Habitat complexity influences neuron number in six species of Puerto Rican Anolis

Biology Letters, Journal Year: 2024, Volume and Issue: 20(2)

Published: Feb. 1, 2024

Elucidating the selective forces shaping diversity of vertebrate brains continues to be a major area inquiry, particularly as it relates cognition. Historically brain evolution was interpreted through lens relative size; however, recent evidence has challenged this approach. Investigating neuroanatomy at finer scale, such neuron number, can provide new insights into in context information processing capacity. Ecological factors, complexity species' habitat, place demands on cognition that could shape neuroanatomy. In study, we investigate relationship between number and habitat three regions across six closely related anole species from Puerto Rico. After controlling for mass, found neurons increased with telencephalon ‘rest brain,’ but not cerebellum. Our results demonstrate shaped Rican radiation further role evolution.

Language: Английский

Multiple within species comparisons show Tanganyikan cichlid fish have larger brains in less structurally complex habitats

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 8, 2024

Abstract Many studies have found a link between higher habitat structural complexity and increased relative brain size in vertebrates. Here we explore this relationship multi-species comparison, comparing ten species of wild cichlids that differ their social territorial behaviour, but which occur across four ecologically similar structurally diverse rocky habitats. This design allows us to perform repeated intra-specific comparisons, avoiding confounds associated with comparisons boundaries. We sampled 147 fish, analysing architecture while controlling for body mass species-specific variability compared complexity, quantified using underwater video three-dimensional reconstructions. Our results challenge the Clever Foraging Hypothesis (CFH), posits greater correlates larger sizes. Contrary CFH, fish from least complex had significantly brains. Additionally, analysis indicated significant enlargement cerebellum less habitats, whereas hypothalamus showed non-significant negative trend. Taken together, these indicate lower may impose cognitive demands on spatial memory navigation due limited refuges predation risk. study highlights need reconsider assumed linear positive environmental development, suggesting simpler environments might also ecological challenges drive evolution. findings underscore importance considering intra-species specific different habitats

Language: Английский