体温の高い動物は草食動物に進化しやすい(Animals with higher body temperatures are more likely to evolve into herbivores, study finds)

2024-08-19 アリゾナ大学

A male chuckwalla (a type of desert-dwelling iguana) that was spotted near Phoenix, Arizona.
John Wiens

<関連情報>

• https://news.arizona.edu/news/animals-higher-body-temperatures-are-more-likely-evolve-herbivores-study-finds
• https://onlinelibrary.wiley.com/doi/10.1111/geb.13900

四肢動物の食進化と体温: クールな老肉食動物とホットな若草食動物 Diet Evolution and Body Temperature in Tetrapods: Cool Old Carnivores and Hot Young Herbivores

Kristen E. Saban, John J. Wiens
Global Ecology and Biogeography  Published: 18 August 2024
DOI:https://doi.org/10.1111/geb.13900

ABSTRACT

Aim
Diet is a key aspect of life in animals. There have been numerous independent origins of herbivorous diet across animals, but the factors that explain these origins remain poorly understood. One potentially crucial factor is body temperature (T_b), as the gut-dwelling bacteria that help digest cellulose in many herbivores are thought to require high temperatures. However, analyses in birds, lizards and mammals found only limited evidence for higher T_b in herbivores than in carnivores. These analyses tested whether diet explains T_b evolution. Here, we focus instead on testing whether T_b helps explain the evolution of diet across tetrapods.

Location
Global.

Time Period
Past 350 million years.

Major Taxa Studied
Tetrapods.

Methods
We analysed 1712 species with matched data on diet and T_b using diverse phylogenetic methods.

Results
Ancestral reconstructions indicated that tetrapods likely had a carnivorous ancestor, followed by repeated transitions to omnivory and herbivory, especially in the last 110 million years. Thus, extant herbivorous lineages in tetrapods are relatively young, in contrast to many older carnivorous lineages. They are also relatively unstable in that reversals from herbivory back to omnivory and from omnivory back to carnivory were as frequent as the origins of herbivory and omnivory. Using phylogenetic logistic regression, we support the hypothesis that higher T_b helps explain the evolution of herbivory across tetrapods and within birds, mammals, lepidosaurs and turtles. Phylogenetic path analyses suggest that T_b generally drives the evolution of herbivory, and not vice versa. Our analyses also suggest that T_b is more important for the evolution of herbivory than large body size or diurnal diel activity, which are both significant predictors of herbivory in some cases.

Main Conclusions
Our results show for the first time that T_b is a significant predictor of diet evolution among and within many major animal clades.