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3.  Histology shows that elongated neck ribs in sauropod dinosaurs are ossified tendons 
Biology Letters  2012;8(6):1032-1035.
The histology of cervical ribs of Sauropoda reveals a primary bone tissue, which largely consists of longitudinally oriented mineralized collagen fibres, essentially the same tissue as found in ossified tendons. The absence of regular periosteal bone and the dominance of longitudinal fibres contradict the ventral bracing hypothesis (VBH) postulated for sauropod necks. The VBH predicts histologically primary periosteal bone with fibres oriented perpendicular to the rib long axis, indicative of connective tissue between overlapping hyperelongated cervical ribs. The transformation of the cervical ribs into ossified tendons makes the neck more flexible and implies that tension forces acted mainly along the length of the neck. This is contrary to the VBH, which requires compressive forces along the neck. Tension forces would allow important neck muscles to shift back to the trunk region, making the neck much lighter.
doi:10.1098/rsbl.2012.0778
PMCID: PMC3497149  PMID: 23034173
Sauropoda; histology; cervical ribs; ossified tendons; neck mechanics
4.  Congruent responses to weather variability in high arctic herbivores 
Biology Letters  2012;8(6):1002-1005.
Assessing the role of weather in the dynamics of wildlife populations is a pressing task in the face of rapid environmental change. Rodents and ruminants are abundant herbivore species in most Arctic ecosystems, many of which are experiencing particularly rapid climate change. Their different life-history characteristics, with the exception of their trophic position, suggest that they should show different responses to environmental variation. Here we show that the only mammalian herbivores on the Arctic islands of Svalbard, reindeer (Rangifer tarandus) and sibling voles (Microtus levis), exhibit strong synchrony in population parameters. This synchrony is due to rain-on-snow events that cause ground ice and demonstrates that climate impacts can be similarly integrated and expressed in species with highly contrasting life histories. The finding suggests that responses of wildlife populations to climate variability and change might be more consistent in Polar regions than elsewhere owing to the strength of the climate impact and the simplicity of the ecosystem.
doi:10.1098/rsbl.2012.0764
PMCID: PMC3497145  PMID: 23015455
arvicolinae; caribou; ungulate
5.  Retention of ice-associated amphipods: possible consequences for an ice-free Arctic Ocean 
Biology Letters  2012;8(6):1012-1015.
Recent studies predict that the Arctic Ocean will have ice-free summers within the next 30 years. This poses a significant challenge for the marine organisms associated with the Arctic sea ice, such as marine mammals and, not least, the ice-associated crustaceans generally considered to spend their entire life on the underside of the Arctic sea ice. Based upon unique samples collected within the Arctic Ocean during the polar night, we provide a new conceptual understanding of an intimate connection between these under-ice crustaceans and the deep Arctic Ocean currents. We suggest that downwards vertical migrations, followed by polewards transport in deep ocean currents, are an adaptive trait of ice fauna that both increases survival during ice-free periods of the year and enables re-colonization of sea ice when they ascend within the Arctic Ocean. From an evolutionary perspective, this may have been an adaptation allowing success in a seasonally ice-covered Arctic. Our findings may ultimately change the perception of ice fauna as a biota imminently threatened by the predicted disappearance of perennial sea ice.
doi:10.1098/rsbl.2012.0517
PMCID: PMC3497112  PMID: 22977068
Arctic; sea-ice fauna; conceptual model; deep sea; migration; life history
6.  Evolutionary dynamics of taxonomic structure 
Biology Letters  2012;8(6):1070.
doi:10.1098/rsbl.2012.0780
PMCID: PMC3497150
7.  What is macroecology? 
Biology Letters  2012;8(6):904-906.
