scholarly journals Large brain size is associated with low extra‐pair paternity across bird species

2021 ◽  
Vol 11 (19) ◽  
pp. 13601-13608
Author(s):  
Min Chen ◽  
Guopan Li ◽  
Jinlong Liu ◽  
Shaobin Li
Keyword(s):  
Brain Size ◽  
Bird Species ◽  
Extra Pair Paternity ◽  
Large Brain

Brain size evolution in small mammals: test of the expensive tissue hypothesis

Mammalia ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ying Jiang ◽  
Jia Yu Wang ◽  
Xiao Fu Huang ◽  
Chun Lan Mai ◽  
Wen Bo Liao
Keyword(s):  
Small Mammals ◽  
Brain Size ◽  
Reproductive Investment ◽  
Generalized Least Squares ◽  
Offspring Number ◽  
Size Evolution ◽  
Large Brain ◽  
Species Evolution ◽  
The Cost ◽  
Expensive Tissue Hypothesis

Abstract Brain size exhibits significant changes within and between species. Evolution of large brains can be explained by the need to improve cognitive ability for processing more information in changing environments. However, brains are among the most energetically expensive organs. Enlarged brains can impose energetic demands that limit brain size evolution. The expensive tissue hypothesis (ETH) states that a decrease in the size of another expensive tissue, such as the gut, should compensate for the cost of a large brain. We studied the interplay between energetic limitations and brain size evolution in small mammals using phylogenetically generalized least squares (PGLS) regression analysis. Brain mass was not correlated with the length of the digestive tract in 37 species of small mammals after correcting for phylogenetic relationships and body size effects. We further found that the evolution of a large brain was not accompanied by a decrease in male reproductive investments into testes mass and in female reproductive investment into offspring number. The evolution of brain size in small mammals is inconsistent with the prediction of the ETH.

scholarly journals Brain regions associated with visual cues are important for bird migration

2015 ◽  
Vol 11 (11) ◽  
pp. 20150678 ◽  
Author(s):  
Orsolya Vincze ◽  
Csongor I. Vágási ◽  
Péter L. Pap ◽  
Gergely Osváth ◽  
Anders Pape Møller
Keyword(s):  
Visual Cues ◽  
Optic Lobe ◽  
Brain Size ◽  
Relative Size ◽  
Bird Species ◽  
Interspecific Variation ◽  
Brain Regions ◽  
Long Distance ◽  
Migration Distance ◽  
Whole Brain

Long-distance migratory birds have relatively smaller brains than short-distance migrants or residents. Here, we test whether reduction in brain size with migration distance can be generalized across the different brain regions suggested to play key roles in orientation during migration. Based on 152 bird species, belonging to 61 avian families from six continents, we show that the sizes of both the telencephalon and the whole brain decrease, and the relative size of the optic lobe increases, while cerebellum size does not change with increasing migration distance. Body mass, whole brain size, optic lobe size and wing aspect ratio together account for a remarkable 46% of interspecific variation in average migration distance across bird species. These results indicate that visual acuity might be a primary neural adaptation to the ecological challenge of migration.

scholarly journals Why are there so few smart mammals (but so many smart birds)?

2008 ◽  
Vol 5 (1) ◽  
pp. 125-129 ◽  
Author(s):  
Karin Isler ◽  
Carel P Van Schaik
Keyword(s):  
Body Size ◽  
Brain Size ◽  
Population Increase ◽  
Large Brain ◽  
Cooperatively Breeding ◽  
Steep Decline ◽  
Relative Brain Size ◽  
Altricial Birds ◽  
Rates Of Growth ◽  
Very High

