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Ocean acidification but not warming alters sex determination in the Sydney rock oyster, Saccostrea glomerata
Whether sex determination of marine organisms can be altered by ocean acidification and warming during this century remains a significant, unanswered question. Here, we show that exposure of the protandric hermaphrodite oyster, Saccostrea glomerata to ocean acidification, but not warming, alters sex determination resulting in changes in sex ratios. After just one reproductive cycle there were 16% more females than males. The rate of gametogenesis, gonad area, fecundity, shell length, extracellular pH and survival decreased in response to ocean acidification. Warming as a sole stressor slightly increased the rate of gametog...
Source: Proceedings of the Royal Society B: Biological Sciences - February 14, 2018 Category: Biology Authors: Parker, L. M., O'Connor, W. A., Byrne, M., Dove, M., Coleman, R. A., Pörtner, H.-O., Scanes, E., Virtue, P., Gibbs, M., Ross, P. M. Tags: ecology, environmental science Global change and conservation Source Type: research

Whole genome duplication and transposable element proliferation drive genome expansion in Corydoradinae catfishes
Genome size varies significantly across eukaryotic taxa and the largest changes are typically driven by macro-mutations such as whole genome duplications (WGDs) and proliferation of repetitive elements. These two processes may affect the evolutionary potential of lineages by increasing genetic variation and changing gene expression. Here, we elucidate the evolutionary history and mechanisms underpinning genome size variation in a species-rich group of Neotropical catfishes (Corydoradinae) with extreme variation in genome size—0.6 to 4.4 pg per haploid cell. First, genome size was quantified in 65 species and mapped o...
Source: Proceedings of the Royal Society B: Biological Sciences - February 14, 2018 Category: Biology Authors: Marburger, S., Alexandrou, M. A., Taggart, J. B., Creer, S., Carvalho, G., Oliveira, C., Taylor, M. I. Tags: genetics, genomics, evolution Genetics and genomics Source Type: research

The influence of the few: a stable 'oligarchy controls information flow in house-hunting ants
Animals that live together in groups often face difficult choices, such as which food resource to exploit, or which direction to flee in response to a predator. When there are costs associated with deadlock or group fragmentation, it is essential that the group achieves a consensus decision. Here, we study consensus formation in emigrating ant colonies faced with a binary choice between two identical nest-sites. By individually tagging each ant with a unique radio-frequency identification microchip, and then recording all ant-to-ant ‘tandem runs’—stereotyped physical interactions that communicate informat...
Source: Proceedings of the Royal Society B: Biological Sciences - February 14, 2018 Category: Biology Authors: Richardson, T. O., Mullon, C., Marshall, J. A. R., Franks, N. R., Schlegel, T. Tags: behaviour, ecology Source Type: research

Trade-offs between microbial growth phases lead to frequency-dependent and non-transitive selection
Mutations in a microbial population can increase the frequency of a genotype not only by increasing its exponential growth rate, but also by decreasing its lag time or adjusting the yield (resource efficiency). The contribution of multiple life-history traits to selection is a critical question for evolutionary biology as we seek to predict the evolutionary fates of mutations. Here we use a model of microbial growth to show that there are two distinct components of selection corresponding to the growth and lag phases, while the yield modulates their relative importance. The model predicts rich population dynamics when ther...
Source: Proceedings of the Royal Society B: Biological Sciences - February 14, 2018 Category: Biology Authors: Manhart, M., Adkar, B. V., Shakhnovich, E. I. Tags: microbiology, theoretical biology, evolution Source Type: research

Wound treatment and selective help in a termite-hunting ant
Open wounds are a major health risk in animals, with species prone to injuries likely developing means to reduce these risks. We therefore analysed the behavioural response towards open wounds on the social and individual level in the termite group-hunting ant Megaponera analis. During termite raids, some ants get injured by termite soldiers (biting off extremities), after the fight injured ants get carried back to the nest by nest-mates. We observed treatment of the injury by nest-mates inside the nest through intense allogrooming at the wound. Lack of treatment increased mortality from 10% to 80% within 24 h, most likely...
Source: Proceedings of the Royal Society B: Biological Sciences - February 14, 2018 Category: Biology Authors: Frank, E. T., Wehrhahn, M., Linsenmair, K. E. Tags: behaviour, evolution, health and disease and epidemiology Source Type: research

High rates of vessel noise disrupt foraging in wild harbour porpoises (Phocoena phocoena)
Shipping is the dominant marine anthropogenic noise source in the world's oceans, yet we know little about vessel encounter rates, exposure levels and behavioural reactions for cetaceans in the wild, many of which rely on sound for foraging, communication and social interactions. Here, we used animal-borne acoustic tags to measure vessel noise exposure and foraging efforts in seven harbour porpoises in highly trafficked coastal waters. Tagged porpoises encountered vessel noise 17–89% of the time and occasional high-noise levels coincided with vigorous fluking, bottom diving, interrupted foraging and even cessation of...
Source: Proceedings of the Royal Society B: Biological Sciences - February 14, 2018 Category: Biology Authors: Wisniewska, D. M., Johnson, M., Teilmann, J., Siebert, U., Galatius, A., Dietz, R., Madsen, P. T. Tags: behaviour, ecology, environmental science Source Type: research

