most of such studies, it has become clear that many genes of moderate or small effects contribute to the phenotype.1, 2, 3, 4 Hence, the attention has turned toward the loci falling below the GWA cut-off, which may contribute to the phenotype

One of the main reasons why amputees report poor satisfaction with prostheses is their excessive weight perceived,1 despite the fact that they typically weigh less than half of the natural limb.2 Weight perception can be a subjective percept that is influenced by cognitive processes.3, 4, 5 Even though recent developments in prosthetics have shown that sensory feedback restoration positively influences

Toxin-antidote elements (TAs) are selfish genetic dyads that spread in populations by selectively killing non-carriers. TAs are common in prokaryotes, but very few examples are known in animals. Here, we report the discovery of maternal-effect TAs in both C. tropicalis and C. briggsae, two distant relatives of C. elegans. In C. tropicalis, multiple TAs combine to cause a striking degree of intraspecific

Stereocilia on auditory sensory cells are actin-based protrusions that mechanotransduce sound into an electrical signal. These stereocilia are arranged into a bundle with three rows of increasing length to form a staircase-like morphology that is required for hearing. Stereocilia in the shorter rows, but not the tallest row, are mechanotransducing because they have force-sensitive channels localized

Honeybees1 and bumblebees2 perform learning flights when leaving a newly discovered flower. During these flights, bees spend a portion of the time turning back to face the flower when they can memorize views of the flower and its surroundings. In honeybees, learning flights become longer when the reward offered by a flower is increased.3 We show here that bumblebees behave in a similar way, and we

Analysis of single-cell measurements of bacterial growth and division often relied on testing preconceived models of cell size control mechanisms. Such an approach could limit the scope of data analysis and prevent us from uncovering new information. Here, we take an “agnostic” approach by applying regression methods to multiple simultaneously measured cellular variables, which allow us to infer dependencies

The ongoing global COVID-19 pandemic calls for unprecedented efforts from the biosciences. In return it offers the opportunity to study an emerging pathogen and follow its spread and adaptation to the human host in real time. So far, the virus SARS-CoV-2 has only changed very subtly, which is good news for vaccination hopes. Michael Gross reports.

Bainbridge and Baker [1] argue that boundary extension (BE), false memory beyond a view, is an artifact of stimulus selection. They dismiss theoretical explanations that include scene construction [2,3], and suggest removal of BE from textbooks. Their empirical work is an admirable study of scene errors, but the bridge between their data and their sweeping conclusions about BE is not well-grounded

Intraub posits the existence of two separate processes in scene memory: one in which we automatically extrapolate the visual information in a scene beyond its boundaries (scene construction), and one in which we normalize our memories to either a schema or an average (normalization). She claims that scene construction will lead to transformations exclusively in the direction of boundary extension (BE)

In July 2016, a mummified carcass of an ancient wolf (Canis lupus) pup (specimen YG 648.1) was discovered in thawing permafrost in the Klondike goldfields, near Dawson City, Yukon, Canada (Figure 1A). The wolf pup mummy was recovered along a small tributary of Last Chance Creek during hydraulic thawing that exposed the permafrost sediment in which it was preserved. This mummified wolf pup is important

A new metagenomics study has shown that marine viruses recently acquired genes encoding light-gated ion channels from green algae. These so-called channelrhodopsin genes may allow the viruses to manipulate the swimming behavior of the algae they infect.

During a brief increase in temperature, cells undergoing spermatogenesis, but not oogenesis, activate transposons. This sexual dimorphism suggests that temperature stress during spermatogenesis provides a unique opportunity for transposons to mobilize and modify genomes, driving evolutionary change without substantially affecting reproduction.

Studies in island systems underpin much of our knowledge of macroevolution. A new study of the Galápagos giant daisies adds to this tradition. A time-calibrated phylogeny is presented that offers insights into the factors associated with diversification, providing a framework for further studies to investigate processes underlying these findings.

An investigation of how mitotic spindle size scales with cell size in early zebrafish embryos reveals fundamental principles of spindle organization. Spindle size depends primarily on microtubule number, which is regulated by a reaction–diffusion system when cells are large, and by signals from the plasma membrane when they are small.

The mode and tempo of human dispersal to the far-flung Pacific Islands has been a source of fascination for centuries. New ancient DNA data from the archipelago of Vanuatu shed light on the ancient migrations that shaped the history of human settlement in the Pacific.

Whilst tissues form during development, some cells are extruded from epithelial monolayers. Rather than dying or differentiating, a new study shows that displaced cells can reintegrate after dividing. Surprisingly, this ‘intrusion’ pathway shares common features with axon guidance.

A new study that regularly resets the background community to time zero shows how eco-evolutionary dynamics affect bacteria living in a diverse community.

Recognizing and remembering dangerous pathogens is of the utmost importance for an animal's survival. Nematodes use a digested bacterial small RNA molecule as a cue of pathogenicity. Inheritance of this RNA even protects the progeny from infection.