The symposium ‘What is Macroecology?’ was held in London on 20 June 2012. The event was the inaugural meeting of the Macroecology Special Interest Group of the British Ecological Society and was attended by nearly 100 scientists from 11 countries. The meeting reviewed the recent development of the macroecological agenda. The key themes that emerged were a shift towards more explicit modelling of ecological processes, a growing synthesis across systems and scales, and new opportunities to apply macroecological concepts in other research fields.
doi:10.1098/rsbl.2012.0672
PMCID: PMC3497138  PMID: 22915630
macroecology; spatial scale; process-based model; theory; ecosystem; disease
8.  Daphnia magna shows reduced infection upon secondary exposure to a pathogen 
Biology Letters  2012;8(6):972-975.
Previous pathogen exposure is an important predictor of the probability of becoming infected. This is deeply understood for vertebrate hosts, and increasingly so for invertebrate hosts. Here, we test if an initial pathogen exposure changes the infection outcome to a secondary pathogen exposure in the natural host–pathogen system Daphnia magna and Pasteuria ramosa. Hosts were initially exposed to an infective pathogen strain, a non-infective pathogen strain or a control. The same hosts underwent a second exposure, this time to an infective pathogen strain, either immediately after the initial encounter or 48 h later. We observed that an initial encounter with a pathogen always conferred protection against infection compared with controls.
doi:10.1098/rsbl.2012.0581
PMCID: PMC3497123  PMID: 22875818
within-generation immune priming; Daphnia; immunological loitering
9.  Evolution of trees and mycorrhizal fungi intensifies silicate mineral weathering 
Biology Letters  2012;8(6):1006-1011.
Forested ecosystems diversified more than 350 Ma to become major engines of continental silicate weathering, regulating the Earth's atmospheric carbon dioxide concentration by driving calcium export into ocean carbonates. Our field experiments with mature trees demonstrate intensification of this weathering engine as tree lineages diversified in concert with their symbiotic mycorrhizal fungi. Preferential hyphal colonization of the calcium silicate-bearing rock, basalt, progressively increased with advancement from arbuscular mycorrhizal (AM) to later, independently evolved ectomycorrhizal (EM) fungi, and from gymnosperm to angiosperm hosts with both fungal groups. This led to ‘trenching’ of silicate mineral surfaces by AM and EM fungi, with EM gymnosperms and angiosperms releasing calcium from basalt at twice the rate of AM gymnosperms. Our findings indicate mycorrhiza-driven weathering may have originated hundreds of millions of years earlier than previously recognized and subsequently intensified with the evolution of trees and mycorrhizas to affect the Earth's long-term CO2 and climate history.
doi:10.1098/rsbl.2012.0503
PMCID: PMC3497110  PMID: 22859556
biological weathering; arbuscular mycorrhiza; ectomycorrhiza; land plant evolution; silicate mineral weathering; global change ecology
10.  Conservation physiology of marine fishes: advancing the predictive capacity of models 
Biology Letters  2012;8(6):900-903.
At the end of May, 17 scientists involved in an EU COST Action on Conservation Physiology of Marine Fishes met in Oristano, Sardinia, to discuss how physiology can be better used in modelling tools to aid in management of marine ecosystems. Current modelling approaches incorporate physiology to different extents, ranging from no explicit consideration to detailed physiological mechanisms, and across scales from a single fish to global fishery resources. Biologists from different sub-disciplines are collaborating to rise to the challenge of projecting future changes in distribution and productivity, assessing risks for local populations, or predicting and mitigating the spread of invasive species.
doi:10.1098/rsbl.2012.0609
PMCID: PMC3497128  PMID: 22859560
conservation physiology; species distribution; modelling; climate effects
11.  Challenges in global biodiversity conservation and solutions that cross sociology, politics, economics and ecology 
Biology Letters  2012;8(6):897-899.
The study and practice of conservation biology is inherently interdisciplinary, addresses short and long time-scales and occurs within complex human–natural interfaces. Zoos and aquaria, in partnership with researchers, other non-government organizations, government, industry and educators, are combining knowledge of species and ecosystems with economics, psychology and law to create solutions for conserving biodiversity. From 22 to 25 May, the Conservation Forum of the European Association of Zoos and Aquaria was a venue for discussing conservation research, education and interventions, from the scale of villages to global policy.
doi:10.1098/rsbl.2012.0596
PMCID: PMC3497126  PMID: 22832128
biodiversity conservation; zoos; stakeholder engagement; evaluating conservation effectiveness; policy
12.  Human punishment is motivated by inequity aversion, not a desire for reciprocity 
Biology Letters  2012;8(5):802-804.
