Large Brains, Small Guts: The Expensive Tissue Hypothesis Supported within Anurans

The American Naturalist, Journal Year: 2016, Volume and Issue: 188(6), P. 693 - 700

Published: Sept. 21, 2016

Brain size differs substantially among species, and several hypotheses have been proposed to explain the evolution of brain size. Because is most energetically expensive organs in vertebrate body, trade-offs hypothesized exert constraints on evolution. Prominently, tissue hypothesis (ETH) proposes that reducing another organ, such as gut, should compensate for cost a large brain. But energetic may also drive covariation between other costly traits—such body maintenance, locomotion, or reproduction—as formulated energy trade-off hypothesis. To date, these mainly tested homeothermic animals within ectothermic animals, primarily fishes. Here, we undertake comparative test interplay limitations amphibians. After controlling phylogenetic relationships size, find negative correlation mass length digestive tract 30 species anurans. We further accompanied by an increase female reproductive investment into egg Our results suggest follows general patterns across clades.

Language: Английский

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Population density and structure drive differential investment in pre- and postmating sexual traits in frogs

Evolution, Journal Year: 2017, Volume and Issue: 71(6), P. 1686 - 1699

Published: April 10, 2017

Sexual selection theory predicts a trade‐off between premating (ornaments and armaments) postmating (testes ejaculates) sexual traits, assuming that growing maintaining these traits is costly total reproductive investments are limited. The number of males in competition, the gains from investing level sperm competition all predicted to influence how allocate their finite resources traits. Yet, empirical examination predictions currently scarce. Here, we studied relative expenditure on pre‐ among frog species varying population density, operational sex ratio, competing for each clutch eggs. We found intensifying struggle monopolize fertilizations as more clasp same female fertilize her eggs shifts male investment toward production away weaponry. This shift, which mediated by density associated male–male likely also explains our much broader sample anuran species. Our results highlight power such multilevel approach resolving evolution allocation trade‐offs.

Language: Английский

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Large-brained frogs mature later and live longer

Evolution, Journal Year: 2018, Volume and Issue: 72(5), P. 1174 - 1183

Published: April 3, 2018

Brain sizes vary substantially across vertebrate taxa, yet, the evolution of brain size appears tightly linked to life histories. For example, larger brained species generally live longer than smaller species. A requires more time grow and develop at a cost exceeded gestation period delayed weaning age. The slower development may be compensated by better homeostasis control increased cognitive abilities, both which should increase survival probabilities hence span. To date, this relationship between span seems well established in homoeothermic animals, especially mammals. Whether pattern occurs also other clades vertebrates remains enigmatic. Here, we undertake first comparative test an ectothermic group, anuran amphibians. After controlling for effects shared ancestry body size, find positive correlation age sexual maturation, 40 frogs. Moreover, that ventral regions, including olfactory bulbs, are long-lived Our results indicate history follows general clades.

Language: Английский

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Ejaculate evolution in external fertilizers: Influenced by sperm competition or sperm limitation?

Evolution, Journal Year: 2017, Volume and Issue: 72(1), P. 4 - 17

Published: Oct. 4, 2017

The evolution of sperm quality and quantity is shaped by various selective processes, with competition generally considered the primary agent. Particularly in external fertilizers, however, limitation through gamete dispersal can also influence investments, but empirical data examining this effect are limited. Here, we studied relative importance spawning conditions explaining macroevolutionary patterns size number within two taxa fertilization differences their reproductive biology. In frogs, swim slowly for up to hours as they penetrate gelatinous egg coating, whereas fish typically fast, very short‐lived (seconds minutes), often face a relatively higher risk being moved away from ova currents. Our phylogenetic models path analyses revealed different trajectories ejaculate these taxa. Sperm responded primarily variation anurans, more strongly water turbulence fishes. Whereas results across anurans align general expectation that sexual selection main driver evolution, our findings fishes suggest has been underappreciated.

Language: Английский

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Seasonality and brain size are negatively associated in frogs: evidence for the expensive brain framework

Scientific Reports, Journal Year: 2017, Volume and Issue: 7(1)

Published: Nov. 24, 2017

Abstract The challenges of seasonal environments are thought to contribute brain evolution, but in which way is debated. According the Cognitive Buffer Hypothesis (CBH) size should increase with seasonality, as cognitive benefits a larger help overcoming periods food scarcity via, for instance, increased behavioral flexibility. However, line Expensive Brain Framework (EBF) decrease seasonality because smaller confers energetic scarcity. Empirical evidence inconclusive and mostly limited homoeothermic animals. Here we used phylogenetic comparative analyses test impact on evolution across 30 species anurans (frogs) experiencing wide range temperature precipitation. Our results support EBF relative optic tectum were negatively correlated variability temperature. In contrast, found no association between precipitation length dry season either or sizes other major regions. We suggest that seasonality-induced resulting from higher constrains anurans. Less may therefore facilitate brains poikilothermic

Language: Английский

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Sexual selection impacts brain anatomy in frogs and toads

