Brain Evolution, Development, and Plasticity

Harris, Rayna M.; O’Connell, Lauren A.; Hofmann, Hans A.

doi:10.1002/9781118316757.ch15

Cited by 3 publications

(3 citation statements)

References 128 publications

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“…Many animals, including humans, exhibit brain plasticity over the course of their lifetime (May, ; Nava and Röder, ; Harris et al , ). Plasticity is widespread even at the adult stage in insects (Fahrbach and Van Nest, ; Fahrbach et al , ; Simões and Rhiner, ; Sugie et al , ).…”

Section: Introductionmentioning

confidence: 99%

Queen Dominance May Reduce Worker Mushroom Body Size in a Social Bee

Jaumann

Seid

Simons

et al. 2019

Developmental Neurobiology

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The mushroom body (MB) is an area of the insect brain involved in learning, memory, and sensory integration. Here, we used the sweat bee Megalopta genalis (Halictidae) to test for differences between queens and workers in the volume of the MB calyces. We used confocal microscopy to measure the volume of the whole brain, MB calyces, optic lobes, and antennal lobes of queens and workers. Queens had larger brains, larger MB calyces, and a larger MB calyces:whole brain ratio than workers, suggesting an effect of social dominance in brain development. This could result from social interactions leading to smaller worker MBs, or larger queen MBs. It could also result from other factors, such as differences in age or sensory experience. To test these explanations, we next compared queens and workers to other groups. We compared newly emerged bees, bees reared in isolation for 10 days, bees initiating new observation nests, and bees initiating new natural nests collected from the field to queens and workers. Queens did not differ from these other groups. We suggest that the effects of queen dominance over workers, rather than differences in age, experience, or reproductive status, are responsible for the queen-worker differences we observed. Worker MB development may be affected by queen aggression directly and/or manipulation of larval nutrition, which is provisioned by the queen. We found no consistent differences in the size of antennal lobes or optic lobes associated with differences in age, experience, reproductive status, or social caste.

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Section: Introductionmentioning

confidence: 99%

Queen Dominance May Reduce Worker Mushroom Body Size in a Social Bee

Jaumann

Seid

Simons

et al. 2019

Developmental Neurobiology

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“…The majority of studies that examine the evolution of brain size have made use of cross‐species comparisons; however, these analyses can be complicated by phylogenetic relationships and unaccounted for ecological or life‐history factors (Harris, O'Connell, & Hofmann, ; Healy & Rowe, ; Logan et al., ). Intraspecific studies across populations are valuable as they can partially control for some of the potentially confounding variables that inherently complicate the interpretation of interspecies comparisons (Gonda et al., ; Logan et al., ).…”

Section: Introductionmentioning

confidence: 99%

Wild and laboratory exposure to cues of predation risk increases relative brain mass in male guppies

et al. 2018

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There is considerable diversity in brain size within and among species, and substantial dispute over the causes, consequences and importance of this variation. Comparative and developmental studies are essential in addressing this controversy. Predation pressure has been proposed as a major force shaping brain, behaviour and life history. The Trinidadian guppy, Poecilia reticulata, shows dramatic variation in predation pressure across populations. We compared the brain mass of guppies from high and low predation populations collected in the wild. Male but not female guppies exposed to high predation possessed heavier brains for their body size compared to fish from low predation populations. The brain is a plastic organ, so it is possible that the population differences we observed were partly due to developmental responses rather than evolved differences. In a follow‐up study, we raised guppies under cues of predation risk or in a control condition. Male guppies exposed to predator cues early in life had heavier brains relative to their body size than control males, while females showed no significant effect of treatment. Collectively our results suggest that male guppies exposed to predation invest more in neural tissue, and that these differences are at least partly driven by plastic responses. A http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.13128/suppinfo is available for this article.

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“…Larger relative brain size is associated with enhanced cognitive abilities that can evolve in response to various ecological pressures. The environment could impose cognitive challenges and select for behaviours that would ultimately impact brain size due to adaptation or plasticity [12][13][14][15][16][17]. We know habitat complexity [18][19][20], foraging strategies and other environmental factors can be strong drivers of brain size [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Divergence in brain size and brain region volumes across wild guppy populations

et al. 2022

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Complex evolutionary dynamics have produced extensive variation in brain anatomy in the animal world. In guppies, Poecilia reticulata , brain size and anatomy have been extensively studied in the laboratory contributing to our understanding of brain evolution and the cognitive advantages that arise with brain anatomical variation. However, it is unclear whether these laboratory results can be translated to natural populations. Here, we study brain neuroanatomy and its relationship with sexual traits across 18 wild guppy populations in diverse environments. We found extensive variation in female and male relative brain size and brain region volumes across populations in different environment types and with varying degrees of predation risk. In contrast with laboratory studies, we found differences in allometric scaling of brain regions, leading to variation in brain region proportions across populations. Finally, we found an association between sexual traits, mainly the area of black patches and tail length, and brain size. Our results suggest differences in ecological conditions and sexual traits are associated with differences in brain size and brain regions volumes in the wild, as well as sexual dimorphisms in the brain's neuroanatomy.

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Brain Evolution, Development, and Plasticity

Cited by 3 publications

References 128 publications

Queen Dominance May Reduce Worker Mushroom Body Size in a Social Bee

Queen Dominance May Reduce Worker Mushroom Body Size in a Social Bee

Wild and laboratory exposure to cues of predation risk increases relative brain mass in male guppies

Divergence in brain size and brain region volumes across wild guppy populations

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