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Proceedings. Biological Sciences

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https://www.readbyqxmd.com/read/27903878/a-spiking-neural-model-of-adaptive-arm-control
#1
Travis DeWolf, Terrence C Stewart, Jean-Jacques Slotine, Chris Eliasmith
We present a spiking neuron model of the motor cortices and cerebellum of the motor control system. The model consists of anatomically organized spiking neurons encompassing premotor, primary motor, and cerebellar cortices. The model proposes novel neural computations within these areas to control a nonlinear three-link arm model that can adapt to unknown changes in arm dynamics and kinematic structure. We demonstrate the mathematical stability of both forms of adaptation, suggesting that this is a robust approach for common biological problems of changing body size (e...
November 30, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27903877/assessing-the-manipulative-potentials-of-monkeys-apes-and-humans-from-hand-proportions-implications-for-hand-evolution
#2
Ming-Jin Liu, Cai-Hua Xiong, Di Hu
The hand structure possesses a greater potential for performing manipulative skills than is typically observed, whether in humans or non-human anthropoids. However, a precise assessment of the potential manipulative skills of hands has been challenging, which hampers our understanding of the evolution of manipulative abilities in anthropoid hands. Here, we establish a functional model to quantitatively infer the manipulative potentials of anthropoid hands based on hand proportions. Our results reveal a large disparity of manipulative potentials among anthropoid hands...
November 30, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27903876/handicap-principle-implies-emergence-of-dimorphic-ornaments
#3
Sara M Clifton, Rosemary I Braun, Daniel M Abrams
Species spanning the animal kingdom have evolved extravagant and costly ornaments to attract mating partners. Zahavi's handicap principle offers an elegant explanation for this: ornaments signal individual quality, and must be costly to ensure honest signalling, making mate selection more efficient. Here, we incorporate the assumptions of the handicap principle into a mathematical model and show that they are sufficient to explain the heretofore puzzling observation of bimodally distributed ornament sizes in a variety of species...
November 30, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27903875/slow-and-steady-the-evolution-of-cranial-disparity-in-fossil-and-recent-turtles
#4
Christian Foth, Walter G Joyce
Turtles (Testudinata) are a diverse group of amniotes that have a rich fossil record that extends back to the Late Triassic, but little is known about global patterns of disparity through time. We here investigate the cranial disparity of 172 representatives of the turtle lineage and their ancestors grouped into 20 time bins ranging from the Late Triassic until the Recent using two-dimensional geometric morphometrics. Three evolutionary phases are apparent in all three anatomical views investigated. In the first phase, disparity increases gradually from the Late Triassic to the Palaeogene with only a minor perturbation at the K/T extinct event...
November 30, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27903874/life-history-characteristics-influence-physiological-strategies-to-cope-with-hypoxia-in-himalayan-birds
#5
S Barve, A A Dhondt, V B Mathur, Z A Cheviron
Hypobaric hypoxia at high elevation represents an important physiological stressor for montane organisms, but optimal physiological strategies to cope with hypoxia may vary among species with different life histories. Montane birds exhibit a range of migration patterns; elevational migrants breed at high elevations but winter at low elevations or migrate further south, while high-elevation residents inhabit the same elevation throughout the year. Optimal physiological strategies to cope with hypoxia might therefore differ between species that exhibit these two migratory patterns, because they differ in the amount time spent at high elevation...
November 30, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27903873/timing-of-head-movements-is-consistent-with-energy-minimization-in-walking-ungulates
#6
David M Loscher, Fiete Meyer, Kerstin Kracht, John A Nyakatura
Many ungulates show a conspicuous nodding motion of the head when walking. Until now, the functional significance of this behaviour remained unclear. Combining in vivo kinematics of quadrupedal mammals with a computer model, we show that the timing of vertical displacements of the head and neck is consistent with minimizing energy expenditure for carrying these body parts in an inverted pendulum walking gait. Varying the timing of head movements in the model resulted in increased metabolic cost estimate for carrying the head and neck of up to 63%...
November 30, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27903872/egg-size-investment-in-superb-fairy-wrens-helper-effects-are-modulated-by-climate
#7
N E Langmore, L D Bailey, R G Heinsohn, A F Russell, R M Kilner
Natural populations might exhibit resilience to changing climatic conditions if they already show adaptive flexibility in their reproductive strategies. In cooperative breeders, theory predicts that mothers with helpers should provide less care when environmental conditions are favourable, but maintain high investment when conditions are challenging. Here, we test for evidence of climate-mediated flexibility in maternal investment in the cooperatively breeding superb fairy-wren Malurus cyaneus We focus on egg size because in this species egg size influences offspring size, and females reduce egg investment when there are helpers at the nest...
