The power of sister crops: intercropping courgette and common bean changes floral morphology and increases diversity of flower visitors

ABSTRACT Acknowledging species interactions is essential for managing diversity in complex agricultural systems. To understand the neighbouring plant effect on flower number and size, we performed a greenhouse experiment with paired pots in three treatments: focal plant (common bean/courgette) with conspecific neighbour, heterospecific neighbour or empty pot. Common beans without neighbours produced more flowers than when accompanied. Common bean with conspecific neighbours produced more flowers than with heterospecific neighbours, with larger standard petals. Courgettes with heterospecific neighbours had flowers with deeper corollas than with conspecific neighbours. To understand effects on visitation and production, we performed a field experiment comparing courgette monoculture, common bean monoculture and three intercroppings, varying the crop ratio. Species composition of floral visitors differed significantly between monoculture and intercropping. The six plots (6/21) with highest diversity were intercropping. Intercropping courgette and common bean can change floral morphology and alter plant–pollinator interactions in the agroecosystem, enhancing pollinator diversity. Key policy insights this article provides an empirical basis for the adoption of multispecies consortia in agroecosystems as an instrument to foster local pollinator biodiversity; it provides empirical evidence that neighbouring plant species identity can have an effect on flowers’ morphological traits, which may be an important consideration when planning and managing agroecosystems; it reinforces that diversified crop systems, with known ecological advantages, can be grown without production loss; it supports that scientific development towards more sustainable food systems should include traditional knowledge systems. GRAPHICAL ABSTRACT