The expensive brain hypothesis predicts an interspecific link between relative brain size and life-history pace. Indeed, animals with relatively large brains have reduced rates of growth and reproduction. However, they also have increased total lifespan. Here we show that the reduction in production with increasing brain size is not fully compensated by the increase in lifespan. Consequently, the maximum rate of population increase ( r max ) is negatively correlated with brain mass. This result is not due to a confounding effect of body size, indicating that the well-known correlation between r max and body size is driven by brain size, at least among homeothermic vertebrates. Thus, each lineage faces a ‘grey ceiling’, i.e. a maximum viable brain size, beyond which r max is so low that the risk of local or species extinction is very high. We found that the steep decline in r max with brain size is absent in taxa with allomaternal offspring provisioning, such as cooperatively breeding mammals and most altricial birds. These taxa thus do not face a lineage-specific grey ceiling, which explains the far greater number of independent origins of large brain size in birds than mammals. We also predict that (absolute and relative) brain size is an important predictor of macroevolutionary extinction patterns.

scholarly journals The couple that sings together stays together: duetting, aggression and extra-pair paternity in a promiscuous bird species

2016 ◽  
Vol 12 (2) ◽  
pp. 20151025 ◽  
Author(s):  
Daniel T. Baldassarre ◽  
Emma I. Greig ◽  
Michael S. Webster
Keyword(s):  
Physical Aggression ◽  
Bird Species ◽  
Mate Guarding ◽  
Pair Bond ◽  
Behavioural Consistency ◽  
Extra Pair Paternity ◽  
Paternity Assurance

When individuals mate outside the pair bond, males should employ behaviours such as aggression or vocal displays (e.g. duetting) that help assure paternity of the offspring they care for. We tested whether male paternity was associated with aggression or duetting in the red-backed fairy-wren, a species exhibiting high rates of extra-pair paternity. During simulated territorial intrusions, aggression and duetting were variable among and repeatable within males, suggesting behavioural consistency of individuals. Males with quicker and stronger duet responses were cuckolded less often than males with slower and weaker responses. In contrast, physical aggression was not correlated with male paternity. These results suggest that either acoustic mate guarding or male–female vocal negotiations via duetting lead to increased paternity assurance, whereas physical aggression does not.

scholarly journals Brain enlargement and dental reduction were not linked in hominin evolution

2017 ◽  
Vol 114 (3) ◽  
pp. 468-473 ◽  
Author(s):  
Aida Gómez-Robles ◽  
Jeroen B. Smaers ◽  
Ralph L. Holloway ◽  
P. David Polly ◽  
Bernard A. Wood
Keyword(s):  
Brain Size ◽  
Behavioral Changes ◽  
Modern Humans ◽  
Distinctive Features ◽  
Hominin Evolution ◽  
Large Brain ◽  
Dental Reduction ◽  
Selection For ◽  
Brain Reorganization ◽  
Evolutionary Simulations

The large brain and small postcanine teeth of modern humans are among our most distinctive features, and trends in their evolution are well studied within the hominin clade. Classic accounts hypothesize that larger brains and smaller teeth coevolved because behavioral changes associated with increased brain size allowed a subsequent dental reduction. However, recent studies have found mismatches between trends in brain enlargement and posterior tooth size reduction in some hominin species. We use a multiple-variance Brownian motion approach in association with evolutionary simulations to measure the tempo and mode of the evolution of endocranial and dental size and shape within the hominin clade. We show that hominin postcanine teeth have evolved at a relatively consistent neutral rate, whereas brain size evolved at comparatively more heterogeneous rates that cannot be explained by a neutral model, with rapid pulses in the branches leading to later Homo species. Brain reorganization shows evidence of elevated rates only much later in hominin evolution, suggesting that fast-evolving traits such as the acquisition of a globular shape may be the result of direct or indirect selection for functional or structural traits typical of modern humans.

scholarly journals Selection for brain size impairs innate, but not adaptive immune responses

2016 ◽  
Vol 283 (1826) ◽  
pp. 20152857 ◽  
Author(s):  
Alexander Kotrschal ◽  
Niclas Kolm ◽  
Dustin J. Penn
Keyword(s):  
Immune Responses ◽  
Poecilia Reticulata ◽  
Brain Size ◽  
Innate Immune Responses ◽  
Rejection Reaction ◽  
Trade Off ◽  
Large Brain ◽  
Rejection Response ◽  
Selection For ◽  
Acquired Immune Responses

