A Distributed Experiment Demonstrates Widespread Sodium Limitation in Grassland Food Webs

Insects from Texas to Minnesota crave salt and search through their grassland homes to find it. A team from the University of Oklahoma put 5,000 miles on their research vehicles in the 2017 field season to study the nutritional preferences of grassland insect communities. A simple experiment repeated over 54 grassland sites revealed that after two days, prairie patches splashed with simulated cow urine averaged 70% more bugs than those splashed with water. In effect, plants do not need salt, but plant eaters do. There was also a geographical twist: Grasslands that were less salty hosted insects with keener cravings for salt. These photographs illustrate the article “A distributed experiment demonstrates widespread sodium limitation in grassland food webs” by Ellen A. R. Welti, Nathan J. Sanders, Kirsten M. deBeurs, and Michael Kaspari published in Ecology. https://doi.org/10.1002/ecy.260