Landscape configurational heterogeneity by small-scale agriculture, not crop diversity, maintains pollinators and plant reproduction in western Europe
Agricultural intensification is one of the main causes for the current biodiversity crisis. While reversing habitat loss on agricultural land is challenging, increasing the farmland configurational heterogeneity (higher field border density) and farmland compositional heterogeneity (higher crop diversity) has been proposed to counteract some habitat loss. Here, we tested whether increased farmland configurational and compositional heterogeneity promote wild pollinators and plant reproduction in 229 landscapes located in four major western European agricultural regions. High-field border density consistently increased wild ...
Source: Proceedings of the Royal Society B: Biological Sciences - February 14, 2018 Category: Biology Authors: Hass, A. L., Kormann, U. G., Tscharntke, T., Clough, Y., Baillod, A. B., Sirami, C., Fahrig, L., Martin, J.-L., Baudry, J., Bertrand, C., Bosch, J., Brotons, L., Burel, F., Georges, R., Giralt, D., Marcos-Garcia, M. A., Ricarte, A., Siriwardena, G., Batar Tags: ecology Source Type: research

Quantitative analysis of the complete larval settlement process confirms Crisp's model of surface selectivity by barnacles
For barnacle cypris larvae at the point of settlement, selection of an appropriate surface is critical. Since post-settlement relocation is usually impossible, barnacles have evolved finely tuned surface-sensing capabilities to identify suitable substrata, and a temporary adhesion system for extensive surface exploration. The pattern of exploratory behaviour appears complex and may last for several hours, imposing significant barriers to quantitative measurement. Here, we employ a novel tracking system that enables simultaneous analysis of the larval body movement of multiple individuals over their entire planktonic phase....
Source: Proceedings of the Royal Society B: Biological Sciences - February 14, 2018 Category: Biology Authors: Aldred, N., Alsaab, A., Clare, A. S. Tags: behaviour Source Type: research

Foraging and fasting can influence contaminant concentrations in animals: an example with mercury contamination in a free-ranging marine mammal
Large fluctuations in animal body mass in relation to life-history events can influence contaminant concentrations and toxicological risk. We quantified mercury concentrations in adult northern elephant seals (Mirounga angustirostris) before and after lengthy at sea foraging trips (n = 89) or fasting periods on land (n = 27), and showed that mercury concentrations in blood and muscle changed in response to these events. The highest blood mercury concentrations were observed after the breeding fast, whereas the highest muscle mercury concentrations were observed when seals returned to land to moult. Mean female blood mercur...
Source: Proceedings of the Royal Society B: Biological Sciences - February 7, 2018 Category: Biology Authors: Peterson, S. H., Ackerman, J. T., Crocker, D. E., Costa, D. P. Tags: physiology, ecology, environmental science Source Type: research

Seed ingestion and germination in rattlesnakes: overlooked agents of rescue and secondary dispersal
Seed dispersal is a key evolutionary process and a central theme in the population ecology of terrestrial plants. The primary producers of most land-based ecosystems are propagated by and maintained through various mechanisms of seed dispersal that involve both abiotic and biotic modes of transportation. By far the most common biotic seed transport mechanism is zoochory, whereby seeds, or fruits containing them, are dispersed through the activities of animals. Rodents are one group of mammals that commonly prey on seeds (granivores) and play a critical, often destructive, role in primary dispersal and the dynamics of plant...
Source: Proceedings of the Royal Society B: Biological Sciences - February 7, 2018 Category: Biology Authors: Reiserer, R. S., Schuett, G. W., Greene, H. W. Tags: ecology, evolution Source Type: research

Deep-sea starfish from the Arctic have well-developed eyes in the dark
Asteroids, starfish, are important members of the macro-benthos in almost all marine environments including the deep sea. Starfish are in general assumed to be largely olfactory guided, but recent studies have shown that two tropical shallow water species rely on vision alone to find their habitat at short distances. Their compound eyes are found at the tip of each arm and they vary little between examined species. Still, nothing is known about vision in the species found in the aphotic zone of the deep sea or whether they even have eyes. Here, 13 species of starfish from Greenland waters, covering a depth range from shall...
Source: Proceedings of the Royal Society B: Biological Sciences - February 7, 2018 Category: Biology Authors: Birk, M. H., Blicher, M. E., Garm, A. Tags: neuroscience, behaviour, ecology Neuroscience and cognition Source Type: research

Diversity change during the rise of tetrapods and the impact of the 'Carboniferous rainforest collapse
The Carboniferous and early Permian were critical intervals in the diversification of early four-limbed vertebrates (tetrapods), yet the major patterns of diversity and biogeography during this time remain unresolved. Previous estimates suggest that global tetrapod diversity rose continuously across this interval and that habitat fragmentation following the ‘Carboniferous rainforest collapse’ (CRC) drove increased endemism among communities. However, previous work failed to adequately account for spatial and temporal biases in sampling. Here, we reassess early tetrapod diversity and biogeography with a new glob...
Source: Proceedings of the Royal Society B: Biological Sciences - February 7, 2018 Category: Biology Authors: Dunne, E. M., Close, R. A., Button, D. J., Brocklehurst, N., Cashmore, D. D., Lloyd, G. T., Butler, R. J. Tags: palaeontology, evolution Palaeobiology Source Type: research

