White Paper: An Integrated Perspective on the Causes of Hypometric Metabolic Scaling in Animals

Integrative and Comparative Biology, Journal Year: 2022, Volume and Issue: 62(5), P. 1395 - 1418

Published: Aug. 6, 2022

Larger animals studied during ontogeny, across populations, or species, usually have lower mass-specific metabolic rates than smaller (hypometric scaling). This pattern is observed regardless of physiological state (e.g. basal, resting, field, maximally-active). The scaling metabolism highly correlated with the many life history traits, behaviors, variables, and cellular/molecular properties, making determination causation this challenging. For across-species comparisons resting locomoting (but less so for populations ontogeny), mechanisms at cellular level are becoming clear. Lower larger species rest due to a) contents expensive tissues (brains, liver, kidneys), b) slower ion leak membranes least partially membrane composition, pump ATPase activities. costs locomotion lower-frequency muscle activity, myosin Ca++ activities, likely more elastic energy storage. evolutionary explanation(s) hypometric remain(s) controversial. One subset hypotheses relies on constraints changes in geometry size; example, surface-to-volume ratios exchange surfaces may constrain nutrient heat exchange, cross-sectional areas muscles tendons relative body mass would make fragile without compensation. Another suggests that arises from biotic interactions selection, experiencing selection growth neurolocomotor performance. A additional third type explanation comes population genetics. their effective sizes subsequent drift deleterious mutations, reducing maximal performance rates. Resolving associated variables a major challenge organismal biology. To aid progress, we identify some variation terminology use has impeded cross-field conversations scaling. We also suggest promising directions field move forward include: 1) studies examining linkages between ontogenetic, population-level, cross-species allometries, 2) linking ecological phylogenetic context, 3) consider multiple, possibly interacting hypotheses, 4) obtaining better data correlates rate such as lifespan, reproduction.

Language: Английский

Divergent evolution of colony‐level metabolic scaling in ants

Journal of Animal Ecology, Journal Year: 2025, Volume and Issue: unknown

Published: May 7, 2025

Abstract Metabolic scaling—the relationship between organismal metabolic rate ( R ) and body mass M )—is an important property of life. In general, this has been summarized by the scaling function, = aM b . Both elevation a exponent have shown to diverge among taxa ecological groups. However, it is unclear whether divergence observed in unitary organisms also occurs at higher levels biological organization, such as eusocial colonies. We used published literature assemble estimates active colonies their for 51 species ants, along with three ecologically traits available data: trophic level (herbivorous predaceous), foraging coordination (solitary trunk trail) caste polymorphism (polymorphic vs. monomorphic). Interspecific colony was steeper (higher occupying polymorphic versus monomorphic workers. Species had ). These findings are consistent divergent selection on colony‐level scaling. conclude that dependence evolved across organization should be explicitly considered both social evolution theories.

Language: Английский

Transcriptomic analysis of mosaic brain differentiation underlying complex division of labor in a social insect

The Journal of Comparative Neurology, Journal Year: 2023, Volume and Issue: 531(8), P. 853 - 865

Published: March 9, 2023

Concerted developmental programming may constrain changes in component structures of the brain, thus limiting ability selection to form an adaptive mosaic size-variable brain compartments independent total size or body size. Measuring patterns gene expression underpinning scaling conjunction with anatomical atlases can aid identifying influences concerted and/or evolution. Species exhibiting exceptional and behavioral polyphenisms provide excellent systems test predictions evolution models by quantifying expression. We examined a remarkably polymorphic behaviorally complex social insect, leafcutter ant Atta cephalotes. The majority significant differential observed among three morphologically, behaviorally, neuroanatomically differentiated worker groups was attributable However, we also found evidence unexplained morphological variation transcriptomic analysis identified not linearly correlated but sometimes mirroring neuropil scaling. Additionally, enriched ontology terms associated nucleic acid regulation, metabolism, neurotransmission, sensory perception, further supporting relationship between expression, mosaicism, labor role. These findings demonstrate that workers underpins neuroanatomical differentiation agrarian division A.

Language: Английский