Distance-associated responses of arthropod communities to flower strips in contrasting agroecosystems

Flower strips have been proposed as a strategy to enhance biodiversity and support beneficial arthropods in intensive farming systems; however, evidence of their effectiveness under Mexican conditions remains scarce. We evaluated the effects of flower strips on arthropod diversity at field margin and adjacent crop areas in two contrasting agroecosystems in Mexico: El Batán (maize) and CENEB (wheat), each comprising a single field. A flower strip was established along one field margin, and arthropods were sampled over three years using malaise traps placed within the flower strip and at site-specific distances into the adjacent crop fields, reflecting differences in field width. Arthropods abundance and richness of taxonomic and functional groups at each distance were analyzed using generalized linear mixed models, with contrast comparation against the farthest in-field distance at each site (112 m in El Batán and 200 m in CENEB). Arthropod responses differed strongly between sites, with non-linear distance patterns at El Batán and predominantly linear declines at CENEB. Across both sites, more than 980,000 arthropods representing over 170 taxonomic groups were collected. Total arthropod abundance and richness were significantly higher in the flower strip. At El Batán, 35% of total captures were recorded in the flower strips, with most of taxonomic groups showing significant increases. At CENEB, 28% of catches were recorded in the flower strips, with fewer taxonomic groups showing substantial increases. Functional groups, including both biological control agents and potential pest species, increased within the flower strip at both sites, although only a short-range spillover into crop fields detected at El Batán, varying seasonally. Overall, flower strips enhanced arthropod diversity at field margins while effects within crops were generally localized and context-dependent, emphasizing the importance of strategic design and placement to maximize ecological benefits in intensively managed agroecosystems.