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Contributed Poster

Session: Climate Change: Plants

PS 43-175 - Effects of experimental warming on floral scent and other traits in a subalpine herb

Wednesday, August 9, 2023
5:00 PM – 6:30 PM PDT
Location: ESA Exhibit Hall
Abstract: Floral volatiles, visual traits, and rewards mediate attraction and defense in plant-pollinator and plant-herbivore interactions, but these floral traits may be disrupted by global warming through direct effects of temperature or longer term impacts on plant resources. We examined the effect of warming on floral and leaf volatile emissions, floral morphology, plant height, nectar production, and oviposition by seed predators using open-top chambers that warmed plants in their native environment +2-3 °C on average (+6-11 °C increase in daily maxima) for 2-4 weeks across 1-3 years at 3 sites in Colorado, USA. Volatiles were sampled from two closely related species of subalpine Ipomopsis with different pollinators: I. aggregata (n = 154 plants), visited mainly by hummingbirds, and I. tenuituba (n = 93), often visited by hawkmoths. While warming had no detected effects on nighttime volatiles of I. tenuituba or leaf volatiles, the daytime floral volatiles of both species responded to warming, with impacts that depended on the site, year, and duration of warming. In addition to the long-term effect of warming, temperature at the time of sampling also affected the emissions of I. aggregata floral volatiles. Warming had little (less than 10%) effect on floral morphology (corolla length and width) for both species and no effect on nectar concentration, maximum inflorescence height, or flower redness in I. aggregata. In I. aggregata, warming increased nectar production by 52%, a response that would attract more hummingbird visits, and reduced oviposition by fly seed predators by 72% or more. These results suggest that floral traits can show different levels of resiliency or plasticity to temperature changes in alpine environments, with potential effects on animal behaviors that help or hinder plant reproduction.