For thousands of years, humans have artificially selected for increased yield in cropping systems. This has become more critical as arable land is decreasing and populations are increasing. Soybean has been cultivated for 4,000 years and breeding programs have increased yield by 431% from in the last hundred years, ultimately influencing physiology, photosynthetic rates, and nitrogen uptake. Plant growth and reproductive output (yield) is inversely related to plant defense. Therefore, higher yielding varieties may experience differences in herbivory compared to older varieties. We examine soybean looper consumption and growth on 19 soybean cultivars. Larval growth was not different among varieties, but consumption decreased on more recent varieties, perhaps due to increased foliar nitrogen in recent varieties.
