Spider guilds in a maize polyculture respond differently to plant diversification, landscape composition and stage of the agricultural cycle

Abstract

Agroecosystem simplification for greater food production has led to the loss of ecosystem services such as pest control by predators. Plant diversification has shown excellent potential to improve the diversity of crop predators such as spiders. However, in agroecosystems with frequent disturbances such as annual crops, it is unknown whether the effect of plant diversification on spiders depends on the surrounding landscape and the stages of the agricultural cycle (i.e., periods with differences in vegetation, weather and agricultural practices). Here, we evaluated the effect and interaction of local management (plant diversification), landscape (forest areas) and agricultural cycle on the richness and abundance from the main spider guilds of a maize polyculture in Mexico. We found that greater crop diversification (i.e., addition of legumes and leafy plants) caused a greater abundance of ground‐hunting spiders. We also show that a larger area of forest around the crop favours a greater richness and abundance of ground‐ and vegetation‐hunting spiders. We found that each stage of the agricultural cycle had a different spider richness and abundance, ground hunters were more common at the beginning of the agricultural cycle, while vegetation hunters and web‐builders were more common during the peak developmental stages of the crops. Our findings support the idea that to foster functionally diverse spider communities that potentially enhance natural pest control, we must jointly manage plant elements within the crop, in the surrounding landscape, considering the high dynamics of spider communities throughout the agricultural cycle.