Humans involved in cooperative interactions willingly pay a cost to punish cheats. However, the proximate motives underpinning punitive behaviour are currently debated. Individuals who interact with cheats experience losses, but they also experience lower payoffs than the cheating partner. Thus, the negative emotions that trigger punishment may stem from a desire to reciprocate losses or from inequity aversion. Previous studies have not disentangled these possibilities. Here, we use an experimental approach to ask whether punishment is motivated by inequity aversion or by a desire for reciprocity. We show that humans punish cheats only when cheating produces disadvantageous inequity, while there is no evidence for reciprocity. This finding challenges the notion that punishment is motivated by a simple desire to reciprocally harm cheats and shows that victims compare their own payoffs with those of partners when making punishment decisions.
doi:10.1098/rsbl.2012.0470
PMCID: PMC3441003  PMID: 22809719
punishment; inequity aversion; reciprocity
13.  Climate change and marine life 
Biology Letters  2012;8(6):907-909.
A Marine Climate Impacts Workshop was held from 29 April to 3 May 2012 at the US National Center of Ecological Analysis and Synthesis in Santa Barbara. This workshop was the culmination of a series of six meetings over the past three years, which had brought together 25 experts in climate change ecology, analysis of large datasets, palaeontology, marine ecology and physical oceanography. Aims of these workshops were to produce a global synthesis of climate impacts on marine biota, to identify sensitive habitats and taxa, to inform the current Intergovernmental Panel on Climate Change (IPCC) process, and to strengthen research into ecological impacts of climate change.
doi:10.1098/rsbl.2012.0530
PMCID: PMC3497116  PMID: 22791706
climate change; marine science; detection and attribution
14.  North Sea ecosystem change from swimming crabs to seagulls 
Biology Letters  2012;8(5):821-824.
A recent increase in sea temperature has established a new ecosystem dynamic regime in the North Sea. Climate-induced changes in decapods have played an important role. Here, we reveal a coincident increase in the abundance of swimming crabs and lesser black-backed gull colonies in the North Sea, both in time and in space. Swimming crabs are an important food source for lesser black-backed gulls during the breeding season. Inhabiting the land, but feeding mainly at sea, lesser black-backed gulls provide a link between marine and terrestrial ecosystems, since the bottom-up influence of allochthonous nutrient input from seabirds to coastal soils can structure the terrestrial food web. We, therefore, suggest that climate-driven changes in trophic interactions in the marine food web may also have ensuing ramifications for the coastal ecology of the North Sea.
doi:10.1098/rsbl.2012.0474
PMCID: PMC3441004  PMID: 22764111
climate change; food web; Larus fuscus graelsii; plankton; Polybius henslowii; sea temperature
15.  Infants prefer the faces of strangers or mothers to morphed faces: an uncanny valley between social novelty and familiarity 
Biology Letters  2012;8(5):725-728.
The ‘uncanny valley’ response is a phenomenon involving the elicitation of a negative feeling and subsequent avoidant behaviour in human adults and infants as a result of viewing very realistic human-like robots or computer avatars. It is hypothesized that this uncanny feeling occurs because the realistic synthetic characters elicit the concept of ‘human’ but fail to satisfy it. Such violations of our normal expectations regarding social signals generate a feeling of unease. This conflict-induced uncanny valley between mutually exclusive categories (human and synthetic agent) raises a new question: could an uncanny feeling be elicited by other mutually exclusive categories, such as familiarity and novelty? Given that infants prefer both familiarity and novelty in social objects, we address this question as well as the associated developmental profile. Using the morphing technique and a preferential-looking paradigm, we demonstrated uncanny valley responses of infants to faces of mothers (i.e. familiarity) and strangers (i.e. novelty). Furthermore, this effect strengthened with the infant's age. We excluded the possibility that infants detect and avoid traces of morphing. This conclusion follows from our finding that the infants equally preferred strangers’ faces and the morphed faces of two strangers. These results indicate that an uncanny valley between familiarity and novelty may accentuate the categorical perception of familiar and novel objects.
doi:10.1098/rsbl.2012.0346
PMCID: PMC3440980  PMID: 22696289
face perception; uncanny valley; development; preferential-looking; mother; stranger
16.  Biologically meaningful coverage indicators for eliminating malaria transmission 
Biology Letters  2012;8(5):874-877.
