Volume 78, Issue 12, 1 December 2024

Environmental conditions may alter the nature of selection on populations imposed by biotic interactions, causing variation in the strength of local adaptation to biotic interactions across sites. To investigate the influence of an environmental gradient on local adaptation to a biotic interaction, we cross-combined teosinte (Zea mays ssp. mexicana) and associated rhizosphere biota collected across an environmental gradient in a greenhouse common garden experiment. Signals of local adaptation between teosinte and biota did vary in strength across the environmental gradient but were weak—despite the strong effects of biota source on teosinte fitness and traits.