How oxygen gave rise to eukaryotic sex
How did full meiotic eukaryotic sex evolve and what was the immediate advantage allowing it to develop? We propose that the crucial determinant can be found in internal reactive oxygen species (ROS) formation at the start of eukaryotic evolution approximately 2 x 109 years ago. The large amount of ROS coming from a bacterial endosymbiont gave rise to DNA damage and vast increases in host genome mutation rates. Eukaryogenesis and chromosome evolution represent adaptations to oxidative stress. The host, an archaeon, most probably already had repair mechanisms based on DNA pairing and recombination, and possibly some kind of ...
Source: Proceedings of the Royal Society B: Biological Sciences - February 7, 2018 Category: Biology Authors: Hörandl, E., Speijer, D. Tags: biochemistry, physiology, evolution Review articles Source Type: research

Profound genetic divergence and asymmetric parental genome contributions as hallmarks of hybrid speciation in polyploid toads
The evolutionary causes and consequences of allopolyploidization, an exceptional pathway to instant hybrid speciation, are poorly investigated in animals. In particular, when and why hybrid polyploids versus diploids are produced, and constraints on sources of paternal and maternal ancestors, remain underexplored. Using the Palearctic green toad radiation (including bisexually reproducing species of three ploidy levels) as model, we generate a range-wide multi-locus phylogeny of 15 taxa and present four new insights: (i) at least five (up to seven) distinct allotriploid and allotetraploid taxa have evolved in the Pleistoce...
Source: Proceedings of the Royal Society B: Biological Sciences - February 7, 2018 Category: Biology Authors: Betto-Colliard, C., Hofmann, S., Sermier, R., Perrin, N., Stöck, M. Tags: genetics, evolution Source Type: research

Rapid juvenile hormone downregulation in subordinate wasp queens facilitates stable cooperation
In this study, we randomly assigned wasps to cooperative groups, assessed dominance behaviour during group formation, then measured levels of juvenile hormone (JH), a hormone that mediates Polistes fertility. Within three hours, lowest ranking subordinates had less JH than dominants or solitary controls, indicating that group formation caused rapid JH reduction in low-ranking subordinates. In a second experiment, we measured the behavioural consequences of experimentally increasing subordinate JH. Subordinates with high JH-titres received significantly more aggression than control subordinates or subordinates from groups w...
Source: Proceedings of the Royal Society B: Biological Sciences - February 7, 2018 Category: Biology Authors: Tibbetts, E. A., Fearon, M. L., Wong, E., Huang, Z. Y., Tinghitella, R. M. Tags: behaviour, physiology Source Type: research

Repeatable group differences in the collective behaviour of stickleback shoals across ecological contexts
Establishing how collective behaviour emerges is central to our understanding of animal societies. Previous research has highlighted how universal interaction rules shape collective behaviour, and that individual differences can drive group functioning. Groups themselves may also differ considerably in their collective behaviour, but little is known about the consistency of such group variation, especially across different ecological contexts that may alter individuals' behavioural responses. Here, we test if randomly composed groups of sticklebacks differ consistently from one another in both their structure and movement ...
Source: Proceedings of the Royal Society B: Biological Sciences - February 7, 2018 Category: Biology Authors: Jolles, J. W., Laskowski, K. L., Boogert, N. J., Manica, A. Tags: behaviour, ecology Source Type: research

Genomics of end-Pleistocene population replacement in a small mammal
Current species distributions at high latitudes are the product of expansion from glacial refugia into previously uninhabitable areas at the end of the last glaciation. The traditional view of postglacial colonization is that southern populations expanded their ranges into unoccupied northern territories. Recent findings on mitochondrial DNA (mtDNA) of British small mammals have challenged this simple colonization scenario by demonstrating a more complex genetic turnover in Britain during the Pleistocene–Holocene transition where one mtDNA clade of each species was replaced by another mtDNA clade of the same species....
Source: Proceedings of the Royal Society B: Biological Sciences - February 7, 2018 Category: Biology Authors: Kotlik, P., Markova, S., Konczal, M., Babik, W., Searle, J. B. Tags: evolution Source Type: research

Evidence for parent-of-origin effects and interparental conflict in seeds of an ancient flowering plant lineage
Theoretical and empirical studies have long connected the evolutionary innovation of endosperm, a genetically biparental product of a double fertilization process unique to flowering plants (angiosperms), to conflicting parental interests over offspring provisioning. Yet, none of these studies examined interparental conflict in representatives of any of the most ancient angiosperm lineages. We performed reciprocal interploidy crosses in the water lily Nymphaea thermarum, a member of one of the most ancient angiosperm lineages, Nymphaeales. We find that an excess of paternal genomes is associated with an increase in endospe...
Source: Proceedings of the Royal Society B: Biological Sciences - February 7, 2018 Category: Biology Authors: Povilus, R. A., Diggle, P. K., Friedman, W. E. Tags: plant science, evolution Source Type: research

