In Greenstar Meadow at the University of Michigan Biological Stations (UMBS) I will establish a precipitation manipulation experiment that combines a 40% increase in spring precipitation with a 40% decrease in summer precipitation. By increasing spring and reducing summer precipitation, this precipitation manipulation will more accurately mimic future climate conditions in northern Michigan, where summer droughts are projected to intensify despite increases in spring and winter precipitation (Frankson et al. 2022). Specifically, mean spring precipitation is projected to increase by 20% and mean summer precipitation is projected to decrease by 10% in northern Michigan (Climate Impacts 2022). Spring precipitation may increase up to 39% while summer precipitation may decrease up to 36% (Sun et al. 2015), so this experiment will simulate more severe changes in seasonal precipitation projected by climate models. To increase precipitation in the spring (May-June), I will track weekly rainfall and manually irrigate plots once per week to increase precipitation by 40% based on the amount of weekly precipitation. To decrease precipitation in the summer (July-August), I will install rain out shelters using standard methods (Yahdjian and Sala 2002). Rainout shelters will be 2-m2 but I will collect data in the internal 1-m2 meter to avoid edge effects (Yahdjian and Sala 2002). The roof will consist of V-shaped acrylic panels placed at an angle to intercept precipitation while allowing light penetration (Yahdjian and Sala 2002). I will install a gutter on the low side of the roof to transport intercepted precipitation to a storage tank (Yahdjian and Sala 2002). For control plots, I will construct rainout shelters but place roof panels upside down to allow for ambient precipitation while accounting for potential shelter effects (Yahdjian and Sala 2002). In the summer, I will place roof panels upright in treatment plots so 40% of rainfall is intercepted and stop weekly plot irrigation. To limit belowground lateral water movement between experimental plots, I will insert plastic sheets around the exterior of each rainout shelter to a depth of 20-cm (Zhang et al. 2019). I will factorially combine the precipitation treatment with insect reduction to determine the combined and interactive effects of insect herbivore loss and altered precipitation. I will reduce insect presence and insect herbivory by applying a permethrin insecticide every two weeks using a backpack sprayer (Blue et al. 2011; Souza et al. 2016). I will have 32 experimental plots total (4 experimental treatments with 8 replicates per treatment). I will quantify treatment effects on the plant community by identifying all of the plant species present and estimating species percent cover at peak season. I will measure soil moisture, soil temperature, and air temperature by installing TMS-4 probes in each plot (Wild et al. 2019) to monitor rain out shelter effects on microclimate and quantify relationships between microclimate, plant community structure, functional traits, and productivity. For functional trait analysis, I will collect trait data from 5 individuals of each species in each experimental plot. I will measure traits related to the resource use strategy and drought tolerance (i.e., leaf area [LA], specific leaf area [SLA], leaf mass per area [LMA]) as these traits relate directly to experimental treatments and are known to respond to changes in water availability (Perez-Harguindeguy et al. 2014; Kramp et al. 2022). I will additionally measure plant hydraulic traits (stomatal pore index [SPI]; leaf level water use efficiency [WUE]) as these traits may be more effective at predicting productivity response to altered precipitation relative to traits associated with the leaf economics spectrum (Griffin-Nolan et al. 2018). Finally, I will harvest plant biomass from a 20 x 50 cm strip for each experimental plot by clipping all plant species at the soil level to quantify productivity. I will then separate plant species by functional group for each plot, dry plant biomass for at least 72 hours at 60ºC and then weigh dried plants. I will scale plant dry mass measurements to 1-m2 to estimate plot-level plant biomass by functional group. I will collect insects at peak season to quantify changes in insect abundance, diversity, and community structure in response to altered precipitation timing. In control and precipitation manipulation plots, I will collect insects using 50 mL centrifuge tube pitfall traps filled with a mixture of water and unscented dish soap placed at the center of plots for 72 hours. Upon removing pitfall traps, I will immediately count and store insects in ethanol. I will also perform a 30 second bug-vac sweep to directly collect insects from plants. Following the bug-vac sweep, insects will be transferred into plastic bags and frozen for 24 hours. After being frozen, I will count collected insects and will store them in ethanol. I will later identify all insects to the lowest possible taxonomic level and categorize them by trophic level. References Blue, J. D., Souza, L., Classen, A. T., Schweitzer, J. A., & Sanders, N. J. (2011). The variable effects of soil nitrogen availability and insect herbivory on aboveground and belowground plant biomass in an old-field ecosystem. Oecologia, 167(3), 771-780. Climate impacts. GLISA. (2022). Retrieved December 14, 2022, from https://glisa.umich.edu/resources-tools/climate-impacts/ Frankson, R., K.E. Kunkel, S.M. Champion, and J. Runkle, 2022: Michigan State Climate Summary 2022. NOAA Technical Report NESDIS 150-MI. NOAA/NESDIS, Silver Spring, MD, 4 pp. Griffin‐Nolan, R. J., Bushey, J. A., Carroll, C. J., Challis, A., Chieppa, J., Garbowski, M., ... & Knapp, A. K. (2018). Trait selection and community weighting are key to understanding ecosystem responses to changing precipitation regimes. Functional Ecology, 32(7), 1746-1756. Kramp, R. E., Liancourt, P., Herberich, M. M., Saul, L., Weides, S., Tielbörger, K., & Májeková, M. (2022). Functional traits and their plasticity shift from tolerant to avoidant under extreme drought. Perez-Harguindeguy, N., Diaz, S., Garnier, E., Lavorel, S., Poorter, H., Jaureguiberry, P., ... & Cornelissen, J. H. C. (2013). New handbook for standardised measurement of plant functional traits worldwide. Australian Journal of botany, 64(8), 715-716. Souza, L., Zelikova, T. J., & Sanders, N. J. (2016). Bottom–up and top–down effects on plant communities: nutrients limit productivity, but insects determine diversity and composition. Oikos, 125(4), 566-575. Sun, L., Kunkel, K.E., Stevens, L.E., Buddenberg, A., Dobson, J.G., and Easterling, D.R. (2015). Regional Surface Climate Conditions in CMIP3 and CMIP5 for the United States: Differences, Similarities, and Implications for the U.S. National Climate Assessment. NOAA Technical Report NESDIS 144. National Oceanic and Atmospheric Administration, National Environmental Satellite, Data, and Information Service. http://dx.doi.org/10.7289/V5RB72KG Wild J., Kopecký M., Macek M., Šanda M., Jankovec J., and Haase T. (2019) Climate at ecologically relevant scales: A new temperature and soil moisture logger for long-term microclimate measurement. Agricultural and Forest Meteorology, 268, 40–47. Yahdjian, L., & Sala, O. E. (2002). A rainout shelter design for intercepting different amounts of rainfall. Oecologia, 133(2), 95-101. Zhang, B., Cadotte, M. W., Chen, S., Tan, X., You, C., Ren, T., ... & Han, X. (2019). Plants alter their vertical root distribution rather than biomass allocation in response to changing precipitation. Ecology, 100(11), e02828. Zhang, B., Cadotte, M. W., Chen, S., Tan, X., You, C., Ren, T., ... & Han, X. (2019). Plants alter their vertical root distribution rather than biomass allocation in response to changing precipitation. Ecology, 100(11), e02828.