Although, as in the case of weeds assemblages, we expected insect assemblages to be richer in intercrops than in sole crops [8], we found the opposite response. The differences in insect richness may be related to the specific roles of each crop on insects. It was reported that sunflower attracts and plays host to numerous beneficial insects [39], while soybean is a good protein source for herbivores and, indirectly, for their associated non-herbivores [40]. This last mechanism could explain the higher richness of total and non-herbivore insects observed in soybean sole crops. Sunflower had the same or lower non-herbivores richness than the remaining treatments, suggesting that the attraction of beneficial insects was similar or lower than that in soybean.