As the world's climate warms, the phenologies of interacting organisms in seasonally cold environments may advance at differing rates, leading to alterations in phenological synchrony that can have important ecological consequences. For temperate and boreal species, the timing of early spring development plays a key role in plant-herbivore interactions and can influence insect performance, outbreak dynamics, and plant damage. We used a field-based, meso-scale free-air forest warming experiment (B4WarmED) to examine the effects of elevated temperature on the phenology and performance of forest tent caterpillar (Malacosoma disstria) in relation to the phenology of two host trees, aspen (Populus tremuloides) and birch (Betula papyrifera). Results of our 2-year study demonstrated that spring phenology advanced for both insects and trees, with experimentally manipulated increases in temperature of 1.7 and 3.4 °C. However, tree phenology advanced more than insect phenology, resulting in altered phenological synchrony. Specifically, we observed a decrease in the time interval between herbivore egg hatch and budbreak of aspen in both years and birch in one year. Moreover, warming decreased larval development time from egg hatch to pupation, but did not affect pupal mass. Larvae developed more quickly on aspen than birch, but pupal mass was not affected by host species. Our study reveals that warming-induced phenological shifts can alter the timing of ecological interactions across trophic levels. These findings illustrate one mechanism by which climate warming could mediate insect herbivore outbreaks, and also highlights the importance of climate change effects on trophic interactions.
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Acknowledgments This study was made possible by the efforts of many individuals. artur Stefanski and Roy Rich contributed to the experimental design and establishment of the b4WarmeD infrastructure. additionally, Rich, Stefanski and Karen Rice were instrumental in daily operations and facility management. We also thank Kennedy Rubert-nason, Johnny Uelman, Jana and Mike albers, Mark Guth-miller, Michael hillstrom, Paul Kloppenburg, John letlebo, andrew helm and many b4WarmeD interns for laboratory and field assistance. The b4WarmeD project was supported by US Department of energy Grant no. De-FG02-07eR64456, and this work was also funded by US Department of agriculture nIFa aFRI Grant no. 2011-67013-30147 and the University of Wisconsin college of agricultural and life Sciences.
- Climate change
- Malacosoma disstria
- Plant-insect interactions