Mosquitoes, which evade contact with long-lasting insecticidal nets and indoor residual sprays, by feeding outdoors or upon animals, are primary malaria vectors in many tropical countries. They can also dominate residual transmission where high coverage of these front-line vector control measures is achieved. Complementary strategies, which extend insecticide coverage beyond houses and humans, are required to eliminate malaria transmission in most settings. The overwhelming diversity of the world's malaria transmission systems and optimal strategies for controlling them can be simply conceptualized and mapped across two-dimensional scenario space defined by the proportion of blood meals that vectors obtain from humans and the proportion of human exposure to them which occurs indoors.
doi:10.1098/rsbl.2012.0352
PMCID: PMC3440981  PMID: 22647930
GFK insecticides; coverage; malaria; animal; outdoor; mosquito
17.  Gender- and stressor-specific microRNA expression in Tribolium castaneum 
Biology Letters  2012;8(5):860-863.
MicroRNAs (miRNAs) are small non-coding RNAs mediating post-transcriptional regulation of gene expression in eukaryotes. Addressing their role in regulation of physiological adaptations to environmental stress in insects, we selected the red flour beetle Tribolium castaneum as a model. Beetles were fed with the bacterial entomopathogen Pseudomonas entomophila (to mimic natural infection), injected with peptidoglycan (experimental setting of strong immune responses) or subjected to either mild heat shock or starvation. Differential expression of selected immunity- and stress-related genes was quantified using real-time PCR, and expression and induction of 455 mature arthropod miRNAs were determined using proprietary microarrays. We found that Tribolium exhibits both gender- and stressor-specific adjustment of immune gene and miRNA expression. Strikingly, we discovered that the number of stressor-induced miRNAs in females is remarkably higher than in males. This observation could support the hypothesis called Bateman's principle in immunity that predicts gender-specific immune responses because females gain fitness through increased longevity, whereas males gain fitness by increasing mating rates. Our results suggest that Tribolium males and females display differential regulatory elements, both pre- and post-transcriptional, likely resulting from different investment strategies in life-history traits.
doi:10.1098/rsbl.2012.0273
PMCID: PMC3440968  PMID: 22628099
Tribolium castaneum; microRNA; gender studies; epigenetic; immunity; environmental stress
18.  Molecular dating of human-to-bovid host jumps by Staphylococcus aureus reveals an association with the spread of domestication 
Biology Letters  2012;8(5):829-832.
Host species switches by bacterial pathogens leading to new endemic infections are important evolutionary events that are difficult to reconstruct over the long term. We investigated the host switching of Staphylococcus aureus over a long evolutionary timeframe by developing Bayesian phylogenetic methods to account for uncertainty about past host associations and using estimates of evolutionary rates from serially sampled whole-genome data. Results suggest multiple jumps back and forth between human and bovids with the first switch from humans to bovids taking place around 5500 BP, coinciding with the expansion of cattle domestication throughout the Old World. The first switch to poultry is estimated at around 275 BP, long after domestication but still preceding large-scale commercial farming. These results are consistent with a central role for anthropogenic change in the emergence of new endemic diseases.
doi:10.1098/rsbl.2012.0290
PMCID: PMC3440972  PMID: 22628096
Bayesian phylogenetics; molecular clocks; bacterial evolution; host switching
19.  Radar aeroecology: exploring the movements of aerial fauna through radio-wave remote sensing 
Biology Letters  2012;8(5):698-701.
