Effects of water extracts of desert locust frass collected under umbrella thorn trees in the Mauritanian desert on the number of A., B. Egg pods laid, and C., D. Holes dug by adult female desert locusts presented with extracts mixed with sand. Frass were collected at sites #1 and #2 in 2016 and 2017, respectively. Two cups containing frass extracts (treated) and water (control) were simultaneously presented to locusts in each of two locust cages for seven or five days, and the data were combined. Numbers in parentheses indicate the total numbers of days observed. Bars on histograms indicate one standard deviation. Asterisks indicate a significant difference at the 5% level with a t-test. n.s. indicates no significant difference.