scholarly journals No gains for bigger brains: Functional and neuroanatomical consequences of relative brain size in a parasitic wasp

2019 ◽  
Author(s):  
Emma Woude ◽  
Jitte Groothuis ◽  
Hans M. Smid
Keyword(s):  
Brain Size ◽  
Parasitic Wasp ◽  
Relative Brain Size

scholarly journals Nasonia Parasitic Wasps Escape from Haller's Rule by Diphasic, Partially Isometric Brain-Body Size Scaling and Selective Neuropil Adaptations

2017 ◽  
Vol 90 (3) ◽  
pp. 243-254 ◽  
Author(s):  
Jitte Groothuis ◽  
Hans M. Smid
Keyword(s):  
Body Size ◽  
Brain Size ◽  
Parasitic Wasp ◽  
Volumetric Analysis ◽  
Relative Volume ◽  
Trichogramma Evanescens ◽  
Size Scaling ◽  
Relative Brain Size ◽  
Brain Architecture ◽  
Size Relation

Haller's rule states that brains scale allometrically with body size in all animals, meaning that relative brain size increases with decreasing body size. This rule applies both on inter- and intraspecific comparisons. Only 1 species, the extremely small parasitic wasp Trichogramma evanescens, is known as an exception and shows an isometric brain-body size relation in an intraspecific comparison between differently sized individuals. Here, we investigated if such an isometric brain-body size relationship also occurs in an intraspecific comparison with a slightly larger parasitic wasp, Nasonia vitripennis, a species that may vary 10-fold in body weight upon differences in levels of scramble competition during larval development. We show that Nasonia exhibits diphasic brain-body size scaling: larger wasps scale allometrically, following Haller's rule, whereas the smallest wasps show isometric scaling. Brains of smaller wasps are, therefore, smaller than expected and we hypothesized that this may lead to adaptations in brain architecture. Volumetric analysis of neuropil composition revealed that wasps of different sizes differed in relative volume of multiple neuropils. The optic lobes and mushroom bodies in particular were smaller in the smallest wasps. Furthermore, smaller brains had a relatively smaller total neuropil volume and larger cellular rind than large brains. These changes in relative brain size and brain architecture suggest that the energetic constraints on brain tissue outweigh specific cognitive requirements in small Nasonia wasps.

Brains of early carnivores

Paleobiology ◽  
1977 ◽  
Vol 3 (4) ◽  
pp. 333-349 ◽  
Author(s):  
Leonard Radinsky
Keyword(s):  
Fossil Record ◽  
Brain Size ◽  
Biological Significance ◽  
Evolutionary Trends ◽  
Relative Brain Size

It is commonly believed that the brains of the ancestors of modern carnivores (miacids) were superior to (e.g., larger than) those of other early carnivores (creodonts and mesonychids). Examination of the fossil record of brains of early carnivores reveals no evidence to support that belief. Moreover, evolutionary trends towards increasing relative brain size and an expansion of neocortex are seen in both miacids and creodonts. The neocortex expanded in a different way in miacids than in creodonts and mesonychids (evidenced by different sulcal patterns), but the biological significance of the observed differences is unknown.

scholarly journals RELATIVE BRAIN SIZE AND FEEDING STRATEGIES IN THE CHIROPTERA

Evolution ◽  
1978 ◽  
Vol 32 (4) ◽  
pp. 740-751 ◽  
Author(s):  
John F. Eisenberg ◽  
Don E. Wilson
Keyword(s):  
Brain Size ◽  
Feeding Strategies ◽  
Relative Brain Size

A look at relative brain size in mammals

1982 ◽  
Vol 34 (2) ◽  
pp. 101-104 ◽  
Author(s):  
Este Armstrong
Keyword(s):  
Brain Size ◽  
Relative Brain Size

Relative Brain Size, Encephalization Quotient

2021 ◽  
pp. 6560-6562
Author(s):  
Mateo Peñaherrera Aguirre ◽  
Heitor BarcellosFerreira Fernandes ◽  
Michael A Woodley of Menie
Keyword(s):  
Brain Size ◽  
Encephalization Quotient ◽  
Relative Brain Size

Synthesis

2019 ◽  
pp. 423-472
Author(s):  
Georg F. Striedter ◽  
R. Glenn Northcutt
Keyword(s):  
Functional Organization ◽  
Brain Size ◽  
Brain Regions ◽  
Brain Areas ◽  
Nervous Systems ◽  
Internal Organization ◽  
Vertebrate Brain ◽  
Relative Brain Size

After summarizing the earlier chapters, which focused on the evolution of specific lineages, this chapter examines general patterns in the evolution of vertebrate nervous systems. Most conspicuous is that relative brain size and complexity increased independently in many lineages. The proportional size of individual brain regions tends to change predictably with absolute brain size (and neurogenesis timing), but the scaling rules vary across lineages. Attempts to link variation in the size of individual brain areas (or entire brains) to behavior are complicated in part because the connections, internal organization, and functions of individual brain regions also vary across phylogeny. In addition, major changes in the functional organization of vertebrate brains were caused by the emergence of novel brain regions (e.g., neocortex in mammals and area dorsalis centralis in teleosts) and novel circuits. These innovations significantly modified the “vertebrate brain Bauplan,” but their mechanistic origins and implications require further investigation.

scholarly journals Do Different Methods Yield Equivalent Estimations of Brain Size in Birds?

2020 ◽  
Vol 95 (2) ◽  
pp. 113-122
Author(s):  
Diego Ocampo ◽  
César Sánchez ◽  
Gilbert Barrantes
Keyword(s):  
Body Size ◽  
Brain Size ◽  
Brain Mass ◽  
Wide Range ◽  
Evolutionary Studies ◽  
Relative Brain Size ◽  
Using Data ◽  
Endocranial Volume ◽  
The Brain ◽  
Size Estimates

The ratio of brain size to body size (relative brain size) is often used as a measure of relative investment in the brain in ecological and evolutionary studies on a wide range of animal groups. In birds, a variety of methods have been used to measure the brain size part of this ratio, including endocranial volume, fixed brain mass, and fresh brain mass. It is still unclear, however, whether these methods yield the same results. Using data obtained from fresh corpses and from published sources, this study shows that endocranial volume, mass of fixed brain tissue, and fresh mass provide equivalent estimations of brain size for 48 bird families, in 19 orders. We found, however, that the various methods yield significantly different brain size estimates for hummingbirds (Trochilidae). For hummingbirds, fixed brain mass tends to underestimate brain size due to reduced tissue density, whereas endocranial volume overestimates brain size because it includes a larger volume than that occupied by the brain.

scholarly journals Smart Moves: Effects of Relative Brain Size on Establishment Success of Invasive Amphibians and Reptiles

PLoS ONE ◽  
2011 ◽  
Vol 6 (4) ◽  
pp. e18277 ◽  
Author(s):  
Joshua J. Amiel ◽  
Reid Tingley ◽  
Richard Shine
Keyword(s):  
Brain Size ◽  
Establishment Success ◽  
Relative Brain Size
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