Global increases in ultraviolet (UV) radiation have led to greater interest in its current and potential effects on organisms, including insects and plants. Here we report the short-term effects of UV on soybean aphids (Aphis glycines Matsumura), a common phytophagous pest of soybeans. We examined how modified amounts of UV radiation affect soybean aphids by focusing on changes in 1) soybean aphid densities and 2) within plant distribution. In a laboratory experiment artificially adding UV decreased soybean densities compared to a low UV control. In a field experiment blocking UV had minimal effects on soybean aphid densities. Further observations suggest that soybean aphid location could mediate UV effects; the soybean leaf may shield aphids from some direct harmful effects of UV. Our results demonstrate the potential importance of UV to insect herbivores and how insect behavior may mitigate negative effects.