An international and interdisciplinary Radar Aeroecology Workshop was held at the National Weather Center on 5–6 March 2012 on the University of Oklahoma campus in Norman, OK, USA. The workshop brought together biologists, meteorologists, radar engineers and computer scientists from 22 institutions and four countries. A central motivation behind the Radar Aeroecology Workshop was to foster better communication and cross-disciplinary collaboration among a diverse spectrum of researchers, and promote a better understanding of the ecology of animals that move within and use the Earth's lower atmosphere (aerosphere).
doi:10.1098/rsbl.2012.0384
PMCID: PMC3440989  PMID: 22628093
radar; aeroecology; phenology; migration
20.  Social learning of a communicative signal in captive chimpanzees 
Biology Letters  2012;8(4):498-501.
The acquisition of linguistic competency from more experienced social partners is a fundamental aspect of human language. However, there is little evidence that non-human primates learn to use their vocalizations from social partners. Captive chimpanzees (Pan troglodytes) produce idiosyncratic vocal signals that are used intentionally to capture the attention of a human experimenter. Interestingly, not all apes produce these sounds, and it is unclear what factors explain this difference. We tested the hypothesis that these attention-getting (AG) sounds are socially learned via transmission between mothers and their offspring. We assessed 158 chimpanzees to determine if they produced AG sounds. A significant association was found between mother and offspring sound production. This association was attributable to individuals who were raised by their biological mother—as opposed to those raised by humans in a nursery environment. These data support the hypothesis that social learning plays a role in the acquisition and use of communicative vocal signals in chimpanzees.
doi:10.1098/rsbl.2012.0113
PMCID: PMC3391466  PMID: 22438489
chimpanzee; vocal learning; language evolution
21.  Chicks, like children, spontaneously reorient by three-dimensional environmental geometry, not by image matching 
Biology Letters  2012;8(4):492-494.
Spatial reorientation by layout geometry occurs in numerous species, but its underlying mechanisms are debated. While some argue that navigating animals' sense of place is based on geometric computations over three-dimensional representations, others claim it depends on panoramic image-matching processes. Because children reorient by subtle three-dimensional perturbations of the terrain and not by salient two-dimensional brightness contours on surfaces or freestanding columns, children's sense of place cannot be explained by image matching. To test image-matching theories in a different species, the present experiment investigates the reorientation performance of domestic chicks (Gallus gallus) in environments similar to those used with children. Chicks, like children, spontaneously reoriented by geometric relationships of subtle three-dimensional terrains, and not by salient two-dimensional brightness contours on surfaces or columns. These findings add to the evidence for homologous navigation systems in humans and other vertebrates, and they cast doubt on image-matching theories of reorientation in these species.
doi:10.1098/rsbl.2012.0067
PMCID: PMC3391460  PMID: 22417791
navigation; reorientation; geometry; image matching
22.  Hermit crabs perceive the extent of their virtual bodies 
Biology Letters  2012;8(4):495-497.
A flexible body image is required by animals if they are to adapt to body changes and move effectively within a structurally complex environment. Here, we show that terrestrial hermit crabs, Coenobita rugosus, which frequently change shells, can modify walking behaviour, dependent on the shape of the shell. Hermit crabs walked along a corridor that had alternating left and right corners; if it was narrow at the corner, crabs rotated their bodies to avoid the wall, indicating an awareness of environmental obstacles. This rotation increased when a plastic plate was attached to the shell. We suggest that the shell, when extended by the plate, becomes assimilated to the hermit crab's own body. While there are cases of a tool being assimilated with the body, our result is the first example of the habitat where an animal lives and/or carries being part of a virtual body.
doi:10.1098/rsbl.2012.0085
PMCID: PMC3391464  PMID: 22378741
body; hermit crab; tool use; adaptation; part and whole
23.  Selective bird predation on the peppered moth: the last experiment of Michael Majerus 
Biology Letters  2012;8(4):609-612.