Evolutionary time drives global tetrapod diversity
Global variation in species richness is widely recognized, but the explanation for what drives it continues to be debated. Previous efforts have focused on a subset of potential drivers, including evolutionary rate, evolutionary time (maximum clade age of species restricted to a region), dispersal (migration from one region to another), ecological factors and climatic stability. However, no study has evaluated these competing hypotheses simultaneously at a broad spatial scale. Here, we examine their relative contribution in determining the richness of the most comprehensive dataset of tetrapods to our knowledge (84% of the...
Source: Proceedings of the Royal Society B: Biological Sciences - February 7, 2018 Category: Biology Authors: Marin, J., Rapacciuolo, G., Costa, G. C., Graham, C. H., Brooks, T. M., Young, B. E., Radeloff, V. C., Behm, J. E., Helmus, M. R., Hedges, S. B. Tags: ecology, evolution Source Type: research

School is out on noisy reefs: the effect of boat noise on predator learning and survival of juvenile coral reef fishes
Noise produced by anthropogenic activities is increasing in many marine ecosystems. We investigated the effect of playback of boat noise on fish cognition. We focused on noise from small motorboats, since its occurrence can dominate soundscapes in coastal communities, the number of noise-producing vessels is increasing rapidly and their proximity to marine life has the potential to cause deleterious effects. Cognition—or the ability of individuals to learn and remember information—is crucial, given that most species rely on learning to achieve fitness-promoting tasks, such as finding food, choosing mates and re...
Source: Proceedings of the Royal Society B: Biological Sciences - January 31, 2018 Category: Biology Authors: Ferrari, M. C. O., McCormick, M. I., Meekan, M. G., Simpson, S. D., Nedelec, S. L., Chivers, D. P. Tags: cognition, ecology, environmental science Behaviour Source Type: research

Redirected aggression as a conflict management tactic in the social cichlid fish Julidochromis regani
This study provides, to our knowledge, the first evidence that redirected aggression functions to manage conflict in social fish. (Source: Proceedings of the Royal Society B: Biological Sciences)
Source: Proceedings of the Royal Society B: Biological Sciences - January 31, 2018 Category: Biology Authors: Ito, M. H., Yamaguchi, M., Kutsukake, N. Tags: behaviour Source Type: research

Equilibrium dynamics of European pre-industrial populations: the evidence of carrying capacity in human agricultural societies
Human populations tend to grow steadily, because of the ability of people to make innovations, and thus overcome and extend the limits imposed by natural resources. It is therefore questionable whether traditional concepts of population ecology, including environmental carrying capacity, can be applied to human societies. The existence of carrying capacity cannot be simply inferred from population time-series, but it can be indicated by the tendency of populations to return to a previous state after a disturbance. So far only indirect evidence at a coarse-grained scale has indicated the historical existence of human carryi...
Source: Proceedings of the Royal Society B: Biological Sciences - January 31, 2018 Category: Biology Authors: Fanta, V., Salek, M., Zouhar, J., Sklenicka, P., Storch, D. Tags: ecology Source Type: research

Reinterpretation of a previously described Jehol bird clarifies early trophic evolution in the Ornithuromorpha
STM35-3 from the Yixian Formation is the only Early Cretaceous ornithuromorph preserving direct evidence of granivory. The crop contains numerous seeds and the preservation of gastroliths presumably within the ventriculus indicates this diet was paired with the presence of a gastric mill as in living granivorous birds. STM35-3 was originally referred to Hongshanornis longicresta, member of a diverse clade of small, basal ornithuromorphs with elongate hindlimbs known as the Hongshanornithidae. Hindlimb proportions suggest that hongshanornithids were wading birds, an ecological inference somewhat in conflict with direct evid...
Source: Proceedings of the Royal Society B: Biological Sciences - January 31, 2018 Category: Biology Authors: Zheng, X., O'Connor, J. K., Wang, X., Wang, Y., Zhou, Z. Tags: palaeontology Palaeobiology Source Type: research

Evolutionary conserved neural signature of early life stress affects animal social competence
In vertebrates, the early social environment can persistently influence behaviour and social competence later in life. However, the molecular mechanisms underlying variation in animal social competence are largely unknown. In rats, high-quality maternal care causes an upregulation of hippocampal glucocorticoid receptors (gr) and reduces offspring stress responsiveness. This identifies gr regulation as a candidate mechanism for maintaining variation in animal social competence. We tested this hypothesis in a highly social cichlid fish, Neolamprologus pulcher, reared with or without caring parents. We find that the molecular...
Source: Proceedings of the Royal Society B: Biological Sciences - January 31, 2018 Category: Biology Authors: Nyman, C., Fischer, S., Aubin-Horth, N., Taborsky, B. Tags: molecular biology, behaviour, ecology Source Type: research