Both the brain and the immune system are energetically demanding organs, and when natural selection favours increased investment into one, then the size or performance of the other should be reduced. While comparative analyses have attempted to test this potential evolutionary trade-off, the results remain inconclusive. To test this hypothesis, we compared the tissue graft rejection (an assay for measuring innate and acquired immune responses) in guppies ( Poecilia reticulata ) artificially selected for large and small relative brain size. Individual scales were transplanted between pairs of fish, creating reciprocal allografts, and the rejection reaction was scored over 8 days (before acquired immunity develops). Acquired immune responses were tested two weeks later, when the same pairs of fish received a second set of allografts and were scored again. Compared with large-brained animals, small-brained animals of both sexes mounted a significantly stronger rejection response to the first allograft. The rejection response to the second set of allografts did not differ between large- and small-brained fish. Our results show that selection for large brain size reduced innate immune responses to an allograft, which supports the hypothesis that there is a selective trade-off between investing into brain size and innate immunity.

scholarly journals The degree of extra-pair paternity increases with genetic variability

1998 ◽  
Vol 95 (16) ◽  
pp. 9390-9395 ◽  
Author(s):  
Marion Petrie ◽  
Claudie Doums ◽  
Anders Pape Møller
Keyword(s):  
Genetic Variability ◽  
Bird Species ◽  
Interspecific Variation ◽  
Genetic Quality ◽  
Extra Pair Paternity ◽  
Genome Wide ◽  
Random Priming ◽  
Confounding Variables ◽  
Socially Monogamous

The amount of extra-pair paternity in socially monogamous bird species varies from 0% to 76% extra-pair offspring. The causes of this remarkable interspecific variation are largely unknown, although intraspecific analyses suggest that females seek extra-pair matings to improve the genetic quality of their offspring. If this is a general explanation for the occurrence of extra-pair matings, then proportionally more females should seek to modify the paternity of their clutch when there is more variation among males in their genetic quality. Here we test this prediction in birds and show that interspecific variation in the proportion of extra-pair offspring is positively related to the proportion of polymorphic loci as measured by protein electrophoresis, even when controlling for potentially confounding variables. Genetic variability was also assessed, for sister pairs of species and populations differing significantly in extra-pair paternity, by using random priming, which provides an estimate of genome-wide diversity. We found that genetic diversity was higher in the populations with a higher level of extra-pair paternity. These results suggest that the amount of genetic variability in a population may be an important factor influencing mating patterns.

scholarly journals High-throughput whole-brain mapping of rhesus monkey at micron resolution

2020 ◽  
Author(s):  
Fang Xu ◽  
Yan Shen ◽  
Lufeng Ding ◽  
Chao-Yu Yang ◽  
Heng Tan ◽  
...  
Keyword(s):  
Rhesus Monkey ◽  
Large Scale ◽  
High Efficiency ◽  
Brain Size ◽  
Integrative Approach ◽  
Whole Brain ◽  
3 Dimensional ◽  
Large Brain ◽  
Thalamocortical Projections ◽  
Distinct Features

AbstractWhole-brain mesoscale mapping of primates has been hindered by large brain size and the relatively low throughput of available microscopy methods. Here, we present an integrative approach that combines primate-optimized tissue sectioning and clearing with ultrahigh-speed, large-scale, volumetric fluorescence microscopy, capable of completing whole-brain imaging of a rhesus monkey at 1 µm × 1 µm × 2.5 µm voxel resolution within 100 hours. A progressive strategy is developed for high-efficiency, long-range tracing of individual axonal fibers through the dataset of hundreds of terabytes, establishing a “Serial sectioning and clearing, 3-dimensional Microscopy, with semi-Automated Reconstruction and Tracing” (SMART) pipeline. This system supports effective connectome-scale mapping of large primates that reveals distinct features of thalamocortical projections of the rhesus monkey brain at the level of individual axonal fibers.

The Evolutions of Large Brain Size in Mammals: The ‘Over-700-Gram Club Quartet'

2013 ◽  
Vol 82 (1) ◽  
pp. 68-78 ◽  
Author(s):  
Paul R. Manger ◽  
Muhammad A. Spocter ◽  
Nina Patzke
Keyword(s):  
Brain Size ◽  
Large Brain
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