Colour variation in the peppered moth Biston betularia was long accepted to be under strong natural selection. Melanics were believed to be fitter than pale morphs because of lower predation at daytime resting sites on dark, sooty bark. Melanics became common during the industrial revolution, but since 1970 there has been a rapid reversal, assumed to have been caused by predators selecting against melanics resting on today's less sooty bark. Recently, these classical explanations of melanism were attacked, and there has been general scepticism about birds as selective agents. Experiments and observations were accordingly carried out by Michael Majerus to address perceived weaknesses of earlier work. Unfortunately, he did not live to publish the results, which are analysed and presented here by the authors. Majerus released 4864 moths in his six-year experiment, the largest ever attempted for any similar study. There was strong differential bird predation against melanic peppered moths. Daily selection against melanics (s ≃ 0.1) was sufficient in magnitude and direction to explain the recent rapid decline of melanism in post-industrial Britain. These data provide the most direct evidence yet to implicate camouflage and bird predation as the overriding explanation for the rise and fall of melanism in moths.
doi:10.1098/rsbl.2011.1136
PMCID: PMC3391436  PMID: 22319093
natural selection; cryptic coloration; ecological genetics; insectivorous birds; melanism; lepidoptera
24.  A male-killing Wolbachia carries a feminizing factor and is associated with degradation of the sex-determining system of its host 
Biology Letters  2012;8(3):412-415.
Endosymbiotic bacteria of the genus Wolbachia induce diverse reproductive alterations in their insect hosts. Wolbachia (wSca) infecting the moth Ostrinia scapulalis causes unusual male killing, in which males (genotype: ZZ) selectively die during embryonic and larval development, whereas females (genotype: ZW), in turn, selectively die when cured of infection. To gain insight into the interaction between wSca and the host, we analysed phenotypic and genetic sexes of the embryos and larvae of normal, wSca-infected, and infected-and-cured O. scapulalis by diagnosing the sex-specifically spliced transcripts of Osdsx—a homologue of the sex-determining gene doublesex—and sex chromatin in interphase nuclei, respectively. It was observed that the female-type Osdsx was expressed in the infected male (ZZ) progenies destined to die, whereas the male-type Osdsx was expressed in the cured female (ZW) progenies destined to die. These findings suggest that (i) wSca, a male killer, carries a genetic factor that feminizes the male host, (ii) the sex-determining system of the host is degraded, and (iii) a mismatch between the genetic and phenotypic sexes underlies the sex-specific death.
doi:10.1098/rsbl.2011.1114
PMCID: PMC3367752  PMID: 22219393
Ostrinia scapulalis; male killing; feminization; masculinization; doublesex; Wolbachia
25.  International Society for Wildlife Endocrinology: the future of endocrine measures for reproductive science, animal welfare and conservation biology 
Biology Letters  2012;8(5):695-697.
Hormone analysis is a precise and widely accepted tool for monitoring reproductive function and responses to stressors. Although hormones are present and can be measured in various biological matrices, non-invasive methods have gained popularity over the past 30 years as a more practical approach for assessing ovarian, testicular and, more recently, adrenocortical activity in intractable wildlife species. Non-invasive hormone monitoring also has been key to understanding biological mechanisms related to observed behaviours of captive and free-ranging animals. Despite the increasing popularity of this research field, wildlife endocrinologists have not had a specific forum for sharing and discussing their latest findings, technical developments and common challenges. To provide such a communication platform, the International Society for Wildlife Endocrinology (ISWE) was established in 2010, followed by an international meeting held on 3–4 November 2011 at the Toronto Zoo, Canada. Over several sessions, keynote speakers and participants discussed recent developments of new and innovative methods for hormone monitoring, as well as the latest advances in basic endocrinology as applied to adrenal function, reproductive physiology, animal health, ecology and evolution. Here, we introduce ISWE to the scientific community and discuss how this new society will serve as a resource for wildlife endocrinologists worldwide.
doi:10.1098/rsbl.2011.1181
PMCID: PMC3440958  PMID: 22219389
non-invasive hormone monitoring; behavioural endocrinology; environmental endocrinology; conservation endocrinology; reproductive hormones; stress hormones

Results 1-25 (25)