Low intensity blood parasite infections do not reduce the aerobic performance of migratory birds
Blood parasites (Haemosporidia) are thought to impair the flight performance of infected animals, and therefore, infected birds are expected to differ from their non-infected counterparts in migratory capacity. Since haemosporidians invade host erythrocytes, it is commonly assumed that infected individuals will have compromised aerobic capacity, but this has not been examined in free-living birds. We tested if haemosporidian infections affect aerobic performance by examining metabolic rates and exercise endurance in migratory great reed warblers (Acrocephalus arundinaceus) experimentally treated with Plasmodium relictum pG...
Source: Proceedings of the Royal Society B: Biological Sciences - January 31, 2018 Category: Biology Authors: Hahn, S., Bauer, S., Dimitrov, D., Emmenegger, T., Ivanova, K., Zehtindjiev, P., Buttemer, W. A. Tags: physiology, ecology, health and disease and epidemiology Source Type: research

Understanding heterogeneities in mosquito-bite exposure and infection distributions for the elimination of lymphatic filariasis
It is well known that individuals in the same community can be exposed to a highly variable number of mosquito bites. This heterogeneity in bite exposure has consequences for the control of vector-borne diseases because a few people may be contributing significantly to transmission. However, very few studies measure sources of heterogeneity in a way which is relevant to decision-making. We investigate the relationship between two classic measures of heterogeneity, spatial and individual, within the context of lymphatic filariasis, a parasitic mosquito-borne disease. Using infection and mosquito-bite data for five villages ...
Source: Proceedings of the Royal Society B: Biological Sciences - January 31, 2018 Category: Biology Authors: Irvine, M. A., Kazura, J. W., Hollingsworth, T. D., Reimer, L. J. Tags: health and disease and epidemiology Ecology Source Type: research

Imitation of novel conspecific and human speech sounds in the killer whale (Orcinus orca)
Vocal imitation is a hallmark of human spoken language, which, along with other advanced cognitive skills, has fuelled the evolution of human culture. Comparative evidence has revealed that although the ability to copy sounds from conspecifics is mostly uniquely human among primates, a few distantly related taxa of birds and mammals have also independently evolved this capacity. Remarkably, field observations of killer whales have documented the existence of group-differentiated vocal dialects that are often referred to as traditions or cultures and are hypothesized to be acquired non-genetically. Here we use a do-as-I-do ...
Source: Proceedings of the Royal Society B: Biological Sciences - January 31, 2018 Category: Biology Authors: Abramson, J. Z., Hernandez-Lloreda, M. V., Garcia, L., Colmenares, F., Aboitiz, F., Call, J. Tags: behaviour, cognition Source Type: research

Priority effects are weakened by a short, but not long, history of sympatric evolution
Priority effects, or the effects of species arrival history on local species abundances, have been documented in a range of taxa. However, factors determining the extent to which priority effects affect community assembly remain unclear. Using laboratory populations of the bacterium Pseudomonas fluorescens, we examined whether shared evolutionary history affected the strength of priority effects. We hypothesized that sympatric evolution of populations belonging to the same guild would lead to niche differentiation, resulting in phenotypic complementarity that weakens priority effects. Consistent with this hypothesis, we fo...
Source: Proceedings of the Royal Society B: Biological Sciences - January 31, 2018 Category: Biology Authors: Zee, P. C., Fukami, T. Tags: ecology, evolution Source Type: research

Social brain volume is associated with in-degree social network size among older adults
This study provides insight into understanding how the social brain is uniquely associated with sociocentric measures derived from a global network. (Source: Proceedings of the Royal Society B: Biological Sciences)
Source: Proceedings of the Royal Society B: Biological Sciences - January 24, 2018 Category: Biology Authors: Kwak, S., Joo, W.-t., Youm, Y., Chey, J. Tags: neuroscience, behaviour, cognition Neuroscience and cognition Source Type: research

Cooperative defence operates by social modulation of biogenic amine levels in the honey bee brain
The defence of a society often requires that some specialized members coordinate to repel a threat at personal risk. This is especially true for honey bee guards, which defend the hive and may sacrifice their lives upon stinging. Central to this cooperative defensive response is the sting alarm pheromone, which has isoamyl acetate (IAA) as its main component. Although this defensive behaviour has been well described, the neural mechanisms triggered by IAA to coordinate stinging have long remained unknown. Here we show that IAA upregulates brain levels of serotonin and dopamine, thereby increasing the likelihood of an indiv...
Source: Proceedings of the Royal Society B: Biological Sciences - January 24, 2018 Category: Biology Authors: Nouvian, M., Mandal, S., Jamme, C., Claudianos, C., d'Ettorre, P., Reinhard, J., Barron, A. B., Giurfa, M. Tags: neuroscience, behaviour Neuroscience and cognition Source Type: research

Phanerozoic pO2 and the early evolution of terrestrial animals
Concurrent gaps in the Late Devonian/Mississippian fossil records of insects and tetrapods (i.e. Romer's Gap) have been attributed to physiological suppression by low atmospheric pO2. Here, updated stable isotope inputs inform a reconstruction of Phanerozoic oxygen levels that contradicts the low oxygen hypothesis (and contradicts the purported role of oxygen in the evolution of gigantic insects during the late Palaeozoic), but reconciles isotope-based calculations with other proxies, like charcoal. Furthermore, statistical analysis demonstrates that the gap between the first Devonian insect and earliest diverse insect ass...
Source: Proceedings of the Royal Society B: Biological Sciences - January 24, 2018 Category: Biology Authors: Schachat, S. R., Labandeira, C. C., Saltzman, M. R., Cramer, B. D., Payne, J. L., Boyce, C. K. Tags: palaeontology, ecology, evolution Palaeobiology Source Type: research