November 30, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27903871/decline-and-recovery-of-a-large-carnivore-environmental-change-and-long-term-trends-in-an-endangered-brown-bear-population
#8
Isabel Martínez Cano, Fernando González Taboada, Javier Naves, Alberto Fernández-Gil, Thorsten Wiegand
Understanding what factors drive fluctuations in the abundance of endangered species is a difficult ecological problem but a major requirement to attain effective management and conservation success. The ecological traits of large mammals make this task even more complicated, calling for integrative approaches. We develop a framework combining individual-based modelling and statistical inference to assess alternative hypotheses on brown bear dynamics in the Cantabrian range (Iberian Peninsula). Models including the effect of environmental factors on mortality rates were able to reproduce three decades of variation in the number of females with cubs of the year (Fcoy), including the decline that put the population close to extinction in the mid-nineties, and the following increase in brown bear numbers...
November 30, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27903870/sea-level-driven-glacial-age-refugia-and-post-glacial-mixing-on-subtropical-coasts-a-palaeohabitat-and-genetic-study
#9
Greer A Dolby, Ryan Hechinger, Ryan A Ellingson, Lloyd T Findley, Julio Lorda, David K Jacobs
Using a novel combination of palaeohabitat modelling and genetic mixture analyses, we identify and assess a sea-level-driven recolonization process following the Last Glacial Maximum (LGM). Our palaeohabitat modelling reveals dramatic changes in estuarine habitat distribution along the coast of California (USA) and Baja California (Mexico). At the LGM (approx. 20 kya), when sea level was approximately 130 m lower, the palaeo-shoreline was too steep for tidal estuarine habitat formation, eliminating this habitat type from regions where it is currently most abundant, and limiting such estuaries to a northern and a southern refugium separated by 1000 km...
November 30, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27903869/within-group-behavioural-consequences-of-between-group-conflict-a-prospective-review
#10
REVIEW
Andrew N Radford, Bonaventura Majolo, Filippo Aureli
Conflict is rife in group-living species and exerts a powerful selective force. Group members face a variety of threats from extra-group conspecifics, from individuals looking for reproductive opportunities to rival groups seeking resources. Theory predicts that such between-group conflict should influence within-group behaviour. However, compared with the extensive literature on the consequences of within-group conflict, relatively little research has considered the behavioural impacts of between-group conflict...
November 30, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27903868/allee-effect-in-polar-bears-a-potential-consequence-of-polychlorinated-biphenyl-contamination
#11
Viola Pavlova, Jacob Nabe-Nielsen, Rune Dietz, Christian Sonne, Volker Grimm
Polar bears (Ursus maritimus) from East Greenland and Svalbard exhibited very high concentrations of polychlorinated biphenyls (PCBs) in the 1980s and 1990s. In Svalbard, slow population growth during that period was suspected to be linked to PCB contamination. In this case study, we explored how PCBs could have impacted polar bear population growth and/or male reproductive success in Svalbard during the mid-1990s by reducing the fertility of contaminated males. A dose-response relationship linking the effects of PCBs to male polar bear fertility was extrapolated from studies of the effects of PCBs on sperm quality in rodents...
November 30, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27903867/in-situ-developmental-responses-of-tropical-sea-urchin-larvae-to-ocean-acidification-conditions-at-naturally-elevated-pco2-vent-sites
#12
Miles D Lamare, Michelle Liddy, Sven Uthicke
Laboratory experiments suggest that calcifying developmental stages of marine invertebrates may be the most ocean acidification (OA)-sensitive life-history stage and represent a life-history bottleneck. To better extrapolate laboratory findings to future OA conditions, developmental responses in sea urchin embryos/larvae were compared under ecologically relevant in situ exposures on vent-elevated pCO2 and ambient pCO2 coral reefs in Papua New Guinea. Echinometra embryos/larvae were reared in meshed chambers moored in arrays on either venting reefs or adjacent non-vent reefs...
November 30, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27881757/correction-to-high-evolutionary-constraints-limited-adaptive-responses-to-past-climate-changes-in-toad-skulls
#13
Monique Nouailhetas Simon, Fabio Andrade Machado, Gabriel Marroig
No abstract text is available yet for this article.
November 30, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27881756/a-combinatorial-approach-to-angiosperm-pollen-morphology
#14
Luke Mander
Angiosperms (flowering plants) are strikingly diverse. This is clearly expressed in the morphology of their pollen grains, which are characterized by enormous variety in their shape and patterning. In this paper, I approach angiosperm pollen morphology from the perspective of enumerative combinatorics. This involves generating angiosperm pollen morphotypes by algorithmically combining character states and enumerating the results of these combinations. I use this approach to generate 3 643 200 pollen morphotypes, which I visualize using a parallel-coordinates plot...
