Discovery of novel predators and predation patterns after dark

Predation is often a key factor maintaining herbivore populations below pest status in annual crops. However, in many cases, the predators causing significant mortality to particular pests in the field are not well understood. In particular, the complex of nocturnally active predators feeding on pest species is usually unknown.

The predator complexes attacking lepidopteran eggs in annual crops (cotton, corn and soybean) at locations in three states were determined with the goal of characterizing diurnal and nocturnal predator complexes, determining the role of nocturnal predators in lepidopteran pest mortality, and quantifying diel patterns of predation. The evaluations reported here focused on the predator complexes feeding on lepidopteran pests [Helicoverpa zea Boddie and Spodopteran exigua Hübner, (Lepidoptera: Noctuidae)]. This work has been conducted using direct observation to accurately measure and identify predation of lepidopteran eggs while removing the bias towards day active predators.

The predators causing mortality were usually different between day and night with little overlap of dominant predator species. Nocturnal predators that were novel were discovered and considered important in two of the three locations. It is likely that there are nocturnally active predators in many crops that are important yet are not perceived as such. Whether nocturnal predation is important in all crops and in all environments is unknown, however these studies demonstrate that there is much to be learned from the study of nocturnal predation.