Prevalence of disruptive selection predicts extent of species differentiation in Lake Victoria cichlids
Theory suggests that speciation with gene flow is most likely when both sexual and ecological selection are divergent or disruptive. Divergent sexual and natural selection on the visual system have been demonstrated before in sympatric, morphologically similar sister species of Lake Victoria cichlids, but this does not explain the subtle morphological differences between them. To investigate the significance of natural selection on morphology during speciation, we here ask whether the prevalence of disruptive ecological selection differs between sympatric sister species that are at different stages of speciation. Some of o...
Source: Proceedings of the Royal Society B: Biological Sciences - January 24, 2018 Category: Biology Authors: van Rijssel, J. C., Moser, F. N., Frei, D., Seehausen, O. Tags: ecology, evolution Source Type: research

Whole-body photoreceptor networks are independent of 'lenses in brittle stars
We present the first evidence of photoreceptor networks in three Ophiocoma species, both with and without microlenses and colour-changing behaviour. High-resolution microscopy, immunohistochemistry and synchrotron tomography demonstrate that putative photoreceptors cover the animals' oral, lateral and aboral surfaces, but are absent at the hypothesized focal points of the microlenses. The structural optics of these crystal ‘lenses’ are an exaptation and do not fulfil any apparent visual role. This contradicts previous studies, yet the photoreceptor network in Ophiocoma appears even more widespread than previous...
Source: Proceedings of the Royal Society B: Biological Sciences - January 24, 2018 Category: Biology Authors: Sumner-Rooney, L., Rahman, I. A., Sigwart, J. D., Ullrich-Lüter, E. Tags: behaviour, physiology, evolution Morphology and biomechanics Source Type: research

Simpler grammar, larger vocabulary: How population size affects language
Languages with many speakers tend to be structurally simple while small communities sometimes develop languages with great structural complexity. Paradoxically, the opposite pattern appears to be observed for non-structural properties of language such as vocabulary size. These apparently opposite patterns pose a challenge for theories of language change and evolution. We use computational simulations to show that this inverse pattern can depend on a single factor: ease of diffusion through the population. A population of interacting agents was arranged on a network, passing linguistic conventions to one another along netwo...
Source: Proceedings of the Royal Society B: Biological Sciences - January 24, 2018 Category: Biology Authors: Reali, F., Chater, N., Christiansen, M. H. Tags: cognition, computational biology, evolution Neuroscience and cognition Source Type: research

Simple decision rules underlie collaborative hunting in yellow saddle goatfish
Collaborative hunting, the coordination of animal behaviour in space and time to capture prey, is reported in several vertebrate species. However, previous studies are observational, hampering our ability to identify individual decision rules that result in collaboration. We experimentally investigated collaborative hunting in yellow saddle goatfish (Parupeneus cyclostomus) by exposing pairs to a mock prey that fled to an artificial shelter with multiple entrances. The first fish to initiate the chase (the ‘initiator’) was always closest to the prey and pursued it directly in its path. Conversely, the behaviour...
Source: Proceedings of the Royal Society B: Biological Sciences - January 24, 2018 Category: Biology Authors: Steinegger, M., Roche, D. G., Bshary, R. Tags: behaviour, ecology, evolution Source Type: research

Trust your gut: using physiological states as a source of information is almost as effective as optimal Bayesian learning
Approaches to understanding adaptive behaviour often assume that animals have perfect information about environmental conditions or are capable of sophisticated learning. If such learning abilities are costly, however, natural selection will favour simpler mechanisms for controlling behaviour when faced with uncertain conditions. Here, we show that, in a foraging context, a strategy based only on current energy reserves often performs almost as well as a Bayesian learning strategy that integrates all previous experiences to form an optimal estimate of environmental conditions. We find that Bayesian learning gives a strong ...
Source: Proceedings of the Royal Society B: Biological Sciences - January 24, 2018 Category: Biology Authors: Higginson, A. D., Fawcett, T. W., Houston, A. I., McNamara, J. M. Tags: behaviour, ecology, evolution Source Type: research

How animals follow the stars
Throughout history, the stars have provided humans with ever more information about our world, enabling increasingly accurate systems of navigation in addition to fuelling some of the greatest scientific controversies. What information animals have evolved to extract from a starry sky and how they do so, is a topic of study that combines the practical and theoretical challenges faced by both astronomers and field biologists. While a number of animal species have been demonstrated to use the stars as a source of directional information, the strategies that these animals use to convert this complex and variable pattern of di...
Source: Proceedings of the Royal Society B: Biological Sciences - January 24, 2018 Category: Biology Authors: Foster, J. J., Smolka, J., Nilsson, D.-E., Dacke, M. Tags: neuroscience, behaviour Review articles Source Type: research

