Like night and day: a review of nocturnal predator communities and predation in annual row crop agroecosystems

Abstract Biological control through arthropod predation is one of the most economically important ecosystem services in agriculture. Because of this, documenting predator communities’ ecological and behavioral responses to the environment and the resultant changes to predator activity and predation are crucial to agricultural sustainability. Temporal variability in resources, environmental conditions, and arthropod behavior is increasingly recognized for its ecological importance. However, this recognition is largely focused on shifts in diurnal aspects of the ecosystem. Nocturnal predation can match or exceed diurnal predation across predatory taxa, so ignoring nocturnal predation risks overlooking species that contribute significantly to predation services. This review assembles current knowledge about nocturnal predation in annual row crops, outlines its importance, and advocates for further work in this understudied area. Comprehensive identification of predator communities is quite rare, with nocturnal communities even more woefully under-researched than their diurnal counterparts. This represents a major blind spot in entomology, especially for predation ecology, and even persists where predation is known to primarily occur nocturnally, allowing severe underestimation of pest control by nocturnal predators. The more ephemeral nature of predation and the difficulty of direct documentation preclude many passive collection methods, especially for evaluating diel activity of the predatory complex in situ. Further, changing climates may differentially affect diurnal and nocturnal predators, leading to significant impacts on predation outcomes. Both nocturnal and diurnal predators face spiking temperatures and their associated desiccation threat and phenological shifts though different activity patterns will likely alter the impact of the changing climate on these predatory complexes.