Evolution of Bower Complexity and Cerebellum Size in Bowerbirds

Day, Lainy B.; Westcott, David A.; Olster, Deborah H.

doi:10.1159/000085048

Cited by 92 publications

(65 citation statements)

References 69 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is a problem as one current method of measuring the Te in the literature is to estimate Te volume only on sections of tissue on which the Hp has also been measured (e.g. Sherry et al 1993;Cristol et al 2003;Day et al 2005Day et al , 2008. Since the Te is longer than the Hp, this means that parts of the Te that are anterior and posterior to the Hp may not have been included in the calculation.…”

Section: Problems With the Compatibility Of Data Across Studiesmentioning

confidence: 99%

Is bigger always better? A critical appraisal of the use of volumetric analysis in the study of the hippocampus

Roth

Brodin

Smulders

et al. 2010

Phil. Trans. R. Soc. B

View full text Add to dashboard Cite

A well-developed spatial memory is important for many animals, but appears especially important for scatter-hoarding species. Consequently, the scatter-hoarding system provides an excellent paradigm in which to study the integrative aspects of memory use within an ecological and evolutionary framework. One of the main tenets of this paradigm is that selection for enhanced spatial memory for cache locations should specialize the brain areas involved in memory. One such brain area is the hippocampus (Hp). Many studies have examined this adaptive specialization hypothesis, typically relating spatial memory to Hp volume. However, it is unclear how the volume of the Hp is related to its function for spatial memory. Thus, the goal of this article is to evaluate volume as a main measurement of the degree of morphological and physiological adaptation of the Hp as it relates to memory. We will briefly review the evidence for the specialization of memory in food-hoarding animals and discuss the philosophy behind volume as the main currency. We will then examine the problems associated with this approach, attempting to understand the advantages and limitations of using volume and discuss alternatives that might yield more specific hypotheses. Overall, there is strong evidence that the Hp is involved in the specialization of spatial memory in scatter-hoarding animals. However, volume may be only a coarse proxy for more relevant and subtle changes in the structure of the brain underlying changes in behaviour. To better understand the nature of this brain/memory relationship, we suggest focusing on more specific and relevant features of the Hp, such as the number or size of neurons, variation in connectivity depending on dendritic and axonal arborization and the number of synapses. These should generate more specific hypotheses derived from a solid theoretical background and should provide a better understanding of both neural mechanisms of memory and their evolution.

show abstract

Section: Problems With the Compatibility Of Data Across Studiesmentioning

confidence: 99%

Is bigger always better? A critical appraisal of the use of volumetric analysis in the study of the hippocampus

Roth

Brodin

Smulders

et al. 2010

Phil. Trans. R. Soc. B

View full text Add to dashboard Cite

show abstract

“…However, different ways of measuring whole brain size do not always result in the same outcome. For example, while cranial measurements correlate with bower complexity (Madden 2001), brain mass does not (Day et al 2005). These problems are typically explained away by the argument, based on plausibility alone that any error introduced into the dataset will be random, rather than introducing any kind of bias.…”

Section: Brain Size (A) What Is It?mentioning

confidence: 99%

A critique of comparative studies of brain size

Healy¹,

2006

View full text Add to dashboard Cite

Newcastle upon Tyne NE2 4HH, UKIn recent years, there have been over 50 comparative analyses carried out in which social or ecological variables have been used to explain variation in whole brain size, or a part thereof, in a range of vertebrate species. Here, we review this body of work, pointing out that there are a number of substantial problems with some of the assumptions that underpin the hypotheses (e.g. what brain size means), with the data collection and with the ways in which the data are combined in the analyses. These problems are particularly apparent in those analyses in which attempts are made to correlate complex behaviour with parts of the brain that carry out multiple functions. We conclude that now is the time to substantiate these results with data from experimental manipulations.

show abstract

“…Body mass data of males (or, when information for males was not available, the mean mass of males and females or the average of body mass range) were obtained from Dunning (1993). When information for certain species was not available from the latter, this was taken from del Hoyo et al (1992Hoyo et al ( -2002Hoyo et al ( , 2003Hoyo et al ( -2010, from Day et al (2005) for the Great Bowerbird Chlamydera nuchalis and from BirdLife International (2011) for the Flame-breasted Fruit Dove Ptilinopus marchei. For the Barn Owl Tyto alba, we used information on the North American subspecies (T. a. pratincola).…”

Section: Body Size and Coarse-grained Habitat Informationmentioning

confidence: 99%

On Showy Dwarfs and Sober Giants: Body Size as a Constraint for the Evolution of Bird Plumage Colouration

Galván¹,

Negro

Rodríguez

et al. 2013

Acta Ornithologica

View full text Add to dashboard Cite

Abstract. The evolution of bird plumage colouration may be explained by a wide range of selective pressures, including both defensive and advertising needs. However, the relationship between plumage colouration and body size has never been investigated in detail. Here we hypothesize that body size represents a constraint for the evolution of plumage colour heterogeneity because the relative number of body feathers was suggested to increase as body size decreases, and in the case of carotenoid-based colourations because the concentrations of circulating carotenoids decrease with increasing body size. Here we test these predictions on a dataset comprising measurements of male plumage colour heterogeneity using a model of avian visual perception in 111 species from 55 families of birds. A test of the correlation between number of feathers and body size in 92 species of birds showed a positive, instead of negative as previously suggested, association between these variables. As predicted, there was a negative relationship between plumage colour heterogeneity (measured as colour span, a measure of the contrast among colour patches) and body size after controlling for the effects of phylogeny, sexual dichromatism, colour vision type and habitat, and we suggest that the negative allometry shown by carotenoid levels may be the mechanism responsible for this negative relationship. Plumage colour heterogeneity was lower in species inhabiting open environments than in more vegetated habitats. Our results offer a general explanation for interspecific variation in bird colour heterogeneity through an association with body size.

show abstract

Evolution of Bower Complexity and Cerebellum Size in Bowerbirds

Cited by 92 publications

References 69 publications

Is bigger always better? A critical appraisal of the use of volumetric analysis in the study of the hippocampus

Is bigger always better? A critical appraisal of the use of volumetric analysis in the study of the hippocampus

A critique of comparative studies of brain size

On Showy Dwarfs and Sober Giants: Body Size as a Constraint for the Evolution of Bird Plumage Colouration

Contact Info

Product

Resources

About