Evidence that fertility trades off with early offspring fitness as males age
Models of ageing predict that sperm function and fertility should decline with age as sperm are exposed to free radical damage and mutation accumulation. However, theory also suggests that mating with older males should be beneficial for females because survival to old age is a demonstration of a male's high genetic and/or phenotypic quality. Consequently, declines in sperm fitness may be offset by indirect fitness benefits exhibited in offspring. While numerous studies have investigated age-based declines in male fertility, none has taken the integrated approach of studying age-based effects on both male fertility and off...
Source: Proceedings of the Royal Society B: Biological Sciences - January 24, 2018 Category: Biology Authors: Johnson, S. L., Zellhuber-McMillan, S., Gillum, J., Dunleavy, J., Evans, J. P., Nakagawa, S., Gemmell, N. J. Tags: behaviour, ecology, evolution Source Type: research

Species delimitation for the molecular taxonomy and ecology of the widely distributed microbial eukaryote genus Euplotes (Alveolata, Ciliophora)
Recent advances in high-throughput sequencing and metabarcoding technologies are revolutionizing our understanding of the diversity and ecology of microbial eukaryotes (protists). The interpretation of protist diversity and the elucidation of their ecosystem function are, however, impeded by problems with species delimitation, especially as it applies to molecular taxonomy. Here, using the ciliate Euplotes as an example, we describe approaches for species delimitation based on integrative taxonomy by using evolutionary and ecological perspectives and selecting the most appropriate metabarcoding gene markers as proxies for ...
Source: Proceedings of the Royal Society B: Biological Sciences - January 24, 2018 Category: Biology Authors: Zhao, Y., Yi, Z., Warren, A., Song, W. B. Tags: taxonomy and systematics, ecology, evolution Source Type: research

Brain size affects performance in a reversal-learning test
It has become increasingly clear that a larger brain can confer cognitive benefits. Yet not all of the numerous aspects of cognition seem to be affected by brain size. Recent evidence suggests that some more basic forms of cognition, for instance colour vision, are not influenced by brain size. We therefore hypothesize that a larger brain is especially beneficial for distinct and gradually more complex aspects of cognition. To test this hypothesis, we assessed the performance of brain size selected female guppies (Poecilia reticulata) in two distinct aspects of cognition that differ in cognitive complexity. In a standard r...
Source: Proceedings of the Royal Society B: Biological Sciences - January 24, 2018 Category: Biology Authors: Buechel, S. D., Boussard, A., Kotrschal, A., van der Bijl, W., Kolm, N. Tags: behaviour, cognition, evolution Source Type: research

Native turncoats and indirect facilitation of species invasions
At local scales, native species can resist invasion by feeding on and competing with would-be invasive species. However, this relationship tends to break down or reverse at larger scales. Here, we consider the role of native species as indirect facilitators of invasion and their potential role in this diversity-driven ‘invasion paradox’. We coin the term ‘native turncoats’ to describe native facilitators of non-native species and identify eight ways they may indirectly facilitate species invasion. Some are commonly documented, while others, such as indirect interactions within competitive communitie...
Source: Proceedings of the Royal Society B: Biological Sciences - January 24, 2018 Category: Biology Authors: Northfield, T. D., Laurance, S. G. W., Mayfield, M. M., Paini, D. R., Snyder, W. E., Stouffer, D. B., Wright, J. T., Lach, L. Tags: theoretical biology, ecology Source Type: research

Masking of an auditory behaviour reveals how male mosquitoes use distortion to detect females
The mating behaviour of many mosquito species is mediated essentially by sound: males follow and mate with a female mid-flight by detecting and tracking the whine of her flight-tones. The stereotypical rapid frequency modulation (RFM) male behaviour, initiated in response to the detection of the female's flight-tones, has provided a means of investigating these auditory mechanisms while males are free-flying. Mosquitoes hear with their antennae, which vibrate to near-field acoustic excitation. The antennae generate nonlinear vibrations (distortion products, DPs) at frequencies that are equal to the difference between the t...
Source: Proceedings of the Royal Society B: Biological Sciences - January 24, 2018 Category: Biology Authors: Simoes, P. M. V., Ingham, R., Gibson, G., Russell, I. J. Tags: behaviour, physiology Source Type: research

Behavioural tactic predicts preoptic-hypothalamic gene expression more strongly than developmental morph in fish with alternative reproductive tactics
Reproductive success relies on the coordination of social behaviours, such as territory defence, courtship and mating. Species with extreme variation in reproductive tactics are useful models for identifying the neural mechanisms underlying social behaviour plasticity. The plainfin midshipman (Porichthys notatus) is a teleost fish with two male reproductive morphs that follow widely divergent developmental trajectories and display alternative reproductive tactics (ARTs). Type I males defend territories, court females and provide paternal care, but will resort to cuckoldry if they cannot maintain a territory. Type II males ...
Source: Proceedings of the Royal Society B: Biological Sciences - January 17, 2018 Category: Biology Authors: Tripp, J. A., Feng, N. Y., Bass, A. H. Tags: neuroscience, behaviour, bioinformatics Neuroscience and cognition Source Type: research

Correction to 'Species identity and depth predict bleaching severity in reef-building corals: shall the deep inherit the reef
(Source: Proceedings of the Royal Society B: Biological Sciences)
Source: Proceedings of the Royal Society B: Biological Sciences - January 17, 2018 Category: Biology Authors: Muir, P. R., Marshall, P. A., Abdulla, A., Aguirre, J. D. Tags: ecology Corrections Source Type: research

