Effects of elevated CO2 and temperature on the performance of a diet specialized neotropical herbivore and its host plant

• Published in: Biotropica 2024-11, Vol.56 (6), p.n/a
• Main Authors: Vencl, Fredric V., Bartram, Stefan, Winter, Klaus, Boland, Wilhelm, Srygley, Robert B.
• Format: Article
• Language: English
• Subjects: Acromis sparsa; Ambient temperature; Availability; Biomass; Camonea umbellata; Carbon dioxide; Carbon dioxide concentration; Climate change; Climate prediction; Cohorts; Diet; ecological specialization; Environmental impact; Global warming; Growth rate; Herbivores; High temperature; Host plants; Larvae; Leaves; Mortality; Nitrogen; Panama; plant–herbivore interactions; Pupae; Survival; Tellurium; Temperature; tropical wet forest; Vines
• ISSN: 0006-3606; 1744-7429
• DOI: 10.1111/btp.13371

Little is known about the potential responses of ecologically specialized tropical species to atmospheric change and global warming. In 2 years of greenhouse experiments simulating climate change impacts, we quantified the effects of mean ambient temperature, elevated temperature (Te), current ambient CO2 concentration ([CO2]a), and doubled CO2 concentration ([CO2]e) on biomass, growth rate, and foliar chemistry of the morning glory vine, Camonea umbellata. In addition, we measured the impacts of climate change simulations on the performance and survival of the tortoise beetle, Acromis sparsa, which feeds exclusively on C. umbellata. Full‐sib A. sparsa larval broods were divided into cohorts. Each cohort was placed in one of four temperature‐CO2 controlled chambers and fed leaves grown in their respective treatments. Vines growing in [CO2]e more than doubled their biomass and their leaves expanded faster. The [CO2]a and Te treatments interacted to yield the greatest foliar [C]. Vines in [CO2]e and Te had the greatest C:N ratios, the lowest availability of nitrogen, and highest larval mortality. Whereas pupae were smaller and suffered lower survival in Te, pupal mass and survival increased in both the [CO2]e and Te treatments. Overall, the simultaneous elevation of both [CO2] and temperature caused declines in host quality, larval survivorship, and pupal mortality that were not observed when only one climate factor was altered. Based on this first tropical experimental study, we predict that C. umbellata will benefit from elevation of temperature and atmospheric [CO2] by altering its foliar chemistry to the detriment of its diet‐specialized herbivore enemy. in Spanish is available with online material. Resumen Se sabe poco sobre las posibles respuestas de las especies tropicales ecológicamente especializadas al cambio atmosférico y al calentamiento global. En dos años de experimentos de invernadero simulando los impactos del cambio climático, cuantificamos los efectos de la temperatura ambiente (Ta), la temperatura elevada (Te), la concentración ambiental actual de CO2 ([CO2]a) y la concentración duplicada de CO2 ([CO2]e) sobre la biomasa, la tasa de crecimiento y la química foliar de la enredadera morning glory, Camonea umbellata. Además, medimos los impactos de las simulaciones de cambio climático sobre el rendimiento y la supervivencia del escarabajo tortuga, Acromis sparsa, que se alimenta exclusivamente de C. umbellata. Las crías larvarias de hermanos