Insect floral visitors vary spatiotemporally and influence fruit production in mango orchards

Wild insects are efficient pollinators of many crops, but their pollination services can vary across space and time. Yet, this spatiotemporal variability and its effect on fruit production remain understudied in many tropical crop systems. We investigated how spatiotemporal variations in unmanaged flower-visitors influence mango (Mangifera indica cv. Kensington Pride) fruit production in the Darwin region of Northern Territory, Australia. Surveys were conducted on mango trees located at increasing distances (up to 200 m) from orchard edges adjacent to native vegetation during different times of day. Additionally, a complementary exploratory nocturnal survey was also performed on each farm. We found a strong decline in the abundance and diversity of flower visitor with increasing distance from the native vegetation. Diurnal assemblages were overwhelmingly dominated by native stingless bees (Tetragonula spp.) (46.1% of visits), while nocturnal visits were primarily by moths (55.9%), although nocturnal data were limited. The abundance of stingless bees declined sharply with distance from native vegetation, closely mirroring the decline in mango fruit production at both early and harvest stages. Although hover flies (the second most abundant) exhibited complementary spatial and temporal visitation patterns, their presence could not fully offset the negative effect of reduced stingless bee activity deeper in the orchard. Surprisingly, honey bee (Apis mellifera) visitation was minimal. Our study highlights the critical role of native vegetation in sustaining wild pollination services and suggests that integrating managed stingless bee hives, along with maintaining natural habitat buffers and optimising orchard block size, could enhance mango fruit yield through improved pollination.