Ecology and Evolution, Journal Year: 2016, Volume and Issue: 6(19), P. 7070 - 7079

Published: Sept. 12, 2016

Abstract Natural selection is a major force in the evolution of vertebrate brain size, but role sexual size remains enigmatic. At least two opposing schools thought predict relationship between and size. Sexual should facilitate larger brains because better cognitive abilities may aid competition for mates. However, it also restrict due to energetic trade‐offs tissue sexually selected traits. Here, we examined patterns on anatomy male anurans (frogs toads), group where strength differs markedly among species, using phylogenetically controlled generalized least‐squared ( PGLS ) regression analyses. The analysis revealed that 43 Chinese anuran neither mating system, nor type courtship, or testes mass was significantly associated with relative While none those factors related olfactory nerves, optic tecta, telencephalon, cerebellum, bulbs were relatively monogamous species calls during courtship. Our findings support mosaic model suggest while investigated aspects do not seem play prominent anurans, they impact their anatomy.

Language: Английский

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Body mass variation is negatively associated with brain size: Evidence for the fat‐brain trade‐off in anurans

Evolution, Journal Year: 2020, Volume and Issue: 74(7), P. 1551 - 1557

Published: May 4, 2020

Species can evolve diverse strategies to survive periods of uncertainty. Animals may either invest in energy storage, allowing them decrease foraging costs, such as locomotion or risk predation, they better cognitive abilities helping flexibly adapt their behavior meet novel challenges. Here, we test this idea a fat-brain trade-off 38 species Chinese anurans by relating the coefficient variation body mass (CVbodymass ; an indicator how much animals into storage over season) brain anatomical features. After correcting for shared ancestry and mass, found negative relationship between relative size CVbodymass . This indicates that seem physiological buffering during shortages. As similar patterns have been reported arboreal mammals primates our findings suggest trade-off, where harsh conditions, be general pattern across vertebrates.

Language: Английский

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Brain size evolution in the frog Fejervarya limnocharis supports neither the cognitive buffer nor the expensive brain hypothesis

Journal of Zoology, Journal Year: 2016, Volume and Issue: 302(1), P. 63 - 72

Published: Dec. 21, 2016

Abstract Variable environmental conditions affect brain size evolution. To explain inter‐ and intraspecific variation among vertebrates, two adaptive hypotheses – the expensive hypothesis ( EBH ) cognitive buffer CBH have been proposed. The EBF proposes that relative is reduced in animals experience longer periods of low food availability fluctuating environments. Alternatively, states a major advantage relatively large to enhance abilities We found considerable sizes structures Asian grass frog Fejervarya limnocharis populations. Inconsistent with predictions , individuals living habitats medium temperatures length growth seasons at middle latitude and/or altitude had brain, suggesting habitat‐induced energetic constraints do not play an important role shaping Moreover, we also detected significant intersexual difference telencephalon size. Specifically, none was correlated temperature season related habitats, although strongly affected cerebellum. Our findings decline both frog. Furthermore, our results suggest sex‐specificity environmental‐induced evolution adult frogs associated reproductive behaviors spawning site selection.

Language: Английский

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Latitudinal variation in body size in Fejervarya limnocharis supports the inverse of Bergmann’s rule

Animal Biology, Journal Year: 2018, Volume and Issue: 68(2), P. 113 - 128

Published: Jan. 1, 2018

Abstract Bergmann’s rule states that within a species of endotherms smaller individuals are found in warmer conditions, which is consistent for nearly all endotherms, while ectotherms body size patterns less consistent. As ectothermic vertebrates, the morphology amphibians likely impacted by climatic conditions. Here, we examined latitudinal variation ranid frog, Fejervarya limnocharis , based on literature and our own data mean 3637 from 50 populations average age 2873 40 China. The results showed was positively correlated with environmental temperature, but not precipitation. Body negatively latitude among this species, supported inverse rule. Our findings suggest larger low-latitude associated longer growing season related to higher temperature.

Language: Английский

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Altitudinal variation in male reproductive investment in a polyandrous frog species (Hyla gongshanensis jingdongensis)

Animal Biology, Journal Year: 2016, Volume and Issue: 66(3-4), P. 289 - 303

Published: Jan. 1, 2016

Competition for fertilization in multi-male group spawning can drive variation male reproductive investment (i.e., testis mass and sperm size). Inter-population comparisons of energetic availability allocation along geographical gradients allow insights into the mechanisms shaping investments animals. Although inter-population differences female clutch size egg size) have been studied extensively across a wide range taxa, little information on males is available. Here, we altitudinal length among three populations Jingdong tree frog ( Hyla gongshanensis jingdongensis ), polyandrous species, Yunnan Province China. The results showed that individuals exhibited smaller testes at higher altitudes while was positively correlated with body size, condition age. Longer observed middle-altitude population. Moreover, found number length. Our correlational findings suggest environmental constraints high altitude select less offspring number.

Language: Английский

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