Abstract
Global warming is generally predicted to increase the intensity of herbivore pressure on plants. Support for this prediction often comes from short-term studies, or studies conducted in controlled laboratory settings. We examined the effect of long-term experimental warming on an aphid-sagebrush interaction (Obtusicauda coweni and Artemisia tridentata) in natural field plots in the Rocky Mountains. In no year did we find support for the prediction that warming increased aphid abundance or population growth. In fact, warming decreased aphid density on sagebrush in one year, tended to decrease aphids in a second year, and had no effect in a third year. In enclosures that excluded predators, warming decreased aphid population growth by an amount consistent with observed field density differences. Warming increased sagebrush carbon:nitrogen (C∶N) ratio and plant size, but there was no significant correlation between these variables and aphid growth or density. In a separate snow-manipulation experiment in unwarmed plots, the timing of snowmelt did not affect aphid density. In conclusion, warming reduced or did not affect aphid density in each of three years, but this effect could not be explained by differences in plant size, bulk C∶N ratio, predation, or snowmelt date. Our results suggest that long-term studies within a natural community context may provide counterexamples to the prediction that warming will increase herbivore pressure on plants.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 8
Claim · model-written summary
Warming decreased aphid density on sagebrush in one year.
- Taxon
- Artemisia tridentata
Artemisia tridentatae1 - Treatment
- warminge0
- Interactor
- Obtusicauda coweniObtusicauda cowenie1herbivore
- Outcome
- aphid densitye0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“warming decreased aphid density on sagebrush in one year”
e1“Obtusicauda coweni and Artemisia tridentata”
Claim · model-written summary
Warming tended to decrease aphids in a second year.
- Taxon
- Artemisia tridentataArtemisia tridentatae1
- Treatment
- warminge2
- Interactor
- Obtusicauda coweniObtusicauda cowenie1herbivore
- Outcome
- aphidse0
- Direction
- decreasee0
- Qualifier
- in a second yeare0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“tended to decrease aphids in a second year”
e1“Obtusicauda coweni and Artemisia tridentata”
e2“warming decreased aphid density on sagebrush”
Claim · model-written summary
Warming had no effect on aphid density in a third year.
- Taxon
- Artemisia tridentataArtemisia tridentatae2
- Treatment
- warminge1
- Interactor
- Obtusicauda coweniObtusicauda cowenie2herbivore
- Outcome
- aphid densitye1
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“had no effect in a third year”
e1“warming decreased aphid density on sagebrush”
e2“Obtusicauda coweni and Artemisia tridentata”
Claim · model-written summary
In predator exclusion enclosures, warming decreased aphid population growth.
- Taxon
- Artemisia tridentataArtemisia tridentatae1
- Treatment
- warminge0
- Interactor
- Obtusicauda coweniObtusicauda cowenie1herbivore
- Outcome
- aphid population growthe0
- Direction
- decreasede0
- Setting
- enclosures that excluded predatorse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In enclosures that excluded predators, warming decreased aphid population growth by an amount consistent with observed field density differences”
e1“Obtusicauda coweni and Artemisia tridentata”
Claim · model-written summary
Warming increased sagebrush carbon:nitrogen ratio.
- Taxon
- Artemisia tridentataArtemisia tridentatae1
- Treatment
- Warminge0
- Outcome
- sagebrush carbon:nitrogen (C∶N) ratioe0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Warming increased sagebrush carbon:nitrogen (C∶N) ratio and plant size”
e1“Obtusicauda coweni and Artemisia tridentata”
Claim · model-written summary
Warming increased sagebrush plant size.
- Taxon
- Artemisia tridentataArtemisia tridentatae1
- Treatment
- Warminge0
- Outcome
- plant sizee0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Warming increased sagebrush carbon:nitrogen (C∶N) ratio and plant size”
e1“Obtusicauda coweni and Artemisia tridentata”
Claim · model-written summary
Sagebrush carbon:nitrogen ratio and plant size were not significantly correlated with aphid growth or density.
- Taxon
- Artemisia tridentataArtemisia tridentatae2
- Interactor
- Obtusicauda coweniObtusicauda cowenie2herbivore
- Outcome
- aphid growth or densitye0
- Qualifier
- no significant correlatione0
Not reportedOrgan / stageDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“there was no significant correlation between these variables and aphid growth or density”
e1“Warming increased sagebrush carbon:nitrogen (C∶N) ratio and plant size”
e2“Obtusicauda coweni and Artemisia tridentata”
Claim · model-written summary
Snowmelt timing did not affect aphid density in unwarmed plots.
- Taxon
- Artemisia tridentataArtemisia tridentatae1
- Treatment
- timing of snowmelte0
- Interactor
- Obtusicauda coweniObtusicauda cowenie1herbivore
- Outcome
- aphid densitye0
- Direction
- did not affecte0
- Setting
- unwarmed plotse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In a separate snow-manipulation experiment in unwarmed plots, the timing of snowmelt did not affect aphid density”
e1“Obtusicauda coweni and Artemisia tridentata”