Woodratโ diets Reveal a Nuance Beyondโ “Jack-of-All-Trades”
A comprehensive, eight-year study of woodrat populations across North America is challenging conventional understandings ofโ dietary generalization in animals. Researchersโข from Utah State University and the Northโข Carolina โMuseum of Natural Sciences, publishingโข in โthe Proceedings of the Nationalโข Academy of Sciences, found that while woodrats exhibit a range โขof dietary approaches,โ even those considered “generalists” demonstrate surprisinglyโฃ focused eating habits. The research was funded by the National โคScience Foundation.
The study,โ led by USU assistant professor Rebecca Weinstein, analyzed the diets of over 500 individual woodrats across 13 โขspecies and 57 populations.โ It revealed a spectrum of feeding strategies, from highlyโ specialized species that consistently consume aโ narrow range of โplants – potentially as a way โขto mitigate the โriskโ of consuming poisonous vegetation – to generalists.โฃ However,Weinstein explains,these generalists aren’tโ the “jack-of-all-trades,master of none” โคoften assumed.โ “They’re more accurately described as jacks-of-all-trades, master of some,” she says.
The research highlights theโข trade-offs inherent in both dietary specialization โฃand generalization. Surprisingly,generalist woodratsโข were โขobserved continuing to consume toxic plants โlike creosote even when less harmful alternatives were available,suggesting the energetic or behavioral costs of incorporating newโ food sources can outweigh the benefits.
“Even wiht hundreds of individuals and 13 โคspecies analyzed, we wereโฃ struck by the sheer variety in their diets,” notes co-author and โขUniversityโฃ of Utah distinguished professor, Denise Dearing.โฃ “Even the generalists are selective, demonstrating that both narrow and diverse diets come with associated costs.”
Woodrats โprove to be an ideal model for studying animal diets due to their โabundance, diverse habitats, and tolerance for consuming โขplants withโ potent chemicalโฃ defenses. They readily โฃconsume plants like creosote, mesquite, and juniper, despite their high levels of alkaloids and terpenes. Furthermore,โฃ their small size andโข cooperative nature – readily providing fecal samples in traps – have allowed researchers to leverage cutting-edge DNA metabarcodingโค technology.
This technology, advanced by next-generation sequencing, has revolutionizedโ dietaryโ analysis, allowing scientistsโ to identify the plants consumed by woodrats with unprecedented accuracy. Researchers tracked โa single woodrat population over five years, combining dietary analysis of droppings with โindividual mark-recapture data to understand patterns at both broad landscape scales and within a single group.
Ultimately, โฃWeinstein emphasizes, โคunderstanding the constraints on animalโ dietsโ is crucial for predicting how speciesโ will respond to environmental changes and for gaining a deeper understandingโข of complex ecological interactions within foodโข webs. The findings offer valuable insights into species persistence and the dynamics of changing ecosystems.