Experimental heatwaves negatively impact sperm quality in the zebra finch
For sexually reproducing species, functionally competent sperm are critical to reproduction. While high atmospheric temperatures are known to influence the timing of breeding, incubation and reproductive success in birds, the effect of temperature on sperm quality remains largely unexplored. Here, we experimentally investigated the impact of ecologically relevant extreme temperatures on cloacal temperature and sperm morphology and motility in zebra finches Taeniopygia guttata. We periodically sampled males exposed to 30°C or 40°C temperatures daily for 14 consecutive days. Following a 12-day (23°C) recovery per...
Source: Proceedings of the Royal Society B: Biological Sciences - January 17, 2018 Category: Biology Authors: Hurley, L. L., McDiarmid, C. S., Friesen, C. R., Griffith, S. C., Rowe, M. Tags: behaviour, ecology Source Type: research

Mutual assessment during ritualized fighting in mantis shrimp (Stomatopoda)
Safe and effective conflict resolution is critical for survival and reproduction. Theoretical models describe how animals resolve conflict by assessing their own and/or their opponent's ability (resource holding potential, RHP), yet experimental tests of these models are often inconclusive. Recent reviews have suggested this uncertainty could be alleviated by using multiple approaches to test assessment models. The mantis shrimp Neogonodactylus bredini presents visual displays and ritualistically exchanges high-force strikes during territorial contests. We tested how N. bredini contest dynamics were explained by any of thr...
Source: Proceedings of the Royal Society B: Biological Sciences - January 17, 2018 Category: Biology Authors: Green, P. A., Patek, S. N. Tags: behaviour, biomechanics, ecology Source Type: research

Urbanization and anticoagulant poisons promote immune dysfunction in bobcats
Understanding how human activities influence immune response to environmental stressors can support biodiversity conservation across increasingly urbanizing landscapes. We studied a bobcat (Lynx rufus) population in urban southern California that experienced a rapid population decline from 2002–2005 due to notoedric mange. Because anticoagulant rodenticide (AR) exposure was an underlying complication in mange deaths, we aimed to understand sublethal contributions of urbanization and ARs on 65 biochemical markers of immune and organ function. Variance in immunological variables was primarily associated with AR exposur...
Source: Proceedings of the Royal Society B: Biological Sciences - January 17, 2018 Category: Biology Authors: Serieys, L. E. K., Lea, A. J., Epeldegui, M., Armenta, T. C., Moriarty, J., VandeWoude, S., Carver, S., Foley, J., Wayne, R. K., Riley, S. P. D., Uittenbogaart, C. H. Tags: immunology, physiology, ecology Source Type: research

Bayesian inference reveals positive but subtle effects of experimental fishery closures on marine predator demographics
Global forage-fish landings are increasing, with potentially grave consequences for marine ecosystems. Predators of forage fish may be influenced by this harvest, but the nature of these effects is contentious. Experimental fishery manipulations offer the best solution to quantify population-level impacts, but are rare. We used Bayesian inference to examine changes in chick survival, body condition and population growth rate of endangered African penguins Spheniscus demersus in response to 8 years of alternating time–area closures around two pairs of colonies. Our results demonstrate that fishing closures improved ch...
Source: Proceedings of the Royal Society B: Biological Sciences - January 17, 2018 Category: Biology Authors: Sherley, R. B., Barham, B. J., Barham, P. J., Campbell, K. J., Crawford, R. J. M., Grigg, J., Horswill, C., McInnes, A., Morris, T. L., Pichegru, L., Steinfurth, A., Weller, F., Winker, H., Votier, S. C. Tags: ecology Global change and conservation Source Type: research

The evolution of sexual signal modes and associated sensor morphology in fireflies (Lampyridae, Coleoptera)
Animals employ different sexual signal modes (e.g. visual, acoustic, chemical) in different environments and behavioural contexts. If sensory structures are costly, then evolutionary shifts in primary signal mode should be associated with changes in sensor morphology. Further, sex differences are expected if male and female signalling behaviours differ. Fireflies are known for their light displays, but many species communicate exclusively with pheromones, including species that recently lost their light signals. We performed phylogenetically controlled analyses of male eye and antenna size in 46 North American taxa, and fo...
Source: Proceedings of the Royal Society B: Biological Sciences - January 17, 2018 Category: Biology Authors: Stanger-Hall, K. F., Sander Lower, S. E., Lindberg, L., Hopkins, A., Pallansch, J., Hall, D. W. Tags: behaviour, ecology, evolution Source Type: research

Rapid phenotypic evolution following shifts in life cycle complexity
This study demonstrates that the consequences of life cycle evolution can be detected at very fine scales of divergence. Rapid evolutionary responses can result from shifts in selective regimes following changes in life cycle complexity. (Source: Proceedings of the Royal Society B: Biological Sciences)
Source: Proceedings of the Royal Society B: Biological Sciences - January 17, 2018 Category: Biology Authors: Bonett, R. M., Phillips, J. G., Ledbetter, N. M., Martin, S. D., Lehman, L. Tags: developmental biology, ecology, evolution Source Type: research