Wild bees live adjacent to cultivated fields. From the cited letter in Nature: "Our second finding was that the insecticide seed coating correlated with reduced

Wild bees live adjacent to cultivated fields. From the cited letter in Nature: "Our second finding was that the insecticide seed coating correlated with reduced nesting of the solitary bee O. bicornis. To investigate this we placed three trap nests containing 27 O. bicornis cocoons (ExtendedData Fig. 1) adjacent to each of the 16 fields before the beginning of oilseed rape flowering and monitored if emerging females started to build brood cells. In six of the eight control fields, but in none of the fields treated with the insecticide seed coating, females started to build brood cells (Wilcoxon test Z 5 2.84, P 5 0.0045; Fig. 2b). Although the reasons why the bees failed to build brood cells when exposed to the insecticide treatment remain unclear, a reduced capacity to navigate[8,9,20,21] is a possible explanation."