November 30, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27881755/unravelling-darwin-s-entangled-bank-architecture-and-robustness-of-mutualistic-networks-with-multiple-interaction-types
#15
Wesley Dáttilo, Nubia Lara-Rodríguez, Pedro Jordano, Paulo R Guimarães, John N Thompson, Robert J Marquis, Lucas P Medeiros, Raul Ortiz-Pulido, Maria A Marcos-García, Victor Rico-Gray
Trying to unravel Darwin's entangled bank further, we describe the architecture of a network involving multiple forms of mutualism (pollination by animals, seed dispersal by birds and plant protection by ants) and evaluate whether this multi-network shows evidence of a structure that promotes robustness. We found that species differed strongly in their contributions to the organization of the multi-interaction network, and that only a few species contributed to the structuring of these patterns. Moreover, we observed that the multi-interaction networks did not enhance community robustness compared with each of the three independent mutualistic networks when analysed across a range of simulated scenarios of species extinction...
November 30, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27881754/neuroendocrine-correlates-of-sex-role-reversal-in-barred-buttonquails
#16
Cornelia Voigt
Sex differences in brain structure and behaviour are well documented among vertebrates. An excellent model exploring the neural mechanisms of sex differences in behaviour is represented by sex-role-reversed species. In the majority of bird species, males compete over access to mates and resources more strongly than do females. It is thought that the responsible brain regions are therefore more developed in males than in females. Because these behaviours and brain regions are activated by androgens, males usually have increased testosterone levels during breeding...
November 30, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27881753/how-can-we-estimate-natural-selection-on-endocrine-traits-lessons-from-evolutionary-biology
#17
REVIEW
Frances Bonier, Paul R Martin
An evolutionary perspective can enrich almost any endeavour in biology, providing a deeper understanding of the variation we see in nature. To this end, evolutionary endocrinologists seek to describe the fitness consequences of variation in endocrine traits. Much of the recent work in our field, however, follows a flawed approach to the study of how selection shapes endocrine traits. Briefly, this approach relies on among-individual correlations between endocrine phenotypes (often circulating hormone levels) and fitness metrics to estimate selection on those endocrine traits...
November 30, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27881752/female-monkeys-use-both-the-carrot-and-the-stick-to-promote-male-participation-in-intergroup-fights
#18
T Jean Marie Arseneau-Robar, Anouk Lisa Taucher, Eliane Müller, Carel van Schaik, Redouan Bshary, Erik P Willems
Group-level cooperation often poses a social dilemma in which joint action may be difficult to achieve. Theoretical models and experimental work on humans show that social incentives, such as punishment of defectors and rewarding of cooperators, can promote cooperation in groups of unrelated individuals. Here, we demonstrate that these processes can operate in a non-human animal species, and be used to effectively promote the production of a public good. We took advantage of the fact that intergroup fights in vervet monkeys (Chlorocebus aethiops pygerythrus) are characterized by episodes of intergroup aggression with pauses in-between...
November 30, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27881751/artificial-selection-on-male-genitalia-length-alters-female-brain-size
#19
Séverine D Buechel, Isobel Booksmythe, Alexander Kotrschal, Michael D Jennions, Niclas Kolm
Male harassment is a classic example of how sexual conflict over mating leads to sex-specific behavioural adaptations. Females often suffer significant costs from males attempting forced copulations, and the sexes can be in an arms race over male coercion. Yet, despite recent recognition that divergent sex-specific interests in reproduction can affect brain evolution, sexual conflict has not been addressed in this context. Here, we investigate whether artificial selection on a correlate of male success at coercion, genital length, affects brain anatomy in males and females...
November 30, 2016: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/27881750/experimental-evidence-that-honeybees-depress-wild-insect-densities-in-a-flowering-crop
#20
Sandra A M Lindström, Lina Herbertsson, Maj Rundlöf, Riccardo Bommarco, Henrik G Smith
While addition of managed honeybees (Apis mellifera) improves pollination of many entomophilous crops, it is unknown if it simultaneously suppresses the densities of wild insects through competition. To investigate this, we added 624 honeybee hives to 23 fields of oilseed rape (Brassica napus L.) over 2 years and made sure that the areas around 21 other fields were free from honeybee hives. We demonstrate that honeybee addition depresses the densities of wild insects (bumblebees, solitary bees, hoverflies, marchflies, other flies, and other flying and flower-visiting insects) even in a massive flower resource such as oilseed rape...
November 30, 2016: Proceedings. Biological Sciences
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