Increasing ultraviolet radiation (UV) has led to greater interest in its current and potential effects on organisms, including herbivorous insects. Here we report the short-term effects of UV on soybean aphids (Aphis glycines Matsumura), a common phytophagous pest of soybeans. We used two complementary approaches to examine how modifying UV radiation affects this phloemfeeding herbivore via changes to soybean aphid densities and their within plant distribution. We found that artificially adding UV in a lab setting decreased soybean aphid population size compared to a low UV control; however, blocking UV radiation in the field had minimal effects on aphid density. Further observations suggest that soybean aphid location could mediate UV effects; feeding on the underside of leaves may shield aphids from some harmful effects of UV. Our results demonstrate the potential importance of UV to insect herbivores and how behavior may influence such effects.

Studies of the effects of climate change on migratory bird behavior have established that many species are shifting the average day of year of their arrival at nesting sites earlier. If migrating birds are adapted to arrive at the optimum stage in the growth season to maximize the availability of resources, then migration phenology shifts may result in arrival at nesting sites at selectively disadvantageous points in seasonal development of the nesting ecosystem. First arrival dates (FAD) are changing for many species, but we know little about shifts in the corresponding accumulated growing degree units (AGDU) of arrival date in association with increasing global temperatures. By transcribing field notes for migrant arrival times during the years of 1910-1950 in the region around Fargo, ND, we obtained a detailed and robust description of historical phenological patterns. Comparison of the arrival times of 83 of the same species in the same location over the past 10 years indicate that the majority of bird species studied are arriving earlier than they did historically. The accumulated growing degree units at the time of arrival deviated from past values by as much as 4-5% higher or lower depending on the species. In general, short-distance migrants have advanced their arrival times and reduced the AGDU at the time of arrival relative to long-distance migrants. These results indicate that changing climate is influencing bird migration patterns and leading to arrival of migrants at different points in the progress of the growing season relative to the past. The impacts of this divergence on fitness and selection are expected to influence the nature of future bird communities.